{
  "spore": "profile",
  "id": "cubic-boron-nitride",
  "spore_version": "0.2",
  "family": "carbide-nitride-boride-ceramics",
  "name": "Cubic boron nitride",
  "abbreviation": "cBN",
  "role": "superabrasive and heat-spreading ceramic",
  "category": "ceramics",
  "type": "nitrides",
  "summary": "Cubic boron nitride (cBN, also written c-BN) is the cubic form of boron nitride, with a sphalerite lattice like diamond. Nanografi gives a Vickers hardness of 33 to 45 GPa for commercial polycrystalline cBN with micrometre grains. Wikipedia gives a density of 3.45 g/cm3 for c-BN. A chemical record for CAS 10043-11-5 says cBN oxidises in air above 1100 °C, while Nanografi says a protective B2O3 layer prevents further oxidation up to 1300 °C, so the two sources disagree on the oxidation limit.\n",
  "best_for": "Grinding and machining hardened steel with a superabrasive (Wikipedia and Superabrasives Powder), and heat spreading where the 3.45 g/cm3 density and 2.1 refractive index are design inputs",
  "weakest_at": "Oxidation in air above about 1100 °C, and a hardness that depends strongly on whether the material is pure polycrystalline cBN or a sintered compact with binder",
  "identity": {
    "formula": "BN, cubic boron nitride (one boron and one nitrogen atom per formula unit, in a cubic sphalerite lattice like diamond)",
    "cas": "10043-11-5",
    "crystal_system": "cubic",
    "space_group": "F43m",
    "designations": [
      {
        "system": "Trade name",
        "code": "Borazon",
        "note": "Trade name for cubic BN; the source attributes it to Diamond Innovations",
        "source": "nanografi-cbn",
        "where": "Closing paragraph on trade names"
      },
      {
        "system": "Trade name",
        "code": "Cubonite",
        "note": "Trade name for cubic BN, listed as from Russian vendors",
        "source": "nanografi-cbn",
        "where": "Closing paragraph on trade names"
      },
      {
        "system": "Trade name",
        "code": "Elbor",
        "note": "Trade name for cubic BN, listed as from Russian vendors",
        "source": "nanografi-cbn",
        "where": "Closing paragraph on trade names"
      }
    ],
    "source": "wiki-cbn",
    "where": "Infobox and structure section: space group F43m and sphalerite structure; the CAS number is listed for boron nitride in general (ChemicalBook record, Wikipedia infobox)"
  },
  "tags": {
    "environments": [],
    "stresses": [
      "extreme-heat"
    ],
    "applications": [
      "mechanisms",
      "electronics-and-chips"
    ]
  },
  "properties": [
    {
      "benchmark": "vickers_hardness",
      "label": "Vickers hardness, commercial polycrystalline cBN with micrometre grains",
      "value": 33,
      "value_high": 45,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "form": "polycrystalline cBN with micrometre grains (commercial)",
        "test": "Vickers (HV), as printed",
        "temperature": "not stated",
        "unit_in_source": "GPa"
      },
      "method": "Range printed in a supplier article on cBN nanopowders; the load is not stated in the passage read",
      "status": "ground",
      "source": "nanografi-cbn",
      "where": "Hardness paragraph, sentence giving 33-45 GPa Vickers hardness (HV)",
      "source_detail": {
        "title": "Cubic Boron Nitride Nanopowders: The New Diamond, Properties, and Applications (Nanografi)",
        "url": "https://shop.nanografi.com/blog/cubic-boron-nitride-nanopowders-the-new-diamond-properties-and-applications/",
        "kind": "web",
        "license": "Vendor article, cited not reproduced"
      }
    },
    {
      "benchmark": "vickers_hardness",
      "label": "Vickers microhardness, polycrystalline cBN layer in a sintered compact (first example)",
      "value": 3000,
      "value_high": 3200,
      "bound": "exact",
      "unit": "kg/mm2",
      "scope": "material",
      "conditions": {
        "form": "polycrystalline cBN layer of a sintered compact with a cobalt-rich binder, not pure cBN",
        "test": "Vickers, as printed",
        "unit_in_source": "Kg/mm 2"
      },
      "method": "Micro hardness measurement printed in the first example of the patent description",
      "status": "ground",
      "source": "us-patent-5326380",
      "where": "First example, sentence beginning Micro hardness on the polycrystalline cBN layer",
      "source_detail": {
        "title": "US Patent 5,326,380: Synthesis of polycrystalline cubic boron nitride",
        "url": "https://patents.google.com/patent/US5326380",
        "year": 1994,
        "kind": "report",
        "license": "Patent document, cited not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, c-BN (cubic boron nitride)",
      "value": 3.45,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "c-BN, cubic form",
        "unit_in_source": "g/cm3"
      },
      "method": "Value printed in the Wikipedia infobox for boron nitride, where c-BN is given separately from h-BN",
      "status": "ground",
      "source": "wiki-cbn",
      "where": "Infobox, density row, c-BN value",
      "source_detail": {
        "title": "Cubic boron nitride, Wikipedia",
        "url": "https://en.wikipedia.org/wiki/Cubic_boron_nitride",
        "kind": "web",
        "license": "CC BY-SA, cited not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, beta-BN (cubic)",
