{
  "spore": "profile",
  "id": "chromium-carbide",
  "spore_version": "0.2",
  "family": "carbide-nitride-boride-ceramics",
  "name": "Chromium carbide (Cr3C2)",
  "abbreviation": "Cr3C2",
  "role": "hard grey-black carbide powder for thermal-spray wear coatings, cutting tools and wear parts",
  "category": "ceramics",
  "type": "carbides",
  "summary": "Chromium carbide (Cr3C2) is a hard, grey-black ceramic powder with an orthorhombic crystal structure. Stanford Advanced Materials gives a melting point of 1890 °C and a microhardness of 2280 kg/mm2 for its Cr3C2 powder, with no test method stated. Its 2012 safety data sheet gives a specific gravity of 6.68 gm/cc and a melting point of 1980.0 °C, so the two supplier melting values disagree. A 2022 first-principles study calculates a Young's modulus of 423.7 GPa and a theoretical hardness of 18.2 GPa for Cr3C2; these are calculated values, not measurements.\n",
  "best_for": "Hard wear-resistant coatings and tool or mould parts, where the powder is used for thermal spray (the supplier FAQ lists thermal spray coatings for wear protection)",
  "weakest_at": "Oxidation at high temperature: the sources read make only a general claim and give no oxidation onset, and the supplier SDS warns that moisture releases methane",
  "identity": {
    "formula": "Cr3C2",
    "cas": "12012-35-0",
    "crystal_system": "orthorhombic",
    "space_group": "Pnma",
    "designations": [],
    "source": "paper",
    "where": "Introduction (Cr3C2 listed as Pnma among the binary chromium carbides); Section 2, Table 2 text 'For orthorhombic system (Cr7C3, Cr3C2)'. CAS printed on the supplier product page (sam-product) and SDS (sam-msds)."
  },
  "tags": {
    "environments": [],
    "stresses": [
      "extreme-heat"
    ],
    "applications": [
      "mechanisms",
      "structures"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Specific gravity printed in the supplier SDS",
      "value": 6.68,
      "bound": "exact",
      "unit": "gm/cc",
      "scope": "material",
      "conditions": {
        "basis": "printed as Specific Gravity (water=1); no temperature, powder form or test method printed",
        "unit_in_source": "gm/cc"
      },
      "method": "Manufacturer SDS value (Stanford Advanced Materials, version 2.0, revision 5 September 2012)",
      "status": "ground",
      "source": "sam-msds",
      "where": "Section III, Specific Gravity (water=1) row",
      "source_detail": {
        "title": "Material Safety Data Sheet: Chromium carbide, Cr3C2 (Stanford Advanced Materials, version 2.0, revision 5 September 2012), hosted by Sputter Targets",
        "id": "CAS 12012-35-0",
        "url": "https://www.sputtertargets.net/Public/pdf/chromium-carbide-msds.pdf",
        "year": 2012,
        "kind": "datasheet",
        "license": "supplier document (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density printed on a second supplier page",
      "value": 6.68,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "basis": "printed as Density in the Specifications section; not labelled true or bulk; no temperature or test method printed"
      },
      "method": "Supplier specification value",
      "status": "ground",
      "source": "sputter-cr3c2",
      "where": "Specifications section, Density row",
      "source_detail": {
        "title": "Chromium Carbide Powder product page, Sputter Targets (Cr3C2 specifications)",
        "url": "https://www.sputtertargets.net/chromium-carbide-powder/",
        "kind": "web",
        "license": "supplier page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "value": 1890,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "stated by the supplier with no test method; the description paragraph on the same page also gives 1890°C"
      },
      "method": "Supplier specification value",
      "status": "ground",
      "source": "sam-product",
      "where": "Specification section, Melting point row; Description paragraph",
      "source_detail": {
        "title": "Chromium Carbide (Cr3C2) Powder product page, Stanford Advanced Materials (specification, description, applications, safety and FAQ sections)",
        "id": "CAS 12012-35-0; catalog CR1314",
        "url": "https://www.samaterials.com/chromium/1314-chromium-carbide-cr3c2-powder.html",
        "kind": "web",
        "license": "supplier page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, 2012 supplier SDS (conflicts with the product page)",
      "value": 1980,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "printed as Melting Point: 1980.0 C in the SDS physical characteristics; no test method"
      },
      "method": "Manufacturer SDS value",
      "status": "ground",
      "note": "This value disagrees with the 1890 °C product-page value. Both are kept side by side; neither is backed by a measurement method in the sources read.",
      "source": "sam-msds",
      "where": "Section III, Melting Point row",
      "source_detail": {
        "title": "Material Safety Data Sheet: Chromium carbide, Cr3C2 (Stanford Advanced Materials, version 2.0, revision 5 September 2012), hosted by Sputter Targets",
        "id": "CAS 12012-35-0",
        "url": "https://www.sputtertargets.net/Public/pdf/chromium-carbide-msds.pdf",
        "year": 2012,
        "kind": "datasheet",
        "license": "supplier document (cited, not reproduced)"
      }
    },
    {
      "benchmark": "boiling_point",
      "value": 3800,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "printed as Boiling Point: 3800.0 C in the SDS physical characteristics; no pressure or method printed"
      },
      "method": "Manufacturer SDS value",
      "status": "ground",
      "note": "Not checked against any other source read in this run; kept only as printed.",
      "source": "sam-msds",
