Al2O3-99.5% ZTA (Zirconia-toughened alumina)
Reinforced grade
Use when alumina's strength and toughness are marginal — impact-loaded wear parts, mill liners, cutting/forming tools and load-bearing bio/industrial components.
Values for the ZTA condition
Other Al2O3-99.5% tempers and conditions
Al2O3-99.5% is listed in 6 conditions; see the grade overview at Al2O3-99.5%.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
82–86 % Al2O3, high glass-phase debased alumina | Cheapest alumina body for bulk insulators, bushings and low-stress wear liners where dielectric loss and thermal conductivity are not critical. | — | 130 | — | 1,000 HV | 15 W/m·K |
93–95 % Al2O3 | Workhorse mid-purity alumina for pump seals, valve plates, thread guides and general electrical insulation at moderate cost. | — | 175 | — | 1,200 HV | 20 W/m·K |
96–99 % Al2O3 substrate/technical grade | Standard thick-film/hybrid substrate and vacuum-braze alumina: good metallization compatibility and as-fired surface at lower cost than 99.5 %. | — | 200 | — | 1,350 HV | 25 W/m·K |
A-995Default 99.5 % Al2O3 high-purity sintered | Default high-purity grade: pick for RF/microwave and thin-film substrates, vacuum feedthroughs, laser tubes and severe wear/corrosion service. | — | 260 | — | 1,550 HV | 32 W/m·K |
ZTAThis page Zirconia-toughened alumina | Use when alumina's strength and toughness are marginal — impact-loaded wear parts, mill liners, cutting/forming tools and load-bearing bio/industrial components. | — | 350 | — | 1,500 HV | 22 W/m·K |
Static-dissipative alumina | Choose where charge build-up must be bled off — wafer-handling end effectors, test-socket and precision-electronics tooling — accepting reduced dielectric use. | — | — | — | 1,400 HV | 22 W/m·K |
What is Al2O3-99.5% ZTA?
Al2O3-99.5% ZTA is Al2O3-99.5% in the ZTA grade — use when alumina's strength and toughness are marginal — impact-loaded wear parts, mill liners, cutting/forming tools and load-bearing bio/industrial components. Al2O3-99.5% ZTA has a tensile strength of 350 MPa (50.8 ksi), stronger than 71% of ceramic grades. The elastic modulus is 340 GPa (49.3 Msi). Al2O3-99.5% ZTA has a density of 4.2 g/cm³ (0.152 lb/in³), lighter than 56% of ceramic grades. It melts at 2,050°C (3,722 °F). A-995 is the default condition FabDigit quotes; ZTA is available on request or by drawing note.
Advantages
- Good corrosion resistance — 92/100, better than 88% of ceramic grades
- Polishes to a fine finish — 90/100, better than 78% of ceramic grades
- High service temperature — 1,400°C (2,552 °F), better than 77% of ceramic grades
- Low embodied carbon — 5.2 kg CO₂/kg, better than 75% of ceramic grades
Al2O3-99.5% ZTA properties
Typical room-temperature values for Al2O3-99.5% ZTA; 17 are specific to this condition. Other listed values are Al2O3-99.5% reference data and may not represent this condition. Bars are the position among ceramic grades.
Physical4
Al2O3-99.5% ZTA has a density of 4.2 g/cm³ (0.152 lb/in³), lighter than 56% of ceramic grades. It melts at 2,050°C (3,722 °F).
Mechanical12
Al2O3-99.5% ZTA has a tensile strength of 350 MPa (50.8 ksi), stronger than 71% of ceramic grades. The elastic modulus is 340 GPa (49.3 Msi).
Thermal5
Al2O3-99.5% ZTA is rated for continuous service to 1,400°C (2,552 °F). It conducts heat at 22 W/m·K (12.7 BTU/hr·ft·°F), better than 51% of ceramic grades. Thermal expansion is 7.8 µm/m·K (4.33 µin/in·°F).
Electrical5
Al2O3-99.5% ZTA is an electrical insulator with a dielectric strength of 18 kV/mm (457.2 V/mil) and a resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (92/100), better than 88% of ceramic grades.
Sustainability4
Producing a kilogram of Al2O3-99.5% ZTA takes about 65 MJ of energy and emits 5.2 kg of CO₂ — less than 74% of ceramic grades. Typical recycled content is 0%.
