AlN-HR
Grade
AlN-HR = high-resistance grade
Choose when insulation resistance must stay high at elevated temperature or under DC bias (ESC bodies, HV isolators, high-voltage power modules).
Values for the AlN-HR condition
Other AlN tempers and conditions
AlN is listed in 5 conditions; see the grade overview at AlN.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Machinable AlN–BN composite | Pick when parts must be turned/milled with carbide tooling after firing and moderate thermal conductivity is acceptable. | — | — | — | 400 HV | 70 W/m·K |
AlN-180Default Pressureless-sintered high thermal conductivity substrate grade | Standard commercial power-electronics substrate/heat-spreader grade; pick when maximum heat spreading with full dielectric isolation is needed. | — | — | — | 1,100 HV | 180 W/m·K |
AlN-HRThis page High-resistance grade | Choose when insulation resistance must stay high at elevated temperature or under DC bias (ESC bodies, HV isolators, high-voltage power modules). | — | — | — | 1,100 HV | 150 W/m·K |
Microwave-lossy AlN composite | Choose for TWT/klystron RF attenuators, terminations and absorber rods needing high dielectric loss plus AlN-level heat removal. | — | — | — | 1,150 HV | 80 W/m·K |
Pressure (hot-pressed / HIP) sintered aluminium nitride | Use for near-zero-porosity, highest-strength AlN parts and large blanks where an isotropic, fully dense body matters more than substrate cost. | — | — | — | 1,200 HV | 160 W/m·K |
What is AlN-HR?
AlN-HR is AlN in the AlN-HR grade — choose when insulation resistance must stay high at elevated temperature or under DC bias (ESC bodies, HV isolators, high-voltage power modules). AlN-HR has a tensile strength of 200 MPa (29 ksi), stronger than 60% of ceramic grades. The elastic modulus is 320 GPa (46.4 Msi). AlN-HR has a density of 3.28 g/cm³ (0.118 lb/in³), lighter than 69% of ceramic grades. It melts at 2,200°C (3,992 °F). AlN-180 is the default condition FabDigit quotes; AlN-HR is available on request or by drawing note.
Advantages
- Conducts heat well — 150 W/m·K (86.7 BTU/hr·ft·°F), better than 93% of ceramic grades
AlN-HR properties
Typical room-temperature values for AlN-HR; 10 are specific to this condition. Other listed values are AlN reference data and may not represent this condition. Bars are the position among ceramic grades.
Physical4
AlN-HR has a density of 3.28 g/cm³ (0.118 lb/in³), lighter than 69% of ceramic grades. It melts at 2,200°C (3,992 °F).
Mechanical11
AlN-HR has a tensile strength of 200 MPa (29 ksi), stronger than 60% of ceramic grades. The elastic modulus is 320 GPa (46.4 Msi).
Thermal5
AlN-HR is rated for continuous service to 900°C (1,652 °F). It conducts heat at 150 W/m·K (86.7 BTU/hr·ft·°F), better than 93% of ceramic grades. Thermal expansion is 4.4 µm/m·K (2.44 µin/in·°F).
Electrical5
AlN-HR is an electrical insulator with a dielectric strength of 20 kV/mm (508 V/mil) and a resistivity of 1×10¹³ Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (85/100), better than 69% of ceramic grades.
Sustainability4
Producing a kilogram of AlN-HR takes about 280 MJ of energy and emits 22 kg of CO₂ — more than 71% of ceramic grades. Typical recycled content is 0%.
Manufacturability3
AlN-HR's machinability is not recommended (5/100, worse than 59% of ceramic grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with AlN-HR
Is AlN easy to machine?
Green/pre-sintered bodies can be milled or laser-scribed cheaply; fired AlN needs diamond grinding, lapping or laser/ultrasonic machining, and dry machining is preferred to limit surface hydrolysis.
Can AlN be welded?
Not weldable — joined by active-metal brazing (Ti/Ag-Cu-Ti), DBC/AMB copper bonding, glass frit or metallized (Mo-Mn/W) plus Ni-plated brazing.
Can AlN be formed, bent or molded?
Tape cast for substrates, dry/isostatic pressed or injection moulded for shapes, then debound and sintered ~1750–1850 °C in flowing N₂ with Y₂O₃ aid; allow ~17–20 % linear shrinkage.
What surface finishes work on AlN?
Lapped/polished to Ra <0.05 µm for substrates; thin-film Ti/Ni/Au sputtering, thick-film W/Mo-Mn metallization, DBC or AMB copper are standard; avoid prolonged exposure to hot water or alkaline cleaners.
AlN 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 |
|---|---|---|
| Nas AlN | 31 – 34.2 | 33 |
| Yadded as Y₂O₃ sintering aid (typ. 2–5 wt% Y₂O₃) | 0.8 – 3.5 | 2 |
| Olattice + grain-boundary oxygen; lower O = higher thermal conductivity | 0.3 – 2 | 1 |
| Cresidual from carbothermal powder | ≤ 0.15 | 0.05 |
| Albalance, ~65 wt% | balance | — |
AlN-HR — frequently asked
What is AlN-HR used for?
AlN-HR is typically used for power electronics substrates, LED heat sinks, microwave device packaging and RF windows. In short: 180 W/m·K dielectric ceramic; power substrate standard; costlier than alumina.
What is the tensile strength of AlN-HR?
AlN-HR has a typical tensile strength of 200 MPa (29 ksi) — stronger than 60% of ceramic grades. Strength varies by condition: see the 5 listed tempers.
Is AlN-HR easy to machine?
Not especially — machinability is rated not recommended (5/100, worse than 59% of ceramic grades). Green/pre-sintered bodies can be milled or laser-scribed cheaply; fired AlN needs diamond grinding, lapping or laser/ultrasonic machining, and dry machining is preferred to limit surface hydrolysis.
Can AlN-HR be welded?
Not weldable — joined by active-metal brazing (Ti/Ag-Cu-Ti), DBC/AMB copper bonding, glass frit or metallized (Mo-Mn/W) plus Ni-plated brazing.
What surface finishes work on AlN-HR?
Lapped/polished to Ra <0.05 µm for substrates; thin-film Ti/Ni/Au sputtering, thick-film W/Mo-Mn metallization, DBC or AMB copper are standard; avoid prolonged exposure to hot water or alkaline cleaners.
Can AlN-HR be formed, bent or molded?
Tape cast for substrates, dry/isostatic pressed or injection moulded for shapes, then debound and sintered ~1750–1850 °C in flowing N₂ with Y₂O₃ aid; allow ~17–20 % linear shrinkage.
What is the maximum service temperature of AlN-HR?
AlN-HR is rated for continuous use to about 900°C (1,652 °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)
- Aluminum Nitride (AlN) technical ceramic datasheets — CoorsTek / Kyocera / CeramTec / Maruwa (2023)
- MatWeb / Ceramic property tables for AlN — MatWeb LLC (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.