CVD diamond (polycrystalline and single-crystal) CVD diamond
C, carbon in the diamond cubic structure (eight atoms per unit cell, Wikipedia) · cubic
CVD diamond is carbon grown from hydrocarbon gas by chemical vapour deposition, as polycrystalline plates or as single crystals.
Evidence level
2 of 5
Lab-measured
- 0Predicted only. No one has made it, or no measurement exists.
- 1Calculated. Only calculated or predicted values from sources.
- 2Lab-measured. Measured properties with their conditions stated.
- 3Space-relevant tests. Measured in conditions relevant to space, such as vacuum or atomic oxygen.
- 4Ground-qualified. Qualified for an application on the ground.
- 5Flown or field-proven. Flight or field results exist.
Carry heat
greater than 2200 W/(m·K) at 300 K
Stay dimensionally stable
1.0 ppm/K at 300 K
Weight
3.52 g/cm3
Pass light
71.4 % at 1 mm
Hard
81 ± 18 GPa
Recipe, share of the weight
- C 100.0%Carbon
Best for
Heat spreaders and high-power laser windows, where thermal conductivity above 2000 W/(m·K) at 300 K matters most
Weakest at
Size and thickness: polycrystalline optical windows up to Ø 135 mm and 3 mm thick, single-crystal plates up to 7 x 7 x 2 mm (Element Six)
Risk at a glance
- People Low. Mixed; no classification for CVD diamond itself was read
- If it fails Moderate. Fracture under load, with wide strength spread
- Corrosion Low. Rain impact damage threshold velocity is printed as 525 m/s for polycrystalline optical grade.
Quick facts: CVD diamond
| Property | Value | Basis |
|---|---|---|
| Density | 3.52 g/cm³ | 1 sourced value |
| Young's modulus | 1,000 to 1,100 GPa | 1 sourced value |
| Thermal conductivity | at least 1,000 W/(m·K) | 6 sourced values across conditions |
| Thermal expansion (CTE) | 1 ppm/K | 1 sourced value |
| Specific heat | 520 to 536 J/(kg·K) | 2 sourced values across conditions |
What is the density of CVD diamond?
CVD diamond has a density of 3.52 g/cm³. The source and test conditions are listed in the properties table on this page.
What is the thermal conductivity of CVD diamond?
CVD diamond has a thermal conductivity of at least 1,000 W/(m·K). The range covers 6 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is the coefficient of thermal expansion of CVD diamond?
CVD diamond has a coefficient of thermal expansion of 1 ppm/K. The source and test conditions are listed in the properties table on this page.
What is the Young's modulus of CVD diamond?
CVD diamond has a Young's modulus of 1,000 to 1,100 GPa. The source and test conditions are listed in the properties table on this page.
What is CVD diamond used for?
Uses recorded in the sources include Heat spreaders for high-power GaN transistors, MMICs and laser diodes; Optical windows for high-power CO2 and solid-state lasers; RF and microwave windows in high-power gyrotrons.
Why it exists
CVD diamond has the highest thermal conductivity of any material, according to Element Six. Its polycrystalline optical grade is printed at greater than 2200 W/(m·K) at 300 K, and its RF grade at greater than 2000 W/(m·K) at 300 K. A Coherent single-crystal optical grade sheet prints at least 2200 W/(m·K) with no temperature given. That is why the material is used as a heat spreader under high-power electronics and as a window in high-power lasers.
Where it's used
Heat spreaders
Element Six Diafilm heat spreaders are stated for high-power, high-density circuits, including GaN discrete transistors, MMICs and laser diodes. The Diafilm TM200 grade is printed at greater than 2000 W/(m·K) at 300 K.
Laser windows
Element Six lists optical windows for high-power CO2 and solid-state lasers, and says CVD diamond windows allow much higher laser power densities than other materials.
RF windows
Element Six says CVD RF diamond windows are used in nuclear fusion experiments, in gyrotrons above 2 MW and as containment windows in waveguides.
Laser and power-electronics heat sinks
A 2019 open-access chapter says CVD diamond heat sinks are used for high-power laser diodes and transistor high power devices, and names AlGaN/GaN HEMTs on CVD diamond substrates (Vieira da Silva Neto et al., 2019).
Recipe
C, carbon in the diamond cubic structure (eight atoms per unit cell, Wikipedia)
Diamond is pure carbon with a cubic crystal structure (Wikipedia). Synthetic diamond can be grown from hydrocarbon gases by chemical vapour deposition (Wikipedia). Coherent describes its single-crystal optical grade as made by plasma-enhanced chemical vapour deposition (Coherent datasheet).
| Ingredient | Atoms per unit | Share of the weight | What it does |
|---|---|---|---|
| Carbon C | 1 | 100.0% | The whole material. The PubChem carbon element record prints a molecular weight of 12.011. |
Weight shares are calculated from standard atomic weights.
What it can do
Carry heat
greater than 2200 W/(m·K) at 300 K
measured
Element Six prints greater than 2200 W/(m·K) at 300 K for polycrystalline optical grade and for single-crystal optical grade. At 425 K it prints greater than 1600 W/(m·K) for the polycrystalline optical grade.
Stay dimensionally stable
1.0 ppm/K at 300 K
measured
The coefficient of thermal expansion is 1.0 ppm/K at 300 K and 4.4 ppm/K at 1000 K, per Element Six. The Diafilm article prints 1.0 ± 0.1 ppm/K at 300 K.
Weight
3.52 g/cm3
measured
Density is printed as 3.52 x 10³ kg m⁻³ in the Element Six brochure and as 3.52 x 10³ kg/m³ in the Diafilm article.
Pass light
71.4 % at 1 mm
measured
Polycrystalline optical grade transmits 71.4 % through 1 mm of material over 8 to 200 µm, per Element Six.
Hard
81 ± 18 GPa
measured
Polycrystalline CVD diamond is printed at a hardness of 81 ± 18 GPa, and single crystal at 70 - 120 GPa.
How it compares
The Element Six brochure prints thermal conductivity above 2000 W/(m·K) at 300 K for the RF and optical grades, and the Coherent single-crystal sheet prints at least 2200 W/(m·K), and the Diafilm article gives 1000 and 2000 W/(m·K) for the TM100 and TM200 grades. The two sources give different specific heat figures, 520 J/(kg·K) at 300 K in the trade article and 0.536 J/g-K at 25 °C on the Coherent sheet, so read them with their temperatures in view. For birefringence the Element Six table gives 1e-4 for its single-crystal optical grade, while the Coherent sheet gives less than 5e-5, so grades and sources need to be matched before comparing.
The same measurements for each material, so you can compare them. Each row names the key condition under the value; the full conditions and methods are in the numbered notes under Technical details.
