{ "spore": "profile", "id": "sialon", "spore_version": "0.2", "family": "carbide-nitride-boride-ceramics", "name": "SiAlON (silicon aluminium oxynitride)", "abbreviation": "SiAlON", "role": "wear-resistant structural ceramic", "category": "ceramics", "type": "nitrides", "summary": "SiAlON is a ceramic solid solution based on silicon nitride, in which aluminium and oxygen replace part of the silicon and nitrogen. The sources give a density of 3.1 to 3.7 g/cc (INSACO table), 3.25 g.cm-3 for the Syalon 101 grade, and maximum service temperatures of 1200 to 1700 degC depending on the table. The Syalon 101 bending strength is printed as 945 MPa. The sources describe it as a wear and heat-resistant material for molten-metal handling and machine parts; its weak point is thermal shock.", "best_for": "Heat-resistant and wear-resistant machine parts and molten-metal handling parts, where toughness is not the main requirement", "weakest_at": "Thermal shock and fracture toughness; the glassy grain-boundary phase limits strength at high temperature in pressureless-sintered grades", "identity": { "formula": "Si6-zAlzOzN8-z (beta-SiAlON, z from 0 to 4.2)", "designations": [], "source": "syalons-guide", "where": "beta-SiAlON Ceramics section, general formula" }, "tags": { "environments": [], "stresses": [ "extreme-heat", "thermal-cycling", "mechanical-wear" ], "applications": [ "structures", "mechanisms", "electronics-and-chips" ] }, "properties": [ { "benchmark": "density", "label": "Density, Syalon 101", "value": 3.25, "bound": "exact", "unit": "g.cm-3", "scope": "material", "conditions": { "grade": "Syalon 101 (beta-SiAlON), as named in the table title", "test": "no test conditions printed in the table" }, "method": "Typical value in a table of typical physical and mechanical properties", "status": "ground", "source": "azom-syalon101", "where": "Table 1 (Key Properties section), Density row", "source_detail": { "title": "AZoM article 15727: SiAlON (Syalon 101) typical physical and mechanical properties, molten-metal and wear uses", "id": "AZoM article ArticleID=15727", "url": "https://www.azom.com/article.aspx?ArticleID=15727", "year": 2018, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "elastic_modulus", "label": "Young's modulus, Syalon 101", "value": 288, "bound": "exact", "unit": "GPa", "scope": "material", "conditions": { "grade": "Syalon 101 (beta-SiAlON)", "test": "no test conditions printed in the table" }, "method": "Typical value in a table of typical physical and mechanical properties", "status": "ground", "source": "azom-syalon101", "where": "Table 1 (Key Properties section), Young's Modulus row", "source_detail": { "title": "AZoM article 15727: SiAlON (Syalon 101) typical physical and mechanical properties, molten-metal and wear uses", "id": "AZoM article ArticleID=15727", "url": "https://www.azom.com/article.aspx?ArticleID=15727", "year": 2018, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "flexural_strength", "label": "Bend strength, Syalon 101", "value": 945, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "grade": "Syalon 101 (beta-SiAlON)", "test": "bend test; no test conditions printed in the table" }, "method": "Typical value in a table of typical physical and mechanical properties", "status": "ground", "source": "azom-syalon101", "where": "Table 1 (Key Properties section), Bend Strength row", "source_detail": { "title": "AZoM article 15727: SiAlON (Syalon 101) typical physical and mechanical properties, molten-metal and wear uses", "id": "AZoM article ArticleID=15727", "url": "https://www.azom.com/article.aspx?ArticleID=15727", "year": 2018, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "fracture_toughness", "label": "Fracture toughness K1c, Syalon 101", "value": 7.7, "bound": "exact", "unit": "MPa.m 0.5", "scope": "material", "conditions": { "grade": "Syalon 101 (beta-SiAlON)", "test": "method not printed in the table" }, "method": "Typical value in a table of typical physical and mechanical properties; property name is not in the canonical list", "status": "ground", "source": "azom-syalon101", "where": "Table 1 (Key Properties section), Fracture Toughness K1c row", "source_detail": { "title": "AZoM article 15727: SiAlON (Syalon 101) typical physical and mechanical properties, molten-metal and wear uses", "id": "AZoM article ArticleID=15727", "url": "https://www.azom.com/article.aspx?ArticleID=15727", "year": 2018, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "hardness", "label": "Hardness, Syalon 101 (type not printed)", "value": 