      "value": 3480,
      "bound": "exact",
      "unit": "kg/m3",
      "scope": "material",
      "conditions": {
        "form": "beta-BN (cubic)",
        "unit_in_source": "kg.m-3"
      },
      "method": "Value printed in the density by polymorph entries of the chemical record for CAS 10043-11-5, which covers boron nitride in general",
      "status": "ground",
      "source": "chemicalbook-cas",
      "where": "Physical properties, density by polymorph, beta-BN (cubic) entry",
      "source_detail": {
        "title": "ChemicalBook: boron nitride, CAS 10043-11-5, chemical properties and hazard record",
        "url": "https://chemicalbook.com/CASEN_10043-11-5.htm",
        "kind": "database",
        "license": "Chemical database record, cited not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, beta-BN (cubic)",
      "value": 3027,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "beta-BN (cubic)",
        "unit_in_source": "°C"
      },
      "method": "Value printed in the melting point entries of the chemical record for CAS 10043-11-5, which covers boron nitride in general",
      "status": "ground",
      "source": "chemicalbook-cas",
      "where": "Physical properties, melting point by polymorph, beta-BN entry, m.p. line",
      "source_detail": {
        "title": "ChemicalBook: boron nitride, CAS 10043-11-5, chemical properties and hazard record",
        "url": "https://chemicalbook.com/CASEN_10043-11-5.htm",
        "kind": "database",
        "license": "Chemical database record, cited not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point of CBN, vendor page",
      "value": 3500,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "CBN, grade not stated",
        "unit_in_source": "°C"
      },
      "method": "Value printed on a superabrasives vendor page; the page's comparison with diamond is internally inconsistent, so the value is kept as printed only",
      "status": "ground",
      "source": "superabrasives-performance",
      "where": "Paragraph on the melting point of CBN compared with diamond",
      "source_detail": {
        "title": "Performance and applications of CBN abrasives (Superabrasives Powder)",
        "url": "https://www.superabrasivespowder.com/performance-and-applications-of-cbn-abrasives.html",
        "kind": "web",
        "license": "Vendor article, cited not reproduced"
      }
    },
    {
      "benchmark": "sublimation_temperature",
      "label": "Sublimation temperature of c-BN (Wikipedia infobox)",
      "value": 2973,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "c-BN",
        "pressure": "not stated in the infobox",
        "unit_in_source": "°C"
      },
      "method": "Value printed in the Wikipedia infobox beside the note sublimates (c-BN)",
      "status": "ground",
      "source": "wiki-cbn",
      "where": "Infobox, melting or decomposition row, c-BN value",
      "source_detail": {
        "title": "Cubic boron nitride, Wikipedia",
        "url": "https://en.wikipedia.org/wiki/Cubic_boron_nitride",
        "kind": "web",
        "license": "CC BY-SA, cited not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index, c-BN",
      "value": 2.1,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "form": "c-BN",
        "wavelength": "not stated"
      },
      "method": "Value printed in the Wikipedia infobox, which gives a separate value for h-BN",
      "status": "ground",
      "source": "wiki-cbn",
      "where": "Infobox, refractive index row, c-BN value",
      "source_detail": {
        "title": "Cubic boron nitride, Wikipedia",
        "url": "https://en.wikipedia.org/wiki/Cubic_boron_nitride",
        "kind": "web",
        "license": "CC BY-SA, cited not reproduced"
      }
    },
    {
      "benchmark": "oxidation_onset_temperature",
      "label": "Oxidation in air, stated onset temperature (chemical record)",
      "value": 1100,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "atmosphere": "air",
        "note": "the record covers CAS 10043-11-5, which is boron nitride in general",
        "unit_in_source": "°C"
      },
      "method": "Value in the stability and reactivity text of the chemical record, printed as oxidises in air above 1100 °C",
      "status": "ground",
      "source": "chemicalbook-cas",
      "where": "Stability and reactivity section, oxidation sentence",
      "source_detail": {
        "title": "ChemicalBook: boron nitride, CAS 10043-11-5, chemical properties and hazard record",
        "url": "https://chemicalbook.com/CASEN_10043-11-5.htm",
        "kind": "database",
        "license": "Chemical database record, cited not reproduced"
      }
    },
    {
      "benchmark": "oxidation_protection_temperature",
      "label": "Oxidation protection by a B2O3 layer, cBN",
      "value": 1300,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "atmosphere": "oxygen or air",
        "mechanism": "protective B2O3 layer",
        "unit_in_source": "C"
      },
      "method": "Value printed in the thermal stability paragraph, which says further oxidation is prevented up to this temperature",
      "status": "ground",
      "source": "nanografi-cbn",
      "where": "Thermal stability paragraph, sentence beginning Further oxidation to 1300 C is prevented",
