spore: profile
id: epo-tek-h20e
spore_version: 0.2
family: conductive-epoxy
name: EPO-TEK H20E silver-filled conductive epoxy
abbreviation: H20E
role: Two-part silver-filled epoxy for electrically and thermally conductive die attach
category: electronics
type: solders
summary: |
  EPO-TEK H20E is a two-component, 100 % solids silver-filled epoxy made by Epoxy Technology. Its datasheet (Rev. XIX, August 2024) gives a volume resistivity of 0.0004 Ohm-cm or less at 23 °C and a thermal conductivity of 2.5 W/mK by laser flash. The datasheet calls it a NASA approved low outgassing adhesive, but no outgassing number was found in any source we hold.
best_for: 'Die attach where a conductive, solder-free joint is needed: volume resistivity of 0.0004 Ohm-cm or less and 2.5 W/mK by laser flash, cured at 150 °C for 1 hour'
weakest_at: 'Heat flow compared with solder: junction-to-case thermal resistance of 6.7 to 7.0 °C/W against 4.0 to 5.0 °C/W for solder in the datasheet TO-18 test, and no outgassing value found'
identity:
  formula: 'Two-part 100 % solids silver-filled epoxy: silver powder (at least 60 % of Part A by weight) in an epoxy phenol novolac resin (30 to 60 % of Part A by weight), per the Part A SDS'
  source: epotek-tds-2024
  where: Title block and Product Description (two components, 100 % solids); SDS Part A Section 3.2 for composition
  designations:
    - system: Trade name
      code: EPO-TEK® H20E
      source: meridian-h20e-page
      where: Product page title
tags:
  environments: []
  stresses: []
  applications:
    - electronics-and-chips
    - thermal-control
    - optics-and-cameras
properties:
  - benchmark: electrical_resistivity
    label: Volume resistivity at 23 °C
    value: 0.0004
    bound: upper
    unit: Ohm-cm
    scope: material
    conditions:
      temperature: 23 °C
      cure: 150 °C / 1 hour
      test_basis: asterisked in the datasheet as a lot-acceptance test
    method: Printed as ≤ 0.0004 Ohm-cm; the datasheet marks the test as made on a lot-acceptance basis
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Electrical and Thermal Properties, Volume Resistivity row
  - benchmark: thermal_conductivity
    label: Thermal conductivity, laser flash
    value: 2.5
    unit: W/mK
    scope: material
    conditions:
      method_as_printed: Laser Flash
      cure: 150 °C / 1 hour
    method: Printed as 2.5 W/mK based on the standard method Laser Flash
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Electrical and Thermal Properties, first Thermal Conductivity row
  - benchmark: thermal_conductivity
    label: Thermal conductivity, from thermal resistance data
    value: 29
    unit: W/mK
    scope: material
    conditions:
      basis: derived from thermal resistance data with the printed formula R = L x K-1 x A-1
    method: Printed by the manufacturer as derived from thermal resistance data, not measured by laser flash; the datasheet does not reconcile it with the laser-flash value
    status: calculated
    note: 'Two thermal conductivities are printed for the same adhesive: 2.5 W/mK by laser flash and 29 W/mK from thermal resistance data. Use the laser-flash value for material comparisons.'
    source: epotek-tds-2024
    where: Typical Properties, Electrical and Thermal Properties, second Thermal Conductivity row
  - benchmark: thermal_resistance_junction_to_case
    label: Junction-to-case thermal resistance, H20E die attach
    value: 6.7
    value_high: 7
    bound: range
    unit: °C/W
    scope: cell
    conditions:
      package: TO-18 with nickel-gold metallised 20 x 20 mil chips
      bond_line: 2 mils thick
    method: Printed as 6.7 to 7.0 °C/W for EPO-TEK H20E in the TO-18 test
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Thermal Resistance (Junction to Case) row, H20E line
  - benchmark: thermal_resistance_junction_to_case
    label: Junction-to-case thermal resistance, solder die attach (comparison)
    value: 4
    value_high: 5
    bound: range
    unit: °C/W
    scope: cell
    conditions:
      package: TO-18 with nickel-gold metallised 20 x 20 mil chips
      attach: solder, type not printed
      bond_thickness: not printed for solder
    method: Printed as 4.0 to 5.0 °C/W for solder in the same TO-18 test
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Thermal Resistance (Junction to Case) row, Solder line
  - benchmark: glass_transition_temperature
    label: Glass transition temperature, dynamic test
    value: 80
    bound: lower
    unit: °C
    scope: material
    conditions:
      method_as_printed: Dynamic cure 20 to 200 °C, ISO 25 min; ramp -10 to 200 °C at 20 °C/min
      cure: 150 °C / 1 hour
    method: Printed as ≥ 80 °C; the datasheet marks the test as a lot-acceptance test
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Glass Transition Temp. (Tg) row
  - benchmark: cte
    label: Coefficient of thermal expansion, below Tg
    value: 31
    unit: 10^-6 in/in/°C