15, "bound": "exact", "unit": "GPa", "scope": "material", "conditions": { "grade": "Syalon 101 (beta-SiAlON)", "test": "hardness scale and load not printed in the table" }, "method": "Typical value in a table of typical physical and mechanical properties", "status": "ground", "source": "azom-syalon101", "where": "Table 1 (Key Properties section), Hardness row", "source_detail": { "title": "AZoM article 15727: SiAlON (Syalon 101) typical physical and mechanical properties, molten-metal and wear uses", "id": "AZoM article ArticleID=15727", "url": "https://www.azom.com/article.aspx?ArticleID=15727", "year": 2018, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "thermal_conductivity", "label": "Thermal conductivity, Syalon 101", "value": 28, "bound": "exact", "unit": "W/m.K", "scope": "material", "conditions": { "grade": "Syalon 101 (beta-SiAlON)", "temperature": "not printed in the table" }, "method": "Typical value in a table of typical physical and mechanical properties", "status": "ground", "source": "azom-syalon101", "where": "Table 1 (Key Properties section), Thermal Conductivity row", "source_detail": { "title": "AZoM article 15727: SiAlON (Syalon 101) typical physical and mechanical properties, molten-metal and wear uses", "id": "AZoM article ArticleID=15727", "url": "https://www.azom.com/article.aspx?ArticleID=15727", "year": 2018, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "max_service_temp", "label": "Maximum operating temperature, Syalon 101", "value": 1200, "bound": "exact", "unit": "°C", "scope": "material", "conditions": { "grade": "Syalon 101 (beta-SiAlON)", "basis": "maximum operating temperature as printed in the table" }, "method": "Typical value in a table of typical physical and mechanical properties", "status": "ground", "source": "azom-syalon101", "where": "Table 1 (Key Properties section), Maximum Operating Temperature row", "source_detail": { "title": "AZoM article 15727: SiAlON (Syalon 101) typical physical and mechanical properties, molten-metal and wear uses", "id": "AZoM article ArticleID=15727", "url": "https://www.azom.com/article.aspx?ArticleID=15727", "year": 2018, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "density", "label": "Density, SiAlON (INSACO table, range)", "value": 3.1, "value_high": 3.7, "bound": "range", "unit": "gm/cc", "scope": "material", "conditions": { "product": "SiAlON, the table names no grade", "temperature": "room temperature, per the table footnote" }, "method": "Range printed in a table of properties attributed to INSACO", "status": "ground", "source": "azom-insaco", "where": "Mechanical Properties table, Density row", "source_detail": { "title": "AZoM article 5065: SiAlON properties table attributed to INSACO Inc.", "id": "AZoM article ArticleID=5065", "url": "https://www.azom.com/article.aspx?ArticleID=5065", "year": 2008, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "hardness", "label": "Hardness, SiAlON (INSACO table, range)", "value": 1600, "value_high": 1800, "bound": "range", "unit": "Knoop", "scope": "material", "conditions": { "product": "SiAlON, the table names no grade", "temperature": "room temperature, per the table footnote" }, "method": "Range printed in a table of properties attributed to INSACO", "status": "ground", "source": "azom-insaco", "where": "Mechanical Properties table, Hardness row", "source_detail": { "title": "AZoM article 5065: SiAlON properties table attributed to INSACO Inc.", "id": "AZoM article ArticleID=5065", "url": "https://www.azom.com/article.aspx?ArticleID=5065", "year": 2008, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "ultimate_tensile_strength", "label": "Tensile strength, SiAlON (INSACO table)", "value": 28, "bound": "exact", "unit": "kpsi", "scope": "material", "conditions": { "product": "SiAlON, the table names no grade", "temperature": "room temperature, per the table footnote" }, "method": "Value printed in a table of properties attributed to INSACO", "status": "ground", "source": "azom-insaco", "where": "Mechanical Properties table, Tensile Strength row", "source_detail": { "title": "AZoM article 5065: SiAlON properties table attributed to INSACO Inc.", "id": "AZoM article ArticleID=5065", "url": "https://www.azom.com/article.aspx?ArticleID=5065", "year": 2008, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "flexural_strength", "label": "Flexural strength, SiAlON (INSACO table)", "value": 110, "bound": "exact", "unit": "kpsi", "scope": "material", "conditions": { "product": "SiAlON, the table names no grade", "temperature": "room temperature, per the table footnote" }, "method": "Value