      "source_detail": {
        "title": "Cubic Boron Nitride Nanopowders: The New Diamond, Properties, and Applications (Nanografi)",
        "url": "https://shop.nanografi.com/blog/cubic-boron-nitride-nanopowders-the-new-diamond-properties-and-applications/",
        "kind": "web",
        "license": "Vendor article, cited not reproduced"
      }
    },
    {
      "benchmark": "thermal_stability_temperature",
      "label": "Thermal stability of a cBN abrasive, vendor claim",
      "value": 1250,
      "value_high": 1350,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "cBN abrasive, grade not stated",
        "unit_in_source": "degrees Celsius"
      },
      "method": "Range printed on a superabrasives vendor page under heat resistance; the page does not describe it as an oxidation test",
      "status": "ground",
      "source": "superabrasives-characteristics",
      "where": "Heat resistance paragraph, sentence beginning can withstand temperatures of 1250-1350",
      "source_detail": {
        "title": "Characteristics of cubic boron nitride (CBN) (Superabrasives Powder)",
        "url": "https://www.superabrasivespowder.com/news/characteristics-of-cubic-boron-nitride-cbn.html",
        "kind": "web",
        "license": "Vendor article, cited not reproduced"
      }
    },
    {
      "benchmark": "hbn_conversion_temperature",
      "label": "Conversion of cBN to h-BN in nitrogen after 12 hours",
      "value": 1525,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "atmosphere": "nitrogen",
        "time": "12 hours",
        "unit_in_source": "°C"
      },
      "method": "Value printed in the thermal stability paragraph of the nanopowder article",
      "status": "ground",
      "source": "nanografi-cbn",
      "where": "Thermal stability paragraph, sentence on conversion to h-BN in nitrogen after 12 hours",
      "source_detail": {
        "title": "Cubic Boron Nitride Nanopowders: The New Diamond, Properties, and Applications (Nanografi)",
        "url": "https://shop.nanografi.com/blog/cubic-boron-nitride-nanopowders-the-new-diamond-properties-and-applications/",
        "kind": "web",
        "license": "Vendor article, cited not reproduced"
      }
    },
    {
      "benchmark": "lattice_constant",
      "label": "Lattice constant a, cubic (fcc) BN",
      "value": 0.3615,
      "bound": "exact",
      "unit": "nm",
      "scope": "material",
      "conditions": {
        "structure": "cubic (fcc), as printed",
        "unit_in_source": "nm"
      },
      "method": "Value printed in the crystal structure entries of the chemical record for CAS 10043-11-5",
      "status": "ground",
      "source": "chemicalbook-cas",
      "where": "Crystal structure entries, cubic (fcc) line",
      "source_detail": {
        "title": "ChemicalBook: boron nitride, CAS 10043-11-5, chemical properties and hazard record",
        "url": "https://chemicalbook.com/CASEN_10043-11-5.htm",
        "kind": "database",
        "license": "Chemical database record, cited not reproduced"
      }
    },
    {
      "benchmark": "synthesis_pressure",
      "label": "Pressure for direct conversion of hexagonal BN to cBN",
      "value": 5,
      "value_high": 18,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "starting_material": "hexagonal BN",
        "process": "direct conversion",
        "unit_in_source": "GPa"
      },
      "method": "Range printed in the synthesis paragraph of the nanopowder article",
      "status": "ground",
      "source": "nanografi-cbn",
      "where": "Synthesis paragraph, sentence on direct hBN to cBN conversion",
      "source_detail": {
        "title": "Cubic Boron Nitride Nanopowders: The New Diamond, Properties, and Applications (Nanografi)",
        "url": "https://shop.nanografi.com/blog/cubic-boron-nitride-nanopowders-the-new-diamond-properties-and-applications/",
        "kind": "web",
        "license": "Vendor article, cited not reproduced"
      }
    },
    {
      "benchmark": "synthesis_temperature",
      "label": "Temperature for direct conversion of hexagonal BN to cBN",
      "value": 1730,
      "value_high": 3230,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "starting_material": "hexagonal BN",
        "process": "direct conversion",
        "unit_in_source": "C"
      },
      "method": "Range printed in the synthesis paragraph of the nanopowder article",
      "status": "ground",
      "source": "nanografi-cbn",
      "where": "Synthesis paragraph, sentence on direct hBN to cBN conversion",
      "source_detail": {
        "title": "Cubic Boron Nitride Nanopowders: The New Diamond, Properties, and Applications (Nanografi)",
        "url": "https://shop.nanografi.com/blog/cubic-boron-nitride-nanopowders-the-new-diamond-properties-and-applications/",
        "kind": "web",
        "license": "Vendor article, cited not reproduced"
      }
    },
    {
      "benchmark": "uv_emission_wavelength",
      "label": "UV emission wavelength range of cBN with a voltage applied",
      "value": 215,
      "value_high": 250,
      "bound": "exact",
      "unit": "nm",
      "scope": "material",
      "conditions": {
        "excitation": "voltage applied",
        "note": "the source says the range applies to c-BN or h-BN"
      },
