Mg2SiO4 C-250
Grade · default condition
C-250 = dense forsterite
Choose for vacuum-tight metal/glass seals, microwave-tube and high-frequency insulators needing very low dielectric loss.
Values for the C-250 condition
Other Mg2SiO4 tempers and conditions
Mg2SiO4 is listed in 2 conditions; see the grade overview at Mg2SiO4.
- C-240
- C-250
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Porous forsterite | Choose for non-gas-tight, lower-cost insulating bodies, spacers and heater supports where open porosity and lower strength are acceptable. | — | 25 | — | 500 HV | 2 W/m·K |
C-250DefaultThis page Dense forsterite | Choose for vacuum-tight metal/glass seals, microwave-tube and high-frequency insulators needing very low dielectric loss. | — | 65 | — | 750 HV | 4 W/m·K |
What is Mg2SiO4 C-250?
Mg2SiO4 C-250 is Mg2SiO4 in the C-250 grade — choose for vacuum-tight metal/glass seals, microwave-tube and high-frequency insulators needing very low dielectric loss. Mg2SiO4 C-250 has a tensile strength of 65 MPa (9.43 ksi), weaker than 62% of ceramic grades. The elastic modulus is 130 GPa (18.9 Msi). Mg2SiO4 C-250 has a density of 2.85 g/cm³ (0.103 lb/in³), lighter than 79% of ceramic grades. It melts at 1,890°C (3,434 °F).
Advantages
- Low embodied carbon — 2.6 kg CO₂/kg, better than 90% of ceramic grades
- Lightweight — 2.85 g/cm³ (0.103 lb/in³), better than 79% of ceramic grades
Limitations
- Hard to polish — 60/100, worse than 79% of ceramic grades
Mg2SiO4 C-250 properties
Typical room-temperature values for Mg2SiO4 C-250; 16 are specific to this condition. Other listed values are Mg2SiO4 reference data and may not represent this condition. Bars are the position among ceramic grades.
Physical4
Mg2SiO4 C-250 has a density of 2.85 g/cm³ (0.103 lb/in³), lighter than 79% of ceramic grades. It melts at 1,890°C (3,434 °F).
Mechanical11
Mg2SiO4 C-250 has a tensile strength of 65 MPa (9.43 ksi), weaker than 62% of ceramic grades. The elastic modulus is 130 GPa (18.9 Msi).
Thermal5
Mg2SiO4 C-250 is rated for continuous service to 1,000°C (1,832 °F). It conducts heat at 3.5 W/m·K (2.02 BTU/hr·ft·°F), worse than 74% of ceramic grades. Thermal expansion is 9 µm/m·K (5 µin/in·°F).
Electrical5
Mg2SiO4 C-250 is an electrical insulator with a dielectric strength of 13 kV/mm (330.2 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental2
Corrosion resistance is very good (75/100), better than 50% of ceramic grades.
Sustainability4
Producing a kilogram of Mg2SiO4 C-250 takes about 32 MJ of energy and emits 2.6 kg of CO₂ — less than 91% of ceramic grades. Typical recycled content is 0%.
Manufacturability3
Mg2SiO4 C-250's machinability is not recommended (8/100, better than 69% of ceramic grades).
Common Calculations4
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Mg2SiO4 C-250
Is Mg2SiO4 easy to machine?
Machine in the green or bisque state; fired bodies require diamond grinding/lapping and chip easily at edges.
Can Mg2SiO4 be welded?
Not weldable — joined by active-metal brazing (Ti/Zr-containing filler) or Mo–Mn metallizing plus Ni plating and brazing for vacuum-tight seals.
Can Mg2SiO4 be formed, bent or molded?
Dry pressing, isostatic pressing, extrusion or slip casting of talc/magnesia batches, then firing at ~1300–1450 °C with tight kiln control to avoid periclase or protoenstatite phases.
What surface finishes work on Mg2SiO4?
Fired glazing improves surface resistivity and cleanability; metallized/plated pads used for brazing, otherwise lapped or diamond-polished.
Mg2SiO4 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 |
|---|---|---|
| MgOforsterite stoichiometry 57.3 wt% MgO | 50 – 58 | 55 |
| Al2O3from clay/talc raw materials | 0 – 3 | 1 |
| CaO+BaOsintering aid / glassy bond | 0 – 3 | 1 |
| Fe2O3impurity, kept low for low dielectric loss | 0 – 0.5 | 0.2 |
| SiO2forsterite stoichiometry 42.7 wt% SiO2 | ≥ 38 (balance) | — |
Mg2SiO4 C-250 — frequently asked
What is Mg2SiO4 C-250 used for?
Mg2SiO4 C-250 is typically used for vacuum tube seals, electrical insulators and high-frequency insulation parts. In short: CTE-matched sealing ceramic; forsterite silicate insulator; 1000 °C service limit.
What is the tensile strength of Mg2SiO4 C-250?
Mg2SiO4 C-250 has a typical tensile strength of 65 MPa (9.43 ksi) — weaker than 62% of ceramic grades. Strength varies by condition: see the 2 listed tempers.
Is Mg2SiO4 C-250 easy to machine?
Not especially — machinability is rated not recommended (8/100, better than 69% of ceramic grades). Machine in the green or bisque state; fired bodies require diamond grinding/lapping and chip easily at edges.
Can Mg2SiO4 C-250 be welded?
Not weldable — joined by active-metal brazing (Ti/Zr-containing filler) or Mo–Mn metallizing plus Ni plating and brazing for vacuum-tight seals.
What surface finishes work on Mg2SiO4 C-250?
Fired glazing improves surface resistivity and cleanability; metallized/plated pads used for brazing, otherwise lapped or diamond-polished.
Can Mg2SiO4 C-250 be formed, bent or molded?
Dry pressing, isostatic pressing, extrusion or slip casting of talc/magnesia batches, then firing at ~1300–1450 °C with tight kiln control to avoid periclase or protoenstatite phases.
What is the maximum service temperature of Mg2SiO4 C-250?
Mg2SiO4 C-250 is rated for continuous use to about 1,000°C (1,832 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- IEC 60672-3 Ceramic and glass insulating materials – Part 3: Specifications for individual materials (Types C-240, C-250) — IEC (1997)
- Engineered Materials Handbook Vol. 4: Ceramics and Glasses — ASM International (1991)
- Technical ceramics – steatite / forsterite product data — CeramTec / Kyocera (2023)
- Phase Diagrams for Ceramists – MgO–SiO2 system — American Ceramic Society (1985)
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.