| Measurement | CVD diamond |
|---|---|
| Thermal behavior and safety | |
| Thermal conductivity, polycrystalline CVD diamond, optical grade, 300 K | > 2200 W/(m·K)1 |
| Thermal conductivity, polycrystalline CVD diamond, RF grade, 300 K | > 2000 W/(m·K)2 |
| Thermal conductivity, single-crystal CVD diamond, optical grade, 300 K | > 2200 W/(m·K)3 |
| Thermal conductivity, polycrystalline CVD diamond, optical grade, 425 K | > 1600 W/(m·K)4 |
| Thermal conductivity, single-crystal CVD diamond sheet (SCD-O), temperature not stated | > 2200 W/(m·K)5 |
| Thermal conductivity, Element Six Diafilm TM100, 300 K | > 1000 W/(m·K)6 |
| Thermal conductivity, Element Six Diafilm TM200, 300 K | > 2000 W/(m·K)7 |
| Specific heat capacity, CVD diamond, 500 KValue printed in a manufacturer properties table | 520 J/(kg·K)11 |
| Specific heat capacity, Diafilm grades, 300 K | 520 J/(kg·K)12 |
| Specific heat capacity, single-crystal CVD diamond sheet (SCD-O), 25 °CValue printed in a manufacturer datasheet | 0.536 J/g-K13 |
| Thermal diffusivity, Element Six Diafilm TM200, 300 K | > 11.1 cm²/s29 |
| Physical and electrical | |
| Density, CVD diamond | 3.52 g/cm³10 |
| Hardness, polycrystalline CVD diamond | 81 GPa15 |
| Hardness, single-crystal CVD diamondRange printed in a manufacturer properties table | 70 to 120 GPa |
| Temperature behavior | |
| Temperature coefficient of refractive index (dn/dT), CVD diamondValue printed in a manufacturer properties table | 9.6×10^-6 K-1 |
| Other measurements | |
| Coefficient of thermal expansion, CVD diamond, 300 KValue printed in a manufacturer properties table | 1 ppm/K8 |
| Coefficient of thermal expansion, CVD diamond, 1000 KValue printed in a manufacturer properties table | 4.4 ppm/K9 |
| Young's modulus, Element Six Diafilm grades | 1000 to 1100 GPa14 |
| Refractive index, CVD diamond at 10.6 µmValue printed in a manufacturer properties table | 2.376 - |
| Refractive index, CVD diamond at 1550 nmValue printed in a manufacturer properties table | 2.386 - |
| Refractive index, CVD diamond at 1064 nmValue printed in a manufacturer properties table | 2.392 -16 |
| Birefringence, single-crystal CVD diamond, optical plus grade | < 5×10^-5 -17 |
| Birefringence, single-crystal CVD diamond, optical gradeValue printed in a manufacturer properties table | 1×10^-4 -18 |
| Absorption coefficient at 10.6 µm, polycrystalline CVD diamond, optical grade | < 0.07 cm-119 |
| Absorption coefficient at 10.6 µm, single-crystal CVD diamond, optical grade | < 0.05 cm-120 |
| Absorption coefficient at 1064 nm, single-crystal CVD diamond, optical plus grade | < 0.005 cm-121 |
| Transmittance at 1 mm thickness, polycrystalline CVD diamond, optical grade, 8 to 200 µmValue printed in a manufacturer properties table | 71.4 %22 |
| Dielectric constant, polycrystalline CVD diamond, 35 GHz | 5.68 -23 |
| Loss tangent at 145 GHz, polycrystalline CVD diamond, optical gradeRange printed in a manufacturer properties table | 8×10^-6 to 2×10^-5 -24 |
| Loss tangent at 145 GHz, polycrystalline CVD diamond, RF gradeRange printed in a manufacturer properties table | 1×10^-5 to 1×10^-4 -25 |
| Fracture stress, single-crystal CVD diamond, optical grade and optical plus | 3500 MPa26 |
| Sand erosion, polycrystalline CVD diamond, optical grade | 2.1 mg/kg27 |
| Emittance at 10 µm, CVD diamond, 573 KValue printed in a manufacturer properties table | 0.02 -28 |
Why choose it, and why not
Good for
- Heat spreading: greater than 2200 W/(m·K) at 300 K for the optical grades, per Element Six.
- High-power laser windows: absorption at 10.6 µm below 0.07 cm-1 for polycrystalline optical grade.
- Erosion resistance: sand erosion of 2.1 ± 0.6 mg/kg at 100 m/s for polycrystalline optical grade.
Watch out for
- Size: polycrystalline optical windows top out at Ø 135 mm and 3 mm thick, and single-crystal plates at 7 x 7 x 2 mm.
- Strength spread: a Weibull modulus of 2.5 with a fracture stress of 3500 MPa for single crystal, and the brochure does not explain the scatter.
- No atomic-oxygen, oxidation or radiation data were read for this profile. The hazard entries come from an abrasive-powder SDS and element-level PubChem notifications, not from a CVD plate SDS.
CVD diamond is printed at greater than 2200 W/(m·K) at 300 K for the Element Six optical grades and at least 2200 W/(m·K) on the Coherent sheet, and the Diafilm article gives greater than 2000 W/(m·K) at 300 K for the TM200 grade. Its size limits, the 2.5 Weibull modulus on fracture stress, and the missing CVD-specific hazard and space-environment data are the main gaps.
Technical details
For scientists and researchers. Everything above comes from the record below: every number with its method, its conditions and its source.
Notes
The method, full conditions and any caveat for the numbered rows above.
| # | Measurement | Method | Conditions | Caveat |
|---|---|---|---|---|
| 1 | Thermal conductivity, polycrystalline CVD diamond, optical grade, 300 K | Lower limit printed in a manufacturer properties table | grade polycrystalline CVD diamond, optical gradetemperature 300 Kunit in source W m-1 K-1, printed as >2200 | — |
| 2 | Thermal conductivity, polycrystalline CVD diamond, RF grade, 300 K | Lower limit printed in a manufacturer properties table | grade polycrystalline CVD diamond, RF gradetemperature 300 Kunit in source W m-1 K-1, printed as >2000 | — |
| 3 | Thermal conductivity, single-crystal CVD diamond, optical grade, 300 K | Lower limit printed in a manufacturer properties table | grade single-crystal CVD diamond, optical gradetemperature 300 Kunit in source W m-1 K-1, printed as >2200 | — |
| 4 | Thermal conductivity, polycrystalline CVD diamond, optical grade, 425 K | Lower limit printed in a manufacturer properties table | grade polycrystalline CVD diamond, optical gradetemperature 425 Kunit in source W m-1 K-1, printed as >1600 | — |
| 5 | Thermal conductivity, single-crystal CVD diamond sheet (SCD-O), temperature not stated | Lower limit printed in a manufacturer datasheet; no temperature given | grade single-crystal CVD diamond, optical grade (SCD-O), table labels it Thermal Gradetemperature not stated on the datasheetunit in source W/mK, printed as ≥2,200 | Matches the Element Six single-crystal optical grade value at 300 K, but the datasheet does not print the temperature. |
| 6 | Thermal conductivity, Element Six Diafilm TM100, 300 K | Lower limit printed in a trade article that reports Element Six product data | grade Element Six Diafilm TM100, polycrystalline CVD heat spreadertemperature 300 Kunit in source W/m-K, printed as better than 1,000 | — |
| 7 | Thermal conductivity, Element Six Diafilm TM200, 300 K | Lower limit printed in a trade article that reports Element Six product data | grade Element Six Diafilm TM200, polycrystalline CVD heat spreadertemperature 300 Kunit in source W/m-K, printed as better than 2,000 | — |
| 8 | Coefficient of thermal expansion, CVD diamond, 300 K | — | grade polycrystalline and single-crystal CVD diamond (same value printed for both)temperature 300 Kunit in source ppm K-1 | The Diafilm article prints 1.0 ± 0.1 ppm/K at 300 K for four Diafilm grades, which agrees. |
| 9 | Coefficient of thermal expansion, CVD diamond, 1000 K | — | grade polycrystalline and single-crystal CVD diamond (same value printed for both)temperature 1000 Kunit in source ppm K-1 | — |
| 10 | Density, CVD diamond | Value printed as 3.52 in a manufacturer properties table under the heading x 10³ kg m⁻³; the same figure is entered in g/cm3 (1 g/cm3 = 1000 kg/m3). The Diafilm article prints 3.52 x 10³ kg/m³ for its four grades. | grade polycrystalline and single-crystal CVD diamond (same value printed for both)unit in source 3.52 x 10³ kg m⁻³ (printed in the table heading, which equals 3.52 g/cm3) | — |
| 11 | Specific heat capacity, CVD diamond, 500 K | — | grade polycrystalline and single-crystal CVD diamond (same value printed for both)temperature 500 Kunit in source J Kg-1 K-1 | — |
| 12 | Specific heat capacity, Diafilm grades, 300 K | Value printed in a trade article that reports Element Six product data | grade Element Six Diafilm TM grades (printed for all four)temperature 300 Kunit in source J/kg/K | — |
| 13 | Specific heat capacity, single-crystal CVD diamond sheet (SCD-O), 25 °C | — | grade single-crystal CVD diamond, optical grade (SCD-O)temperature 25 °Cunit in source J/g-K | Differs in unit form and temperature from the 520 J/(kg·K) values; 0.536 J/g-K is 536 J/(kg·K). Both are kept, with their temperatures. |
| 14 | Young's modulus, Element Six Diafilm grades | Range printed in a trade article that reports Element Six product data | grade Element Six Diafilm TM grades (same printed range for all four)temperature not statedunit in source GPa, printed as 1,000 to 1,100 | The Element Six brochure prints 1050 in the Young's modulus row with no unit, so that value is not entered. |