      "method": "Range printed in the optical paragraph of the nanopowder article",
      "status": "ground",
      "source": "nanografi-cbn",
      "where": "Optical paragraph, sentence beginning UV light is emitted in 215-250 nm range",
      "source_detail": {
        "title": "Cubic Boron Nitride Nanopowders: The New Diamond, Properties, and Applications (Nanografi)",
        "url": "https://shop.nanografi.com/blog/cubic-boron-nitride-nanopowders-the-new-diamond-properties-and-applications/",
        "kind": "web",
        "license": "Vendor article, cited not reproduced"
      }
    },
    {
      "benchmark": "chemical_resistance_temperature",
      "label": "Temperature range of chemical resistance to ferrous metals",
      "value": 1500,
      "value_high": 1600,
      "bound": "exact",
      "unit": "K",
      "scope": "material",
      "conditions": {
        "counterpart": "ferrous metals",
        "unit_in_source": "K"
      },
      "method": "Range printed in the chemical stability sentence of the nanopowder article",
      "status": "ground",
      "source": "nanografi-cbn",
      "where": "Chemical stability sentence, up to 1500-1600 K",
      "source_detail": {
        "title": "Cubic Boron Nitride Nanopowders: The New Diamond, Properties, and Applications (Nanografi)",
        "url": "https://shop.nanografi.com/blog/cubic-boron-nitride-nanopowders-the-new-diamond-properties-and-applications/",
        "kind": "web",
        "license": "Vendor article, cited not reproduced"
      }
    },
    {
      "benchmark": "reducing_atmosphere_stability_temperature",
      "label": "Stability in a reducing atmosphere, stated upper limit",
      "value": 1500,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "atmosphere": "reducing",
        "note": "the record covers CAS 10043-11-5, which is boron nitride in general",
        "unit_in_source": "°C"
      },
      "method": "Value printed in the stability and reactivity text of the chemical record",
      "status": "ground",
      "source": "chemicalbook-cas",
      "where": "Stability and reactivity section, sentence beginning stable in reducing atmospheres up to 1500",
      "source_detail": {
        "title": "ChemicalBook: boron nitride, CAS 10043-11-5, chemical properties and hazard record",
        "url": "https://chemicalbook.com/CASEN_10043-11-5.htm",
        "kind": "database",
        "license": "Chemical database record, cited not reproduced"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Air at high temperature",
      "headline": "Sources disagree on where cBN starts to oxidise in air: 1100 °C in a chemical record, and protection to 1300 °C in a vendor article.",
      "effect": "A chemical record for CAS 10043-11-5 says the material oxidises in air above 1100 °C. Nanografi says a protective B2O3 layer prevents further oxidation up to 1300 °C in oxygen or air. Neither source gives an oxidation rate or a test duration for cBN.",
      "rating": "moderate",
      "conditions": {
        "atmosphere": "air or oxygen",
        "exposure": "not stated"
      },
      "source": "chemicalbook-cas",
      "where": "Stability and reactivity section, oxidation sentence"
    },
    {
      "environment": "Nitrogen at high temperature",
      "headline": "Heating cBN in nitrogen converts it to hexagonal BN.",
      "effect": "Nanografi says conversion to h-BN is possible in nitrogen after 12 hours at 1525 °C. No conversion rate below that temperature was read.",
      "rating": "moderate",
      "conditions": {
        "atmosphere": "nitrogen",
        "time": "12 hours"
      },
      "source": "nanografi-cbn",
      "where": "Thermal stability paragraph"
    },
    {
      "environment": "Ferrous metals at high temperature",
      "headline": "cBN resists chemical attack from ferrous metals up to 1500 to 1600 K.",
      "effect": "Nanografi says cBN is not chemically attacked by ferrous metals up to 1500-1600 K, which is why it is used for ferrous work. A vendor page says cBN does not easily react with iron-group elements, but gives no temperature for that statement.",
      "rating": "low",
      "conditions": {
        "counterpart": "ferrous metals",
        "temperature_range": "1500 to 1600 K"
      },
      "source": "nanografi-cbn",
      "where": "Chemical stability sentence"
    },
    {
      "environment": "Water and humid air",
      "headline": "The chemical record for CAS 10043-11-5 lists the material as hygroscopic and incompatible with water, but the record covers boron nitride in general.",
      "effect": "ChemicalBook lists incompatibility with oxidising agents and water, and a hygroscopic note, for CAS 10043-11-5. No cBN-specific humidity or water test was read.",
      "rating": "unknown",
      "conditions": {
        "record": "CAS 10043-11-5, boron nitride in general"
      },
      "source": "chemicalbook-cas",
      "where": "Stability and reactivity text"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "The chemical record for CAS 10043-11-5 prints the signal word Danger and several GHS pictograms. It lists skin irritation, serious eye damage and respiratory irritation among its hazard statements. The record covers boron nitride in general, so these are not cBN-only classifications.",
        "ghs": [
          "H226",
          "H315",
          "H318",
