Sialon GP
Grade
GP = general-purpose sintered sialon
Lower-cost, slightly less dense grade for wear plates, nozzles and molten-metal handling where peak strength is not required.
Values for the GP condition
Other Sialon tempers and conditions
Sialon is listed in 3 conditions; see the grade overview at Sialon.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
GPThis page 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 |
What is Sialon GP?
Sialon GP is Sialon in the GP grade — lower-cost, slightly less dense grade for wear plates, nozzles and molten-metal handling where peak strength is not required. Sialon GP has a tensile strength of 350 MPa (50.8 ksi), stronger than 71% of ceramic grades. The elastic modulus is 250 GPa (36.3 Msi). Sialon GP has a density of 3.15 g/cm³ (0.114 lb/in³), lighter than 73% of ceramic grades. It melts at 1,800°C (3,272 °F). BETA is the default condition FabDigit quotes; GP is available on request or by drawing note.
Sialon GP properties
Typical room-temperature values for Sialon GP; 11 are specific to this condition. Other listed values are Sialon reference data and may not represent this condition. Bars are the position among ceramic grades.
Physical3
Sialon GP has a density of 3.15 g/cm³ (0.114 lb/in³), lighter than 73% of ceramic grades. It melts at 1,800°C (3,272 °F).
Mechanical11
Sialon GP has a tensile strength of 350 MPa (50.8 ksi), stronger than 71% of ceramic grades. The elastic modulus is 250 GPa (36.3 Msi).
Thermal5
Sialon GP is rated for continuous service to 1,100°C (2,012 °F). It conducts heat at 16 W/m·K (9.24 BTU/hr·ft·°F), worse than 56% of ceramic grades. Thermal expansion is 3 µm/m·K (1.67 µin/in·°F).
Electrical5
Sialon GP 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 (85/100), better than 69% of ceramic grades.
Sustainability4
Producing a kilogram of Sialon GP 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 GP's machinability is not recommended (6/100, better than 61% of ceramic grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Sialon GP
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.
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.
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 | — |
Sialon GP — frequently asked
What is Sialon GP used for?
Sialon GP 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 GP?
Sialon GP 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 GP easy to machine?
Not especially — machinability is rated not recommended (6/100, better than 61% 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 GP 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 GP?
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 GP 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 GP?
Sialon GP is rated for continuous use to about 1,100°C (2,012 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.