Amorphous Graphite C90
Grade
C90 = fixed carbon 88–92 %, beneficiated grade
Beneficiated grade for pencil leads, lubricant/conductive fillers and carbon brushes where lower ash is required.
Values for the C90 condition
Other Amorphous Graphite tempers and conditions
Amorphous Graphite is listed in 4 conditions; see the grade overview at Amorphous Graphite.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Fixed carbon 70–80 %, run-of-mine / low grade | Cheapest grade for foundry coatings, refractory ramming mixes and low-spec carbon raising where ash is tolerated. | — | 4 | 0.15 | 25 HV | 10 W/m·K |
C85Default Fixed carbon 80–85 %, standard commercial grade | Default workhorse grade: steel/iron carbon raiser, refractory and friction-material filler at lowest cost per unit carbon. | — | 5 | 0.2 | 15 HV | 20 W/m·K |
C90This page Fixed carbon 88–92 %, beneficiated grade | Beneficiated grade for pencil leads, lubricant/conductive fillers and carbon brushes where lower ash is required. | — | 6 | 0.2 | 12 HV | 30 W/m·K |
Fixed carbon ≥94 %, chemically purified | Acid/alkali-purified high-carbon grade for battery, conductive-coating and high-grade refractory use where ash must be minimal. | — | 7 | 0.25 | 10 HV | 40 W/m·K |
What is Amorphous Graphite C90?
Amorphous Graphite C90 is Amorphous Graphite in the C90 grade — beneficiated grade for pencil leads, lubricant/conductive fillers and carbon brushes where lower ash is required. Amorphous Graphite C90 has a tensile strength of 6 MPa (0.87 ksi), weaker than 95% of ceramic grades. Elongation at break is 0.2% and the elastic modulus is 8 GPa (1.16 Msi). Amorphous Graphite C90 has a density of 2.22 g/cm³ (0.0802 lb/in³), lighter than 87% of ceramic grades. It melts at 3,650°C (6,602 °F). C85 is the default condition FabDigit quotes; C90 is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.2 kg CO₂/kg, better than 99% of ceramic grades
- Easy to machine — 92/100, better than 97% of ceramic grades
- Lightweight — 2.22 g/cm³ (0.0802 lb/in³), better than 87% of ceramic grades
- Ductile — tolerates forming and impact — 0.2%, better than 81% of ceramic grades
- Good corrosion resistance — 88/100, better than 77% of ceramic grades
Limitations
- Low fracture toughness — 0.85 MPa·√m (0.774 ksi·√in), worse than 98% of ceramic grades
- Low stiffness — 8 GPa (1.16 Msi), worse than 96% of ceramic grades
Amorphous Graphite C90 properties
Typical room-temperature values for Amorphous Graphite C90; 15 are specific to this condition. Other listed values are Amorphous Graphite reference data and may not represent this condition. Bars are the position among ceramic grades.
Physical2
Amorphous Graphite C90 has a density of 2.22 g/cm³ (0.0802 lb/in³), lighter than 87% of ceramic grades. It melts at 3,650°C (6,602 °F).
Mechanical9
Amorphous Graphite C90 has a tensile strength of 6 MPa (0.87 ksi), weaker than 95% of ceramic grades. Elongation at break is 0.2% and the elastic modulus is 8 GPa (1.16 Msi).
Thermal5
Amorphous Graphite C90 is rated for continuous service to 470°C (878 °F). It conducts heat at 30 W/m·K (17.3 BTU/hr·ft·°F), better than 60% of ceramic grades. Thermal expansion is 5.5 µm/m·K (3.06 µin/in·°F).
Electrical2
Amorphous Graphite C90 has an electrical resistivity of 5×10⁻⁴ Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (88/100), better than 77% of ceramic grades.
Sustainability4
Producing a kilogram of Amorphous Graphite C90 takes about 15 MJ of energy and emits 1.2 kg of CO₂ — less than 99% of ceramic grades. Typical recycled content is 0%.
Manufacturability1
Amorphous Graphite C90's machinability is excellent (92/100, better than 97% of ceramic grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Amorphous Graphite C90
Is Amorphous Graphite easy to machine?
Supplied as powder, not machined; pressed/binder-bonded shapes cut easily but produce abrasive, conductive dust requiring extraction.
Can Amorphous Graphite be welded?
Not weldable — joined only by carbonaceous cements or resin/pitch binders in bonded articles.
Can Amorphous Graphite be formed, bent or molded?
Compacted, extruded or isostatically pressed with clay, pitch or resin binder; fine particle size aids packing but low crystallinity gives weak green bodies.
What surface finishes work on Amorphous Graphite?
Used as-milled to specified mesh (typically 200–800 mesh); surface treatment limited to drying, air classification or acid/alkali purification.
Amorphous Graphite chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Cfixed carbon, default C85 grade | 80 – 85 | 83 |
| volatile matter | 0.5 – 2.5 | 1.5 |
| moisture | 0 – 1 | 0.5 |
| Simportant for carbon-raiser use | 0 – 0.3 | 0.1 |
| ash (SiO2+Al2O3+Fe2O3)mainly silicate gangue | ≥ 12 (balance) | — |
Amorphous Graphite C90 — frequently asked
What is Amorphous Graphite C90 used for?
Amorphous Graphite C90 is typically used for foundry carbon raiser, lubricant filler, brake linings and pencil lead. In short: lowest-cost natural graphite; low crystallinity, low conductivity; bulk carbon-raiser powder.
What is the tensile strength of Amorphous Graphite C90?
Amorphous Graphite C90 has a typical tensile strength of 6 MPa (0.87 ksi) — weaker than 95% of ceramic grades. Strength varies by condition: see the 4 listed tempers.
Is Amorphous Graphite C90 easy to machine?
Yes — machinability is rated excellent (92/100, better than 97% of ceramic grades). Supplied as powder, not machined; pressed/binder-bonded shapes cut easily but produce abrasive, conductive dust requiring extraction.
Can Amorphous Graphite C90 be welded?
Not weldable — joined only by carbonaceous cements or resin/pitch binders in bonded articles.
What surface finishes work on Amorphous Graphite C90?
Used as-milled to specified mesh (typically 200–800 mesh); surface treatment limited to drying, air classification or acid/alkali purification.
Can Amorphous Graphite C90 be formed, bent or molded?
Compacted, extruded or isostatically pressed with clay, pitch or resin binder; fine particle size aids packing but low crystallinity gives weak green bodies.
What is the maximum service temperature of Amorphous Graphite C90?
Amorphous Graphite C90 is rated for continuous use to about 470°C (878 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- GB/T 3519 (Microcrystalline graphite) — SAC (2008)
- Industrial Minerals & Rocks — Graphite — SME (2006)
- ASM Handbook, Engineered Materials — Carbon and Graphite — ASM International (1991)
- Mineral Commodity Summaries — Graphite (Natural) — USGS (2024)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.