Silicon Nitride · print state · default condition
Silicon Nitride Sintered
Properties of the Sintered condition, compared with the other Silicon Nitride tempers.
Standard dense grade for general structural, wear and high-temperature parts; best cost/performance for complex near-net shapes.
What is Silicon Nitride Sintered?
Silicon Nitride Sintered is Silicon Nitride in the Sintered condition — standard dense grade for general structural, wear and high-temperature parts; best cost/performance for complex near-net shapes. Silicon Nitride Sintered has a tensile strength of 450 MPa (65.3 ksi), stronger than 77% of ceramic grades. Elongation at break is 0% and the elastic modulus is 310 GPa (45 Msi). Silicon Nitride Sintered has a density of 3.22 g/cm³ (0.116 lb/in³), lighter than 71% of ceramic grades. It melts at 1,900°C (3,452 °F).
Advantages
- Good corrosion resistance — 92/100, better than 88% of ceramic grades
- Polishes to a fine finish — 92/100, better than 87% of ceramic grades
Silicon Nitride Sintered properties
Typical room-temperature values for Silicon Nitride Sintered — 12 properties are specific to this condition; the rest are grade-level values shared by every Silicon Nitride temper. Each bar shows where the value sits among the ceramic grades in FabDigit's library — further right is higher.
Physical4
Silicon Nitride Sintered has a density of 3.22 g/cm³ (0.116 lb/in³), lighter than 71% of ceramic grades. It melts at 1,900°C (3,452 °F).
Mechanical12
Silicon Nitride Sintered has a tensile strength of 450 MPa (65.3 ksi), stronger than 77% of ceramic grades. Elongation at break is 0% and the elastic modulus is 310 GPa (45 Msi).
Thermal5
Silicon Nitride Sintered is rated for continuous service to 1,200°C (2,192 °F). It conducts heat at 25 W/m·K (14.4 BTU/hr·ft·°F), better than 56% of ceramic grades. Thermal expansion is 3.2 µm/m·K (1.78 µin/in·°F).
Electrical5
Silicon Nitride Sintered is an electrical insulator with a dielectric strength of 15 kV/mm (381 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (92/100), better than 88% of ceramic grades.
Sustainability4
Producing a kilogram of Silicon Nitride Sintered takes about 170 MJ of energy and emits 12 kg of CO₂ — more than 59% of ceramic grades. Typical recycled content is 0%.
Manufacturability3
Silicon Nitride 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 Silicon Nitride tempers and conditions
Silicon Nitride is also supplied in 6 other conditions. The full side-by-side table is on the Silicon Nitride overview.
- SinteredDefaultStandard dense grade for general structural, wear and high-temperature parts; best cost/performance for complex near-net shapes.450 MPa tensile
- HIPedPick when defect-free, fully dense material is required — bearing balls/rollers, high-cycle-fatigue and highly stressed parts.550 MPa tensile
- C935Gas-tight, essentially zero-porosity sintered silicon nitride classified as IEC 60672-3 material group C-935 for electrical/electronic insulating parts, combining ≥600 MPa bending strength with high dielectric strength.400 MPa tensile
- RBSNLow-cost, near-zero-shrinkage porous grade for large refractory shapes, thermocouple sheaths, riser tubes and molten-aluminium hardware where strength is secondary.160 MPa tensile
- HPSNChoose for the highest strength in simple plate/blank geometries (cutting inserts, tooling); shapes limited and properties slightly anisotropic.1,650 HV
- SRBSNRoute that starts from cheap Si powder and then densifies; gives near-SSN properties with less shrinkage and lower raw-material cost for larger parts.1,450 HV
- HTCY2O3-based, low-oxygen, coarse-β-grain grade for AMB power-module substrates: 70–100 W/m·K with substrate-grade strength and toughness.1,450 HV
Working with Silicon Nitride Sintered
Is Silicon Nitride easy to machine?
Green/bisque machining with carbide tooling is the economical route; after sintering only diamond grinding, lapping and laser/ultrasonic machining work (electrically insulating, so no EDM).