Manufacturability3
Al2O3-99.5% ZTA's machinability is not recommended (4/100, worse than 85% of ceramic grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Al2O3-99.5% ZTA
Is Al2O3-99.5% easy to machine?
Machine green or bisque bodies with carbide tooling allowing ~15–20 % firing shrinkage; fired 99.5 % alumina requires diamond grinding, lapping, ultrasonic or laser machining.
Can Al2O3-99.5% be welded?
Not weldable — join by active-metal (Ti/Ag-Cu) brazing, Mo-Mn metallization plus Ni plating and brazing, glass frit sealing or ceramic adhesives.
Can Al2O3-99.5% be formed, bent or molded?
Formed by dry/isostatic pressing, extrusion, slip or injection casting and tape casting for substrates, then pressureless sintering at 1550–1750 °C (HIP for maximum density).
What surface finishes work on Al2O3-99.5%?
As-fired Ra ≈ 0.3–0.6 µm; lapping/polishing reaches Ra <0.05 µm for thin-film use; laser scribing, thick-film metallization, Ni/Au plating and glazing are standard.
Al2O3-99.5% 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 |
|---|---|---|
| SiO2residual sintering aid / glassy phase | 0 – 0.2 | 0.1 |
| MgOgrain-growth inhibitor | 0 – 0.15 | 0.07 |
| CaO | 0 – 0.1 | 0.03 |
| Na2Okept low for dielectric loss and HV insulation | 0 – 0.1 | 0.05 |
| Fe2O3 | 0 – 0.05 | 0.02 |
| Al2O3sintered polycrystalline corundum, per IEC 60672-3 C-799 / ASTM D2442 Type IV | ≥ 99.5 (balance) | — |
Al2O3-99.5% ZTA — frequently asked
What is Al2O3-99.5% ZTA used for?
Al2O3-99.5% ZTA is typically used for RF/microwave substrates, laser diode submounts and precision hybrid circuits. In short: higher purity than 96 % alumina; 32 W/(m.K) thermal conductivity; thin-film surface finish.
What is the tensile strength of Al2O3-99.5% ZTA?
Al2O3-99.5% ZTA has a typical tensile strength of 350 MPa (50.8 ksi) — stronger than 71% of ceramic grades. Strength varies by condition: see the 6 listed tempers.
Is Al2O3-99.5% ZTA easy to machine?
Not especially — machinability is rated not recommended (4/100, worse than 85% of ceramic grades). Machine green or bisque bodies with carbide tooling allowing ~15–20 % firing shrinkage; fired 99.5 % alumina requires diamond grinding, lapping, ultrasonic or laser machining.
Can Al2O3-99.5% ZTA be welded?
Not weldable — join by active-metal (Ti/Ag-Cu) brazing, Mo-Mn metallization plus Ni plating and brazing, glass frit sealing or ceramic adhesives.
What surface finishes work on Al2O3-99.5% ZTA?
As-fired Ra ≈ 0.3–0.6 µm; lapping/polishing reaches Ra <0.05 µm for thin-film use; laser scribing, thick-film metallization, Ni/Au plating and glazing are standard.
Can Al2O3-99.5% ZTA be formed, bent or molded?
Formed by dry/isostatic pressing, extrusion, slip or injection casting and tape casting for substrates, then pressureless sintering at 1550–1750 °C (HIP for maximum density).
What is the maximum service temperature of Al2O3-99.5% ZTA?
Al2O3-99.5% ZTA is rated for continuous use to about 1,400°C (2,552 °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 (C-780/C-786/C-795/C-799) — IEC (1997)
- ASTM D2442 Standard Specification for Alumina Ceramics for Electrical and Electronic Applications — ASTM (2018)
- GB/T 3927 Test method for volume density and apparent porosity of fine ceramics / — SAC (China) (2018)
- ASM Engineered Materials Handbook Vol. 4: Ceramics and Glasses — ASM International (1991)
- AD-96 / AD-995 alumina material properties — CoorsTek (2023)
- Fine Ceramics technical data — alumina A-473/A-479/A995, ZTA — Kyocera (2023)
- Technical alumina and ZTA property records — MatWeb / CES EduPack material data (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.