Materials/Ceramics/Technical ceramics
Oxide ceramics
oxide-ceramicsAbout oxide ceramics
Oxide ceramics (alumina, zirconia, beryllia, magnesia, titanates, oxide fibres): density, melting point, thermal and mechanical data with sources.
Oxide ceramics are metal-oxygen compounds that resist heat and corrosion and insulate electrically. Alumina and zirconia are the structural workhorses; titanates and some other oxides are chosen for their electrical behaviour.
Properties depend on purity, grain size and density, so each value on these pages names the grade or form it was measured on.
At a glance
- Highest density: Hafnium oxide (HfO2) reaches 9.68 g/cm³. Lowest: RCF starts at 0.064 g/cm³. (25 of 27 grades have a sourced value.)
- Highest melting point: Hafnium oxide (HfO2) reaches 2,900 °C. Lowest: Vanadium pentoxide (V2O5) starts at 681 °C. (20 of 27 grades have a sourced value.)
- Highest thermal conductivity: Beryllium oxide (BeO) reaches 285 W/(m·K). Lowest: RCF starts at 0.08 W/(m·K). (12 of 27 grades have a sourced value.)
Ranges run across the conditions each source reports (temper, heat treatment, form), measured at room temperature where the source says so.
How they compare
The same measurements for every material in the collection. A range means the grade has values under several conditions; "at least" means the source gives a specified minimum. "no data" means no sourced value yet. For ranked tables, open a benchmark.
| Material | Density | Melting point | Thermal conductivity | Young's modulus | Flexural strength | Thermal expansion |
|---|---|---|---|---|---|---|
| Alumina (Al2O3)structural/insulating ceramic | 3.72 to 3.9 g/cm³ | 2,030 to 2,072 °C | 30 W/(m·K) | 370 GPa | 379 MPa | 8.2 ppm/K |
| Barium titanate (BaTiO3)ferroelectric, piezoelectric and high-permittivity perovskite ceramic | 6.06 g/cm³ | 1,618 to 1,625 °C | 6 W/(m·K) | no data | no data | 6.2 to 15.7 ppm/K |
| Beryllium oxide (BeO)electrically insulating, high-thermal-conductivity ceramic (beryllia) | 3.01 g/cm³ | 2,578 °C | 285 W/(m·K) | no data | 221 MPa | no data |
| Calcium titanate (CaTiO3)perovskite oxide ceramic for microwave dielectrics and nuclear wasteforms | 3.86 to 4.1 g/cm³ | 1,975 °C | no data | no data | no data | no data |
| RCFlightweight high-temperature insulation blanket and board | 0.064 to 0.45 g/cm³ | 1,760 °C | 0.08 W/(m·K) | no data | no data | no data |
| Cerium(IV) oxide (CeO2)oxygen-storage oxide, UV-absorbing dopant and radiation-resistant cover-glass additive | 7.65 g/cm³ | 2,600 °C | no data | no data | no data | 11.6 ppm/K |
| Cobalt oxidecobalt oxides used as battery cathode and anode precursors, catalysts, ceramic pigments and solar-selective paints | 5.7 to 6.7 g/cm³ | 1,830 °C | no data | no data | no data | no data |
| Copper oxides (CuO, Cu2O)p-type oxides for solar absorbers and photovoltaic layers, and the copper source in high-temperature superconductor synthesis | 6 - | 1,326 °C | no data | no data | no data | no data |
| Hafnium oxide (HfO2)high-k gate dielectric and thermal barrier coating oxide | 9.68 g/cm³ | 2,758 to 2,900 °C | 1.5 W/(m·K) | no data | no data | no data |
| Iron oxidemagnetic and pigment oxides (hematite, magnetite, ferrite magnets and cores) | 4.7 to 5.24 g/cm³ | no data | 5 to 10 W/(m·K) | 120 to 180 GPa | no data | 9.2 to 13.3 ppm/K |
| LSMperovskite oxide cathode for solid oxide fuel cells and colossal-magnetoresistance manganite | 2 g/cm³ | no data | no data | no data | no data | no data |
| Lead zirconate titanate (PZT)piezoelectric ceramic (lead zirconate titanate solid solution, Pb(Zr,Ti)O3) | 7.8 g/cm³ | no data | no data | no data | no data | -6 to -4 ppm/K |
| MgOrefractory and electrical-insulating ceramic (magnesia) | 3.58 to 3.6 g/cm³ | 2,800 °C | 42 W/(m·K) | 249 GPa | 7 to 103 MPa | 10.8 to 14 ppm/K |
| Nickel oxide (NiO)p-type oxide for transparent layers, solid oxide fuel cell anodes and oxide scales on nickel; carcinogen | 6.67 g/cm³ | 1,984 °C | no data | no data | no data | no data |
| Niobium pentoxide (Nb2O5)high-rate lithium-ion anode oxide, with tantalum pentoxide as the dielectric and optical-film counterpart | 4.6 to 8.2 g/cm³ | 1,500 to 1,872 °C | no data | no data | no data | no data |