          "H335"
        ],
        "source": "chemicalbook-cas",
        "where": "Hazard and regulatory data section, hazard codes and signal word lines"
      },
      {
        "text": "A supplier safety data sheet for a cBN and cemented-carbide tool material prints the signal word Danger and lists cBN as a major constituent by mass. Its hazards come from the binder metals, so it is not a pure cBN classification.",
        "ghs": [],
        "source": "osg-sds",
        "where": "Section 2 signal word line, and the composition table in Section 3"
      }
    ],
    "failure_risks": [
      {
        "mode": "Oxidation in air at high temperature",
        "trigger": "Sustained exposure in air above about 1100 °C",
        "consequence": "Oxidation starts above 1100 °C according to the chemical record, or is prevented up to 1300 °C by a B2O3 layer according to Nanografi. The sources disagree, and no oxidation depth or strength loss for cBN was read.",
        "severity": "moderate",
        "source": "chemicalbook-cas",
        "where": "Stability and reactivity text"
      },
      {
        "mode": "Conversion to hexagonal BN",
        "trigger": "Heating in nitrogen",
        "consequence": "Nanografi says cBN converts to h-BN in nitrogen after 12 hours at 1525 °C, so the cubic phase is lost at that condition.",
        "severity": "moderate",
        "source": "nanografi-cbn",
        "where": "Thermal stability paragraph"
      },
      {
        "mode": "Hardness depends on the form",
        "trigger": "Using a sintered compact with binder in place of pure polycrystalline cBN, or the reverse",
        "consequence": "Commercial polycrystalline cBN is given 33 to 45 GPa Vickers hardness by Nanografi, while a sintered compact with a cobalt-rich binder reads 3000 to 3200 kg/mm2 in the patent example. The form must be named before a hardness value is used.",
        "severity": "moderate",
        "source": "nanografi-cbn",
        "where": "Hardness paragraph"
      },
      {
        "mode": "Thermal-stability figures disagree",
        "trigger": "Using a vendor thermal stability figure as a service limit",
        "consequence": "A vendor article gives a thermal stability of 1250 to 1350 °C, while a chemical record gives 1100 °C as the oxidation onset. Neither is a component design allowable.",
        "severity": "moderate",
        "source": "superabrasives-characteristics",
        "where": "Heat resistance paragraph"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "Name the form (pure polycrystalline cBN, sintered compact or nanopowder) and the hardness test, because the sources give different values for each.",
        "source": "nanografi-cbn",
        "where": "Hardness paragraph and the first patent example"
      },
      {
        "text": "Keep cBN in air below the 1100 °C oxidation onset given by the chemical record, and avoid long holds in nitrogen near 1525 °C.",
        "source": "chemicalbook-cas",
        "where": "Stability and reactivity section"
      },
      {
        "text": "Limit dust. The chemical record lists respiratory irritation among the hazard statements for CAS 10043-11-5.",
        "source": "chemicalbook-cas",
        "where": "Hazard and regulatory data section"
      }
    ],
    "mitigations": []
  },
  "uses": [
    {
      "application": "mechanisms",
      "device": "Abrasive grains and polycrystalline cBN cutting-tool bits",
      "example": "Wikipedia lists cBN as an abrasive, and polycrystalline cBN (PCBN) for machining steel, with cutting-tool bit material as a use.",
      "source": "wiki-cbn",
      "where": "Applications list"
    },
    {
      "application": "electronics-and-chips",
      "device": "Heat spreaders",
      "example": "Wikipedia lists heat spreaders among the uses of c-BN, next to X-ray membranes and sintered large parts. No thermal conductivity value for cBN is recorded in this profile, because the sources read give conflicting or unclear figures.",
      "source": "wiki-cbn",
      "where": "Applications list"
    },
    {
      "application": "electronics-and-chips",
      "device": "Potential UV light emitters",
      "example": "Nanografi says cBN emits UV light in the 215-250 nm range when a voltage is applied. The source does not name a finished device.",
      "source": "nanografi-cbn",
      "where": "Optical paragraph"
    }
  ],
  "supply": [
    {
      "subject": "Boron feedstock (refined borates) for boron nitride",
      "abundance": "USGS 2026: Turkey produced 1,500 thousand metric tons of refined borates in 2025 (1,800 in 2024) and holds reserves of 950,000 thousand metric tons, the largest in the table. The figures are for refined borates, not for cBN or boron nitride powder.",
      "producers": [],
      "critical_lists": [
        {
          "list": "U.S. Final 2025 List of Critical Minerals (boron added in 2025)",
          "listed": true
        }
      ],
      "substitutes": [],
      "source": "usgs-mcs2026-boron",
      "where": "Critical minerals paragraph; World Production and Reserves table, row Turkey, refined borates"
    },
    {
      "subject": "cBN producers",
      "abundance": "No readable source named a cBN producer or gave a cBN production figure. Superabrasives Powder and Nanografi are sales pages for cBN powder, not producers' production data.",
