BeO 99
Grade
99 = beO 99.0 %
Pick the lower-cost pressureless-sintered 99.0 % purity quality for power-resistor substrates and insulating parts that need less than 250 W/m·K thermal conductivity.
Values for the 99 condition
Other BeO tempers and conditions
BeO is listed in 3 conditions; see the grade overview at BeO.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
995Default BeO 99.5 % | Industry workhorse at 99.5 % purity: choose when thermal conductivity, strength and metallizability must be balanced for microwave tubes, laser heat sinks and thick-film power substrates. | — | 130 | — | 1,200 HV | 275 W/m·K |
99This page BeO 99.0 % | Pick the lower-cost pressureless-sintered 99.0 % purity quality for power-resistor substrates and insulating parts that need less than 250 W/m·K thermal conductivity. | — | — | — | 1,100 HV | 240 W/m·K |
BeO 99.8 % hot-pressed / near-theoretical-density grade | Choose the hot-pressed, near-theoretical-density 99.8 % quality for extreme power-density heat sinks, nuclear moderator parts and high-frequency windows; near-zero porosity yields 310 W/m·K. | — | — | — | 1,280 HV | 310 W/m·K |
What is BeO 99?
BeO 99 is BeO in the 99 grade — pick the lower-cost pressureless-sintered 99.0 % purity quality for power-resistor substrates and insulating parts that need less than 250 W/m·K thermal conductivity. BeO 99 has a tensile strength of 130 MPa (18.9 ksi), stronger than 53% of ceramic grades. The elastic modulus is 330 GPa (47.9 Msi). BeO 99 has a density of 2.85 g/cm³ (0.103 lb/in³), lighter than 79% of ceramic grades. It melts at 2,530°C (4,586 °F). 995 is the default condition FabDigit quotes; 99 is available on request or by drawing note.
Advantages
- Conducts heat well — 240 W/m·K (138.7 BTU/hr·ft·°F), better than 96% of ceramic grades
- High service temperature — 1,700°C (3,092 °F), better than 90% of ceramic grades
- Lightweight — 2.85 g/cm³ (0.103 lb/in³), better than 79% of ceramic grades
Limitations
- High embodied carbon — 30 kg CO₂/kg, worse than 91% of ceramic grades
BeO 99 properties
Typical room-temperature values for BeO 99; 10 are specific to this condition. Other listed values are BeO reference data and may not represent this condition. Bars are the position among ceramic grades.
Physical4
BeO 99 has a density of 2.85 g/cm³ (0.103 lb/in³), lighter than 79% of ceramic grades. It melts at 2,530°C (4,586 °F).
Mechanical11
BeO 99 has a tensile strength of 130 MPa (18.9 ksi), stronger than 53% of ceramic grades. The elastic modulus is 330 GPa (47.9 Msi).
Thermal5
BeO 99 is rated for continuous service to 1,700°C (3,092 °F). It conducts heat at 240 W/m·K (138.7 BTU/hr·ft·°F), better than 96% of ceramic grades. Thermal expansion is 7 µm/m·K (3.89 µin/in·°F).
Electrical5
BeO 99 is an electrical insulator with a dielectric strength of 12 kV/mm (304.8 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental2
Corrosion resistance is very good (78/100), better than 53% of ceramic grades.
Sustainability4
Producing a kilogram of BeO 99 takes about 450 MJ of energy and emits 30 kg of CO₂ — more than 94% of ceramic grades. Typical recycled content is 5%.
Manufacturability3
BeO 99's machinability is not recommended (6/100, better than 61% of ceramic grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BeO 99
Is BeO easy to machine?
After sintering, only diamond grinding or laser machining is practical, and all work must be run wet with HEPA extraction; dry dust generation is prohibited. Turn or mill complex geometry in the green state and sinter afterwards.
Can BeO be welded?
Not weldable; hermetic joints are made by Mo-Mn metallising plus nickel plating, then brazing to Kovar or copper with Ag-Cu filler.
Can BeO be formed, bent or molded?
Formed by dry pressing, isostatic pressing or tape casting for thin substrates, then sintered at 1500–1800 °C. Linear shrinkage is about 15–20 %, so tooling must be oversized accordingly.
What surface finishes work on BeO?
Diamond lapping and polishing reach Ra below 0.1 µm. Surfaces accept thick-film or thin-film metallisation (Ti-Pt-Au, Mo-Mn, DBC copper) for soldering and circuit routing.
BeO 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 |
|---|---|---|
| BeOmain crystalline phase, hexagonal wurtzite structure | 99.5 – 99.9 | 99.5 |
| MgOcommon sintering aid, inhibits grain growth | 0 – 0.3 | 0.15 |
| SiO2impurity/sintering aid | 0 – 0.2 | 0.08 |
| Al2O3impurity | 0 – 0.15 | 0.05 |
| Fe2O3 + CaO + otherbalance of trace impurities, total <0.1 % | balance | — |
BeO 99 — frequently asked
What is BeO 99 used for?
BeO 99 is typically used for RF/microwave substrates, laser diode heat sinks, high-power electronic packages and nuclear moderator components. In short: highest-conductivity oxide insulator; toxic dust, contained processing; alternative to aluminium nitride.
What is the tensile strength of BeO 99?
BeO 99 has a typical tensile strength of 130 MPa (18.9 ksi) — stronger than 53% of ceramic grades. Strength varies by condition: see the 3 listed tempers.
Is BeO 99 easy to machine?
Not especially — machinability is rated not recommended (6/100, better than 61% of ceramic grades). After sintering, only diamond grinding or laser machining is practical, and all work must be run wet with HEPA extraction; dry dust generation is prohibited. Turn or mill complex geometry in the green state and sinter afterwards.
Can BeO 99 be welded?
Not weldable; hermetic joints are made by Mo-Mn metallising plus nickel plating, then brazing to Kovar or copper with Ag-Cu filler.
What surface finishes work on BeO 99?
Diamond lapping and polishing reach Ra below 0.1 µm. Surfaces accept thick-film or thin-film metallisation (Ti-Pt-Au, Mo-Mn, DBC copper) for soldering and circuit routing.
Can BeO 99 be formed, bent or molded?
Formed by dry pressing, isostatic pressing or tape casting for thin substrates, then sintered at 1500–1800 °C. Linear shrinkage is about 15–20 %, so tooling must be oversized accordingly.
What is the maximum service temperature of BeO 99?
BeO 99 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)
- Beryllium Oxide (BeO) Ceramic Property Data — American Beryllia / Materion Ceramics (2022)
- Engineering ceramics thermophysical property compilation — NIST / Ceramic Industry data tables (2020)
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.