{
  "spore": "profile",
  "id": "silicon-nitride",
  "spore_version": "0.2",
  "family": "carbide-nitride-boride-ceramics",
  "name": "Silicon nitride",
  "abbreviation": "Si3N4",
  "role": "structural ceramic",
  "category": "ceramics",
  "type": "nitrides",
  "summary": "Silicon nitride is a high-strength structural ceramic used in bearing elements and high-temperature components. Its reported properties depend on the forming and densification route: this profile keeps a gas-pressure-sintered grade, several legacy NIST grades, and a manufacturer bearing grade separate. The available sources show good strength and thermal-shock properties, while also documenting oxidation in hot wet oxygen and contact damage in bearing tests.",
  "best_for": "Structural parts and bearing elements where low mass, wear resistance, high temperature capability, or thermal shock resistance matter.",
  "weakest_at": "Grade-sensitive performance and brittle contact damage; select a process and grade, and use its own design data.",
  "identity": {
    "formula": "Si3N4 (trisilicon tetranitride)",
    "cas": "12033-89-5",
    "designations": [],
    "source": "pubchem-sin3n4",
    "where": "Molecular Formula and CAS sections, CID 3084099"
  },
  "tags": {
    "environments": [
      "launch",
      "deep-space"
    ],
    "stresses": [
      "extreme-heat",
      "thermal-cycling",
      "mechanical-wear"
    ],
    "applications": [
      "propulsion-and-tanks",
      "mechanisms",
      "structures"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Bulk density, gas-pressure-sintered SN-GP",
      "value": 3.18,
      "value_high": 3.3,
      "bound": "range",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP",
        "basis": "manufacturer's test samples",
        "composition": "85-92 wt% Si3N4 plus 8-15 wt% RE2O3/Al2O3 blend per Qsil datasheet"
      },
      "method": "Determined according to DIN 623-2, as stated in footnote [1]",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 2, General Properties, Bulk Density row",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "residual_porosity",
      "label": "Residual porosity, gas-pressure-sintered SN-GP",
      "value": 1,
      "bound": "upper",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP",
        "printed_value": "< 1%"
      },
      "method": "Manufacturer datasheet value; the density and porosity method is identified as DIN 623-2",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 2, General Properties, Residual Porosity row and footnote [1]",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "grain_size",
      "label": "Grain size, longitudinal direction, gas-pressure-sintered SN-GP",
      "value": 1,
      "value_high": 15,
      "bound": "range",
      "unit": "µm",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP",
        "direction": "longitudinal"
      },
      "method": "Manufacturer datasheet range",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 2, General Properties, Grain Size (Longitudinal Direction) row",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "hardness",
      "label": "Hardness, gas-pressure-sintered SN-GP",
      "value": 14.5,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP",
        "test_method_note": "The datasheet footnotes [2] and [3] appear to point to each other's property labels."
      },
      "method": "Manufacturer datasheet value; test-method footnote cross-references are inconsistent in the source",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 3, Mechanical Properties, Hardness row",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "compressive_strength",
      "label": "Compressive strength, gas-pressure-sintered SN-GP",
      "value": 3000,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP",
        "basis": "manufacturer's test samples"
      },
      "method": "Manufacturer datasheet value; no test method is stated for this row",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 3, Mechanical Properties, Compressive Strength row",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "flexural_strength",
      "label": "Bending strength (printed as “Bendig Strength”), gas-pressure-sintered SN-GP",
      "value": 670,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP",
        "basis": "manufacturer's test samples"
      },
      "method": "Value copied as the datasheet's bending-strength row; its [3] method footnote is cross-referenced to hardness and is not used as a test method here",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 3, Mechanical Properties, Bendig Strength row",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "weibull_modulus",
      "label": "Weibull modulus, gas-pressure-sintered SN-GP",
      "value": 20,
      "bound": "exact",
      "unit": "unitless",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP"
      },
      "method": "Manufacturer datasheet value",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 3, Mechanical Properties, Weibull-Modulus row",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "fracture_toughness",
      "label": "Fracture toughness, gas-pressure-sintered SN-GP",
      "value": 6.2,
      "bound": "exact",
      "unit": "MPa·m1/2",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP"
      },
      "method": "Calculated from crack length derived from Vickers hardness indentation, according to Niihara, as stated in footnote [4]",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 3, Mechanical Properties, Fracture Toughness row and footnote [4]",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Young's modulus, gas-pressure-sintered SN-GP",