printed in a table of properties attributed to INSACO", "status": "ground", "source": "azom-insaco", "where": "Mechanical Properties table, Flexural Strength row", "source_detail": { "title": "AZoM article 5065: SiAlON properties table attributed to INSACO Inc.", "id": "AZoM article ArticleID=5065", "url": "https://www.azom.com/article.aspx?ArticleID=5065", "year": 2008, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "poissons_ratio", "label": "Poisson's ratio, SiAlON (INSACO table)", "value": 0.21, "bound": "exact", "unit": "-", "scope": "material", "conditions": { "product": "SiAlON, the table names no grade", "temperature": "room temperature, per the table footnote" }, "method": "Value printed in a table of properties attributed to INSACO", "status": "ground", "source": "azom-insaco", "where": "Mechanical Properties table, Poisson's Ratio row", "source_detail": { "title": "AZoM article 5065: SiAlON properties table attributed to INSACO Inc.", "id": "AZoM article ArticleID=5065", "url": "https://www.azom.com/article.aspx?ArticleID=5065", "year": 2008, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "dielectric_strength", "label": "Dielectric strength, SiAlON (INSACO table)", "value": 212, "bound": "exact", "unit": "ac V/mil", "scope": "material", "conditions": { "product": "SiAlON, the table names no grade", "temperature": "room temperature, per the table footnote" }, "method": "Value printed in a table of properties attributed to INSACO", "status": "ground", "source": "azom-insaco", "where": "Electrical Properties table, Dielectric Strength row", "source_detail": { "title": "AZoM article 5065: SiAlON properties table attributed to INSACO Inc.", "id": "AZoM article ArticleID=5065", "url": "https://www.azom.com/article.aspx?ArticleID=5065", "year": 2008, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "dielectric_constant", "label": "Dielectric constant, SiAlON (INSACO table)", "value": 9.3, "bound": "exact", "unit": "-", "scope": "material", "conditions": { "product": "SiAlON, the table names no grade", "frequency": "1 MHz" }, "method": "Value printed in a table of properties attributed to INSACO", "status": "ground", "source": "azom-insaco", "where": "Electrical Properties table, Dielectric Constant row", "source_detail": { "title": "AZoM article 5065: SiAlON properties table attributed to INSACO Inc.", "id": "AZoM article ArticleID=5065", "url": "https://www.azom.com/article.aspx?ArticleID=5065", "year": 2008, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "thermal_conductivity", "label": "Thermal conductivity, SiAlON (INSACO table, range)", "value": 18, "value_high": 25, "bound": "range", "unit": "W/mK", "scope": "material", "conditions": { "product": "SiAlON, the table names no grade", "temperature": "room temperature, per the table footnote" }, "method": "Range printed in a table of properties attributed to INSACO", "status": "ground", "source": "azom-insaco", "where": "Thermal Properties table, Thermal Conductivity row", "source_detail": { "title": "AZoM article 5065: SiAlON properties table attributed to INSACO Inc.", "id": "AZoM article ArticleID=5065", "url": "https://www.azom.com/article.aspx?ArticleID=5065", "year": 2008, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "specific_heat", "label": "Specific heat, SiAlON (INSACO table)", "value": 0.21, "bound": "exact", "unit": "cal/g°C", "scope": "material", "conditions": { "product": "SiAlON, the table names no grade", "temperature": "room temperature, per the table footnote" }, "method": "Value printed in a table of properties attributed to INSACO", "status": "ground", "source": "azom-insaco", "where": "Thermal Properties table, Specific Heat row", "source_detail": { "title": "AZoM article 5065: SiAlON properties table attributed to INSACO Inc.", "id": "AZoM article ArticleID=5065", "url": "https://www.azom.com/article.aspx?ArticleID=5065", "year": 2008, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "max_service_temp", "label": "Maximum working temperature, SiAlON (INSACO table)", "value": 1700, "bound": "exact", "unit": "°C", "scope": "material", "conditions": { "product": "SiAlON, the table names no grade", "basis": "printed as Maximum Working Temperature" }, "method": "Value printed in a table of properties attributed to INSACO", "status": "ground", "source": "azom-insaco", "where": "Thermal Properties table, Maximum Working Temperature row", "source_detail": { "title": "AZoM article 5065: SiAlON properties table attributed to INSACO Inc.", "id": "AZoM article