Can Silicon Nitride be welded?
Not weldable — join by active-metal brazing (Ti-containing Ag-Cu), metallization + soldering, glass sealing or mechanical shrink-fit; AMB copper bonding is standard for substrates.
Can Silicon Nitride be formed, bent or molded?
Formed as a powder compact: uniaxial/isostatic pressing, injection moulding, slip/tape casting or extrusion, then sintered at 1650–1850 °C under N2 overpressure with ~15–18 % linear shrinkage (RBSN routes are near net shape).
What surface finishes work on Silicon Nitride?
Diamond lapping and polishing give Ra < 0.01 µm on bearing surfaces; CVD/PVD coatings, metallization or lapped-and-honed seal faces are common — no anodizing/plating without prior metallization.
Silicon Nitride 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 |
|---|---|---|
| Y2O3primary sintering aid (rare-earth oxide; may be substituted by Yb2O3/La2O3) | 0 – 8 | 4 |
| Al2O3co-additive; forms grain-boundary glass, lowers thermal conductivity | 0 – 5 | 2 |
| MgOalternative aid, mainly in hot-pressed grades | 0 – 3 | 0 |
| SiO2surface oxide on powder, part of the glass phase | 0.5 – 2.5 | 1.2 |
| Feimpurity | 0 – 0.2 | 0.05 |
| Si3N4predominantly β-Si3N4 after sintering | ≥ 88 (balance) | — |
Silicon Nitride Sintered — frequently asked
What is Silicon Nitride Sintered used for?
Silicon Nitride Sintered is typically used for hybrid bearing balls and rollers, hot rolling bearings, turbocharger rotors, diesel glow plugs, cutting tool inserts for cast iron and welding locator pins and molten aluminum riser tubes. In short: high-toughness silicon nitride.
What is the tensile strength of Silicon Nitride Sintered?
Silicon Nitride Sintered has a typical tensile strength of 450 MPa (65.3 ksi) — stronger than 77% of ceramic grades. Strength varies by condition: see the 7 listed tempers.
Is Silicon Nitride Sintered easy to machine?
Not especially — machinability is rated not recommended (5/100, worse than 58% of ceramic grades). Green/bisque machining with carbide tooling is the economical route; after sintering only diamond grinding, lapping and laser/ultrasonic machining work (electrically insulating, so no EDM).
Can Silicon Nitride Sintered be welded?
Not weldable — join by active-metal brazing (Ti-containing Ag-Cu), metallization + soldering, glass sealing or mechanical shrink-fit; AMB copper bonding is standard for substrates.
What surface finishes work on Silicon Nitride Sintered?
Diamond lapping and polishing give Ra < 0.01 µm on bearing surfaces; CVD/PVD coatings, metallization or lapped-and-honed seal faces are common — no anodizing/plating without prior metallization.
Can Silicon Nitride Sintered be formed, bent or molded?
Formed as a powder compact: uniaxial/isostatic pressing, injection moulding, slip/tape casting or extrusion, then sintered at 1650–1850 °C under N2 overpressure with ~15–18 % linear shrinkage (RBSN routes are near net shape).
What is the maximum service temperature of Silicon Nitride Sintered?
Silicon Nitride Sintered is rated for continuous use to about 1,200°C (2,192 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in Silicon Nitride Sintered?
Yes — Silicon Nitride Sintered is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASM Engineered Materials Handbook, Vol. 4: Ceramics and Glasses — ASM International (1991)
- ISO 26602 — Fine ceramics: Silicon nitride materials for rolling bearing balls and rollers — ISO (2017)
- ASTM C1161 / C1421 — Flexural strength and fracture toughness of advanced ceramics — ASTM (2018)
- Silicon Nitride (Si3N4) material property sheets — CoorsTek (2023)
- Fine Ceramics — Silicon Nitride SN series — Kyocera (2023)
- SL200B / high-thermal-conductivity Si3N4 substrate data — CeramTec / Rogers curamik (2022)
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.