      "value": 290,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP"
      },
      "method": "Manufacturer datasheet value",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 3, Mechanical Properties, Youngs Modulus row",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "poissons_ratio",
      "label": "Poisson ratio, gas-pressure-sintered SN-GP",
      "value": 0.26,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP"
      },
      "method": "Manufacturer datasheet value",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 3, Mechanical Properties, Poisson Ratio row",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Maximum working temperature in air, gas-pressure-sintered SN-GP",
      "value": 1200,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP",
        "atmosphere": "air",
        "basis": "manufacturer-stated maximum working temperature"
      },
      "method": "Manufacturer datasheet value; not a component-specific design allowable",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 4, Thermal Properties, Max. Working Temperature, Air row",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Maximum working temperature in inert atmosphere, gas-pressure-sintered SN-GP",
      "value": 1400,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP",
        "atmosphere": "inert atmosphere",
        "basis": "manufacturer-stated maximum working temperature"
      },
      "method": "Manufacturer datasheet value; not a component-specific design allowable",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 4, Thermal Properties, Max. Working Temperature, Inert Atmosphere row",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "specific_heat",
      "label": "Specific heat capacity, gas-pressure-sintered SN-GP",
      "value": 620,
      "bound": "exact",
      "unit": "J/kgK",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP",
        "temperature": "not stated in this row"
      },
      "method": "Manufacturer datasheet value",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 4, Thermal Properties, Specific Heat Capacity row",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity at 20 °C, gas-pressure-sintered SN-GP",
      "value": 24,
      "bound": "exact",
      "unit": "W/mK",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP",
        "temperature": "20 °C"
      },
      "method": "Manufacturer datasheet value",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 4, Thermal Properties, Thermal Conductivity row",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "cte",
      "label": "Mean coefficient of thermal expansion from room temperature to 1000 °C, gas-pressure-sintered SN-GP",
      "value": 3.2,
      "bound": "exact",
      "unit": "10-6K-1",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP",
        "temperature_range": "RT-1000 °C",
        "printed_unit": "10-6 K-1"
      },
      "method": "Manufacturer datasheet value, in the unit printed",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 4, Thermal Properties, Coeff. of Thermal Expansion, RT-1000 °C row",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "cte",
      "label": "Coefficient of thermal expansion near room temperature, gas-pressure-sintered SN-GP",
      "value": 1.4,
      "bound": "exact",
      "unit": "10-6K-1",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP",
        "temperature_range": "RT ± 20 °C",
        "printed_unit": "10-6 K-1"
      },
      "method": "Manufacturer datasheet value, in the unit printed",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 4, Thermal Properties, Coeff. of Thermal Expansion, RT ± 20 °C row",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "thermal_shock_parameter_r1",
      "label": "Thermal shock parameter R1, gas-pressure-sintered SN-GP",
      "value": 534,
      "bound": "exact",
      "unit": "K",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP",
        "test_case": "critical temperature difference for infinite heat transfer (quenching)"
      },
      "method": "Manufacturer datasheet value; parameter definition is given in footnote [5]",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 4, Thermal Properties, Thermal Shock Parameter R1 row and footnote [5]",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "thermal_shock_parameter_r2",
      "label": "Thermal shock parameter R2, gas-pressure-sintered SN-GP",
      "value": 12822,
      "bound": "exact",
      "unit": "W/m",
      "scope": "material",
      "conditions": {
        "form": "gas-pressure-sintered silicon nitride",
        "grade": "SN-GP",
        "test_case": "finite constant heat transfer (slow heating)"
      },
      "method": "Manufacturer datasheet value; parameter definition is given in footnote [6]",
      "status": "ground",
      "source": "qsil-sn-gp",
      "where": "Section 4, Thermal Properties, Thermal Shock Parameter R2 row and footnote [6]",
      "source_detail": {
        "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
        "id": "F_4-4_26, dated 2022-01-18",
        "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, linked and cited"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, hot-pressed NCX-34",
      "value": 3.37,
      "bound": "exact",
      "unit": "g cm-3",
      "scope": "material",
      "conditions": {
        "form": "hot-pressed silicon nitride",
        "grade": "NCX-34",
        "temperature": "not stated in NIST record"
      },