    scope: material
    conditions:
      region: below Tg
      cure: 150 °C / 1 hour
    method: Printed as 31 x 10-6 in/in/°C; the datasheet uses inch units, so no conversion was made
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Coefficient of Thermal Expansion, Below Tg row
  - benchmark: cte
    label: Coefficient of thermal expansion, above Tg
    value: 158
    unit: 10^-6 in/in/°C
    scope: material
    conditions:
      region: above Tg
      cure: 150 °C / 1 hour
    method: Printed as 158 x 10-6 in/in/°C; the datasheet uses inch units, so no conversion was made
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Coefficient of Thermal Expansion, Above Tg row
  - benchmark: shore_d_hardness
    label: Shore D hardness
    value: 75
    unit: Shore D
    scope: material
    conditions:
      cure: 150 °C / 1 hour
      test_temperature: not printed
    method: Typical value printed on the datasheet; test standard and temperature not printed
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Shore D Hardness row
  - benchmark: lap_shear_strength
    label: Lap shear strength at 23 °C
    value: 1475
    unit: psi
    scope: material
    conditions:
      temperature: 23 °C
      cure: 150 °C / 1 hour
    method: Typical value printed on the datasheet; test standard not printed
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Lap Shear @ 23°C row
  - benchmark: die_shear_strength
    label: Die shear strength at 23 °C, 2024 revision (psi)
    value: 3556
    bound: lower
    unit: psi
    scope: material
    conditions:
      temperature: 23 °C
      revision: Rev. XIX, August 2024
    method: Printed as ≥ 10 Kg / 3,556 psi in the 2024 datasheet
    status: ground
    note: The 2010 copy prints a lower figure, > 5 Kg / 1,700 psi. The two revisions disagree and the datasheet gives no reason.
    source: epotek-tds-2024
    where: Typical Properties, Die Shear @ 23°C row
  - benchmark: die_shear_strength
    label: Die shear strength at 23 °C, 2024 revision (kg)
    value: 10
    bound: lower
    unit: kg
    scope: material
    conditions:
      temperature: 23 °C
      revision: Rev. XIX, August 2024
    method: Printed as ≥ 10 Kg in the same row as the psi figure
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Die Shear @ 23°C row
  - benchmark: die_shear_strength
    label: Die shear strength at 23 °C, 2010 copy
    value: 1700
    bound: lower
    unit: psi
    scope: material
    conditions:
      temperature: 23 °C
      revision: Rev. XI, February 2010 copy
    method: Printed as > 5 Kg / 1,700 psi in the 2010 copy
    status: ground
    note: Lower than the 2024 figure of 3,556 psi; the revisions disagree and the datasheet gives no reason.
    source: tedpella-tn16014
    where: Typical Properties, Die Shear Strength @ 23 °C row
  - benchmark: degradation_temperature
    label: Degradation temperature by TGA
    value: 425
    unit: °C
    scope: material
    conditions:
      method_as_printed: TGA
      cure: 150 °C / 1 hour
    method: Printed as Degradation Temp. (TGA) 425 °C
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Degradation Temp. (TGA) row
  - benchmark: weight_loss
    label: Weight loss at 200 °C
    value: 0.59
    unit: '%'
    scope: material
    conditions:
      temperature: 200 °C
      hold_time: not printed
    method: Printed as 0.59 % weight loss at 200 °C; hold time and atmosphere not printed
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Weight Loss, @ 200°C row
  - benchmark: weight_loss
    label: Weight loss at 250 °C
    value: 1.09
    unit: '%'
    scope: material
    conditions:
      temperature: 250 °C
      hold_time: not printed
    method: Printed as 1.09 % weight loss at 250 °C; hold time and atmosphere not printed
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Weight Loss, @ 250°C row
  - benchmark: weight_loss
    label: Weight loss at 300 °C
    value: 1.67
    unit: '%'
    scope: material
    conditions:
      temperature: 300 °C
      hold_time: not printed
    method: Printed as 1.67 % weight loss at 300 °C; hold time and atmosphere not printed
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Weight Loss, @ 300°C row
  - benchmark: max_service_temp
    label: Suggested operating temperature, intermittent (2024 datasheet)
    value: 300
    bound: upper
    unit: °C
    scope: material
    conditions:
      use: intermittent
    method: Printed as < 300 °C (Intermittent); the datasheet says the data are a guide and not a specification
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Suggested Operating Temperature row
  - benchmark: max_service_temp
    label: Operating temperature, continuous (2010 copy)
    value: 200
    bound: upper
    unit: °C
    scope: material
    conditions:
      use: continuous
    method: Printed as Continuous -55 to 200 °C in the 2010 copy; the 2024 datasheet prints no continuous limit
    status: ground
    source: tedpella-tn16014