ArticleID=5065", "url": "https://www.azom.com/article.aspx?ArticleID=5065", "year": 2008, "kind": "web", "license": "Web article, cited not reproduced" } }, { "benchmark": "flexural_strength", "label": "Highest room-temperature MOR, hot-pressed beta'-SiAlON (review)", "value": 648, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "form": "hot-pressed beta'-SiAlON bodies", "temperature": "room temperature", "basis": "highest value the 1979 review reports for this form; not one grade" }, "method": "Value stated in the text of a 1979 NASA Lewis state-of-the-art review (cites ref. 17 of that review)", "status": "ground", "source": "nasa-tm79207", "where": "Modulus of Rupture section, text", "source_detail": { "title": "NASA TM-79207: State-of-the-Art of SiAlON Materials (Sunil Dutta, Lewis Research Center)", "id": "NTRS 19790022207, N79-30378", "url": "https://ntrs.nasa.gov/citations/19790022207", "year": 1979, "kind": "report", "license": "public domain (NASA)" } }, { "benchmark": "flexural_strength", "label": "Highest room-temperature MOR, pressureless-sintered beta'-SiAlON (review)", "value": 483, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "form": "pressureless-sintered beta'-SiAlON bodies", "temperature": "room temperature", "basis": "highest value the 1979 review reports for this form; not one grade" }, "method": "Value stated in the text of a 1979 NASA Lewis state-of-the-art review (cites ref. 31 of that review)", "status": "ground", "source": "nasa-tm79207", "where": "Modulus of Rupture section, text", "source_detail": { "title": "NASA TM-79207: State-of-the-Art of SiAlON Materials (Sunil Dutta, Lewis Research Center)", "id": "NTRS 19790022207, N79-30378", "url": "https://ntrs.nasa.gov/citations/19790022207", "year": 1979, "kind": "report", "license": "public domain (NASA)" } }, { "benchmark": "flexural_strength", "label": "Highest MOR at 1370 °C, sintered SiAlON (review)", "value": 375, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "form": "sintered SiAlON", "temperature": "1370 °C" }, "method": "Value stated in the text of a 1979 NASA Lewis state-of-the-art review (cites ref. 29 of that review)", "status": "ground", "source": "nasa-tm79207", "where": "Modulus of Rupture section, text", "source_detail": { "title": "NASA TM-79207: State-of-the-Art of SiAlON Materials (Sunil Dutta, Lewis Research Center)", "id": "NTRS 19790022207, N79-30378", "url": "https://ntrs.nasa.gov/citations/19790022207", "year": 1979, "kind": "report", "license": "public domain (NASA)" } } ], "corrosion": [ { "environment": "Oxidation in air at high temperature", "headline": "SiAlON forms a silica-type protective layer in air at high oxygen pressure, but at low oxygen pressure it forms volatile SiO.", "effect": "Cao and Metselaar describe passive oxidation in a related alpha-prime sialon, which forms a protective layer, and active oxidation at lower oxygen partial pressures, which forms volatile SiO. The review does not give a rate for SiAlON in service.", "rating": "low", "conditions": { "basis": "description of oxidation mechanisms in an alpha-prime sialon review, not a test of a named grade", "atmosphere": "oxygen-containing gas" }, "source": "cao-metselaar-1991", "where": "Oxidation Resistance section and Figure 22 (schematic)" }, { "environment": "Molten-metal handling (thermocouple sheaths and level sensors)", "headline": "SiAlON parts are used in molten-metal handling; the sources give no corrosion rate for this service.", "effect": "The AZoM article lists Syalon grades as thermocouple sheaths for molten metal up to 1200 and 1400 °C and a level sensor up to 800 °C. It does not report corrosion or wear rates for these parts.", "rating": "unknown", "conditions": { "grade": "Syalon grades named in the molten-metal section (not identified by grade in the text)", "metal": "not named in the section" }, "source": "azom-syalon101", "where": "Molten Metal Handling section" } ], "risks": { "hazards": [ { "text": "PubChem's GHS section for silicon nitride (trisilicon tetranitride, CID 3084099) reads Not Classified: the compound does not meet GHS hazard criteria for 97.3% (250 of 257) of reports. This is a related compound, not SiAlON; no SiAlON hazard record was found.", "ghs": [], "source": "pubchem-sin3n4", "where": "Safety and Hazards, GHS Classification" } ], "failure_risks": [ { "mode": "Brittle fracture under thermal shock", "trigger": "Rapid temperature change on a SiAlON part", "consequence": "The NASA review attributes poor thermal shock behaviour of beta-SiAlON to its low thermal conductivity and poor fracture toughness. No