      "method": "Manufacturer's indicated value, reproduced in NIST Structural Ceramics Database",
      "status": "ground",
      "source": "nist-scd-z00426",
      "where": "Material 1, NCX-34 specification and Density (mass) section",
      "source_detail": {
        "title": "NIST Structural Ceramics Database, Citation Z00426, silicon nitride entries",
        "url": "https://srdata.nist.gov/CeramicDataPortal/Scd/Z00426",
        "kind": "database",
        "license": "Public domain (NIST), cited"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Elastic modulus, hot-pressed NCX-34",
      "value": 310,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "form": "hot-pressed silicon nitride",
        "grade": "NCX-34",
        "temperature": "not stated in NIST record"
      },
      "method": "Manufacturer's indicated value, reproduced in NIST Structural Ceramics Database",
      "status": "ground",
      "source": "nist-scd-z00426",
      "where": "Material 1, NCX-34 specification and Elastic Modulus section",
      "source_detail": {
        "title": "NIST Structural Ceramics Database, Citation Z00426, silicon nitride entries",
        "url": "https://srdata.nist.gov/CeramicDataPortal/Scd/Z00426",
        "kind": "database",
        "license": "Public domain (NIST), cited"
      }
    },
    {
      "benchmark": "fracture_toughness",
      "label": "Fracture toughness, hot-pressed NCX-34",
      "value": 6.35,
      "bound": "exact",
      "unit": "MPa m1/2",
      "scope": "material",
      "conditions": {
        "form": "hot-pressed silicon nitride",
        "grade": "NCX-34",
        "uncertainty": "± 0.10 MPa m1/2"
      },
      "method": "Surface crack in flexure test; unevaluated in the NIST record",
      "status": "ground",
      "source": "nist-scd-z00426",
      "where": "Material 1, Fracture Toughness section",
      "source_detail": {
        "title": "NIST Structural Ceramics Database, Citation Z00426, silicon nitride entries",
        "url": "https://srdata.nist.gov/CeramicDataPortal/Scd/Z00426",
        "kind": "database",
        "license": "Public domain (NIST), cited"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, hot-isostatically pressed NBD200",
      "value": 3.16,
      "bound": "exact",
      "unit": "g cm-3",
      "scope": "material",
      "conditions": {
        "form": "hot-isostatically pressed silicon nitride",
        "grade": "NBD200",
        "temperature": "not stated in NIST record"
      },
      "method": "Manufacturer's indicated value, reproduced in NIST Structural Ceramics Database",
      "status": "ground",
      "source": "nist-scd-z00426",
      "where": "Material 2, NBD200 specification and Density (mass) section",
      "source_detail": {
        "title": "NIST Structural Ceramics Database, Citation Z00426, silicon nitride entries",
        "url": "https://srdata.nist.gov/CeramicDataPortal/Scd/Z00426",
        "kind": "database",
        "license": "Public domain (NIST), cited"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Elastic modulus, hot-isostatically pressed NBD200",
      "value": 320,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "form": "hot-isostatically pressed silicon nitride",
        "grade": "NBD200",
        "temperature": "not stated in NIST record"
      },
      "method": "Manufacturer's indicated value, reproduced in NIST Structural Ceramics Database",
      "status": "ground",
      "source": "nist-scd-z00426",
      "where": "Material 2, NBD200 specification and Elastic Modulus section",
      "source_detail": {
        "title": "NIST Structural Ceramics Database, Citation Z00426, silicon nitride entries",
        "url": "https://srdata.nist.gov/CeramicDataPortal/Scd/Z00426",
        "kind": "database",
        "license": "Public domain (NIST), cited"
      }
    },
    {
      "benchmark": "fracture_toughness",
      "label": "Fracture toughness, hot-isostatically pressed NBD200",
      "value": 5.41,
      "bound": "exact",
      "unit": "MPa m1/2",
      "scope": "material",
      "conditions": {
        "form": "hot-isostatically pressed silicon nitride",
        "grade": "NBD200",
        "uncertainty": "± 0.24 MPa m1/2"
      },
      "method": "Surface crack in flexure test; unevaluated in the NIST record",
      "status": "ground",
      "source": "nist-scd-z00426",
      "where": "Material 2, Fracture Toughness section",
      "source_detail": {
        "title": "NIST Structural Ceramics Database, Citation Z00426, silicon nitride entries",
        "url": "https://srdata.nist.gov/CeramicDataPortal/Scd/Z00426",
        "kind": "database",
        "license": "Public domain (NIST), cited"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, sintered EC-141",
      "value": 3.22,
      "bound": "exact",
      "unit": "g cm-3",
      "scope": "material",
      "conditions": {
        "form": "sintered silicon nitride",
        "grade": "EC-141",
        "temperature": "not stated in NIST record"
      },
      "method": "Manufacturer's indicated value, reproduced in NIST Structural Ceramics Database",
      "status": "ground",
      "source": "nist-scd-z00426",
      "where": "Material 5, EC-141 specification and Density (mass) section",
      "source_detail": {
        "title": "NIST Structural Ceramics Database, Citation Z00426, silicon nitride entries",
        "url": "https://srdata.nist.gov/CeramicDataPortal/Scd/Z00426",
        "kind": "database",
        "license": "Public domain (NIST), cited"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Elastic modulus, sintered EC-141",