| 15 | Hardness, polycrystalline CVD diamond | Value printed in a manufacturer properties table, with a stated spread of ± 18 GPa | grade polycrystalline CVD diamond (value spans the two polycrystalline columns)unit in source GPa, printed as 81 ± 18 | The spread of ± 18 GPa is printed beside the mean; the brochure does not say whether it is a standard deviation. |
| 16 | Refractive index, CVD diamond at 1064 nm | — | grade polycrystalline and single-crystal CVD diamond (same value printed for both)wavelength 1064 nm | The chart on page 3 of the same brochure reads 2.390 at 1064 nm, so the two values differ by 0.002. The table value is entered. |
| 17 | Birefringence, single-crystal CVD diamond, optical plus grade | Upper limit printed in a manufacturer properties table | grade single-crystal CVD diamond, optical plusunit in source <5 x 10-5 (Δn, dimensionless) | The Coherent SCD-O datasheet prints the same limit, <5 x 10-5 Δn, for its single-crystal optical grade. |
| 18 | Birefringence, single-crystal CVD diamond, optical grade | — | grade single-crystal CVD diamond, optical gradeunit in source 1 x 10-4 (Δn, dimensionless) | The Element Six table gives 1 x 10-4 for this grade, while the Coherent SCD-O datasheet gives less than 5 x 10-5 for its optical grade. Both are kept side by side and the grades may differ. |
| 19 | Absorption coefficient at 10.6 µm, polycrystalline CVD diamond, optical grade | Upper limit printed in a manufacturer properties table | grade polycrystalline CVD diamond, optical gradewavelength 10.6 µmunit in source <0.07 cm-1 | — |
| 20 | Absorption coefficient at 10.6 µm, single-crystal CVD diamond, optical grade | Upper limit printed in a manufacturer properties table | grade single-crystal CVD diamond, optical gradewavelength 10.6 µmunit in source <0.05 cm-1 | The Coherent SCD-O datasheet prints the same limit, 10.6 µm ABS coefficient <0.05 (cm-1). |
| 21 | Absorption coefficient at 1064 nm, single-crystal CVD diamond, optical plus grade | Upper limit printed in a manufacturer properties table | grade single-crystal CVD diamond, optical pluswavelength 1064 nmunit in source <0.005 | The Coherent SCD-O datasheet prints 0.005 (cm-1) at 1.064 µm for its single-crystal optical grade, which agrees. |
| 22 | Transmittance at 1 mm thickness, polycrystalline CVD diamond, optical grade, 8 to 200 µm | — | grade polycrystalline CVD diamond, optical gradethickness 1 mmwavelength 8 to 200 µm | — |
| 23 | Dielectric constant, polycrystalline CVD diamond, 35 GHz | Value printed in a manufacturer properties table, with a stated spread of ± 0.15 | grade polycrystalline CVD diamond (value spans the two polycrystalline columns)frequency 35 GHz | The spread of ± 0.15 is printed beside the value. The brochure gives 4.3 % increase in D at 773 K and does not give the value at that temperature. |
| 24 | Loss tangent at 145 GHz, polycrystalline CVD diamond, optical grade | — | grade polycrystalline CVD diamond, optical gradefrequency 145 GHzunit in source 8 - 20 (x 10-6) | — |
| 25 | Loss tangent at 145 GHz, polycrystalline CVD diamond, RF grade | — | grade polycrystalline CVD diamond, RF gradefrequency 145 GHzunit in source 10 - 100 (x 10-6) | — |
| 26 | Fracture stress, single-crystal CVD diamond, optical grade and optical plus | Value printed in a manufacturer properties table with its Weibull modulus | grade single-crystal CVD diamond, optical grade and optical plus (same value printed for both)weibull modulus 2.5unit in source MPa, Weibull modulus printed in brackets | — |
| 27 | Sand erosion, polycrystalline CVD diamond, optical grade | Value printed in a manufacturer properties table, with a stated spread of ± 0.6 | grade polycrystalline CVD diamond, optical gradesand C300/600velocity 100 m/sunit in source mg kg-1 at 100 ms-1 C300/600 sand | The brochure gives no single-crystal value for sand erosion. |
| 28 | Emittance at 10 µm, CVD diamond, 573 K | — | grade polycrystalline and single-crystal CVD diamond (same value printed for both)wavelength 10 µmtemperature 573 K | At 773 K the same table prints 0.03. |
| 29 | Thermal diffusivity, Element Six Diafilm TM200, 300 K | Lower limit printed in a trade article that reports Element Six product data | grade Element Six Diafilm TM200, polycrystalline CVD heat spreadertemperature 300 Kunit in source cm²/s, printed as greater than 11.1 | — |
Corrosion and compatibility
What happens when it meets other materials and environments.
| Environment | Concern | What happens |
|---|---|---|
| Corrosive chemicals and hostile environments | none | CVD diamond is chemically inert and the manufacturer says it can operate in corrosive environments.1 |
| Rain impact | low | Rain impact damage threshold velocity is printed as 525 m/s for polycrystalline optical grade.2 |
| Sand erosion | low | Sand erosion is 2.1 ± 0.6 mg/kg at 100 m/s for polycrystalline optical grade.3 |
| # | Environment | Details | Test conditions |
|---|---|---|---|
| 1 | Corrosive chemicals and hostile environments | Element Six says its CVD diamond components can operate in highly corrosive and hostile environments and that diamond ATR prisms give the longest lifetimes. The brochure gives no test data, so this is a manufacturer statement, not a measured corrosion rate. | basis manufacturer statement; no chemical, temperature or time given |
| 2 | Rain impact | Element Six prints a rain impact DTV of 525 m/s for polycrystalline optical grade and of 457 - 533 m/s for single crystal. The brochure does not define the abbreviation DTV or give the test set-up in its printed text. | grade polycrystalline optical grade (525) and single crystal (457 - 533)unit in source m s-1 |
| 3 | Sand erosion | Element Six prints a sand erosion value of 2.1 ± 0.6 mg kg-1 at 100 m s-1 with C300/600 sand for polycrystalline optical grade. The brochure gives no value for single crystal, and no exposure time is printed. | grade polycrystalline CVD diamond, optical gradesand C300/600velocity 100 m/s |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
The sources give two different pictures. An SDS for a diamond abrasive powder says the material is not a hazardous substance, and PubChem's element-level notifications for carbon carry eye and respiratory irritation statements.
- Substance
- PubChem's carbon element record aggregates ECHA notifications with GHS07, signal word Warning, H319 "Causes serious eye irritation" and H335 "May cause respiratory irritation". These are for carbon, not for CVD diamond.
- Dust and handling
- The PACE SDS for diamond powders gives precautionary statement P261 "Avoid breathing dust." and says the material is not likely to be hazardous by inhalation. The brochure does not describe dust or powder hazards for the optical and RF grades; it describes the material as chemically inert.
If it fails
These are failure routes found in the sources. The sand erosion and fracture figures are measurements printed by the manufacturer.
- Sand erosion
- Element Six prints 2.1 ± 0.6 mg/kg of sand erosion at 100 m/s for polycrystalline optical grade, with C300/600 sand.
- Fracture
- Element Six prints a fracture stress of 3500 MPa for single-crystal optical grade, with a Weibull modulus of 2.5, and does not say what the modulus means for a part.
- Rain
- Element Six prints a rain impact DTV of 525 m/s for polycrystalline optical grade and of 457 - 533 m/s for single crystal.
Handling and storage
- Size
- Element Six lists polycrystalline optical windows up to Ø 135 mm and 3 mm thick, and single-crystal plates up to 7 x 7 x 2 mm.
- Mounting
- Element Six says windows and mounts can be made with water or air cooling if required.
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Sand erosion of an exposed diamond surfacelow severity | Sand impacting at 100 m/s, in the test used by Element SixElement Six prints 2.1 ± 0.6 mg/kg of mass loss for polycrystalline optical grade. The brochure does not say how much erosion would matter for a given part. |
| Fracture under load, with wide strength spreadmoderate severity | Tensile stress on a single-crystal partElement Six prints a fracture stress of 3500 MPa with a Weibull modulus of 2.5 for single-crystal optical grade and optical plus. The brochure does not explain what the modulus means for a part's strength. |
Handling and storage
- Element Six says CVD diamond can be processed to virtually any shape, and that windows and mounts can be made with water or air cooling if required.
- Element Six lists maximum sizes of up to Ø 135 mm and 3 mm thick for polycrystalline optical grades, and plates up to 7 x 7 x 2 mm for single crystal.
Supply and geography
How common the raw materials are and where they come from.
Synthetic industrial diamond (manufactured bort, grit, dust and powder)
- Recycling
- USGS: in 2025 about 15 million carats of diamond bort, grit, dust and powder were recycled, and at least two companies recovered used industrial diamond material. Manufactured production was estimated at 160 million carats.
- Substitutes
- USGS: cubic boron nitride, fused aluminum oxide and silicon carbide can compete with industrial diamond in some applications.