    where: Typical Properties, Operating Temp row
  - benchmark: min_service_temp
    label: Minimum operating temperature (2010 copy)
    value: -55
    bound: lower
    unit: °C
    scope: material
    conditions:
      use: continuous and intermittent
    method: Printed as -55 °C for both continuous and intermittent operation in the 2010 copy
    status: ground
    source: tedpella-tn16014
    where: Typical Properties, Operating Temp row
  - benchmark: storage_modulus
    label: Storage modulus at 23 °C
    value: 808700
    unit: psi
    scope: material
    conditions:
      temperature: 23 °C
    method: Printed as 808,700 psi; a dynamic storage modulus, not the elastic (Young's) modulus
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Storage Modulus @ 23°C row
  - benchmark: viscosity
    label: Viscosity at 100 rpm and 23 °C
    value: 2200
    value_high: 3200
    bound: range
    unit: cPs
    scope: material
    conditions:
      speed: 100 rpm
      temperature: 23 °C
      state: before cure
    method: Printed as 2,200 to 3,200 cPs; the datasheet marks it as a lot-acceptance test
    status: ground
    source: epotek-tds-2024
    where: Physical Properties, Viscosity (23°C) @ 100 rpm row
  - benchmark: thixotropic_index
    label: Thixotropic index
    value: 4.6
    unit: '-'
    scope: material
    conditions:
      speed: not printed
    method: Printed as 4.6 in the 2024 datasheet; the 2010 copy prints 4.63
    status: ground
    source: epotek-tds-2024
    where: Physical Properties, Thixotropic Index row
  - benchmark: particle_size
    label: Maximum particle size of the filled product
    value: 45
    bound: upper
    unit: microns
    scope: material
    conditions:
      basis: maximum, as printed
    method: Printed as ≤ 45 microns; the datasheet marks it as a lot-acceptance test
    status: ground
    source: epotek-tds-2024
    where: Physical Properties, Particle Size row
  - benchmark: pot_life
    label: Pot life after mixing
    value: 2.5
    unit: days
    scope: material
    conditions:
      mix: Part A and Part B 1:1 by weight
      temperature: not printed
    method: Printed as 2.5 Days in the header table
    status: ground
    source: epotek-tds-2024
    where: Header table, Pot Life row
  - benchmark: specific_gravity
    label: Specific gravity, Part A
    value: 2.03
    unit: '-'
    scope: material
    conditions:
      part: Part A
      temperature: not printed
    method: Printed in the header table; temperature not printed
    status: ground
    source: epotek-tds-2024
    where: Header table, Specific Gravity, Part A row
  - benchmark: specific_gravity
    label: Specific gravity, Part B
    value: 3.07
    unit: '-'
    scope: material
    conditions:
      part: Part B
      temperature: not printed
    method: Printed in the header table; temperature not printed
    status: ground
    source: epotek-tds-2024
    where: Header table, Specific Gravity, Part B row
  - benchmark: specific_gravity
    label: Specific gravity, frozen syringe
    value: 2.67
    unit: '-'
    scope: material
    conditions:
      form: single-component frozen syringe
      temperature: not printed
    method: Printed in the header table as Syringe 2.67; temperature not printed
    status: ground
    source: epotek-tds-2024
    where: Header table, Specific Gravity, Syringe row
  - benchmark: chloride_ion_content
    label: Chloride ion content
    value: 73
    unit: ppm
    scope: material
    conditions:
      basis: as printed; test method and cure state not stated
    method: Printed in the Ion Content row; test method not printed
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Ion Content, Cl- row
  - benchmark: sodium_ion_content
    label: Sodium ion content
    value: 2
    unit: ppm
    scope: material
    conditions:
      basis: as printed; test method and cure state not stated
    method: Printed in the Ion Content row; test method not printed
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Ion Content, Na+ row
  - benchmark: ammonium_ion_content
    label: Ammonium ion content
    value: 98
    unit: ppm
    scope: material
    conditions:
      basis: as printed; test method and cure state not stated
    method: Printed in the Ion Content row; test method not printed
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Ion Content, NH4+ row
  - benchmark: potassium_ion_content
    label: Potassium ion content
    value: 3
    unit: ppm
    scope: material
    conditions:
      basis: as printed; test method and cure state not stated
    method: Printed in the Ion Content row; test method not printed
    status: ground
    source: epotek-tds-2024
    where: Typical Properties, Ion Content, K+ row
corrosion:
  - environment: Heating of the cured adhesive (thermal ageing)
    headline: The cured adhesive loses 0.59 % of its weight at 200 °C and 1.67 % at 300 °C, per the datasheet TGA weight-loss rows.