      "producers": [],
      "critical_lists": [],
      "substitutes": [],
      "source": "nanografi-cbn",
      "where": "Product description; no production data read"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Wikipedia: Cubic boron nitride (structure, density, applications)",
      "type": "database",
      "url": "https://en.wikipedia.org/wiki/Cubic_boron_nitride"
    },
    {
      "title": "ChemicalBook: boron nitride, CAS 10043-11-5, chemical properties and hazard record",
      "type": "database",
      "url": "https://chemicalbook.com/CASEN_10043-11-5.htm"
    },
    {
      "title": "Nanografi: Cubic Boron Nitride Nanopowders, The New Diamond, Properties, and Applications",
      "type": "datasheet",
      "url": "https://shop.nanografi.com/blog/cubic-boron-nitride-nanopowders-the-new-diamond-properties-and-applications/"
    },
    {
      "title": "Superabrasives Powder: Performance and applications of CBN abrasives",
      "type": "datasheet",
      "url": "https://www.superabrasivespowder.com/performance-and-applications-of-cbn-abrasives.html"
    },
    {
      "title": "Superabrasives Powder: Characteristics of cubic boron nitride (CBN)",
      "type": "datasheet",
      "url": "https://www.superabrasivespowder.com/news/characteristics-of-cubic-boron-nitride-cbn.html"
    },
    {
      "title": "US Patent 5,326,380: Synthesis of polycrystalline cubic boron nitride",
      "type": "paper",
      "url": "https://patents.google.com/patent/US5326380",
      "year": 1994
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Boron",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-boron.pdf",
      "year": 2026
    },
    {
      "title": "OSG safety data sheet: CBN/Cemented Carbide tool material",
      "type": "sds",
      "url": "https://res.cloudinary.com/osg-usa-inc/image/upload/v1661778653/Literature/06%20-%20Other/MSDS/OSG_SDS_-_CBN_ozroe3.pdf"
    }
  ],
  "gaps": [
    "Thermal conductivity of cBN is not recorded. The ChemicalBook and Wikipedia tables give cBN conductivity figures, but the table cells were read with uncertain column assignments, so neither is kept as a value.",
    "A Rockwell C hardness range printed on a superabrasives vendor page is not recorded: the range does not fit the HRC scale the page names, and the page gives no load or method.",
    "A nanograined cBN hardness given in GPa on the Nanografi page is not recorded, because the hardness scale and test load are not stated in the passage read.",
    "A cBN Vickers hardness given in VHN in a ChemicalBook table is not recorded: the test load is not printed and the table column is unclear.",
    "Band gap of c-BN is not recorded. Wikipedia lists a band gap in a table cell with an uncertain column, and ChemicalBook's band gap figure is for boron nitride in general.",
    "Melting point is recorded from three sources that disagree: the chemical record gives 3027 °C for beta-BN, a vendor page gives 3500 °C, and Wikipedia gives 2973 °C as sublimation. Each is kept as printed; the sources do not agree on what the number measures.",
    "Crystal structure disagrees between sources: Wikipedia and Nanografi give sphalerite, and the ChemicalBook cubic entry gives wurtzite. The profile uses the sphalerite space group F43m from Wikipedia.",
    "Oxidation onset disagrees: a chemical record gives 1100 °C, Nanografi gives a 1300 °C protection limit, and a vendor page gives a thermal stability range of 1250 to 1350 °C. All three are recorded with their own conditions.",
    "The hazard codes are for CAS 10043-11-5, which covers boron nitride in general. No safety data sheet for a pure cubic BN powder was read. PubChem and ThomasSci could not be read in this run (a bot check and a refused request), and a Sigma-Aldrich sheet found in search covers a hexagonal BN ink, so it was not used.",
    "Boron nitride producers and any cBN production figures were not found in a readable source. The USGS figures are for refined borates, not for cBN.",
    "Element Six's cBN grade datasheets were not found in search results, so no Element Six grade value is recorded.",
    "Wikipedia names Borazon with Hyperion Materials and Technologies as the vendor, while Nanografi names Diamond Innovations. Both are recorded as printed in their sources, and the profile does not choose one.",
    "Atomic weights of boron and nitrogen were not read in this run, so the recipe lists atom counts only.",
    "Fracture toughness, compressive strength, grain-size and grit data, dielectric values, outgassing, erosion, and radiation tolerance for cBN were not found in the sources read.",
    "Properties with names outside the canonical file (vickers_hardness, sublimation_temperature, oxidation_onset_temperature, oxidation_protection_temperature, thermal_stability_temperature, hbn_conversion_temperature, lattice_constant, synthesis_pressure, synthesis_temperature, uv_emission_wavelength, chemical_resistance_temperature, reducing_atmosphere_stability_temperature) are used as printed. Check against property-canon.yaml before import.",
    "The patent hardness values are for a sintered compact with a cobalt-rich binder, not for pure polycrystalline cBN. They are kept separate from the Nanografi value and not averaged."