      "value": 310,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "form": "sintered silicon nitride",
        "grade": "EC-141",
        "temperature": "not stated in NIST record"
      },
      "method": "Manufacturer's indicated value, reproduced in NIST Structural Ceramics Database",
      "status": "ground",
      "source": "nist-scd-z00426",
      "where": "Material 5, EC-141 specification and Elastic Modulus section",
      "source_detail": {
        "title": "NIST Structural Ceramics Database, Citation Z00426, silicon nitride entries",
        "url": "https://srdata.nist.gov/CeramicDataPortal/Scd/Z00426",
        "kind": "database",
        "license": "Public domain (NIST), cited"
      }
    },
    {
      "benchmark": "fracture_toughness",
      "label": "Fracture toughness, sintered EC-141",
      "value": 5.22,
      "bound": "exact",
      "unit": "MPa m1/2",
      "scope": "material",
      "conditions": {
        "form": "sintered silicon nitride",
        "grade": "EC-141",
        "uncertainty": "± 0.18 MPa m1/2"
      },
      "method": "Surface crack in flexure test; unevaluated in the NIST record",
      "status": "ground",
      "source": "nist-scd-z00426",
      "where": "Material 5, Fracture Toughness section",
      "source_detail": {
        "title": "NIST Structural Ceramics Database, Citation Z00426, silicon nitride entries",
        "url": "https://srdata.nist.gov/CeramicDataPortal/Scd/Z00426",
        "kind": "database",
        "license": "Public domain (NIST), cited"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, reaction-bonded NC-350",
      "value": 2.53,
      "bound": "exact",
      "unit": "g cm-3",
      "scope": "material",
      "conditions": {
        "form": "reaction-bonded silicon nitride",
        "grade": "NC-350",
        "temperature": "not stated in NIST record"
      },
      "method": "Manufacturer's indicated value, reproduced in NIST Structural Ceramics Database",
      "status": "ground",
      "source": "nist-scd-z00426",
      "where": "Material 6, NC-350 specification and Density (mass) section",
      "source_detail": {
        "title": "NIST Structural Ceramics Database, Citation Z00426, silicon nitride entries",
        "url": "https://srdata.nist.gov/CeramicDataPortal/Scd/Z00426",
        "kind": "database",
        "license": "Public domain (NIST), cited"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Elastic modulus, reaction-bonded NC-350",
      "value": 180,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "form": "reaction-bonded silicon nitride",
        "grade": "NC-350",
        "temperature": "not stated in NIST record"
      },
      "method": "Manufacturer's indicated value, reproduced in NIST Structural Ceramics Database",
      "status": "ground",
      "source": "nist-scd-z00426",
      "where": "Material 6, NC-350 specification and Elastic Modulus section",
      "source_detail": {
        "title": "NIST Structural Ceramics Database, Citation Z00426, silicon nitride entries",
        "url": "https://srdata.nist.gov/CeramicDataPortal/Scd/Z00426",
        "kind": "database",
        "license": "Public domain (NIST), cited"
      }
    },
    {
      "benchmark": "fracture_toughness",
      "label": "Fracture toughness, reaction-bonded NC-350",
      "value": 1.65,
      "bound": "exact",
      "unit": "MPa m1/2",
      "scope": "material",
      "conditions": {
        "form": "reaction-bonded silicon nitride",
        "grade": "NC-350",
        "uncertainty": "± 0.09 MPa m1/2"
      },
      "method": "Surface crack in flexure test; unevaluated in the NIST record",
      "status": "ground",
      "source": "nist-scd-z00426",
      "where": "Material 6, Fracture Toughness section",
      "source_detail": {
        "title": "NIST Structural Ceramics Database, Citation Z00426, silicon nitride entries",
        "url": "https://srdata.nist.gov/CeramicDataPortal/Scd/Z00426",
        "kind": "database",
        "license": "Public domain (NIST), cited"
      }
    },
    {
      "benchmark": "flexural_strength",
      "label": "Flexural strength (MOR) at 20 °C, NBD-200",
      "value": 900,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "form": "hot-isostatically pressed silicon nitride",
        "grade": "NBD-200",
        "temperature": "20 °C"
      },
      "method": "CoorsTek material table; the page does not state a test standard",
      "status": "ground",
      "source": "coorstek-sn",
      "where": "Properties table, Flexural Strength, MOR (20 °C) row, NBD-200 column; NIST identifies the NBD200 process as hot isostatic pressing",
      "source_detail": {
        "title": "CoorsTek Technical Ceramics, Silicon Nitride material page and grade table",
        "url": "https://www.coorstek.com/en/materials/silicon-nitride/",
        "kind": "datasheet",
        "license": "Manufacturer webpage, cited"
      }
    },
    {
      "benchmark": "fracture_toughness",
      "label": "Fracture toughness, NBD-200",
      "value": 5.5,
      "bound": "exact",
      "unit": "MPa m1/2",
      "scope": "material",
      "conditions": {
        "form": "hot-isostatically pressed silicon nitride",
        "grade": "NBD-200"
      },
      "method": "CoorsTek material table; the page does not state a test method",
      "status": "ground",
      "note": "The older NIST record for NBD200 gives 5.41 ± 0.24 MPa m1/2; the sources do not explain the difference.",
      "source": "coorstek-sn",
      "where": "Properties table, Fracture Toughness row, NBD-200 column; process identified in NIST entry Z00426, Material 2",