    effect: Epoxy Technology prints weight loss at 200, 250 and 300 °C and a degradation temperature of 425 °C. The datasheet gives no hold times, atmosphere or post-heat test results, so these figures are not a service-life or ageing result.
    rating: low
    conditions:
      basis: manufacturer weight-loss figures; hold time and atmosphere not printed
      cure: 150 °C / 1 hour
    source: epotek-tds-2024
    where: Typical Properties, Weight Loss and Degradation Temp. (TGA) rows
  - environment: Ionic residue in the cured adhesive (chloride and ammonium)
    headline: The datasheet prints 73 ppm chloride and 98 ppm ammonium in the adhesive.
    effect: These are the only corrosion-related numbers printed. The datasheet gives no test method, no limit, and no test against metal pads, so the corrosion effect of these ions is not quantified here.
    rating: low
    conditions:
      basis: Ion Content row only; no corrosion test printed
    source: epotek-tds-2024
    where: Typical Properties, Ion Content row
risks:
  hazards:
    - text: 'Part A SDS (GHS US, revision 1/30/2023): skin irritation (H315), may cause an allergic skin reaction (H317), very toxic to aquatic life (H400) and very toxic to aquatic life with long lasting effects (H410). Signal word Warning.'
      ghs:
        - H315
        - H317
        - H400
        - H410
      source: epotek-h20e-sds-partA
      where: Sections 2.1 and 2.2
    - text: Frozen syringe SDS (revision 1/26/2023) adds harmful if swallowed (H302) and causes serious eye damage (H318). Its trade-secret ingredients are a reactive diluent (H302, H318, H336) and a substituted imidazole (H301, H315, H318, H335), each at 1 to 5 %.
      ghs:
        - H301
        - H302
        - H315
        - H317
        - H318
        - H335
        - H336
        - H400
        - H410
      source: epotek-h20e-sds-syringe
      where: Sections 2.1, 2.2 and 3.2
    - text: 'Part A SDS: harmful dust may be released during cutting, milling or grinding of the product. Silver is at least 60 % of Part A by weight (CAS 7440-22-4).'
      ghs: []
      source: epotek-h20e-sds-partA
      where: Section 2.3 and Section 3.2
    - text: PubChem record for bulk silver (CID 23954) lists H400 and H410 from ECHA C&L Inventory aggregated notifications, and lists H361f and H373 under Regulation (EC) No 1272/2008 for silver massive (particle diameter 1 mm or larger). The page states the sources differ. These entries describe bulk silver, not the silver flake in H20E; the Part A SDS above is the product-level source.
      ghs:
        - H400
        - H410
        - H361f
        - H373
      source: pubchem-silver-ghs
      where: GHS Classification section, ECHA C&L Inventory and Regulation (EC) No 1272/2008 entries
    - text: The Epoxy Technology Part A material safety data sheet issued 11/20/96, which is older than the 2023 Part A SDS, lists silver flake at 60 % by weight with CAS 7440-22-4. It gives HMIS ratings of HEALTH 2, FIRE 1 and REACTIVITY 1, which the manufacturer says are estimated.
      ghs: []
      source: epotek-msds-1996
      where: Section II, Hazardous Ingredients; HMIS and ANSI rating lines
  failure_risks:
    - mode: Higher thermal resistance than solder in the die attach
      trigger: Junction-to-case thermal test on TO-18 packages with 20 x 20 mil chips and a 2 mil bond line
      consequence: EPO-TEK H20E measures 6.7 to 7.0 °C/W against 4.0 to 5.0 °C/W for solder in the same test, so the adhesive joint gives a larger temperature rise per watt.
      severity: moderate
      source: epotek-tds-2024
      where: Typical Properties, Thermal Resistance (Junction to Case) rows
    - mode: Performance change after repackaging
      trigger: The material is moved into syringes, bi-paks, cartridges, pouches or other containers
      consequence: The manufacturer says performance may differ from the datasheet and its warranty does not apply to repackaged product.