Natural industrial diamond (mine production, shown for contrast)
- Top producers (2025)
- Russia 42%, Congo (Kinshasa) 18%, Botswana 14%, Zimbabwe 13%, South Africa 8%
- Recycling
- Synthetic diamond accounts for more than 99 % of global industrial diamond production and consumption, and natural diamond for less than 1 % of industrial diamond used (USGS).
Documents
Datasheets, safety data sheets, papers and standards you can open.
Full record
The complete spore, as stored. Free to reuse under CC-BY-4.0. Images keep the licence shown with each one.
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spore: profile
id: cvd-diamond
spore_version: 0.2
family: diamond
name: CVD diamond (polycrystalline and single-crystal)
abbreviation: CVD diamond
role: heat spreader, optical window
category: carbon
type: diamond
summary: |
CVD diamond is carbon grown from hydrocarbon gas by chemical vapour deposition, as polycrystalline plates or as single crystals. Element Six prints a thermal conductivity of greater than 2200 W m-1 K-1 at 300 K for its polycrystalline optical grade and for its single-crystal optical grade. The same brochure prints a density of 3.52 x 10³ kg m⁻³ and a coefficient of thermal expansion of 1.0 ppm/K at 300 K.
best_for: Heat spreaders and high-power laser windows, where thermal conductivity above 2000 W/(m·K) at 300 K matters most
weakest_at: 'Size and thickness: polycrystalline optical windows up to Ø 135 mm and 3 mm thick, single-crystal plates up to 7 x 7 x 2 mm (Element Six)'
identity:
formula: C, carbon in the diamond cubic structure (eight atoms per unit cell, Wikipedia)
crystal_system: cubic
source: wikipedia-diamond
where: 'Crystal structure section: diamond cubic, unit cell side 3.567 angstroms, eight atoms per unit cell'
tags:
environments: []
stresses:
- dust-abrasion
applications:
- thermal-control
- optics-and-cameras
- electronics-and-chips
properties:
- benchmark: thermal_conductivity
label: Thermal conductivity, polycrystalline CVD diamond, optical grade, 300 K
value: 2200
bound: lower
unit: W/(m·K)
scope: material
conditions:
grade: polycrystalline CVD diamond, optical grade
temperature: 300 K
unit_in_source: W m-1 K-1, printed as >2200
method: Lower limit printed in a manufacturer properties table
status: ground
source: e6-optics
where: Page 5, table CVD diamond properties, row Thermal conductivity 300 K, column Polycrystalline Optical grade
- benchmark: thermal_conductivity
label: Thermal conductivity, polycrystalline CVD diamond, RF grade, 300 K
value: 2000
bound: lower
unit: W/(m·K)
scope: material
conditions:
grade: polycrystalline CVD diamond, RF grade
temperature: 300 K
unit_in_source: W m-1 K-1, printed as >2000
method: Lower limit printed in a manufacturer properties table
status: ground
source: e6-optics
where: Page 5, table CVD diamond properties, row Thermal conductivity 300 K, column RF grade
- benchmark: thermal_conductivity
label: Thermal conductivity, single-crystal CVD diamond, optical grade, 300 K
value: 2200
bound: lower
unit: W/(m·K)
scope: material
conditions:
grade: single-crystal CVD diamond, optical grade
temperature: 300 K
unit_in_source: W m-1 K-1, printed as >2200
method: Lower limit printed in a manufacturer properties table
status: ground
source: e6-optics
where: Page 5, table CVD diamond properties, row Thermal conductivity 300 K, column Single crystal Optical grade
- benchmark: thermal_conductivity
label: Thermal conductivity, polycrystalline CVD diamond, optical grade, 425 K
value: 1600
bound: lower
unit: W/(m·K)
scope: material
conditions:
grade: polycrystalline CVD diamond, optical grade
temperature: 425 K
unit_in_source: W m-1 K-1, printed as >1600
method: Lower limit printed in a manufacturer properties table
status: ground
source: e6-optics
where: Page 5, table CVD diamond properties, row Thermal conductivity 425 K, column Polycrystalline Optical grade
- benchmark: thermal_conductivity
label: Thermal conductivity, single-crystal CVD diamond sheet (SCD-O), temperature not stated
value: 2200
bound: lower
unit: W/(m·K)
scope: material
conditions:
grade: single-crystal CVD diamond, optical grade (SCD-O), table labels it Thermal Grade
temperature: not stated on the datasheet
unit_in_source: W/mK, printed as ≥2,200
method: Lower limit printed in a manufacturer datasheet; no temperature given
status: ground
note: Matches the Element Six single-crystal optical grade value at 300 K, but the datasheet does not print the temperature.
source: coherent-scd-o
where: Material Properties table, row Thermal Conductivity
- benchmark: thermal_conductivity
label: Thermal conductivity, Element Six Diafilm TM100, 300 K
value: 1000
bound: lower
unit: W/(m·K)
scope: material
conditions:
grade: Element Six Diafilm TM100, polycrystalline CVD heat spreader
temperature: 300 K
unit_in_source: W/m-K, printed as better than 1,000
method: Lower limit printed in a trade article that reports Element Six product data
status: ground
source: mwrf-diafilm
where: Thermal conductivity table, row Diafilm TM100, column At 300 K
- benchmark: thermal_conductivity
label: Thermal conductivity, Element Six Diafilm TM200, 300 K
value: 2000
bound: lower
unit: W/(m·K)
scope: material
conditions:
grade: Element Six Diafilm TM200, polycrystalline CVD heat spreader
temperature: 300 K
unit_in_source: W/m-K, printed as better than 2,000
method: Lower limit printed in a trade article that reports Element Six product data
status: ground
source: mwrf-diafilm
where: Thermal conductivity table, row Diafilm TM200, column At 300 K
- benchmark: cte
label: Coefficient of thermal expansion, CVD diamond, 300 K
value: 1
unit: ppm/K
scope: material
conditions:
grade: polycrystalline and single-crystal CVD diamond (same value printed for both)
temperature: 300 K
unit_in_source: ppm K-1
method: Value printed in a manufacturer properties table
status: ground
note: The Diafilm article prints 1.0 ± 0.1 ppm/K at 300 K for four Diafilm grades, which agrees.
source: e6-optics
where: Page 5, table CVD diamond properties, row Thermal expansion coefficient 300 K
- benchmark: cte
label: Coefficient of thermal expansion, CVD diamond, 1000 K
value: 4.4
unit: ppm/K
scope: material
conditions:
grade: polycrystalline and single-crystal CVD diamond (same value printed for both)
temperature: 1000 K
unit_in_source: ppm K-1
method: Value printed in a manufacturer properties table
status: ground
source: e6-optics
where: Page 5, table CVD diamond properties, row Thermal expansion coefficient 1000 K
- benchmark: density
label: Density, CVD diamond
value: 3.52
unit: g/cm3
scope: material
conditions:
grade: polycrystalline and single-crystal CVD diamond (same value printed for both)
unit_in_source: 3.52 x 10³ kg m⁻³ (printed in the table heading, which equals 3.52 g/cm3)
method: Value printed as 3.52 in a manufacturer properties table under the heading x 10³ kg m⁻³; the same figure is entered in g/cm3 (1 g/cm3 = 1000 kg/m3). The Diafilm article prints 3.52 x 10³ kg/m³ for its four grades.
status: ground
source: e6-optics
where: Page 5, table CVD diamond properties, row Density
- benchmark: specific_heat
label: Specific heat capacity, CVD diamond, 500 K
value: 520
unit: J/(kg·K)
scope: material
conditions:
grade: polycrystalline and single-crystal CVD diamond (same value printed for both)
temperature: 500 K
unit_in_source: J Kg-1 K-1
method: Value printed in a manufacturer properties table
status: ground
source: e6-optics
where: Page 5, table CVD diamond properties, row Specific heat capacity at 500 K
- benchmark: specific_heat
label: Specific heat capacity, Diafilm grades, 300 K
value: 520
unit: J/(kg·K)
scope: material
conditions:
grade: Element Six Diafilm TM grades (printed for all four)
temperature: 300 K
unit_in_source: J/kg/K
method: Value printed in a trade article that reports Element Six product data
status: ground
source: mwrf-diafilm
where: Other properties list, Specific heat capacity
- benchmark: specific_heat
label: Specific heat capacity, single-crystal CVD diamond sheet (SCD-O), 25 °C
value: 0.536
unit: J/g-K
scope: material
conditions:
grade: single-crystal CVD diamond, optical grade (SCD-O)
temperature: 25 °C
unit_in_source: J/g-K
method: Value printed in a manufacturer datasheet
status: ground
note: Differs in unit form and temperature from the 520 J/(kg·K) values; 0.536 J/g-K is 536 J/(kg·K). Both are kept, with their temperatures.