thermal shock test value is kept here, because the only product page that printed one could not be re-read for verification.", "severity": "high", "source": "nasa-tm79207", "where": "Thermal Shock section" }, { "mode": "Loss of high-temperature strength from grain-boundary glass", "trigger": "Use near the top of the service range in grades sintered without pressure", "consequence": "The NASA review says the glassy grain-boundary phase has a controlling influence on high-temperature properties of sintered bodies. Syalon grades convert this glass to a refractory crystal phase to raise the service temperature.", "severity": "moderate", "source": "nasa-tm79207", "where": "Density and Microstructure section, text" }, { "mode": "Active oxidation to volatile SiO", "trigger": "Operation at low oxygen partial pressure", "consequence": "Cao and Metselaar describe volatile SiO formation under active oxidation, which removes material from the surface.", "severity": "low", "source": "cao-metselaar-1991", "where": "Oxidation Resistance section" } ], "side_effects": [ { "text": "Active oxidation releases volatile SiO gas instead of forming a protective layer.", "affects": "Surface recession and the furnace or chamber atmosphere", "source": "cao-metselaar-1991", "where": "Oxidation Resistance section" } ], "handling": [ { "text": "No handling or storage instructions for SiAlON were found in the sources read; no supplier safety data sheet was retrieved.", "source": "pubchem-sin3n4", "where": "Safety and Hazards (related compound)" } ], "mitigations": [ { "text": "Limit fast temperature changes, since the sources tie thermal shock failure to low conductivity and poor toughness.", "source": "nasa-tm79207", "where": "Thermal Shock section (implication of the finding)" } ] }, "uses": [ { "application": "structures", "device": "Thermocouple sheath for molten metal", "example": "The AZoM article lists Syalon grades as thermocouple sheaths for molten metal, with a stated temperature range of up to 1200 and 1400 °C.", "source": "azom-syalon101", "where": "Molten Metal Handling section" }, { "application": "mechanisms", "device": "Automotive location pin", "example": "In the AZoM article a Syalon 101 pin lasted a year, against 8 hours for a conventional steel pin with an alumina sleeve.", "source": "azom-syalon101", "where": "Wear Components section" }, { "application": "electronics-and-chips", "device": "Semiconductor equipment parts", "example": "Ferrotec lists semiconductor equipment parts, general industry machinery parts, heat-resistant parts and abrasion-resistant parts among SiAlON applications.", "source": "ferrotec-sialon", "where": "Applications section" } ], "supply": [ { "subject": "Aluminium", "producers": [ { "country": "China", "share_percent": 60.8, "year": 2025 }, { "country": "India", "share_percent": 5.7, "year": 2025 }, { "country": "Russia", "share_percent": 5.3, "year": 2025 }, { "country": "Canada", "share_percent": 4.5, "year": 2025 } ], "critical_lists": [ { "list": "USGS 2025 List of Critical Minerals (aluminum)", "listed": true }, { "list": "EU critical raw materials list (aluminium and bauxite merged into one entry)", "listed": true } ], "recycling": "USGS: about 3.6 million tons of aluminum was recovered from purchased scrap in the United States in 2025.", "substitutes": [], "source": "usgs-mcs2026-aluminum", "where": "World smelter production 2025e table (shares calculated by Space Mushroom against the 74,000 thousand t world total); Salient Statistics and Recycling text. Lists: USGS and European Commission pages." }, { "subject": "Silicon", "producers": [ { "country": "China", "share_percent": 87, "year": 2025 }, { "country": "Brazil", "share_percent": 3.9, "year": 2025 }, { "country": "Norway", "share_percent": 2.8, "year": 2025 } ], "critical_lists": [ { "list": "USGS 2025 List of Critical Minerals (silicon added in the 2025 list)", "listed": true }, { "list": "EU critical raw materials list (silicon metal entry)", "listed": true } ], "recycling": "USGS: silicon recycling is insignificant.", "substitutes": [ "USGS: gallium arsenide and germanium are the principal substitutes for silicon in semiconductor and infrared applications." ], "source": "usgs-mcs2026-silicon", "where": "World Production table, silicon metal 2025 (shares calculated by Space Mushroom against the 4,600 thousand t world total, which excludes U.S. production); Recycling and Substitutes text. Lists: USGS and European Commission pages." } ], "media": [], "documents": [ { "title": "International Syalons: Advanced