      "source_detail": {
        "title": "CoorsTek Technical Ceramics, Silicon Nitride material page and grade table",
        "url": "https://www.coorstek.com/en/materials/silicon-nitride/",
        "kind": "datasheet",
        "license": "Manufacturer webpage, cited"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity at 20 °C, NBD-200",
      "value": 29,
      "bound": "exact",
      "unit": "W/m K",
      "scope": "material",
      "conditions": {
        "form": "hot-isostatically pressed silicon nitride",
        "grade": "NBD-200",
        "temperature": "20 °C"
      },
      "method": "CoorsTek material table; the page does not state a test method",
      "status": "ground",
      "source": "coorstek-sn",
      "where": "Properties table, Thermal Conductivity (20 °C) row, NBD-200 column; process identified in NIST entry Z00426, Material 2",
      "source_detail": {
        "title": "CoorsTek Technical Ceramics, Silicon Nitride material page and grade table",
        "url": "https://www.coorstek.com/en/materials/silicon-nitride/",
        "kind": "datasheet",
        "license": "Manufacturer webpage, cited"
      }
    },
    {
      "benchmark": "cte",
      "label": "Coefficient of thermal expansion, NBD-200",
      "value": 2.9,
      "bound": "exact",
      "unit": "1x10-6/°C",
      "scope": "material",
      "conditions": {
        "form": "hot-isostatically pressed silicon nitride",
        "grade": "NBD-200",
        "printed_unit": "1x10-6/°C"
      },
      "method": "CoorsTek material table; unit and value copied as printed",
      "status": "ground",
      "source": "coorstek-sn",
      "where": "Properties table, Coefficient of Thermal Expansion row, NBD-200 column; process identified in NIST entry Z00426, Material 2",
      "source_detail": {
        "title": "CoorsTek Technical Ceramics, Silicon Nitride material page and grade table",
        "url": "https://www.coorstek.com/en/materials/silicon-nitride/",
        "kind": "datasheet",
        "license": "Manufacturer webpage, cited"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Maximum use temperature, NBD-200",
      "value": 1400,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "hot-isostatically pressed silicon nitride",
        "grade": "NBD-200",
        "atmosphere": "not stated on CoorsTek table"
      },
      "method": "Manufacturer-stated maximum use temperature; atmosphere and test method are not stated",
      "status": "ground",
      "source": "coorstek-sn",
      "where": "Properties table, Maximum Use Temperature row, NBD-200 column; process identified in NIST entry Z00426, Material 2",
      "source_detail": {
        "title": "CoorsTek Technical Ceramics, Silicon Nitride material page and grade table",
        "url": "https://www.coorstek.com/en/materials/silicon-nitride/",
        "kind": "datasheet",
        "license": "Manufacturer webpage, cited"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Hot oxygen containing water vapor",
      "headline": "Water vapor increases passive oxidation of hot-pressed silicon nitride.",
      "effect": "The review says silicon nitride forms a protective silica scale in oxidation, but its oxidation depends on sintering aids and impurities. For hot-pressed HS-130, the reported parabolic oxidation rate is higher in wet oxygen than in dry oxygen.",
      "rating": "unknown",
      "conditions": {
        "form": "hot-pressed silicon nitride, grade HS-130",
        "atmosphere": "oxygen with water vapor; see Table 22 for the reported partial pressure"
      },
      "source": "biscay-oxidation",
      "where": "Section 3.1, Oxidation of Si3N4; Section 3.2, Si3N4 in Hot Gases; Table 22"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "The PubChem aggregate for silicon nitride lists the majority of company GHS reports as not meeting hazard criteria, while noting that reports can differ with impurities, additives, and other factors.",
        "ghs": [],
        "source": "pubchem-sin3n4",
        "where": "Safety and Hazards, GHS Classification, CID 3084099"
      },
      {
        "text": "The MilliporeSigma SDS for Aldrich product 334103 (powder) classifies it as not a hazardous substance or mixture and lists no hazards otherwise classified. This is product-specific and does not establish handling requirements for every powder or finished ceramic.",
        "ghs": [],
        "source": "sigma-sds-sin3n4",
        "where": "Sections 1-2"
      }
    ],
    "failure_risks": [
      {
        "mode": "Brittle contact damage in cryogenic bearings",
        "trigger": "NASA tests with silicon nitride rolling elements in 57-mm high-pressure oxidizer turbopump bearings",
        "consequence": "The report describes spalling, striations, locally deformed ball material, and possible scuffing. It says the cause of spalling was not known and discusses a material flaw or high rolling-contact stress as possibilities.",
        "source": "nasa-tm103524",
        "where": "Introduction and Test Results, report pages 1-2 (PDF pages 5-6)"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "For powder handling, the SDS advises avoiding dust formation and breathing dust, using exhaust ventilation where dust forms, and keeping the container tightly closed in a dry, well-ventilated place.",
        "source": "sigma-sds-sin3n4",
        "where": "Sections 6-7"
      },
      {
        "text": "The SDS recommends appropriate eye protection and gloves for the product powder. Use the SDS for the exact grade and process; these instructions are not a substitute for supplier guidance on machining dust.",