      severity: low
      source: epotek-tds-2024
      where: Notes at the top of the datasheet
    - mode: Uneven filler and non-uniform properties
      trigger: Filled material not stirred thoroughly before mixing or use
      consequence: The datasheet says filled systems should be stirred thoroughly before mixing and before use; the effect on conductivity is not quantified in the sources read.
      severity: low
      source: epotek-tds-2024
      where: Notes at the top of the datasheet
  side_effects:
    - text: Weight loss on heating (0.59 % at 200 °C) means volatile material leaves the cured adhesive. The datasheet does not name the volatiles or measure outgassing.
      affects: Nearby optics, sensors or contacts in a vacuum (not tested in the sources read)
      source: epotek-tds-2024
      where: Typical Properties, Weight Loss rows
  handling:
    - text: Mix Part A and Part B 1:1 by weight and use within the 2.5 day pot life.
      source: epotek-tds-2024
      where: Header table, Mix Ratio and Pot Life rows
    - text: Shelf life is one year at room temperature for the bulk product and one year at -40 °C for the frozen syringe.
      source: epotek-tds-2024
      where: Header table, Shelf Life rows
    - text: Wear suitable gloves (neoprene, nitrile or butyl rubber), safety glasses and protective clothing; ensure good ventilation and avoid breathing dust.
      source: epotek-h20e-sds-partA
      where: Sections 7.1 and 8.2 to 8.3
    - text: Stir filled material thoroughly before mixing and before use, and keep containers closed when not in use.
      source: epotek-tds-2024
      where: Notes at the top of the datasheet
    - text: Do not repackage the material into other containers without accepting that the manufacturer's warranty does not apply.
      source: epotek-tds-2024
      where: Notes at the top of the datasheet
  mitigations:
    - text: Cure at the recommended 150 °C for 1 hour. The datasheet warns that minimum alternative cures may not achieve the performance properties.
      source: epotek-tds-2024
      where: Header table, Recommended Cure and Minimum Alternative Cure(s)
uses:
  - application: electronics-and-chips
    device: Semiconductor die attach to lead frames
    example: Die-attaching chips to lead frames; compatible with Si and MEMS chips, 260 °C lead-free reflow and JEDEC Level I packaging requirements.
    source: epotek-tds-2024
    where: Suggested Applications, Semiconductor IC Packaging
  - application: thermal-control
    device: Thermal management in microelectronic packages
    example: Used extensively for thermal management applications due to its high thermal conductivity, which the datasheet quotes as 2.5 W/mK by laser flash.
    source: epotek-tds-2024
    where: Product Description
  - application: electronics-and-chips
    device: Hybrid microelectronics with GaAs chips for radar
    example: Used with GaAs chips for microwave and radar applications up to 77 GHz; a comparable alternative to solder and eutectic die attach, very commonly no more than 1-2 °C/watt difference in thermal resistance.
    source: epotek-tds-2024
    where: Suggested Applications, Hybrid Micro-electronics
  - application: optics-and-cameras
    device: IR-detector and LED die attach for optoelectronics
    example: Die-attaching IR-detector chips onto PCBs or TO-can style headers, and die-attaching LED chips to substrates; adhesion to Ag, Au and Cu plated lead frames and PCBs.
    source: epotek-tds-2024
    where: Suggested Applications, Opto-Electronic Packaging Applications
  - application: electronics-and-chips
    device: Electronics where outgassing is limited (datasheet claim)
    example: The datasheet lists it as a NASA approved low outgassing adhesive; no outgassing value (TML, CVCM or ASTM E595 result) was found in the sources we hold.
    source: epotek-tds-2024
    where: Suggested Applications, Hybrid Micro-electronics, NASA approved bullet
supply:
  - subject: Silver (main filler)
    demand: In 2025 about 25 % of estimated US silver use went to electrical and electronics, and about 3 % to brazing and solder (USGS).
    producers:
      - country: Mexico
        share_percent: 24.2
        year: 2025
      - country: Peru
        share_percent: 13.8
        year: 2025
      - country: China
        share_percent: 13.1
        year: 2025
      - country: Chile
        share_percent: 5.4
        year: 2025
    critical_lists:
      - list: USGS 2025 Final List of Critical Minerals (silver added in 2025)
        listed: true
    recycling: 'USGS: about 1,000 tons of silver was recovered from new and old scrap in 2025 in the US, about 11 % of apparent consumption.'
    substitutes:
      - 'USGS: stainless steel, tantalum and titanium may replace silver in surgical pins and plates, and nonsilver batteries may replace silver batteries in some applications. No substitute for silver in conductive epoxy is named in the text read.'