| Pyrophyllitemachinable ceramic blank and high-pressure gasket mineral | 2.3 g/cm³ | no data | no data | no data | 4 to 400 MPa | 4 to 5 ppm/K |
| Ln2O3dense, high-melting trivalent oxide ceramics for optics and laser hosts | 3.86 to 9.5 g/cm³ | 2,233 to 2,510 °C | no data | no data | no data | no data |
| Silicon monoxide (SiO)evaporation source for thin oxide films and lithium-ion anode material | 2.13 g/cm³ | 1,702 °C | no data | no data | no data | no data |
| Steatite (MgO-SiO2)electrical insulator ceramic | 2.5 to 3.1 g/cm³ | no data | 2 W/(m·K) | 120 GPa | 190 to 220 MPa | 7.7 to 9.2 ppm/K |
| SnO2, ITOtransparent conductor and gas-sensing oxide | 6.8 to 7.13 g/cm³ | 1,630 °C | no data | no data | no data | no data |
| Titanium dioxide (TiO2)white pigment and photocatalyst (anatase and rutile polymorphs) | 3.8 to 4 g/cm³ | 1,850 °C | no data | no data | no data | no data |
| Tungsten trioxide (WO3)electrochromic and gas-sensing oxide | 7.16 to 7.2 g/cm³ | 1,472 °C | no data | no data | no data | no data |
| Vanadium pentoxide (V2O5)catalyst, flow-battery feedstock and infrared-sensor film material | 3.4 - | 681 to 690 °C | no data | no data | no data | no data |
| Yttrium oxide (Y2O3)transparent and plasma-resistant oxide ceramic | 4.84 to 5.01 g/cm³ | 2,410 °C | 10 to 14.5 W/(m·K) | 160 to 188 GPa | 100 to 430 MPa | 7.9 to 8.2 ppm/K |
| Zinc oxide (ZnO)wide-bandgap oxide for thermal-control coatings, varistors and transparent conductors | 5.67 g/cm³ | 1,975 °C | 50 W/(m·K) | no data | no data | no data |
| Magnesia-stabilised zirconiastructural ceramic | 4 to 5.74 g/cm³ | no data | 2.2 to 27 W/(m·K) | 200 to 360 GPa | 450 to 1,040 MPa | 6.9 to 10.4 ppm/K |
| YSZstructural ceramic | 6.02 to 6.07 g/cm³ | no data | 2.2 to 3 W/(m·K) | 195 to 210 GPa | 1,000 to 1,240 MPa | 9 to 10.3 ppm/K |
What these materials are made of
Composition by weight, as printed in the sources for each grade (the first constituents listed).
| Material | Main constituents |
|---|---|
| Alumina (Al2O3) | Al 52.9% · O 47.1% |
| Beryllium oxide (BeO) | Be 36.0% · O 64.0% |
| Cobalt oxide | Co 78.6% · O 21.4% |
| Iron oxide | Fe 69.9% · O 30.1% |
| Lead zirconate titanate (PZT) | Pb 63.6% · Zr 14.6% · Ti 7.1% · O 14.7% |
| MgO | Mg 60.3% · O 39.7% |
| Niobium pentoxide (Nb2O5) | Nb 69.9% · O 30.1% |
| Pyrophyllite | Al 15.0% · Si 31.2% · O 53.3% · H 0.6% |
| SnO2, ITO | In2O3 90% · SnO2 10% |
Where they are used
| Use | Grades |
|---|---|
| Semiconductor process chambers, wafer handling, laser devices and power tubes (ground industrial use) | Alumina (Al2O3) |
| Heat, corrosion and wear resistant parts (ground industrial use) | Alumina (Al2O3) |
| Sheath insulator layers for a thermionic space power system (ground reactor test, not flown) | Alumina (Al2O3) |
| Dielectric in multilayer ceramic capacitors (MLCCs) | Barium titanate (BaTiO3) |
| Lead-free piezoelectric ceramic element | Barium titanate (BaTiO3) |
| Aerospace electronics | Beryllium oxide (BeO) |
| Microwave devices, vacuum tubes, gas lasers and magnetrons | Beryllium oxide (BeO) |
| Heat sinks and spreaders for CPUs, lasers and power amplifiers | Beryllium oxide (BeO) |
| Microwave dielectric resonator ceramic | Calcium titanate (CaTiO3) |
| Microwave absorber (reported application) | Calcium titanate (CaTiO3) |
| Furnace, boiler and heater linings | RCF |
| Reusable spaceplane insulation development (Hermes) | RCF |
| Dryers and industrial furnaces, with calcium silicate board | RCF |
| Solar-cell cover glass made from ceria-doped Micro-Sheet (NASA ground study of radiation effects) | Cerium(IV) oxide (CeO2) |
| Commercial cerium-doped solar cell cover glass (SCHOTT) | Cerium(IV) oxide (CeO2) |
| Lithium-ion anode in laboratory cells (research) | Cobalt oxide |
When each grade fits
| Material | Best for | Weakest at |
|---|---|---|
| Alumina (Al2O3) | Hard, stiff, electrically insulating parts that must stay stable at high temperature (CoorsTek chart: AD-995 volume resistivity above 10^14 ohm-cm at 25 °C) | Brittle fracture and sudden temperature change (fracture toughness 4 to 5 MPa·m½ for AD-995; thermal shock temperature difference of 200 °C for Kyocera's 99% grade) |