        "source": "sigma-sds-sin3n4",
        "where": "Section 8"
      }
    ],
    "mitigations": []
  },
  "uses": [
    {
      "application": "mechanisms",
      "device": "Rolling elements in cryogenic turbopump bearings",
      "example": "NASA evaluated silicon nitride balls in flight-type Space Shuttle Main Engine high-pressure oxidizer turbopump bearings. The report describes a test program, not a claim that the tested configuration flew.",
      "source": "nasa-tm103524",
      "where": "Introduction and Test Equipment, report page 1 (PDF page 5)"
    },
    {
      "application": "propulsion-and-tanks",
      "device": "Aerospace propulsion and control components",
      "example": "CoorsTek lists propulsion and control components among its silicon nitride aerospace and defense applications.",
      "source": "coorstek-sn",
      "where": "Sample Applications by Industry, Aerospace & Defense"
    },
    {
      "application": "mechanisms",
      "device": "High-temperature bearings",
      "example": "PubChem's sources/uses section lists high-temperature ball bearings among reported uses for silicon nitride.",
      "source": "pubchem-sin3n4",
      "where": "Use and Manufacturing, Sources/Uses"
    }
  ],
  "supply": [
    {
      "subject": "Silicon feedstock for silicon nitride; the USGS report does not report silicon nitride production",
      "abundance": "The USGS says world and domestic resources for silicon metal and alloys are abundant and names silica, including quartzite, as the source. Its narrative estimates China at almost 80% of global silicon materials production in 2025. The producer shares below are computed from the report's separate 2025 silicon-metal production column; they describe feedstock, not silicon nitride output.",
      "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 (elemental silicon feedstock)",
          "listed": true
        }
      ],
      "recycling": "Not reported for silicon nitride in the sources read.",
      "substitutes": [],
      "source": "usgs-mcs2026-silicon",
      "where": "Events, Trends, and Issues; World Production; World Resources; critical-minerals discussion. Computed silicon-metal shares: China 4,000/4,600 = 87%, Brazil 180/4,600 = 3.9%, Norway 130/4,600 = 2.8% (2025 column, kt)."
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
      "type": "datasheet",
      "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
      "year": 2022
    },
    {
      "title": "Silicon Nitride material page, CoorsTek",
      "type": "datasheet",
      "url": "https://www.coorstek.com/en/materials/silicon-nitride/"
    },
    {
      "title": "NIST Structural Ceramics Database, Citation Z00426",
      "type": "database",
      "url": "https://srdata.nist.gov/CeramicDataPortal/Scd/Z00426"
    },
    {
      "title": "NASA TM-103524, An Evaluation of Bearings Operating in a Cryogenic Environment with Silicon Nitride Rolling Elements",
      "type": "report",
      "url": "https://ntrs.nasa.gov/api/citations/19910009123/downloads/19910009123.pdf",
      "year": 1991
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026, Silicon",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silicon.pdf",
      "year": 2026
    },
    {
      "title": "PubChem Compound Summary, Trisilicon tetranitride (CID 3084099), PUG-View record",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/3084099/JSON",
      "year": 2026
    },
    {
      "title": "CIAAW 2024 Abridged Standard Atomic Weights",
      "type": "database",
      "url": "https://www.ciaaw.org/abridged-atomic-weights.htm",
      "year": 2024
    },
    {
      "title": "Corrosion Characteristics of Silicon Carbide and Silicon Nitride, Journal of Research of NIST",
      "type": "paper",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC4907592/",
      "year": 1993
    },
    {
      "title": "MilliporeSigma Safety Data Sheet, Silicon nitride, Aldrich 334103, Version 6.3",
      "type": "sds",
      "url": "https://sds.mcmaster.ca/Silicon_Nitride.pdf",
      "year": 2022
    }
  ],
  "gaps": [
    "USGS does not report silicon-nitride producer shares or output; the supply section is explicitly silicon feedstock context.",
    "The exact rare-earth oxide/alumina proportions and rare-earth identity in the SN-GP sintering-aid blend are not specified by the datasheet.",
    "The Qsil datasheet's footnotes [2] and [3] appear cross-referenced to the opposite property labels, so those test methods could not be confidently assigned to hardness and bending strength.",
    "No tensile strength values were found for the specific SN-GP, NIST, or NBD-200 grades in the sources read; the 670 MPa Qsil value is labeled as bending strength, and CoorsTek labels its values as flexural MOR.",
    "The hot-gas oxidation evidence read here is for hot-pressed HS-130; corrosion of every listed grade in other gases, molten salts, and chemical environments remains uncharacterized in this profile.",
    "The Sigma SDS applies to one laboratory powder product; finished ceramic and machining-dust guidance for each manufacturer grade was not found.",
    "NIST's legacy material values and current CoorsTek NBD-200 values differ for fracture toughness; the sources do not explain the difference, so the entries remain separate.",
    "Maximum working/use temperatures are supplier table values; component-specific lifetime, atmosphere, geometry, and design allowables were not established by the sources read."