source: coherent-scd-o
where: Material Properties table, row Specific Heat (25 °C)
- benchmark: elastic_modulus
label: Young's modulus, Element Six Diafilm grades
value: 1000
value_high: 1100
bound: range
unit: GPa
scope: material
conditions:
grade: Element Six Diafilm TM grades (same printed range for all four)
temperature: not stated
unit_in_source: GPa, printed as 1,000 to 1,100
method: Range printed in a trade article that reports Element Six product data
status: ground
note: The Element Six brochure prints 1050 in the Young's modulus row with no unit, so that value is not entered.
source: mwrf-diafilm
where: Other properties list, Young's modulus
- benchmark: hardness
label: Hardness, polycrystalline CVD diamond
value: 81
unit: GPa
scope: material
conditions:
grade: polycrystalline CVD diamond (value spans the two polycrystalline columns)
unit_in_source: GPa, printed as 81 ± 18
method: Value printed in a manufacturer properties table, with a stated spread of ± 18 GPa
status: ground
note: The spread of ± 18 GPa is printed beside the mean; the brochure does not say whether it is a standard deviation.
source: e6-optics
where: Page 5, table CVD diamond properties, row Hardness (GPa)
- benchmark: hardness
label: Hardness, single-crystal CVD diamond
value: 70
value_high: 120
bound: range
unit: GPa
scope: material
conditions:
grade: single-crystal CVD diamond (value spans the two single-crystal columns)
unit_in_source: GPa, printed as 70 - 120
method: Range printed in a manufacturer properties table
status: ground
source: e6-optics
where: Page 5, table CVD diamond properties, row Hardness (GPa)
- benchmark: refractive_index
label: Refractive index, CVD diamond at 10.6 µm
value: 2.376
unit: '-'
scope: material
conditions:
grade: polycrystalline and single-crystal CVD diamond (same value printed for both)
wavelength: 10.6 µm
method: Value printed in a manufacturer properties table
status: ground
source: e6-optics
where: Page 5, table CVD diamond properties, row Refractive index 10.6 µm
- benchmark: refractive_index
label: Refractive index, CVD diamond at 1550 nm
value: 2.386
unit: '-'
scope: material
conditions:
grade: polycrystalline and single-crystal CVD diamond (same value printed for both)
wavelength: 1550 nm
method: Value printed in a manufacturer properties table
status: ground
source: e6-optics
where: Page 5, table CVD diamond properties, row Refractive index 1550 nm
- benchmark: refractive_index
label: Refractive index, CVD diamond at 1064 nm
value: 2.392
unit: '-'
scope: material
conditions:
grade: polycrystalline and single-crystal CVD diamond (same value printed for both)
wavelength: 1064 nm
method: Value printed in a manufacturer properties table
status: ground
note: The chart on page 3 of the same brochure reads 2.390 at 1064 nm, so the two values differ by 0.002. The table value is entered.
source: e6-optics
where: Page 5, table CVD diamond properties, row Refractive index 1064 nm; chart on page 3 for comparison
- benchmark: refractive_index_temperature_coefficient
label: Temperature coefficient of refractive index (dn/dT), CVD diamond
value: 0.0000096
unit: K-1
scope: material
conditions:
grade: polycrystalline and single-crystal CVD diamond (same value printed for both)
unit_in_source: 9.6 x 10-6 (K-1)
method: Value printed in a manufacturer properties table
status: ground
source: e6-optics
where: Page 5, table CVD diamond properties, row dn/dT
- benchmark: birefringence
label: Birefringence, single-crystal CVD diamond, optical plus grade
value: 0.00005
bound: upper
unit: '-'
scope: material
conditions:
grade: single-crystal CVD diamond, optical plus
unit_in_source: <5 x 10-5 (Δn, dimensionless)
method: Upper limit printed in a manufacturer properties table
status: ground
note: The Coherent SCD-O datasheet prints the same limit, <5 x 10-5 Δn, for its single-crystal optical grade.
source: e6-optics
where: Page 5, table CVD diamond properties, row Birefringence, column Optical plus
- benchmark: birefringence
label: Birefringence, single-crystal CVD diamond, optical grade
value: 0.0001
unit: '-'
scope: material
conditions:
grade: single-crystal CVD diamond, optical grade
unit_in_source: 1 x 10-4 (Δn, dimensionless)
method: Value printed in a manufacturer properties table
status: ground
note: The Element Six table gives 1 x 10-4 for this grade, while the Coherent SCD-O datasheet gives less than 5 x 10-5 for its optical grade. Both are kept side by side and the grades may differ.
source: e6-optics
where: Page 5, table CVD diamond properties, row Birefringence, column Single crystal Optical grade
- benchmark: absorption_coefficient
label: Absorption coefficient at 10.6 µm, polycrystalline CVD diamond, optical grade
value: 0.07
bound: upper
unit: cm-1
scope: material
conditions:
grade: polycrystalline CVD diamond, optical grade
wavelength: 10.6 µm
unit_in_source: <0.07 cm-1
method: Upper limit printed in a manufacturer properties table
status: ground
source: e6-optics
where: Page 5, table CVD diamond properties, row Absorption coefficient 10.6 µm, column Polycrystalline Optical grade
- benchmark: absorption_coefficient
label: Absorption coefficient at 10.6 µm, single-crystal CVD diamond, optical grade
value: 0.05
bound: upper
unit: cm-1
scope: material
conditions:
grade: single-crystal CVD diamond, optical grade
wavelength: 10.6 µm
unit_in_source: <0.05 cm-1
method: Upper limit printed in a manufacturer properties table
status: ground
note: The Coherent SCD-O datasheet prints the same limit, 10.6 µm ABS coefficient <0.05 (cm-1).
source: e6-optics
where: Page 5, table CVD diamond properties, row Absorption coefficient 10.6 µm, column Single crystal Optical grade
- benchmark: absorption_coefficient
label: Absorption coefficient at 1064 nm, single-crystal CVD diamond, optical plus grade
value: 0.005
bound: upper
unit: cm-1
scope: material
conditions:
grade: single-crystal CVD diamond, optical plus
wavelength: 1064 nm
unit_in_source: <0.005
method: Upper limit printed in a manufacturer properties table
status: ground
note: The Coherent SCD-O datasheet prints 0.005 (cm-1) at 1.064 µm for its single-crystal optical grade, which agrees.
source: e6-optics
where: Page 5, table CVD diamond properties, row Absorption coefficient 1064 nm, column Single crystal Optical plus
- benchmark: transmittance
label: Transmittance at 1 mm thickness, polycrystalline CVD diamond, optical grade, 8 to 200 µm
value: 71.4
unit: '%'
scope: material
conditions:
grade: polycrystalline CVD diamond, optical grade
thickness: 1 mm
wavelength: 8 to 200 µm
method: Value printed in a manufacturer properties table
status: ground
source: e6-optics
where: Page 5, table CVD diamond properties, row Transmittance 8-200 µm, column Polycrystalline Optical grade
- benchmark: dielectric_constant
label: Dielectric constant, polycrystalline CVD diamond, 35 GHz
value: 5.68
unit: '-'
scope: material
conditions:
grade: polycrystalline CVD diamond (value spans the two polycrystalline columns)
frequency: 35 GHz
method: Value printed in a manufacturer properties table, with a stated spread of ± 0.15
status: ground
note: The spread of ± 0.15 is printed beside the value. The brochure gives 4.3 % increase in D at 773 K and does not give the value at that temperature.
