MgO Ceramic 99.5
Grade · default condition
99.5 = 99.5 % MgO
Standard high-purity technical magnesia — crucibles for reactive metal melting, thermocouple protection tubes and high-temperature insulators.
Values for the 99.5 condition
Other MgO Ceramic tempers and conditions
MgO Ceramic is listed in 4 conditions; see the grade overview at MgO Ceramic.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
96 % MgO | Lowest-cost sintered magnesia with CaO/SiO₂ silicate bond — refractory shapes, crucibles and furnace linings where purity is not critical. | — | 70 | — | 520 HV | 25 W/m·K |
99.5DefaultThis page 99.5 % MgO | Standard high-purity technical magnesia — crucibles for reactive metal melting, thermocouple protection tubes and high-temperature insulators. | — | 100 | — | 620 HV | 40 W/m·K |
99.9 % MgO | Fully dense hot-pressed magnesia for IR windows, optical and ultra-high-temperature insulator applications where translucency and maximum thermal conductivity are needed. | — | 130 | — | 720 HV | 52 W/m·K |
Fused (electro-fused) magnesia grain / bonded shapes | Electric-arc fused periclase with large crystals — best slag corrosion resistance and highest thermal conductivity, used as grain for refractory bricks and as MI heating-element filler. | — | — | — | 600 HV | 45 W/m·K |
What is MgO Ceramic 99.5?
MgO Ceramic 99.5 is MgO Ceramic in the 99.5 grade — standard high-purity technical magnesia — crucibles for reactive metal melting, thermocouple protection tubes and high-temperature insulators. MgO Ceramic 99.5 has a tensile strength of 100 MPa (14.5 ksi), stronger than 50% of ceramic grades. The elastic modulus is 300 GPa (43.5 Msi). MgO Ceramic 99.5 has a density of 3.55 g/cm³ (0.128 lb/in³), lighter than 66% of ceramic grades. It melts at 2,800°C (5,072 °F).
Advantages
- High service temperature — 1,700°C (3,092 °F), better than 90% of ceramic grades
- Low embodied carbon — 3 kg CO₂/kg, better than 88% of ceramic grades
- Easy to machine — 22/100, better than 83% of ceramic grades
Limitations
- Needs corrosion protection — 35/100, worse than 100% of ceramic grades
MgO Ceramic 99.5 properties
Typical room-temperature values for MgO Ceramic 99.5; 14 are specific to this condition. Other listed values are MgO Ceramic reference data and may not represent this condition. Bars are the position among ceramic grades.
Physical4
MgO Ceramic 99.5 has a density of 3.55 g/cm³ (0.128 lb/in³), lighter than 66% of ceramic grades. It melts at 2,800°C (5,072 °F).
Mechanical11
MgO Ceramic 99.5 has a tensile strength of 100 MPa (14.5 ksi), stronger than 50% of ceramic grades. The elastic modulus is 300 GPa (43.5 Msi).
Thermal5
MgO Ceramic 99.5 is rated for continuous service to 1,700°C (3,092 °F). It conducts heat at 40 W/m·K (23.1 BTU/hr·ft·°F), better than 67% of ceramic grades. Thermal expansion is 13.5 µm/m·K (7.5 µin/in·°F).
Electrical5
MgO Ceramic 99.5 is an electrical insulator with a dielectric strength of 12 kV/mm (304.8 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental2
Corrosion resistance is fair (35/100), worse than 100% of ceramic grades.
Sustainability4
Producing a kilogram of MgO Ceramic 99.5 takes about 40 MJ of energy and emits 3 kg of CO₂ — less than 88% of ceramic grades. Typical recycled content is 5%.
Manufacturability3
MgO Ceramic 99.5's machinability is poor (22/100, better than 83% of ceramic grades).
Common Calculations4
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with MgO Ceramic 99.5
Is MgO Ceramic easy to machine?
Machine green or bisque-fired bodies with carbide tooling; fired parts require diamond grinding with dry or oil coolant — never water, which hydrates the surface.
Can MgO Ceramic be welded?
Not weldable; join by ceramic cement, glass frit or active-metal brazing (Ti/Zr-containing filler) in vacuum, allowing for the large CTE mismatch with metals.
Can MgO Ceramic be formed, bent or molded?
Uniaxial or isostatic dry pressing, slip casting in non-aqueous media, extrusion of tubes, or hot pressing; sintering at 1600–1800 °C, often with CaO/B₂O₃ or LiF aids to reach full density.
What surface finishes work on MgO Ceramic?
Diamond lap/polish for optical or seal faces; parts must be dried, vacuum-baked and stored in a desiccator or hermetically sealed to prevent hydration and spalling.
MgO Ceramic 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 |
|---|---|---|
| CaOmain sintering-aid / impurity | 0.02 – 0.3 | 0.1 |
| SiO2forms silicate bond phase | 0.01 – 0.25 | 0.08 |
| Fe2O3 | 0.01 – 0.15 | 0.03 |
| Al2O3 | 0.01 – 0.15 | 0.03 |
| B2O3sometimes added as densification aid | 0 – 0.05 | 0.01 |
| MgOpericlase; balance of high-purity technical grade | ≥ 99.5 (balance) | — |
MgO Ceramic 99.5 — frequently asked
What is MgO Ceramic 99.5 used for?
MgO Ceramic 99.5 is typically used for refractory crucibles, thermocouple sheath insulation, heating element cores and high-temperature furnace linings. In short: highest service temperature oxide; thermally conductive electrical insulator; moisture-sensitive; requires sealed storage.
What is the tensile strength of MgO Ceramic 99.5?
MgO Ceramic 99.5 has a typical tensile strength of 100 MPa (14.5 ksi) — stronger than 50% of ceramic grades. Strength varies by condition: see the 4 listed tempers.
Is MgO Ceramic 99.5 easy to machine?
Not especially — machinability is rated poor (22/100, better than 83% of ceramic grades). Machine green or bisque-fired bodies with carbide tooling; fired parts require diamond grinding with dry or oil coolant — never water, which hydrates the surface.
Can MgO Ceramic 99.5 be welded?
Not weldable; join by ceramic cement, glass frit or active-metal brazing (Ti/Zr-containing filler) in vacuum, allowing for the large CTE mismatch with metals.
What surface finishes work on MgO Ceramic 99.5?
Diamond lap/polish for optical or seal faces; parts must be dried, vacuum-baked and stored in a desiccator or hermetically sealed to prevent hydration and spalling.
Can MgO Ceramic 99.5 be formed, bent or molded?
Uniaxial or isostatic dry pressing, slip casting in non-aqueous media, extrusion of tubes, or hot pressing; sintering at 1600–1800 °C, often with CaO/B₂O₃ or LiF aids to reach full density.
What is the maximum service temperature of MgO Ceramic 99.5?
MgO Ceramic 99.5 is rated for continuous use to about 1,700°C (3,092 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASM Engineered Materials Handbook Vol. 4: Ceramics and Glasses — ASM International (1991)
- Refractories Handbook (Schacht, ed.) — CRC Press (2004)
- Technical magnesia (MgO) ceramic property sheets — CoorsTek / Ortech / Kyocera (2023)
- GB/T 2273 / GB/T 24411 — SAC (2019)
- MatWeb / NIST ceramics property records for magnesium oxide — MatWeb, NIST (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.