    source: usgs-mcs2026-silver
    where: Domestic Production and Use; World Mine Production and Reserves table, 2025e (world total 26,000 t; country shares calculated by Space Mushroom from tonnages); Recycling; Substitutes; Critical minerals paragraph
documents:
  - title: EPO-TEK H20E Technical Data Sheet, Rev. XIX (August 2024), copy on UCSB Protowiki
    type: datasheet
    url: https://protowiki.oasis.ucsb.edu/images/d/d1/H20E_EPOTEK.pdf
    year: 2024
  - title: EPO-TEK H20E Technical Data Sheet, Rev. XI (February 2010), Ted Pella technote 16014
    type: datasheet
    url: https://www.tedpella.com/technote_html/16014%20TN.pdf
    year: 2010
  - title: EPO-TEK H20E PART A Safety Data Sheet, revision 1/30/2023, version 2.0
    type: sds
    url: https://products.meridianadhesives.com/storage/downloads/iloirhohcbjiie5mr06wik5ayj0uwpnr/h20e-sds.pdf
    year: 2023
  - title: EPO-TEK H20E PMF SYRINGE Safety Data Sheet, revision 1/26/2023, version 2.0
    type: sds
    url: https://products.meridianadhesives.com/storage/downloads/9lssjbek3koy3xueumgabqjinafza2ea/h20e-pmf-syringe.pdf
    year: 2023
  - title: USGS Mineral Commodity Summaries 2026, Silver
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silver.pdf
    year: 2026
  - title: PubChem compound record for silver (CID 23954), GHS Classification
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Silver
  - title: Epoxy Technology Part A Material Safety Data Sheet, issued 11/20/96 (older copy, University of Waterloo)
    type: sds
    url: https://uwaterloo.ca/giga-to-nanoelectronics-centre/sites/default/files/uploads/files/epo-tech_h20e.pdf
    year: 1996
gaps:
  - 'No outgassing value found: the datasheet states only ''NASA approved low outgassing adhesive''. The NASA outgassing database search page returned no H20E results when fetched, and a web search for a TML, CVCM or ASTM E595 figure could not be run in this session because the search limit was reached.'
  - The Meridian product page is recorded only for the product name. Its certification wording was read through a summary, not verbatim, so no certification text is quoted.
  - The Part B (hardener) safety data sheet was not read. Only the Part A SDS and the frozen-syringe SDS were read, so Part B hazard classes are not confirmed.
  - No space-environment data (vacuum, radiation, thermal cycling, flight heritage) was read in this run.
  - Dielectric constant and dielectric strength are not printed in the datasheets read.
  - Moisture absorption and humidity ageing are not printed in the datasheets read.
  - Adhesion or resistivity after thermal cycling is not printed in the datasheets read.
  - The 2010 and 2024 datasheets disagree on die shear, operating temperature and cure schedule. Both values are recorded side by side; the datasheets give no reason.
  - The 29 W/mK thermal conductivity is derived from thermal resistance data. The datasheet gives the formula but no measured inputs.
  - Silver supply shares are calculated by Space Mushroom from USGS 2025e mine production tonnages; USGS prints no shares for this table. The EU critical raw materials list was not checked for silver in this run.
  - Silver recycling and substitute text describes silver metal in general, not conductive epoxy.
  - No freely licensed photograph or diagram of H20E was fetched, so the media block is omitted.
  - 'Several property names are not in the canonical file and are used as snake_case names: thermal_resistance_junction_to_case, lap_shear_strength, die_shear_strength, shore_d_hardness, degradation_temperature, weight_loss, storage_modulus, thixotropic_index, particle_size, pot_life, specific_gravity, chloride_ion_content, sodium_ion_content, ammonium_ion_content, potassium_ion_content.'
license: CC-BY-4.0
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 32
  unreachable: 1
  caveats: 3
  note: Read by an AI assistant on 2026-11-01 from the pages named in each entry. The NASA outgassing database search page returned no H20E results. The Meridian product page was read through a summary. Two datasheet revisions (2024 and 2010) disagree on die shear, operating temperature and cure schedule; both values are recorded.
story:
  recipe:
    line: EPO-TEK H20E is a two-component, 100 % solids epoxy filled with silver powder. Part A and Part B are mixed 1:1 by weight. The product is also sold as a single-component frozen syringe. The datasheets do not give the process used to make the filler or the resin.
    parts:
      - name: Silver
        symbol: Ag
        share_note: at least 60 % of Part A by weight (SDS)
        role: Conductive filler. The datasheet gives a maximum particle size of 45 microns.