| Barium titanate (BaTiO3) | Capacitor dielectrics and lead-free piezoelectric ceramics where operation stays well below the Curie point of about 125 to 132 °C | Temperature range: the ferroelectric response is lost above about 125 to 132 °C, and a reactively sintered ceramic reached only about 85% relative density in the 2015 study |
| Beryllium oxide (BeO) | Heat spreaders and packages that must move a lot of heat while staying electrically insulating, where the beryllium dust hazard can be controlled | Health: beryllium dust, fume and mist are toxic and carcinogenic by inhalation. Mechanical strength is lower than alumina according to the American Beryllia page |
| Calcium titanate (CaTiO3) | Microwave dielectric resonator ceramics, usually in composites with a material that offsets its large temperature coefficient | Large positive temperature coefficient of resonant frequency (796.69 ppm/°C in the 2022 sintered ceramic), and preferential leaching of the perovskite phase in strong acid |
| RCF | Furnace, kiln and boiler linings that need a light, low-conductivity blanket up to about 1180 °C in continuous use. | Respirable fibre dust, which is classified as a carcinogen by inhalation, and crystallisation to cristobalite after heating above about 1300 °C, which embrittles the fibre. |
| Cerium(IV) oxide (CeO2) | Radiation-resistant and UV-absorbing cover glass (NASA reports on 1.5 percent ceria-doped Micro-Sheet; SCHOTT describes a cerium-doped cover glass) | Hazard classification in the NITE entry (H371 and H372, lung effects from repeated exposure, signal word Danger), and no space-flight record for pure CeO2 |
| Cobalt oxide | Lithium-ion anode research on Co3O4, where the theoretical capacity (890 mAh/g) is more than twice that of graphite | Supply is concentrated. Congo (Kinshasa) mined an estimated 73% of world cobalt in 2025 (USGS), and cobalt is on the USGS 2025 critical-minerals list |
| Copper oxides (CuO, Cu2O) | Solar-absorbing copper oxide films and p-type oxide layers where the material is cheap and the dark or light colour of the film is acceptable | Heat and oxygen. Cu2O turns into CuO above about 250 °C in air or oxygen, which changes its band gap from 2.17 eV to 1.35 eV, and CuO dissolves in dilute acids. |
| Hafnium oxide (HfO2) | High-k dielectric films for transistors (dielectric constant 22 to 25 in a review table) and high-melting thermal barrier coatings for hot parts | Bulk mechanical data were not found in a source opened for this profile, and the space record is a ground simulation that cut the laser damage threshold by up to 46.80% for debris impact |
| Iron oxide | Cheap, corrosion-resistant magnets and power-transformer cores, and colour-stable pigments | Magnetic strength per volume, which is lower than NdFeB or SmCo magnets, and brittleness of sintered ferrite parts |
| LSM | Solid oxide fuel cell cathode work, where Wikipedia says the thermal expansion is well matched to yttria-stabilized zirconia | The sources read here give no measured electrical conductivity, thermal expansion coefficient or melting point. The Curie range is a Wikipedia figure, not a single measurement. |
| Lead zirconate titanate (PZT) | Transducers and actuators that need a large piezoelectric response well below the Curie point, where lead content is acceptable | Lead content: the supplier SDS classes the powder as a reproductive toxicant, and PI limits operation to 50 % of the Curie temperature |
| MgO | Electrically insulating, heat-conducting filler and sheath for heaters and mineral-insulated cable, from the Morgan Luminex 998 grade (crushable, bulk density 2.20 to 2.49 g/cm3) | Strength and moisture: the crushable grades have a flexural strength of 7 to 71 MPa (Luminex 998, 3-point), and the powder is hygroscopic and reacts with strong acids (ICSC 0504) |
| Nickel oxide (NiO) | p-type transparent conducting films and nickel-based solid oxide fuel cell anode work, under strict dust and inhalation controls | Low conductivity in sputtered films (7.2 to 9.09 S/cm) and a carcinogen hazard (H350, with IARC Group 1 for nickel compounds) |