  ],
  "story": {
    "why": "Cubic boron nitride is a superabrasive ceramic. Nanografi gives a Vickers hardness of 33 to 45 GPa for commercial polycrystalline cBN, and Wikipedia gives a density of 3.45 g/cm3 for c-BN. These two values set the abrasive and heat-spreading case: hardness for grinding hardened steel, and density and oxidation limits for handling it hot.",
    "uses": [
      {
        "where": "Grinding and cutting tools",
        "line": "Wikipedia lists cBN as an abrasive and polycrystalline cBN for machining steel, with cutting-tool bits as a use."
      },
      {
        "where": "Heat spreaders",
        "line": "Wikipedia lists heat spreaders among the uses of c-BN. No thermal conductivity value is recorded here."
      },
      {
        "where": "UV emitters, potential",
        "line": "Nanografi says cBN emits UV light in the 215-250 nm range when a voltage is applied. It names no finished device."
      }
    ],
    "can_do": [
      {
        "label": "Machine steel as a superabrasive",
        "line": "Wikipedia lists cBN as an abrasive and PCBN for machining steel. Nanografi gives 33 to 45 GPa Vickers hardness for commercial polycrystalline cBN.",
        "benchmark": "vickers_hardness",
        "scope": "material",
        "value": "33 to 45 GPa Vickers"
      },
      {
        "label": "Resist ferrous metals",
        "line": "Nanografi says cBN resists chemical attack from ferrous metals up to 1500-1600 K.",
        "benchmark": "chemical_resistance_temperature",
        "scope": "material",
        "value": "1500 to 1600 K"
      },
      {
        "label": "Stay stable in reducing atmospheres",
        "line": "The chemical record for CAS 10043-11-5 says cBN is stable in reducing atmospheres up to 1500 °C, and the record covers boron nitride in general.",
        "benchmark": "reducing_atmosphere_stability_temperature",
        "scope": "material",
        "value": "1500 °C"
      }
    ],
    "compare": "Density figures for cubic boron nitride differ by source: Wikipedia gives 3.45 g/cm3 for c-BN and the chemical record gives 3480 kg/m3 for beta-BN. The melting point is not settled: the chemical record gives 3027 °C, a vendor page gives 3500 °C, and Wikipedia gives 2973 °C for sublimation. The hardness depends on the form: 33 to 45 GPa Vickers for commercial polycrystalline cBN (Nanografi) and 3000 to 3200 kg/mm2 Vickers for a sintered compact with a cobalt-rich binder (patent). These numbers are reported side by side, not averaged.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Melting point",
        "benchmark": "melting_point",
        "scope": "material"
      },
      {
        "label": "Vickers hardness",
        "benchmark": "vickers_hardness",
        "scope": "material"
      }
    ],
    "handling": [
      "Name the form, the hardness test and the supplier, because the values differ with each.",
      "Keep cBN below the 1100 °C oxidation onset in air. Nanografi puts protection to 1300 °C with a B2O3 layer, but this is not a design limit.",
      "Limit dust. The hazard record lists respiratory irritation among its hazard statements."
    ],
    "good_for": [
      "Superabrasive grinding of hardened steel, with a Vickers hardness of 33 to 45 GPa for commercial polycrystalline grades (Nanografi).",
      "Heat spreading in air up to about 1100 °C, with the oxidation limit taken from the chemical record.",
      "UV emission studies at 215 to 250 nm with a voltage applied (Nanografi)."
    ],
    "watch_out": [
      "Oxidation: the sources give 1100 °C and 1300 °C as the limit in air, so use the lower value unless the supplier confirms otherwise.",
      "Form: a sintered compact with binder reads 3000 to 3200 kg/mm2 Vickers, not the 33 to 45 GPa of commercial polycrystalline cBN.",
      "Nitrogen: cBN converts to hexagonal BN after 12 hours at 1525 °C.",
      "No thermal conductivity, erosion, outgassing or radiation value for cBN was recorded, so space durability is not established here."
    ],
    "verdict": "Cubic boron nitride is a superabrasive ceramic with a Vickers hardness of 33 to 45 GPa for commercial polycrystalline grades and a density of 3.45 g/cm3 for c-BN. Its air oxidation limit is disputed, 1100 °C in a chemical record against 1300 °C with a B2O3 layer in a vendor article, so the lower figure should be used. Hardness depends strongly on the form, so the form and test must be named with any value.",
    "recipe": {
      "line": "Cubic boron nitride is the cubic form of BN, with boron and nitrogen atoms in a sphalerite lattice like diamond. It is made by converting hexagonal BN directly at high pressure and high temperature: Nanografi gives 5 to 18 GPa and 1730 to 3230 °C for the direct conversion. A patent describes a sintered polycrystalline compact made from cBN crystals, hBN powder and adjuvants, which is a different product from pure cBN.",
      "parts": [
        {
          "name": "Boron",
          "symbol": "B",
          "role": "One boron atom per formula unit, bonded to nitrogen in the cubic lattice"
        },
        {
          "name": "Nitrogen",
          "symbol": "N",
          "role": "One nitrogen atom per formula unit, bonded to boron in the cubic lattice"
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The classification depends on the record, and it covers boron nitride in general.",
        "points": [
          {
            "label": "Hazard record",
            "line": "The chemical record for CAS 10043-11-5 prints the signal word Danger and lists skin irritation, serious eye damage and respiratory irritation."