silicon nitride and SiAlON ceramics guide (types of SiAlON)", "type": "datasheet", "url": "https://www.syalons.com/wp-content/uploads/2018/03/guide-to-types-of-sialon-ceramics.pdf", "year": 2018 }, { "title": "AZoM: What are SiAlON ceramics? Syalon 101 typical properties table (article 15727)", "type": "datasheet", "url": "https://www.azom.com/article.aspx?ArticleID=15727", "year": 2018 }, { "title": "AZoM: SiAlON ceramic properties table attributed to INSACO (article 5065)", "type": "datasheet", "url": "https://www.azom.com/article.aspx?ArticleID=5065", "year": 2008 }, { "title": "Ferrotec: SiAlON ceramics product page", "type": "datasheet", "url": "https://ceramics.ferrotec.com/materials/advanced/sialon/", "year": 2026 }, { "title": "NASA TM-79207: State-of-the-Art of SiAlON Materials (Dutta, Lewis Research Center, 1979)", "type": "report", "url": "https://ntrs.nasa.gov/citations/19790022207", "year": 1979 }, { "title": "Cao and Metselaar: alpha-prime sialon ceramics, a review (Chemistry of Materials 3, 242, 1991)", "type": "paper", "url": "https://pure.tue.nl/ws/files/1696947/620117.pdf", "year": 1991 }, { "title": "PubChem: Trisilicon tetranitride (silicon nitride, CID 3084099), GHS classification", "type": "database", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/3084099", "year": 2026 }, { "title": "USGS Mineral Commodity Summaries 2026: Aluminum", "type": "report", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-aluminum.pdf", "year": 2026 }, { "title": "USGS Mineral Commodity Summaries 2026: Silicon", "type": "report", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silicon.pdf", "year": 2026 } ], "gaps": [ "No space flight, vacuum, radiation or thermal-vacuum result for SiAlON was found in the sources read.", "No UNS, EN or other standard designation for SiAlON was printed in any source read; the only designation listed is the trade name Syalon 101.", "Coefficient of thermal expansion is printed in the sources with an exponent (x 10-6 per degree C) and is left out; volume resistivity (printed as greater than 10^14 ohm-cm) and the INSACO modulus (printed as 46 x 10^6 psi) are left out for the same reason.", "The Ferrotec, INSACO and AZoM 5065 tables name no grade; those rows are labelled as SiAlON without a grade. Only the AZoM Syalon 101 table names a grade.", "No SiAlON-specific safety data sheet was retrieved; the supplier pages for SiAlON sheet (American Elements, Goodfellow) blocked automated access. The hazard entry uses PubChem's record for silicon nitride, a related compound.", "The sources give a composition range (z from 0 to 4.2), not a fixed formula, so the recipe lists elements without atom counts.", "No corrosion or wear rate for molten aluminium was found; the molten-metal rows describe use, not a measured rate.", "The NASA TM-79207 text is an OCR scan with degree signs and superscripts lost; only values that could be read clearly are used. Its density and thermal expansion values are not used.", "The USGS list of critical minerals page confirms aluminum and silicon; the European Commission page lists silicon metal and merges aluminium into the bauxite entry.", "The Wikipedia SiAlON article gives history and composition only and is not cited for any value in this profile.", "Property names fracture_toughness and hardness are not in the canonical list and are used as short names.", "The densities disagree by source: 3.1 to 3.7 gm/cc (INSACO table) and 3.25 g.cm-3 (Syalon 101). Each is kept with its source.", "The Ferrotec SiAlON product page (ceramics.ferrotec.com) is cited only for its applications list. Its property table was read in this run but the verification fetch was blocked by a Cloudflare page, so its nine property rows (density, bending strength, Young modulus, Vickers hardness, service temperature, thermal conductivity, dielectric constant, water absorption, thermal shock) are left out." ], "story": { "why": "SiAlON is a ceramic solid solution of silicon nitride in which aluminium and oxygen replace part of the silicon and nitrogen. The beta form has the same atomic arrangement as beta silicon nitride, and the sources describe it as having better properties than both silicon nitride and alumina. It is used where heat and wear resistance matter, and the sources list molten-metal handling, cutting and machine parts among its applications.", "uses": [ { "where": "Molten-metal handling", "line": "The AZoM article lists Syalon grades as thermocouple sheaths for molten metal, with a stated range of up to 1200 and 1400 °C." }, { "where": "Automotive wear