source: e6-optics
where: Page 5, table CVD diamond properties, row Dielectric constant D (35 GHz)
- benchmark: dissipation_factor
label: Loss tangent at 145 GHz, polycrystalline CVD diamond, optical grade
value: 0.000008
value_high: 0.00002
bound: range
unit: '-'
scope: material
conditions:
grade: polycrystalline CVD diamond, optical grade
frequency: 145 GHz
unit_in_source: 8 - 20 (x 10-6)
method: Range printed in a manufacturer properties table
status: ground
source: e6-optics
where: Page 5, table CVD diamond properties, row Loss tangent 145 GHz, column Optical grade
- benchmark: dissipation_factor
label: Loss tangent at 145 GHz, polycrystalline CVD diamond, RF grade
value: 0.00001
value_high: 0.0001
bound: range
unit: '-'
scope: material
conditions:
grade: polycrystalline CVD diamond, RF grade
frequency: 145 GHz
unit_in_source: 10 - 100 (x 10-6)
method: Range printed in a manufacturer properties table
status: ground
source: e6-optics
where: Page 5, table CVD diamond properties, row Loss tangent 145 GHz, column RF grade
- benchmark: fracture_stress
label: Fracture stress, single-crystal CVD diamond, optical grade and optical plus
value: 3500
unit: MPa
scope: material
conditions:
grade: single-crystal CVD diamond, optical grade and optical plus (same value printed for both)
weibull_modulus: '2.5'
unit_in_source: MPa, Weibull modulus printed in brackets
method: Value printed in a manufacturer properties table with its Weibull modulus
status: ground
source: e6-optics
where: Page 5, table CVD diamond properties, row Fracture stress (MPa) [Weibull modulus]
- benchmark: sand_erosion
label: Sand erosion, polycrystalline CVD diamond, optical grade
value: 2.1
unit: mg/kg
scope: material
conditions:
grade: polycrystalline CVD diamond, optical grade
sand: C300/600
velocity: 100 m/s
unit_in_source: mg kg-1 at 100 ms-1 C300/600 sand
method: Value printed in a manufacturer properties table, with a stated spread of ± 0.6
status: ground
note: The brochure gives no single-crystal value for sand erosion.
source: e6-optics
where: Page 5, table CVD diamond properties, row Sand erosion
- benchmark: emittance
label: Emittance at 10 µm, CVD diamond, 573 K
value: 0.02
unit: '-'
scope: material
conditions:
grade: polycrystalline and single-crystal CVD diamond (same value printed for both)
wavelength: 10 µm
temperature: 573 K
method: Value printed in a manufacturer properties table
status: ground
note: At 773 K the same table prints 0.03.
source: e6-optics
where: Page 5, table CVD diamond properties, row Emittance at 10 µm, 573 K
- benchmark: thermal_diffusivity
label: Thermal diffusivity, Element Six Diafilm TM200, 300 K
value: 11.1
bound: lower
unit: cm2/s
scope: material
conditions:
grade: Element Six Diafilm TM200, polycrystalline CVD heat spreader
temperature: 300 K
unit_in_source: cm²/s, printed as greater than 11.1
method: Lower limit printed in a trade article that reports Element Six product data
status: ground
source: mwrf-diafilm
where: Thermal diffusivity at 300 K list, row TM200
corrosion:
- environment: Corrosive chemicals and hostile environments
headline: CVD diamond is chemically inert and the manufacturer says it can operate in corrosive environments.
effect: Element Six says its CVD diamond components can operate in highly corrosive and hostile environments and that diamond ATR prisms give the longest lifetimes. The brochure gives no test data, so this is a manufacturer statement, not a measured corrosion rate.
rating: none
conditions:
basis: manufacturer statement; no chemical, temperature or time given
source: e6-optics
where: Page 2, section Unparalleled chemical inertness
- environment: Rain impact
headline: Rain impact damage threshold velocity is printed as 525 m/s for polycrystalline optical grade.
effect: Element Six prints a rain impact DTV of 525 m/s for polycrystalline optical grade and of 457 - 533 m/s for single crystal. The brochure does not define the abbreviation DTV or give the test set-up in its printed text.
rating: low
conditions:
grade: polycrystalline optical grade (525) and single crystal (457 - 533)
unit_in_source: m s-1
source: e6-optics
where: Page 5, table CVD diamond properties, row Rain impact DTV (m s-1)
- environment: Sand erosion
headline: Sand erosion is 2.1 ± 0.6 mg/kg at 100 m/s for polycrystalline optical grade.
effect: Element Six prints a sand erosion value of 2.1 ± 0.6 mg kg-1 at 100 m s-1 with C300/600 sand for polycrystalline optical grade. The brochure gives no value for single crystal, and no exposure time is printed.
rating: low
conditions:
grade: polycrystalline CVD diamond, optical grade
sand: C300/600
velocity: 100 m/s
source: e6-optics
where: Page 5, table CVD diamond properties, row Sand erosion
risks:
hazards:
- text: PubChem's record for the element carbon (CID 5462310) aggregates ECHA C&L notifications for carbon, EC 231-153-3, with GHS07, signal word 'Warning', H319 'Causes serious eye irritation' and H335 'May cause respiratory irritation'. A second ECHA notification for carbon, EC 610-410-7, is listed as Not Classified. These are element-level notifications, not a classification of CVD diamond.
ghs:
- H319
- H335
source: pubchem-carbon-ghs
where: GHS Classification section, ECHA C&L entries (Reference 26 and Reference 29)
- text: PACE Technologies safety data sheet for Diamond Powders (date revised 7/21/2025) is a metallographic abrasive SDS. It states 'Not a hazardous substance or mixture' under GHS, with pictogram, signal word and hazard statements all N/A, and gives precautionary statement 'P261-Avoid breathing dust.' Section 4 says the material is 'not likely to be hazardous by inhalation'. The SDS does not say the diamond is synthetic or CVD-grown.
ghs: []
source: pace-diamond-sds
where: Section 2 Hazard(s) Identification; Section 4 First-Aid Measures, Inhalation; header date revised
failure_risks:
- mode: Sand erosion of an exposed diamond surface
trigger: Sand impacting at 100 m/s, in the test used by Element Six
consequence: Element Six prints 2.1 ± 0.6 mg/kg of mass loss for polycrystalline optical grade. The brochure does not say how much erosion would matter for a given part.
severity: low
source: e6-optics
where: Page 5, row Sand erosion
- mode: Fracture under load, with wide strength spread
trigger: Tensile stress on a single-crystal part
consequence: Element Six prints a fracture stress of 3500 MPa with a Weibull modulus of 2.5 for single-crystal optical grade and optical plus. The brochure does not explain what the modulus means for a part's strength.
severity: moderate
source: e6-optics
where: Page 5, row Fracture stress (MPa) [Weibull modulus]
side_effects: []
handling:
- text: Element Six says CVD diamond can be processed to virtually any shape, and that windows and mounts can be made with water or air cooling if required.
source: e6-optics
where: Page 2 section Sizes and shapes; page 4 section Collaboration in applications development
- text: Element Six lists maximum sizes of up to Ø 135 mm and 3 mm thick for polycrystalline optical grades, and plates up to 7 x 7 x 2 mm for single crystal.
source: e6-optics
where: Page 2 section Sizes and shapes
mitigations: []
uses:
- application: thermal-control
device: Heat spreaders for high-power GaN transistors, MMICs and laser diodes
example: Element Six Diafilm heat spreaders are stated for high-power, high-density circuits, including GaN discrete transistors, MMICs and laser diodes.
source: mwrf-diafilm
where: Article, applications paragraph
- application: optics-and-cameras
device: Optical windows for high-power CO2 and solid-state lasers
example: Element Six lists optical windows and lenses for high-power CO2 lasers and high-power solid-state lasers, and says CVD diamond windows allow much higher laser power densities than other materials.
source: e6-optics
where: Page 3, section Optical windows in high power lasers; page 4, table Example applications
- application: electronics-and-chips
device: RF and microwave windows in high-power gyrotrons
example: Element Six says CVD RF diamond windows are used in nuclear fusion experiments, in gyrotrons above 2 MW and as containment windows in waveguides.
source: e6-optics
where: Page 4, section Optical microwave CVD diamond at the frontiers of science
- application: thermal-control
device: Heat sinks for high-power laser diodes and AlGaN/GaN HEMT transistors
example: A 2019 open-access chapter lists CVD diamond heat sinking components for transistor high power devices and high power laser diodes, and names AlGaN/GaN HEMTs produced on CVD diamond substrates.
source: intech-cvd-heat-sinks
where: Section CVD diamond as a heat spreader or in devices
supply:
- subject: Synthetic industrial diamond (manufactured bort, grit, dust and powder)
producers: []
ranking: China was the leading producer of synthetic industrial diamond in 2025, followed by the United States and Russia; these three produced about 99 % of the world's synthetic industrial diamond. Per-country shares are not printed.
critical_lists: []
recycling: 'USGS: in 2025 about 15 million carats of diamond bort, grit, dust and powder were recycled, and at least two companies recovered used industrial diamond material. Manufactured production was estimated at 160 million carats.'
substitutes:
- 'USGS: cubic boron nitride, fused aluminum oxide and silicon carbide can compete with industrial diamond in some applications.'