  ],
  "story": {
    "why": "Silicon nitride is a structural ceramic whose elongated grains and intergranular phases can give it useful strength and toughness. It appears in bearing elements and aerospace propulsion components, where wear, heat, and thermal shock matter. Processing changes density and fracture behavior substantially, so a material name alone is not a design specification.",
    "uses": [
      {
        "where": "Cryogenic turbopump bearings",
        "line": "NASA evaluated silicon nitride rolling elements in Space Shuttle Main Engine high-pressure oxidizer turbopump bearings; the cited report describes ground testing."
      },
      {
        "where": "Aerospace propulsion and control",
        "line": "CoorsTek lists silicon nitride propulsion and control components as an aerospace and defense application."
      },
      {
        "where": "High-temperature bearings",
        "line": "PubChem's sources/uses record lists high-temperature ball bearings among reported uses for silicon nitride."
      }
    ],
    "can_do": [
      {
        "label": "Carry bending loads",
        "line": "Datasheets report bending or flexural strength for named grades; the test mode is explicitly kept distinct from tensile strength.",
        "benchmark": "flexural_strength",
        "scope": "material"
      },
      {
        "label": "Limit thermal shock",
        "line": "The Qsil SN-GP sheet reports thermal-shock parameters for separate heating and quenching cases.",
        "benchmark": "thermal_shock_parameter_r1",
        "scope": "material"
      },
      {
        "label": "Conduct heat",
        "line": "The Qsil and CoorsTek data give grade-specific thermal conductivity, and the values should be compared only with their listed forms.",
        "benchmark": "thermal_conductivity",
        "scope": "material"
      }
    ],
    "compare": "The data show why silicon nitride needs a form and grade attached to every value. Qsil's SN-GP gas-pressure-sintered grade, NIST's hot-isostatically pressed and sintered records, and the reaction-bonded NC-350 record are separate materials for comparison purposes. The fracture-toughness entries for NBD-200 also differ between the older NIST record and the current CoorsTek table, with no explanation in either source.",
    "compare_rows": [
      {
        "label": "Density by process and grade",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Flexural or bending strength by grade",
        "benchmark": "flexural_strength",
        "scope": "material"
      },
      {
        "label": "Fracture toughness by process and grade",
        "benchmark": "fracture_toughness",
        "scope": "material"
      }
    ],
    "handling": [
      "For powder, follow the exact supplier SDS: avoid dust, use ventilation where dust forms, and keep the container dry and closed.",
      "Do not transfer a bulk property table directly to a component with a different shape, surface, or processing route; the Qsil sheet explicitly limits its data to test samples.",
      "For hot oxygen environments, account for oxidation and water-vapor effects; the available study is limited to a hot-pressed grade."
    ],
    "good_for": [
      "Bearing elements and propulsion hardware where wear resistance and temperature capability matter.",
      "Applications needing low thermal expansion and resistance to thermal shock, provided the selected grade has relevant design data."
    ],
    "watch_out": [
      "Do not combine values from reaction-bonded, sintered, hot-pressed, and gas-pressure-sintered forms as though they were one grade.",
      "The Qsil sheet's hardness and bending-strength method footnotes are ambiguous, and the NBD-200 toughness values differ between sources.",
      "No grade-specific tensile strength or silicon-nitride production share was found in the sources read."
    ],
    "verdict": "Silicon nitride suits demanding bearings and structural parts when its exact grade and processing route are specified. The profile has a strong set of sourced values, including thermal and mechanical data, while the method ambiguity in one datasheet and limited grade-specific oxidation and supply information remain visible.",
    "recipe": {
      "line": "The compound formula is Si3N4: three silicon atoms and four nitrogen atoms, with CIAAW 2024 abridged standard atomic weights of 28.085 and 14.007 respectively. Qsil's gas-pressure-sintered SN-GP grade reports 85 to 92 wt% Si3N4 and 8 to 15 wt% combined RE2O3/Al2O3 sintering aids; the sheet does not split that blend further.",
      "parts": [
        {
          "name": "Silicon nitride matrix",
          "symbol": "Si3N4",
          "role": "The main ceramic phase in the SN-GP grade.",
          "share_percent": 85,
          "share_high": 92,
          "source": "qsil-sn-gp",
          "where": "Section 2, Chemical Composition, Si3N4 (wt.-%) row"
        },
        {
          "name": "Silicon",
          "symbol": "Si",
          "role": "Three silicon atoms in each Si3N4 formula unit.",
          "atoms": 3,
          "atomic_weight": 28.085,
          "source": "ciaaw-atomic-weights",
          "where": "2024 Abridged Standard Atomic Weights, silicon row; atom count from the Si3N4 formula in PubChem CID 3084099"
        },
        {
          "name": "Nitrogen",
          "symbol": "N",
          "role": "Four nitrogen atoms in each Si3N4 formula unit.",
          "atoms": 4,
          "atomic_weight": 14.007,
          "source": "ciaaw-atomic-weights",
          "where": "2024 Abridged Standard Atomic Weights, nitrogen row; atom count from the Si3N4 formula in PubChem CID 3084099"
        },
        {
          "name": "RE2O3/Al2O3 sintering-aid blend",
          "role": "Combined oxide additions reported for the SN-GP grade; exact blend is not specified.",
          "share_percent": 8,
          "share_high": 15,
          "source": "qsil-sn-gp",
          "where": "Section 2, Chemical Composition, RE2O3/Al2O3 (wt.-%) row"
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The powder SDS read here says the named product is not hazardous under its GHS classification, and still gives dust-control and personal-protection instructions.",
        "points": [
          {
            "label": "Powder handling",
            "line": "Avoid dust generation and inhalation; use the handling instructions on the SDS for the exact powder product."