      - name: Epoxy phenol novolac resin
        share_note: 30 to 60 % of Part A by weight (SDS)
        role: The binder that holds the silver and cures into a solid. Part B is not characterised in the sources read.
  risk_groups:
    - title: For people
      level: 2
      verdict: Classed as a skin irritant and skin sensitiser in the Part…
      lead: Both SDSs read here classify the product as an irritant and a sensitiser, so gloves and eye protection apply. The syringe SDS lists two trade-secret ingredients that add eye and oral hazards.
      points:
        - label: Skin
          line: Part A causes skin irritation (H315) and may cause an allergic skin reaction (H317). The SDS names neoprene, nitrile or butyl rubber gloves.
        - label: Eyes
          line: The frozen-syringe SDS classes the product as causing serious eye damage (H318). Wear safety glasses.
        - label: Dust
          line: Harmful dust may be released during cutting, milling or grinding of the material. Avoid breathing the dust.
        - label: Environment
          line: Silver is very toxic to aquatic life (H400) and very toxic with long lasting effects (H410). Avoid release to the environment.
    - title: If a joint runs hot
      lead: This is a heat-flow limit rather than a hazard. In the datasheet TO-18 test the adhesive joint has a higher thermal resistance than solder.
      points:
        - label: Adhesive
          line: Junction-to-case thermal resistance is 6.7 to 7.0 °C/W for H20E in the TO-18 test, with 20 x 20 mil chips and a 2 mil bond line.
        - label: Solder
          line: The same test prints 4.0 to 5.0 °C/W for solder. A higher value means a larger temperature rise per watt.
  why: EPO-TEK H20E is a silver-filled two-part epoxy for attaching chips and making electrical connections in microelectronics. Its datasheet (Rev. XIX, August 2024) gives a volume resistivity of 0.0004 Ohm-cm or less at 23 °C and a thermal conductivity of 2.5 W/mK by laser flash. Engineers choose it where a conductive joint is needed without solder, and the datasheet calls it a NASA approved low outgassing adhesive.
  uses:
    - where: Semiconductor die attach
      line: The datasheet says the adhesive attaches chips to lead frames and is compatible with 260 °C lead-free reflow and JEDEC Level I packaging requirements. It can be snap-cured in line or cured in a box oven.
    - where: Thermal management
      line: The datasheet says it is used extensively for thermal management because of its high thermal conductivity, quoted as 2.5 W/mK by laser flash.
    - where: Hybrid microelectronics and radar
      line: The datasheet says it is used with GaAs chips for microwave and radar applications up to 77 GHz. It is described as a comparable alternative to solder and eutectic die attach, with no more than 1-2 °C/watt difference in thermal resistance in most cases.
    - where: Low-outgassing electronics
      line: The datasheet calls it a NASA approved low outgassing adhesive. No outgassing value (TML, CVCM or ASTM E595 result) was found in the sources we hold, so the claim is recorded without a number.
  can_do:
    - label: Conduct current
      benchmark: electrical_resistivity
      value: 0.0004 Ohm-cm or less
      line: Volume resistivity is 0.0004 Ohm-cm or less at 23 °C after a 150 °C, 1-hour cure, per the 2024 datasheet. The datasheet marks the figure as a lot-acceptance test.
    - label: Carry heat
      benchmark: thermal_conductivity
      value: 2.5 W/mK
      line: Thermal conductivity is 2.5 W/mK by laser flash. The same datasheet also prints 29 W/mK from thermal resistance data, and it does not reconcile the two values.
    - label: Hold a die
      benchmark: lap_shear_strength
      value: 1475 psi lap shear
      line: Lap shear is 1475 psi at 23 °C. Die shear is 3556 psi (at least 10 kg) in the 2024 datasheet, and 1700 psi in the 2010 copy.
    - label: Survive heat
      benchmark: glass_transition_temperature
      value: 80 °C or higher
      line: Glass transition is 80 °C or higher in the dynamic test. The datasheet prints a degradation temperature of 425 °C and a suggested intermittent operating limit of below 300 °C.
  compare: EPO-TEK H20E is an adhesive, not a solder, and the datasheet compares it with solder only for thermal resistance. In the TO-18 test it gives 6.7 to 7.0 °C/W against 4.0 to 5.0 °C/W for solder, so solder has the lower thermal resistance in that test. It is an electrical conductor at 0.0004 Ohm-cm or less, a figure the datasheet does not compare with any solder. For material comparisons, the 2.5 W/mK laser-flash conductivity is the value to use.
  compare_rows:
    - label: Volume resistivity
      benchmark: electrical_resistivity
    - label: Thermal conductivity
      benchmark: thermal_conductivity
    - label: Junction-to-case thermal resistance
      benchmark: thermal_resistance_junction_to_case
  handling:
    - Mix Part A and Part B 1:1 by weight and use within the 2.5 day pot life.