part", "line": "In the AZoM article a Syalon 101 location pin lasted a year, against 8 hours for a conventional steel pin with an alumina sleeve." }, { "where": "Semiconductor and industrial parts", "line": "Ferrotec lists semiconductor equipment parts, general industry machinery parts, heat-resistant parts and abrasion-resistant parts among SiAlON applications." } ], "can_do": [ { "label": "Molten-metal service", "line": "The AZoM article lists thermocouple sheaths for molten metal up to 1200 and 1400 °C.", "scope": "material" }, { "label": "Wear in a part", "line": "A Syalon 101 location pin lasted a year in the AZoM article's automotive example.", "scope": "material" }, { "label": "Bending load at room temperature", "line": "945 MPa for Syalon 101 in the AZoM table.", "scope": "material" }, { "label": "Strength at high temperature", "line": "The NASA review gives 375 MPa as the highest sintered-material MOR at 1370 °C.", "scope": "material" } ], "compare": "The sources describe SiAlON as having better properties than both silicon nitride and alumina, but the NASA review says that room-temperature strength of pressureless-sintered beta'-SiAlON is lower than that of hot-pressed silicon nitride. The published density differs by table: 3.1 to 3.7 g/cc in the INSACO table, 3.25 g.cm-3 for Syalon 101. The maximum service temperature runs from 1200 to 1700 °C across the three tables.", "compare_rows": [ { "label": "Density", "benchmark": "density", "scope": "material" }, { "label": "Maximum service temperature", "benchmark": "max_service_temp", "scope": "material" }, { "label": "Thermal conductivity", "benchmark": "thermal_conductivity", "scope": "material" } ], "handling": [ "No storage or handling instructions for SiAlON were found in the sources read.", "Avoid rapid temperature changes, because the sources tie thermal shock failure to low conductivity and poor toughness.", "Silicon nitride is not classified in the PubChem record; no dust limit was found for SiAlON." ], "good_for": [ "Heat-resistant and abrasion-resistant machine parts, which Ferrotec lists among its SiAlON applications.", "Wear parts in hot or abrasive service, such as the Syalon 101 location pin in the AZoM example." ], "watch_out": [ "Thermal shock: low thermal conductivity and poor fracture toughness make cracking on fast temperature change a risk (NASA review).", "Fracture toughness is 7.7 MPa.m 0.5 for Syalon 101 (AZoM table).", "Glassy grain-boundary phase limits high-temperature strength in pressureless-sintered grades (NASA review).", "Density, service temperature and strength differ by grade and by source; check the grade before using a value." ], "verdict": "SiAlON is a hard, heat-resistant ceramic whose main weakness is thermal shock. Choose the grade for the service temperature and test for thermal cycling.", "recipe": { "line": "SiAlON is a solid solution built on silicon nitride (Si3N4). Silicon and nitrogen are partly replaced by aluminium and oxygen, and a sintering aid such as yttria, magnesia or aluminium nitride is added to densify it.", "parts": [ { "name": "Silicon", "symbol": "Si", "role": "Part of the rigid Si-N framework of silicon nitride; partly replaced by aluminium." }, { "name": "Nitrogen", "symbol": "N", "role": "Part of the framework; partly replaced by oxygen to keep the charge balanced." }, { "name": "Aluminium", "symbol": "Al", "role": "Replaces silicon. In SiAlON the aluminium is coordinated as AlO4, not as AlO6 as in alumina." }, { "name": "Oxygen", "symbol": "O", "role": "Replaces nitrogen, which keeps the charge balanced when aluminium replaces silicon." }, { "name": "Yttria or magnesia (sintering aid)", "symbol": "Y2O3, MgO", "role": "Forms a liquid during sintering that cools to a refractory intergranular glass." } ] }, "risk_groups": [ { "title": "For people", "lead": "No hazard data for SiAlON itself were found. The closest compound with a PubChem GHS record, silicon nitride, is not classified.", "points": [ { "label": "Silicon nitride GHS", "line": "PubChem reports that silicon nitride (trisilicon tetranitride) does not meet GHS hazard criteria for 97.3% (250 of 257) of reports." }, { "label": "Dust", "line": "No dust or inhalation data for SiAlON were found in the sources read." } ], "verdict": "Not classified in the closest PubChem record" }, { "title": "If a part cracks or overheats", "lead": "These are the failure modes the sources describe. No SiAlON incident data were found.", "points": [ { "label": "Thermal shock", "line": "The NASA review attributes poor thermal shock behaviour