Sialon
Sialon is a silicon-aluminum oxynitride ceramic in the nitride family, supplied as beta (BETA), alpha-beta (AB), gas-pressure sintered (GP) and TiN-containing conductive (TIN) grades.
Reference datasheet — Sialon is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the BETA condition
Sialon tempers and conditions
Sialon is supplied in 3 conditions, soft to hard. BETA is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
General-purpose sintered sialon | Lower-cost, slightly less dense grade for wear plates, nozzles and molten-metal handling where peak strength is not required. | 1,350 HV | 16 W/m·K | |||
BETADefault Β-Sialon | Default structural grade: best balance of strength, toughness and thermal shock for thermocouple sheaths, weld pins, riser tubes and pump parts. | 1,550 HV | 21 W/m·K | |||
As built (as printed) | Pick when hardness and hot wear resistance dominate — inserts for turning/milling nickel superalloys and grey cast iron at high speed. | 1,800 HV | 20 W/m·K |
Supply forms, finishes and certifications
Ways Sialon is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
TIN | Sialon–TiN composite | Coating |
What is Sialon?
Sialon is a silicon-aluminum oxynitride ceramic in the nitride family, supplied as beta (BETA), alpha-beta (AB), gas-pressure sintered (GP) and TiN-containing conductive (TIN) grades. It combines Si3N4-like toughness with better oxidation and thermal-shock resistance — 3.25 g/cm³, 288 GPa modulus, 21 W/m·K, service to 1200 °C and a corrosion resistance score of 90 — and is used mainly as cutting inserts for nickel alloys and as molten-metal hardware. Machinability is 4, so sintered parts are diamond-ground only and near-net pressing governs cost; Si3N4 is the closest alternative where oxidation exposure is milder. Sialon has a density of 3.25 g/cm³ (0.117 lb/in³), lighter than 70% of ceramic grades. It melts at 1,800°C (3,272 °F). Sialon has a tensile strength of 350 MPa (50.8 ksi), stronger than 71% of ceramic grades. The elastic modulus is 288 GPa (41.8 Msi).
What is Sialon used for?
- cutting inserts for nickel alloys
- molten metal handling
- thermocouple protection tubes
- wear parts
Advantages
- Good corrosion resistance — 90/100, better than 81% of ceramic grades
- Tough — resists crack growth — 7.7 MPa·√m (7.01 ksi·√in), better than 76% of ceramic grades
Sialon properties
Typical room-temperature values for Sialon-BETA; bars are the position among ceramic grades.
Physical3
Sialon has a density of 3.25 g/cm³ (0.117 lb/in³), lighter than 70% of ceramic grades. It melts at 1,800°C (3,272 °F).
Mechanical11
Sialon has a tensile strength of 350 MPa (50.8 ksi), stronger than 71% of ceramic grades. The elastic modulus is 288 GPa (41.8 Msi).
Thermal5
Sialon is rated for continuous service to 1,200°C (2,192 °F). It conducts heat at 21 W/m·K (12.1 BTU/hr·ft·°F), worse than 52% of ceramic grades. Thermal expansion is 3 µm/m·K (1.67 µin/in·°F).
Electrical5
Sialon is an electrical insulator with a dielectric strength of 15 kV/mm (381 V/mil) and a resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (90/100), better than 81% of ceramic grades.
Sustainability4
Producing a kilogram of Sialon takes about 230 MJ of energy and emits 14 kg of CO₂ — more than 65% of ceramic grades. Typical recycled content is 0%.
Manufacturability3
Sialon's machinability is not recommended (4/100, worse than 85% 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.
Strength versus weight in the ceramic family
Yield strength against density for every ceramic grade FabDigit runs. Sialon is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Sialon
Is Sialon easy to machine?
Green/bisque machining is preferred; after sintering only diamond grinding, lapping or (TiN grade) EDM works — allow ~20 % shrinkage in green design.
Can Sialon be welded?
Not weldable; joined by active-metal brazing (Ti-containing AgCu filler), glass sealing or mechanical shrink/clamp mounts with compliant gaskets.
Can Sialon be formed, bent or molded?
Formed by uniaxial/cold-isostatic pressing, slip or injection moulding of Si3N4+AlN+Al2O3+Y2O3 powder, then pressureless or gas-pressure sintering at 1650–1850 °C in N₂; HIP for maximum density.
Sialon 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 |
|---|---|---|
| Sias β-Si6-zAlzOzN8-z, z ≈ 0.5–1.5 for engineering grades | 42 – 58 | 50 |
| N | 27 – 36 | 34 |
| Alsubstitutes for Si in the lattice | 3 – 14 | 9.5 |
| Olattice O plus grain-boundary glass | 2 – 9 | 5.5 |
| Y (as Y2O3 sintering aid)some grades use Yb2O3/Ce2O3 or MgO instead | 0.5 – 5 | 2.5 |
| Si+Al+O+N balanceimpurities (Fe, Ca) typically < 0.5 % | balance |
What surface finishes work on Sialon?
Diamond lapping/polishing to Ra < 0.05 µm; edges must be honed or chamfered to avoid chipping; CVD/PVD coatings (TiN, Al₂O₃) applied on cutting-tool grades.
Equivalent designations
Standards and trade names that resolve to Sialon in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- 26845
How much does Sialon cost?
Sialon is a high-cost ceramic ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sialon — frequently asked
What is Sialon used for?
Sialon is typically used for cutting inserts for nickel alloys, molten metal handling, thermocouple protection tubes and wear parts. In short: superalloy-turning insert ceramic; best thermal-shock nitride; EDM-capable TiN grade.
What is the tensile strength of Sialon?
Sialon has a typical tensile strength of 350 MPa (50.8 ksi) — stronger than 71% of ceramic grades. Strength varies by condition: see the 3 listed tempers.
Is Sialon easy to machine?
Not especially — machinability is rated not recommended (4/100, worse than 85% of ceramic grades). Green/bisque machining is preferred; after sintering only diamond grinding, lapping or (TiN grade) EDM works — allow ~20 % shrinkage in green design.
Can Sialon be welded?
Not weldable; joined by active-metal brazing (Ti-containing AgCu filler), glass sealing or mechanical shrink/clamp mounts with compliant gaskets.
What surface finishes work on Sialon?
Diamond lapping/polishing to Ra < 0.05 µm; edges must be honed or chamfered to avoid chipping; CVD/PVD coatings (TiN, Al₂O₃) applied on cutting-tool grades.
Can Sialon be formed, bent or molded?
Formed by uniaxial/cold-isostatic pressing, slip or injection moulding of Si3N4+AlN+Al2O3+Y2O3 powder, then pressureless or gas-pressure sintering at 1650–1850 °C in N₂; HIP for maximum density.
What is the maximum service temperature of Sialon?
Sialon is rated for continuous use to about 1,200°C (2,192 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Sialon cost?
Sialon is a high-cost ceramic ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ISO 26845 — Chemical analysis of refractories, general requirements — ISO (2008)
- ASM Engineered Materials Handbook, Vol. 4: Ceramics and Glasses — ASM International (1991)
- Syalon 050 / 101 / 110 / 501 technical datasheets — International Syalon (2023)
- Silicon nitride & sialon cutting tool material data — Kyocera / CoorsTek (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.