| Niobium pentoxide (Nb2O5) | Fast-charging lithium-ion anodes where high rate matters more than energy per gram (modified T-Nb2O5), and UV-stable oxide optical films (Ta2O5) | Low electronic conductivity in pristine T-Nb2O5, which the anode paper says needed doping and coating; the powder is an irritant and no corrosion rate is given in the supplier SDS |
| Pyrophyllite | Blanks that must be cut to shape before firing, and pressure gaskets in high-pressure laboratory presses | Dust from machining (commercial grades can contain respirable crystalline silica) and batch-to-batch variation in a natural mineral |
| Ln2O3 | Dense, high-melting oxide ceramics for optical and laser research; lutetia has the highest melting point and density in the sourced data (Tohoku paper, 2510 °C and 9.5 g/cm3) | Sourced data are thin for most members. Each oxide has about one PubChem density and melting value, several have no crystal-structure or thermal-conductivity figure, and no plasma or space record was read. |
| Silicon monoxide (SiO) | Thin SiO films for optical coatings, and a high-capacity lithium-ion anode where cycle life can be traded (the review describes the capacity; cycle life is the open problem) | Volume change and first-cycle lithium loss in an anode (about 200% volume change, low initial Coulombic efficiency); the space test covers a SiOx coating, not bulk SiO |
| Steatite (MgO-SiO2) | Low-cost electrical insulators and heater supports that must not burn and must hold their shape to about 930 °C (Farnell glazed standoff rating) | Shear and torsion loads, and sudden changes in temperature; steatite is weak in shear, as are glass-type materials (RIKO and Farnell sheet) |
| SnO2, ITO | Transparent conductive ITO films for displays and thin-film solar cells, and SnO2 as the active layer in gas sensors | Indium supply for ITO: China produced 70% of world indium, and USGS reports new Chinese export restrictions on indium from February 2025 |
| Titanium dioxide (TiO2) | White, stable thermal-control coatings that keep their emittance in vacuum up to 550 K (NASA Lewis test of a TiO2 paint and tape) | Suspected carcinogen when inhaled as powder (H351, IARC Group 2B), and its photocatalysis needs ultraviolet light, which current reactors make with mercury lamps |
| Tungsten trioxide (WO3) | Electrochromic films that switch in seconds, and resistive gas sensors for NO2 and NH3 at ppb levels (laboratory results) | Cycling stability and humidity tolerance: a bare WO3 film lost about 25% of its optical transparency over cycling in one study, and the sensor review lists humidity tolerance as a limit |
| Vanadium pentoxide (V2O5) | Lab-scale thermometer films for uncooled infrared sensors, and as a vanadium source for flow batteries and catalysts | Toxicity. Fatal if inhaled (H330) and toxic if swallowed (H301) in the aggregated EU classification, with an occupational limit of 0.05 mg/m3 as V |
| Yttrium oxide (Y2O3) | Plasma-resistant and infrared-transparent ceramic parts (Konoshima lists viewing windows and plasma-resistant use; CoorsTek describes exceptional plasma resistance) | Brittle fracture (fracture toughness 2.5 MPa·m½ in Konoshima's data) and air sensitivity of the powder (the supplier SDS calls it hygroscopic) |
| Zinc oxide (ZnO) | Low-absorptance white thermal-control coating on spacecraft, where flight data show little change in solar absorptance over years when contamination is kept low | Silicone contamination, which raised the solar absorptance of a Z-93P coating from 0.16 to 0.23 in one flight test (POSA-I) |
| Magnesia-stabilised zirconia | Thermal-cycling tools and rollers (Morgan TS grade: 650 MPa, 15 MPa√m and 500 thermal shock) and light alumina-based substrates (ZTA) | Unstabilised zirconia cracks on cooling through 1170 °C; ATZ loses 9.9 to 16.2 per cent strength in hot autoclave ageing; strength falls with temperature (Morgan TS grade: 650 MPa at 20 °C, 360 MPa at 820 °C) |
| YSZ | Strong, tough wear parts and cutting edges that stay cool and dry (CoorsTek sintered YTZP: 1240 MPa and 13 MPa√m) | Hot water or steam: about 12% strength loss after hydrothermal ageing in a cited study; thermal shock limits of 200 to 350 °C |
Materials
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