          }
        ],
        "level": 1,
        "verdict": "Powder SDS not classified"
      },
      {
        "title": "If a bearing part fails",
        "lead": "A NASA cryogenic test report documents contact damage and leaves its cause unresolved.",
        "points": [
          {
            "label": "Contact damage",
            "line": "The report describes spalling, striations, deformed ball areas, and possible scuffing in tested silicon nitride bearing balls."
          }
        ]
      },
      {
        "title": "Hot gas exposure",
        "lead": "Oxidation varies with the sintering aids and impurities, and water vapor can increase it in hot oxygen.",
        "points": [
          {
            "label": "Oxidation",
            "line": "A review describes formation of a protective silica scale but cautions that scale behavior depends on composition and environment."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-20",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 35,
    "unreachable": 0,
    "caveats": 4,
    "note": "Each property is tied to a named grade and form. The Qsil bending/hardness footnotes and the two NBD-200 fracture-toughness entries are flagged in the profile."
  },
  "sources": {
    "qsil-sn-gp": {
      "title": "Qsil, Material Data Sheet for Gas Pressure Sintered Silicon Nitride, SN-GP, Revision 07",
      "id": "F_4-4_26, dated 2022-01-18",
      "url": "https://qsil.com/wp-content/uploads/2023/04/F_4-4_26_Material-Data-Sheet-SN-GP.pdf",
      "year": 2022,
      "kind": "datasheet",
      "license": "Manufacturer datasheet, linked and cited"
    },
    "coorstek-sn": {
      "title": "CoorsTek Technical Ceramics, Silicon Nitride material page and grade table",
      "url": "https://www.coorstek.com/en/materials/silicon-nitride/",
      "kind": "datasheet",
      "license": "Manufacturer webpage, cited"
    },
    "nist-scd-z00426": {
      "title": "NIST Structural Ceramics Database, Citation Z00426, silicon nitride entries",
      "url": "https://srdata.nist.gov/CeramicDataPortal/Scd/Z00426",
      "kind": "database",
      "license": "Public domain (NIST), cited"
    },
    "nasa-tm103524": {
      "title": "NASA TM-103524, An Evaluation of Bearings Operating in a Cryogenic Environment with Silicon Nitride Rolling Elements",
      "id": "NTRS 19910009123",
      "url": "https://ntrs.nasa.gov/api/citations/19910009123/downloads/19910009123.pdf",
      "year": 1991,
      "kind": "report",
      "license": "Public domain (NASA), cited"
    },
    "usgs-mcs2026-silicon": {
      "title": "USGS Mineral Commodity Summaries 2026, Silicon",
      "id": "USGS MCS 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silicon.pdf",
      "year": 2026,
      "kind": "report",
      "license": "Public domain (USGS), cited"
    },
    "pubchem-sin3n4": {
      "title": "PubChem PUG-View record, Trisilicon tetranitride (CID 3084099)",
      "id": "CID 3084099; CAS 12033-89-5",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/3084099/JSON",
      "year": 2026,
      "kind": "database",
      "license": "Public domain (NCBI), cited"
    },
    "ciaaw-atomic-weights": {
      "title": "Commission on Isotopic Abundances and Atomic Weights, 2024 Abridged Standard Atomic Weights",
      "url": "https://www.ciaaw.org/abridged-atomic-weights.htm",
      "year": 2024,
      "kind": "database",
      "license": "CIAAW reference table, cited"
    },
    "biscay-oxidation": {
      "title": "Corrosion Characteristics of Silicon Carbide and Silicon Nitride, Journal of Research of NIST",
      "id": "PMCID PMC4907592",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC4907592/",
      "year": 1993,
      "kind": "paper",
      "license": "Publicly accessible NIST journal review, cited"
    },
    "sigma-sds-sin3n4": {
      "title": "MilliporeSigma Safety Data Sheet, Silicon nitride, Aldrich 334103, Version 6.3",
      "id": "Revision 25 April 2022; CAS 12033-89-5",
      "url": "https://sds.mcmaster.ca/Silicon_Nitride.pdf",
      "year": 2022,
      "kind": "datasheet",
      "license": "Supplier safety data sheet, linked and cited"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/silicon-nitride/"
}