source: usgs-mcs2026-diamond
where: Domestic Production and Use; Events, Trends, and Issues; Recycling; Substitutes
- subject: Natural industrial diamond (mine production, shown for contrast)
producers:
- country: Russia
share_percent: 42
year: 2025
- country: Congo (Kinshasa)
share_percent: 18
year: 2025
- country: Botswana
share_percent: 14
year: 2025
- country: Zimbabwe
share_percent: 13
year: 2025
- country: South Africa
share_percent: 8
year: 2025
critical_lists: []
recycling: Synthetic diamond accounts for more than 99 % of global industrial diamond production and consumption, and natural diamond for less than 1 % of industrial diamond used (USGS).
substitutes: []
source: usgs-mcs2026-diamond
where: Events, Trends, and Issues (natural production shares as printed, 16 of 38 million carats worldwide); World Natural Industrial Diamond Mine Production and Reserves; World Resources
documents:
- title: 'Element Six, Optics: CVD diamond brochure (March 2021)'
type: datasheet
url: https://terpconnect.umd.edu/~antonsen/ENEE681-lectures/element_six_optics_brochure_1.pdf
year: 2021
- title: Coherent, Single Crystal Diamond, Optical Grade (SCD-O) datasheet
type: datasheet
url: https://www.coherent.com/content/dam/coherent/site/en/resources/datasheet/optics/single-crystal-diamond-optical-grade.pdf
year: 2026
- title: Jack Browne, Diamond is precious for thermal dissipation (Microwaves & RF, 2 March 2017)
type: report
url: https://www.mwrf.com/technologies/article/21848133/diamond-is-precious-for-thermal-dissipation
year: 2017
- title: 'USGS Mineral Commodity Summaries 2026: Diamond (Industrial)'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-diamond.pdf
year: 2026
- title: 'Wikipedia: Diamond (crystal structure, synthesis)'
type: database
url: https://en.wikipedia.org/wiki/Diamond
- title: PubChem compound record CID 5462310 (carbon element record)
type: database
url: https://pubchem.ncbi.nlm.nih.gov/compound/5462310
- title: PACE Technologies, Safety Data Sheet, Diamond Powders (date revised 7/21/2025)
type: sds
url: https://www.metallographic.com/sds/Diamond-powders.pdf
year: 2025
- title: PubChem GHS Classification, compound record CID 5462310 (carbon), JSON view
type: database
url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5462310/JSON?heading=GHS+Classification
- title: Vieira da Silva Neto, Fraga and Trava-Airoldi (2019), Development, Properties, and Applications of CVD Diamond-Based Heat Sinks
type: paper
url: https://intechopen.com/chapters/66249
year: 2019
gaps:
- No hazard classification for CVD diamond itself was found. The hazard entries use an SDS for a diamond abrasive powder, which does not say the diamond is synthetic, and PubChem's element-level ECHA notifications for carbon, which conflict with the SDS. Both are recorded side by side.
- No CAS number for synthetic diamond was read. The PubChem name lookup returned CID 5462310, which is the carbon element record and not a diamond-specific entry.
- No atomic-oxygen erosion or reaction data, and no outgassing or total mass loss test for CVD diamond, were found in the pages read in this run.
- No oxidation limit or graphitisation temperature in air was found in the pages read, so the maximum service temperature is not recorded.
- No radiation (total dose or displacement damage) data for CVD diamond were looked up.
- The Element Six Diamond Handbook is cited on page 5 of the brochure but was not opened, so its references are not recorded.
- The Diafilm TM150 and TM180 thermal conductivity values at 300 K and 425 K (printed in the trade article) were not entered; only TM100 and TM200 at 300 K are recorded. Thermal conductivity at 425 K is recorded for the Element Six optical and RF grades only.
- Thermal conductivity at cryogenic temperatures and at 1000 K was not found in the pages read.
- Wikipedia gives 900 to 2320 W m-1 K-1 as a range for identifying diamond with no temperature or condition stated, so it is not entered as a property.
- Critical-mineral list status for industrial diamond was not read. The USGS diamond summary does not state a critical-mineral listing, and the 2025 USGS critical list was not checked in this run.
- Per-country shares of synthetic industrial diamond production are not printed in the USGS summary; only the rank order and the combined share of about 99 % are recorded.
- Element Six lists 1050 for Young's modulus with no unit on page 5; the GPa range from the Diafilm article is entered instead.
- The Element Six nucleation and growth values (800 [10], 400 [15] and so on) and the 633 transmittance row were left out because the brochure does not print a clear unit or meaning for them.
- Property names not in the canonical list (hardness, absorption_coefficient, birefringence, emittance, fracture_stress, sand_erosion, thermal_diffusivity, refractive_index_temperature_coefficient) use snake_case names. The Element Six rain impact DTV abbreviation is not defined in the brochure.
- Only one open-access chapter (2019, IntechOpen) was read for CVD diamond heat sinks, and no peer-reviewed journal paper with measured CVD diamond data was read. A 2019 MDPI article (DOI path 2571-9637/5/1/8) appeared in search but could not be fetched, so it is not used.
sources:
e6-optics:
title: 'Element Six, Optics: CVD diamond brochure (March 2021), pages 2 to 5'
url: https://terpconnect.umd.edu/~antonsen/ENEE681-lectures/element_six_optics_brochure_1.pdf
year: 2021
kind: datasheet
license: Manufacturer brochure, cited, not reproduced
coherent-scd-o:
title: Coherent, Single Crystal Diamond, Optical Grade (SCD-O) datasheet
url: https://www.coherent.com/content/dam/coherent/site/en/resources/datasheet/optics/single-crystal-diamond-optical-grade.pdf
year: 2026
kind: datasheet
license: Manufacturer datasheet, cited, not reproduced
mwrf-diafilm:
title: Jack Browne, Diamond is precious for thermal dissipation, Microwaves & RF, 2 March 2017
url: https://www.mwrf.com/technologies/article/21848133/diamond-is-precious-for-thermal-dissipation
year: 2017
kind: web
license: Trade article reporting Element Six Diafilm data, cited, not reproduced
usgs-mcs2026-diamond:
title: Mineral Commodity Summaries 2026, Diamond (Industrial)
id: USGS MCS 2026, February 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-diamond.pdf
year: 2026
kind: report
license: public domain (USGS)
wikipedia-diamond:
title: Diamond (crystal structure, synthesis), Wikipedia
url: https://en.wikipedia.org/wiki/Diamond
kind: web
license: CC BY-SA 4.0 (cited, not reproduced)
pubchem-carbon:
title: PubChem compound record CID 5462310 (carbon element record)
id: CID 5462310
url: https://pubchem.ncbi.nlm.nih.gov/compound/5462310
kind: database
license: public domain (NCBI)
pace-diamond-sds:
title: PACE Technologies, Safety Data Sheet, Diamond Powders (date revised 7/21/2025)
url: https://www.metallographic.com/sds/Diamond-powders.pdf
year: 2025
kind: datasheet
license: Manufacturer SDS, cited, not reproduced
pubchem-carbon-ghs:
title: PubChem compound record CID 5462310 (carbon), GHS Classification section, JSON view
id: CID 5462310
url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5462310/JSON?heading=GHS+Classification
kind: database
license: public domain (NCBI)
intech-cvd-heat-sinks:
title: Vieira da Silva Neto, Fraga and Trava-Airoldi (2019), Development, Properties, and Applications of CVD Diamond-Based Heat Sinks
id: DOI 10.5772/intechopen.85349
url: https://intechopen.com/chapters/66249
year: 2019
kind: paper
license: open-access chapter (IntechOpen), cited, not reproduced
license: CC-BY-4.0
updated: '2026-11-01'
review:
status: draft
method: assistant
checked_values: 33
unreachable: 1
caveats: 5
note: 'Values were read by an AI assistant on 2026-11-01 from the Element Six brochure (page 5 table read from a rendered image), the Coherent SCD-O datasheet, the Microwaves & RF article (WebFetch), the USGS Mineral Commodity Summaries 2026 diamond text, and Wikipedia (WebFetch). Added in the hazard and use pass: the PACE diamond powder SDS (rev. 7/21/2025), the PubChem GHS Classification JSON for CID 5462310, and the 2019 IntechOpen CVD diamond heat sink chapter. Unreachable: PubChem diamond page (browser check); MDPI page (403, and a mirror refused connection). Caveats: the Element Six and Coherent sources disagree on single-crystal birefringence and on the 1064 nm refractive index; the Young''s modulus unit comes from a trade article; the Diafilm values are from a trade article, not the datasheet; no peer-reviewed paper was read.'
story:
risk_groups:
- title: For people
lead: The sources give two different pictures. An SDS for a diamond abrasive powder says the material is not a hazardous substance, and PubChem's element-level notifications for carbon carry eye and respiratory irritation statements.
level: 1
verdict: Mixed; no classification for CVD diamond itself was read
points:
- label: Substance
line: PubChem's carbon element record aggregates ECHA notifications with GHS07, signal word Warning, H319 "Causes serious eye irritation" and H335 "May cause respiratory irritation". These are for carbon, not for CVD diamond.