    - Store the bulk product at room temperature and the frozen syringe at -40 °C; both have a one-year shelf life.
    - Cure at 150 °C for 1 hour. The datasheet warns that minimum alternative cures may not reach the printed performance.
    - Stir filled material thoroughly before mixing and before use, and keep containers closed.
    - Wear gloves, safety glasses and protective clothing, and avoid breathing dust (Part A SDS).
    - Do not repackage the material without accepting that the manufacturer's warranty does not apply.
  good_for:
    - 'Electrical and thermal conduction in die attach: 0.0004 Ohm-cm or less and 2.5 W/mK by laser flash, per the 2024 datasheet.'
    - Solder-free attach with a 150 °C cure, compatible with 260 °C lead-free reflow according to the datasheet.
    - Hybrid and optoelectronic die attach, including IR detectors, LED dies and GaAs chips for radar up to 77 GHz.
  watch_out:
    - 'Thermal resistance is higher than solder in the TO-18 test: 6.7 to 7.0 °C/W against 4.0 to 5.0 °C/W.'
    - The two datasheet revisions disagree on die shear (3556 psi against 1700 psi) and on continuous operating temperature (200 °C in the 2010 copy only).
    - No outgassing value was found, so the NASA approval claim cannot be checked against a number in this profile.
    - The frozen-syringe SDS lists more hazards than the Part A SDS, including H302 and H318.
  verdict: EPO-TEK H20E is a silver-filled conductive die-attach epoxy with a volume resistivity of 0.0004 Ohm-cm or less and a thermal conductivity of 2.5 W/mK by laser flash, both from the 2024 datasheet. Its junction-to-case thermal resistance is higher than solder's in the datasheet test, and no outgassing value was found to back the NASA approval claim.
sources:
  epotek-tds-2024:
    title: EPO-TEK H20E Technical Data Sheet, Rev. XIX (August 2024)
    id: Epoxy Technology, Inc. EPO-TEK H20E TDS, Rev. XIX, August 2024
    url: https://protowiki.oasis.ucsb.edu/images/d/d1/H20E_EPOTEK.pdf
    year: 2024
    kind: datasheet
    license: manufacturer datasheet, cited not reproduced
  tedpella-tn16014:
    title: EPO-TEK H20E Technical Data Sheet, Rev. XI (February 2010), Ted Pella technote 16014
    id: Epoxy Technology, Inc. EPO-TEK H20E TDS, Rev. XI, February 2010 (copy)
    url: https://www.tedpella.com/technote_html/16014%20TN.pdf
    year: 2010
    kind: datasheet
    license: manufacturer datasheet copy, cited not reproduced
  meridian-h20e-page:
    title: EPO-TEK H20E product page, Meridian Adhesives
    id: Meridian Adhesives product page, accessed 2026-11-01
    url: https://meridianadhesives.com/products/epo-tek-h20e/
    kind: web
    license: distributor web page, linked not reproduced
  epotek-h20e-sds-partA:
    title: EPO-TEK H20E PART A Safety Data Sheet (version 2.0)
    id: Revision 1/30/2023; issue 3/2/2022; version 2.0
    url: https://products.meridianadhesives.com/storage/downloads/iloirhohcbjiie5mr06wik5ayj0uwpnr/h20e-sds.pdf
    year: 2023
    kind: datasheet
    license: supplier SDS, linked not reproduced
  epotek-h20e-sds-syringe:
    title: EPO-TEK H20E PMF SYRINGE Safety Data Sheet (version 2.0)
    id: Revision 1/26/2023; issue 3/2/2022; version 2.0
    url: https://products.meridianadhesives.com/storage/downloads/9lssjbek3koy3xueumgabqjinafza2ea/h20e-pmf-syringe.pdf
    year: 2023
    kind: datasheet
    license: supplier SDS, linked not reproduced
  usgs-mcs2026-silver:
    title: Mineral Commodity Summaries 2026, Silver
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silver.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  pubchem-silver-ghs:
    title: PubChem compound record for silver (CID 23954), GHS Classification
    id: PubChem CID 23954; CAS 7440-22-4
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Silver
    kind: database
    license: public database record, linked not reproduced
  epotek-msds-1996:
    title: Epoxy Technology Part A Material Safety Data Sheet, issued 11/20/96
    id: Epoxy Technology Inc., Billerica MA; date issued 11/20/96
    url: https://uwaterloo.ca/giga-to-nanoelectronics-centre/sites/default/files/uploads/files/epo-tech_h20e.pdf
    year: 1996
    kind: datasheet
    license: manufacturer SDS copy, linked not reproduced