          },
          {
            "label": "Tool composite",
            "line": "A tool safety data sheet that includes cBN lists it as a major constituent by mass, but its hazards come from the binder metals."
          }
        ],
        "level": 1,
        "verdict": "Hazard codes are not cBN-only"
      },
      {
        "title": "If it fails",
        "lead": "These failures come from the sources read. The hardness and oxidation data come from different sources, so each figure is kept with its form and conditions.",
        "points": [
          {
            "label": "Air",
            "line": "Oxidation in air begins above 1100 °C according to the chemical record, or is prevented up to 1300 °C by a B2O3 layer according to Nanografi."
          },
          {
            "label": "Nitrogen",
            "line": "Nanografi says cBN converts to hexagonal BN in nitrogen after 12 hours at 1525 °C."
          },
          {
            "label": "Form",
            "line": "Commercial polycrystalline cBN is given 33 to 45 GPa Vickers hardness, while a sintered compact with binder reads 3000 to 3200 kg/mm2."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Name the form",
            "line": "Name the form, the hardness test and the supplier, because the sources give different values for each form."
          },
          {
            "label": "Temperature",
            "line": "Keep cBN below the 1100 °C oxidation onset in air, and avoid long holds in nitrogen near 1525 °C."
          }
        ]
      }
    ]
  },
  "updated": "2026-11-02",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 18,
    "unreachable": 3,
    "caveats": 6,
    "note": "Values were read by an AI assistant on 2026-11-02 from the web pages and PDFs named in each entry. Unreachable: PubChem (bot check), ThomasSci (refused), CityU cBN property page (blocked), and the MSF cBN review (refused). Caveats: the ChemicalBook and hazard records cover CAS 10043-11-5, which is boron nitride in general; the Wikipedia and ChemicalBook table cells were read with uncertain columns and are not recorded; the patent hardness is for a sintered compact with binder; vendor pages disagree on melting point, oxidation onset and crystal form; the USGS figures are for refined borates."
  },
  "sources": {
    "nanografi-cbn": {
      "title": "Cubic Boron Nitride Nanopowders: The New Diamond, Properties, and Applications (Nanografi)",
      "url": "https://shop.nanografi.com/blog/cubic-boron-nitride-nanopowders-the-new-diamond-properties-and-applications/",
      "kind": "web",
      "license": "Vendor article, cited not reproduced"
    },
    "superabrasives-performance": {
      "title": "Performance and applications of CBN abrasives (Superabrasives Powder)",
      "url": "https://www.superabrasivespowder.com/performance-and-applications-of-cbn-abrasives.html",
      "kind": "web",
      "license": "Vendor article, cited not reproduced"
    },
    "superabrasives-characteristics": {
      "title": "Characteristics of cubic boron nitride (CBN) (Superabrasives Powder)",
      "url": "https://www.superabrasivespowder.com/news/characteristics-of-cubic-boron-nitride-cbn.html",
      "kind": "web",
      "license": "Vendor article, cited not reproduced"
    },
    "chemicalbook-cas": {
      "title": "ChemicalBook: boron nitride, CAS 10043-11-5, chemical properties and hazard record",
      "url": "https://chemicalbook.com/CASEN_10043-11-5.htm",
      "kind": "database",
      "license": "Chemical database record, cited not reproduced"
    },
    "wiki-cbn": {
      "title": "Cubic boron nitride, Wikipedia",
      "url": "https://en.wikipedia.org/wiki/Cubic_boron_nitride",
      "kind": "web",
      "license": "CC BY-SA, cited not reproduced"
    },
    "us-patent-5326380": {
      "title": "US Patent 5,326,380: Synthesis of polycrystalline cubic boron nitride",
      "url": "https://patents.google.com/patent/US5326380",
      "year": 1994,
      "kind": "report",
      "license": "Patent document, cited not reproduced"
    },
    "usgs-mcs2026-boron": {
      "title": "Mineral Commodity Summaries 2026, Boron",
      "id": "USGS MCS 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-boron.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "osg-sds": {
      "title": "OSG safety data sheet, CBN/Cemented Carbide tool material",
      "url": "https://res.cloudinary.com/osg-usa-inc/image/upload/v1661778653/Literature/06%20-%20Other/MSDS/OSG_SDS_-_CBN_ozroe3.pdf",
      "kind": "datasheet",
      "license": "Manufacturer safety data sheet, cited not reproduced"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/cubic-boron-nitride/"
}