- label: Dust and handling
line: The PACE SDS for diamond powders gives precautionary statement P261 "Avoid breathing dust." and says the material is not likely to be hazardous by inhalation. The brochure does not describe dust or powder hazards for the optical and RF grades; it describes the material as chemically inert.
- title: If it fails
lead: These are failure routes found in the sources. The sand erosion and fracture figures are measurements printed by the manufacturer.
points:
- label: Sand erosion
line: Element Six prints 2.1 ± 0.6 mg/kg of sand erosion at 100 m/s for polycrystalline optical grade, with C300/600 sand.
- label: Fracture
line: Element Six prints a fracture stress of 3500 MPa for single-crystal optical grade, with a Weibull modulus of 2.5, and does not say what the modulus means for a part.
- label: Rain
line: Element Six prints a rain impact DTV of 525 m/s for polycrystalline optical grade and of 457 - 533 m/s for single crystal.
- title: Handling and storage
points:
- label: Size
line: Element Six lists polycrystalline optical windows up to Ø 135 mm and 3 mm thick, and single-crystal plates up to 7 x 7 x 2 mm.
- label: Mounting
line: Element Six says windows and mounts can be made with water or air cooling if required.
why: CVD diamond has the highest thermal conductivity of any material, according to Element Six. Its polycrystalline optical grade is printed at greater than 2200 W/(m·K) at 300 K, and its RF grade at greater than 2000 W/(m·K) at 300 K. A Coherent single-crystal optical grade sheet prints at least 2200 W/(m·K) with no temperature given. That is why the material is used as a heat spreader under high-power electronics and as a window in high-power lasers.
uses:
- where: Heat spreaders
line: Element Six Diafilm heat spreaders are stated for high-power, high-density circuits, including GaN discrete transistors, MMICs and laser diodes. The Diafilm TM200 grade is printed at greater than 2000 W/(m·K) at 300 K.
- where: Laser windows
line: Element Six lists optical windows for high-power CO2 and solid-state lasers, and says CVD diamond windows allow much higher laser power densities than other materials.
- where: RF windows
line: Element Six says CVD RF diamond windows are used in nuclear fusion experiments, in gyrotrons above 2 MW and as containment windows in waveguides.
- where: Laser and power-electronics heat sinks
line: A 2019 open-access chapter says CVD diamond heat sinks are used for high-power laser diodes and transistor high power devices, and names AlGaN/GaN HEMTs on CVD diamond substrates (Vieira da Silva Neto et al., 2019).
can_do:
- label: Carry heat
value: greater than 2200 W/(m·K) at 300 K
benchmark: thermal_conductivity
line: Element Six prints greater than 2200 W/(m·K) at 300 K for polycrystalline optical grade and for single-crystal optical grade. At 425 K it prints greater than 1600 W/(m·K) for the polycrystalline optical grade.
- label: Stay dimensionally stable
value: 1.0 ppm/K at 300 K
benchmark: cte
line: The coefficient of thermal expansion is 1.0 ppm/K at 300 K and 4.4 ppm/K at 1000 K, per Element Six. The Diafilm article prints 1.0 ± 0.1 ppm/K at 300 K.
- label: Weight
value: 3.52 g/cm3
benchmark: density
line: Density is printed as 3.52 x 10³ kg m⁻³ in the Element Six brochure and as 3.52 x 10³ kg/m³ in the Diafilm article.
- label: Pass light
value: 71.4 % at 1 mm
benchmark: transmittance
line: Polycrystalline optical grade transmits 71.4 % through 1 mm of material over 8 to 200 µm, per Element Six.
- label: Hard
value: 81 ± 18 GPa
benchmark: hardness
line: Polycrystalline CVD diamond is printed at a hardness of 81 ± 18 GPa, and single crystal at 70 - 120 GPa.
compare: The Element Six brochure prints thermal conductivity above 2000 W/(m·K) at 300 K for the RF and optical grades, and the Coherent single-crystal sheet prints at least 2200 W/(m·K), and the Diafilm article gives 1000 and 2000 W/(m·K) for the TM100 and TM200 grades. The two sources give different specific heat figures, 520 J/(kg·K) at 300 K in the trade article and 0.536 J/g-K at 25 °C on the Coherent sheet, so read them with their temperatures in view. For birefringence the Element Six table gives 1e-4 for its single-crystal optical grade, while the Coherent sheet gives less than 5e-5, so grades and sources need to be matched before comparing.
compare_rows:
- label: Thermal conductivity
benchmark: thermal_conductivity
- label: Density
benchmark: density
- label: Thermal expansion
benchmark: cte
handling:
- Specify the grade, because polycrystalline and single-crystal values differ, and the RF grade is lower than the optical grade for thermal conductivity.
- 'Check the size limits before design: Ø 135 mm by 3 mm for polycrystalline optical grade, and 7 x 7 x 2 mm for single crystal.'
- Read the supplier's SDS for the exact product before use. The PACE SDS covers a diamond abrasive powder, not CVD plate or window material.
good_for:
- 'Heat spreading: greater than 2200 W/(m·K) at 300 K for the optical grades, per Element Six.'
- 'High-power laser windows: absorption at 10.6 µm below 0.07 cm-1 for polycrystalline optical grade.'
- 'Erosion resistance: sand erosion of 2.1 ± 0.6 mg/kg at 100 m/s for polycrystalline optical grade.'
watch_out:
- 'Size: polycrystalline optical windows top out at Ø 135 mm and 3 mm thick, and single-crystal plates at 7 x 7 x 2 mm.'
- 'Strength spread: a Weibull modulus of 2.5 with a fracture stress of 3500 MPa for single crystal, and the brochure does not explain the scatter.'
- No atomic-oxygen, oxidation or radiation data were read for this profile. The hazard entries come from an abrasive-powder SDS and element-level PubChem notifications, not from a CVD plate SDS.
verdict: CVD diamond is printed at greater than 2200 W/(m·K) at 300 K for the Element Six optical grades and at least 2200 W/(m·K) on the Coherent sheet, and the Diafilm article gives greater than 2000 W/(m·K) at 300 K for the TM200 grade. Its size limits, the 2.5 Weibull modulus on fracture stress, and the missing CVD-specific hazard and space-environment data are the main gaps.
recipe:
line: Diamond is pure carbon with a cubic crystal structure (Wikipedia). Synthetic diamond can be grown from hydrocarbon gases by chemical vapour deposition (Wikipedia). Coherent describes its single-crystal optical grade as made by plasma-enhanced chemical vapour deposition (Coherent datasheet).
parts:
- name: Carbon
symbol: C
atoms: 1
atomic_weight: 12.011
role: The whole material. The PubChem carbon element record prints a molecular weight of 12.011.
References
Every number above carries a reference number. Click one to see the source and where in it the value comes from.
| # | Source | Type | Year | Used for |
|---|---|---|---|---|
| Element Six, Optics: CVD diamond brochure (March 2021), pages 2 to 5 | datasheet | 2021 | 35 values | |
| Coherent, Single Crystal Diamond, Optical Grade (SCD-O) datasheet | datasheet | 2026 | 2 values | |
| Jack Browne, Diamond is precious for thermal dissipation, Microwaves & RF, 2 March 2017 | web | 2017 | 6 values | |
| Mineral Commodity Summaries 2026, Diamond (Industrial) | report | 2026 | 2 values | |
| Diamond (crystal structure, synthesis), Wikipedia | web | 1 value | ||
| PubChem compound record CID 5462310 (carbon element record) | database | 0 values | ||
| PACE Technologies, Safety Data Sheet, Diamond Powders (date revised 7/21/2025) | datasheet | 2025 | 1 value | |
| PubChem compound record CID 5462310 (carbon), GHS Classification section, JSON view | database | 1 value | ||
| Vieira da Silva Neto, Fraga and Trava-Airoldi (2019), Development, Properties, and Applications of CVD Diamond-Based Heat Sinks | paper | 2019 | 1 value |
Updated