to low thermal conductivity and poor fracture toughness." }, { "label": "Glass phase", "line": "The NASA review says the glassy grain-boundary phase controls high-temperature properties of sintered bodies." } ], "verdict": "Brittle: thermal shock and grain-boundary glass" }, { "title": "Handling and storage", "points": [ { "label": "Storage", "line": "No storage instructions for SiAlON were found in the sources read." }, { "label": "Molten metal", "line": "The AZoM article describes molten-metal use but gives no corrosion or wear rate for it." } ], "verdict": "No storage or handling statements found" } ] }, "updated": "2026-11-01", "review": { "status": "draft", "method": "assistant", "checked_values": 20, "unreachable": 1, "caveats": 2, "note": "Written by an AI assistant on 2026-11-01 from pages fetched in this run. Supplier safety sheets were blocked; the hazard entry uses the PubChem record for silicon nitride. The Ferrotec property table is left out because the verification fetch was blocked." }, "sources": { "azom-syalon101": { "title": "AZoM article 15727: SiAlON (Syalon 101) typical physical and mechanical properties, molten-metal and wear uses", "id": "AZoM article ArticleID=15727", "url": "https://www.azom.com/article.aspx?ArticleID=15727", "year": 2018, "kind": "web", "license": "Web article, cited not reproduced" }, "azom-insaco": { "title": "AZoM article 5065: SiAlON properties table attributed to INSACO Inc.", "id": "AZoM article ArticleID=5065", "url": "https://www.azom.com/article.aspx?ArticleID=5065", "year": 2008, "kind": "web", "license": "Web article, cited not reproduced" }, "ferrotec-sialon": { "title": "Ferrotec: SiAlON ceramics (advanced ceramics product page)", "id": "Ferrotec advanced ceramics, SiAlON", "url": "https://ceramics.ferrotec.com/materials/advanced/sialon/", "year": 2026, "kind": "datasheet", "license": "Manufacturer page, cited not reproduced" }, "syalons-guide": { "title": "International Syalons: Advanced silicon nitride and SiAlON ceramics, guide to types of SiAlON ceramics", "id": "International Syalons (Newcastle) Limited", "url": "https://www.syalons.com/wp-content/uploads/2018/03/guide-to-types-of-sialon-ceramics.pdf", "year": 2018, "kind": "datasheet", "license": "Manufacturer guide, cited not reproduced" }, "nasa-tm79207": { "title": "NASA TM-79207: State-of-the-Art of SiAlON Materials (Sunil Dutta, Lewis Research Center)", "id": "NTRS 19790022207, N79-30378", "url": "https://ntrs.nasa.gov/citations/19790022207", "year": 1979, "kind": "report", "license": "public domain (NASA)" }, "cao-metselaar-1991": { "title": "alpha'-Sialon ceramics: a review (Cao and Metselaar, Chemistry of Materials 3, 242-252)", "id": "doi:10.1021/cm00014a009", "url": "https://pure.tue.nl/ws/files/1696947/620117.pdf", "year": 1991, "kind": "paper", "license": "repository copy, cited not reproduced" }, "wikipedia-sialon": { "title": "Wikipedia: SiAlON (history and composition only)", "id": "en.wikipedia.org/wiki/Sialon", "url": "https://en.wikipedia.org/wiki/Sialon", "year": 2026, "kind": "web", "license": "CC BY-SA 4.0" }, "pubchem-sin3n4": { "title": "PubChem compound record, Trisilicon tetranitride (silicon nitride), CID 3084099", "id": "CID 3084099", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/3084099", "year": 2026, "kind": "database", "license": "public domain (NCBI)" }, "usgs-mcs2026-aluminum": { "title": "Mineral Commodity Summaries 2026: Aluminum", "id": "USGS MCS 2026, February 2026", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-aluminum.pdf", "year": 2026, "kind": "report", "license": "public domain (USGS)" }, "usgs-mcs2026-silicon": { "title": "Mineral Commodity Summaries 2026: Silicon", "id": "USGS MCS 2026, February 2026", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silicon.pdf", "year": 2026, "kind": "report", "license": "public domain (USGS)" }, "usgs-crit2025": { "title": "About the 2025 List of Critical Minerals (USGS, final list of 60 minerals)", "id": "Final 2025 List of Critical Minerals", "url": "https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals", "year": 2025, "kind": "web", "license": "public domain (USGS)" }, "ec-crm": { "title": "Critical raw materials (European Commission, Regulation (EU) 2024/1252)", "id": "Regulation (EU) 2024/1252", "url": "https://single-market-economy.ec.europa.eu/sectors/raw-materials/areas-specific-interest/critical-raw-materials_en", "year": 2024, "kind": "web", "license": "European Commission web page" } }, "license": "CC-BY-4.0", "url": "https://spacemushroom.com/profiles/sialon/" }