Alumina 99.5 · print state · default condition
Alumina 99.5 Sintered
Properties of the Sintered condition, compared with the other Alumina 99.5 tempers.
Standard dry-pressed / isopressed and air-sintered 99.5 % alumina for insulators, tubes, wear and seal parts.
What is Alumina 99.5 Sintered?
Alumina 99.5 Sintered is Alumina 99.5 in the Sintered condition — standard dry-pressed / isopressed and air-sintered 99.5 % alumina for insulators, tubes, wear and seal parts. Alumina 99.5 Sintered has a tensile strength of 260 MPa (37.7 ksi), stronger than 65% of ceramic grades. The elastic modulus is 372 GPa (54 Msi). Alumina 99.5 Sintered has a density of 3.9 g/cm³ (0.141 lb/in³), lighter than 58% of ceramic grades. It melts at 2,050°C (3,722 °F).
Advantages
- Good corrosion resistance — 95/100, better than 97% of ceramic grades
- 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
Alumina 99.5 Sintered properties
Typical room-temperature values for Alumina 99.5 Sintered — 13 properties are specific to this condition; the rest are grade-level values shared by every Alumina 99.5 temper. Each bar shows where the value sits among the ceramic grades in FabDigit's library — further right is higher.
Physical4
Alumina 99.5 Sintered has a density of 3.9 g/cm³ (0.141 lb/in³), lighter than 58% of ceramic grades. It melts at 2,050°C (3,722 °F).
Mechanical12
Alumina 99.5 Sintered has a tensile strength of 260 MPa (37.7 ksi), stronger than 65% of ceramic grades. The elastic modulus is 372 GPa (54 Msi).
Thermal5
Alumina 99.5 Sintered is rated for continuous service to 1,700°C (3,092 °F). It conducts heat at 32 W/m·K (18.5 BTU/hr·ft·°F), better than 63% of ceramic grades. Thermal expansion is 7 µm/m·K (3.89 µin/in·°F).
Electrical5
Alumina 99.5 Sintered is an electrical insulator with a dielectric strength of 17 kV/mm (431.8 V/mil) and a resistivity of 1×10¹³ Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (95/100), better than 97% of ceramic grades.
Sustainability4
Producing a kilogram of Alumina 99.5 Sintered takes about 52 MJ of energy and emits 3 kg of CO₂ — less than 80% of ceramic grades. Typical recycled content is 0%.
Manufacturability3
Alumina 99.5 Sintered's machinability is not recommended (5/100, worse than 58% of ceramic grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other Alumina 99.5 tempers and conditions
Alumina 99.5 is also supplied in 1 other condition. The full side-by-side table is on the Alumina 99.5 overview.
- SinteredDefaultStandard dry-pressed / isopressed and air-sintered 99.5 % alumina for insulators, tubes, wear and seal parts.260 MPa tensile
- HIPedPick when maximum density, strength and plasma/vacuum performance are required — e.g. semiconductor chamber parts and highly loaded seal faces.320 MPa tensile
Working with Alumina 99.5 Sintered
Is Alumina 99.5 easy to machine?
Green or bisque machine wherever possible; after firing only diamond grinding, lapping, ultrasonic or laser/waterjet cutting works — allow generous grinding stock and avoid sharp internal corners.
Can Alumina 99.5 be welded?
Not weldable; join by active-metal brazing (Ti/Ag-Cu), Mo-Mn metallization plus Ni plating and brazing, glass sealing or structural adhesive.
Can Alumina 99.5 be formed, bent or molded?
Formed as a green body by dry/isostatic pressing, extrusion, slip or injection casting, then sintered at ~1600–1700 °C with ~15–20 % linear shrinkage; HIP adds a second densification cycle.
What surface finishes work on Alumina 99.5?
Lapping/polishing gives <0.05 µm Ra optical-grade faces; metallize (Mo-Mn or thin-film Ti/Pt/Au) for solderable/brazable surfaces; no plating or painting is needed for corrosion protection.
Alumina 99.5 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 |
|---|---|---|
| SiO2sintering aid / impurity | ≤ 0.2 | 0.1 |
| MgOgrain-growth inhibitor | ≤ 0.15 | 0.08 |
| CaO | ≤ 0.1 | 0.04 |
| Na2Oalkali impurity, limited for HV insulators | ≤ 0.1 | 0.05 |
| Fe2O3 | ≤ 0.05 | 0.02 |
| Al2O3purity by weight after firing | ≥ 99.5 (balance) | — |
Alumina 99.5 Sintered — frequently asked
What is Alumina 99.5 Sintered used for?
Alumina 99.5 Sintered is typically used for semiconductor wafer carriers, high-voltage insulators, vacuum feedthroughs and headers, seal faces and pump plungers, wear rings and nozzles and furnace tubes and fixtures. In short: premium high-purity alumina.
What is the tensile strength of Alumina 99.5 Sintered?
Alumina 99.5 Sintered has a typical tensile strength of 260 MPa (37.7 ksi) — stronger than 65% of ceramic grades. Strength varies by condition: see the 2 listed tempers.
Is Alumina 99.5 Sintered easy to machine?
Not especially — machinability is rated not recommended (5/100, worse than 58% of ceramic grades). Green or bisque machine wherever possible; after firing only diamond grinding, lapping, ultrasonic or laser/waterjet cutting works — allow generous grinding stock and avoid sharp internal corners.
Can Alumina 99.5 Sintered be welded?
Not weldable; join by active-metal brazing (Ti/Ag-Cu), Mo-Mn metallization plus Ni plating and brazing, glass sealing or structural adhesive.
What surface finishes work on Alumina 99.5 Sintered?
Lapping/polishing gives <0.05 µm Ra optical-grade faces; metallize (Mo-Mn or thin-film Ti/Pt/Au) for solderable/brazable surfaces; no plating or painting is needed for corrosion protection.
Can Alumina 99.5 Sintered be formed, bent or molded?
Formed as a green body by dry/isostatic pressing, extrusion, slip or injection casting, then sintered at ~1600–1700 °C with ~15–20 % linear shrinkage; HIP adds a second densification cycle.
What is the maximum service temperature of Alumina 99.5 Sintered?
Alumina 99.5 Sintered 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.
Can FabDigit make parts in Alumina 99.5 Sintered?
Yes — Alumina 99.5 Sintered is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- AD-995 Alumina 99.5 % technical data — CoorsTek (2023)
- Fine Ceramics — Alumina (A-995) material property table — Kyocera (2022)
- Engineered Materials Handbook Vol.4: Ceramics and Glasses — ASM International (1991)
- ASTM C1161 / C1327 — flexural strength and Vickers hardness of advanced ceramics — ASTM (2019)
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.