      "where": "Section III, Boiling Point row",
      "source_detail": {
        "title": "Material Safety Data Sheet: Chromium carbide, Cr3C2 (Stanford Advanced Materials, version 2.0, revision 5 September 2012), hosted by Sputter Targets",
        "id": "CAS 12012-35-0",
        "url": "https://www.sputtertargets.net/Public/pdf/chromium-carbide-msds.pdf",
        "year": 2012,
        "kind": "datasheet",
        "license": "supplier document (cited, not reproduced)"
      }
    },
    {
      "benchmark": "vickers_hardness",
      "label": "Microhardness, supplier specification (test not stated)",
      "value": 2280,
      "bound": "exact",
      "unit": "kg/mm2",
      "scope": "material",
      "conditions": {
        "basis": "printed as Microhardness in the Specification section; no load or test method stated"
      },
      "method": "Supplier specification value",
      "status": "ground",
      "source": "sam-product",
      "where": "Specification section, Microhardness row",
      "source_detail": {
        "title": "Chromium Carbide (Cr3C2) Powder product page, Stanford Advanced Materials (specification, description, applications, safety and FAQ sections)",
        "id": "CAS 12012-35-0; catalog CR1314",
        "url": "https://www.samaterials.com/chromium/1314-chromium-carbide-cr3c2-powder.html",
        "kind": "web",
        "license": "supplier page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "theoretical_hardness",
      "label": "Theoretical hardness, first-principles, zero pressure",
      "value": 18.2,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "basis": "calculated at zero applied pressure; the table column is headed H Gao",
        "pressure": "0 GPa"
      },
      "method": "Calculated in a first-principles study (CASTEP, density functional theory); a computed value, not a measurement",
      "status": "calculated",
      "source": "paper",
      "where": "Section 3 text ('The theoretical hardness of Cr7C3, Cr3C2 and Cr23C6 was found to be 13.5, 18.2 and 10.1 GPa'); Table 4",
      "source_detail": {
        "title": "First Principles Investigation of Binary Chromium Carbides Cr7C3, Cr3C2 and Cr23C6: Electronic Structures, Mechanical Properties and Thermodynamic Properties under Pressure",
        "id": "doi:10.3390/ma15020558 (Materials 15(2), 558; PMC8779879)",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC8779879/",
        "year": 2022,
        "kind": "paper",
        "license": "open access (licence as listed by the journal; not checked in this run)"
      }
    },
    {
      "benchmark": "vickers_hardness",
      "label": "Vickers hardness range for Cr3C2 quoted from earlier measurements",
      "value": 15.1,
      "value_high": 18.9,
      "bound": "range",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "basis": "range across earlier studies quoted by the paper, which says reported values differ with sample preparation and measurement protocol; load not given"
      },
      "method": "Range quoted in the paper from other research groups",
      "status": "ground",
      "source": "paper",
      "where": "Introduction, paragraph 2 (Hν (Cr3C2) = 15.1–18.9 GPa, with cited references)",
      "source_detail": {
        "title": "First Principles Investigation of Binary Chromium Carbides Cr7C3, Cr3C2 and Cr23C6: Electronic Structures, Mechanical Properties and Thermodynamic Properties under Pressure",
        "id": "doi:10.3390/ma15020558 (Materials 15(2), 558; PMC8779879)",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC8779879/",
        "year": 2022,
        "kind": "paper",
        "license": "open access (licence as listed by the journal; not checked in this run)"
      }
    },
    {
      "benchmark": "bulk_modulus",
      "value": 314.7,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "basis": "zero pressure; Voigt-Reuss-Hill average of calculated elastic constants"
      },
      "method": "Calculated in a first-principles study (CASTEP, density functional theory)",
      "status": "calculated",
      "source": "paper",
      "where": "Table 2, Cr3C2 row, B/GPa column",
      "source_detail": {
        "title": "First Principles Investigation of Binary Chromium Carbides Cr7C3, Cr3C2 and Cr23C6: Electronic Structures, Mechanical Properties and Thermodynamic Properties under Pressure",
        "id": "doi:10.3390/ma15020558 (Materials 15(2), 558; PMC8779879)",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC8779879/",
        "year": 2022,
        "kind": "paper",
        "license": "open access (licence as listed by the journal; not checked in this run)"
      }
    },
    {
      "benchmark": "shear_modulus",
      "value": 166.1,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "basis": "zero pressure; Voigt-Reuss-Hill average of calculated elastic constants"
      },
      "method": "Calculated in a first-principles study (CASTEP, density functional theory)",
      "status": "calculated",
      "source": "paper",
      "where": "Table 2, Cr3C2 row, G/GPa column",
      "source_detail": {
        "title": "First Principles Investigation of Binary Chromium Carbides Cr7C3, Cr3C2 and Cr23C6: Electronic Structures, Mechanical Properties and Thermodynamic Properties under Pressure",
        "id": "doi:10.3390/ma15020558 (Materials 15(2), 558; PMC8779879)",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC8779879/",
        "year": 2022,
        "kind": "paper",
        "license": "open access (licence as listed by the journal; not checked in this run)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Young's modulus, calculated",
      "value": 423.7,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "basis": "zero pressure; Voigt-Reuss-Hill average of calculated elastic constants"
      },
      "method": "Calculated in a first-principles study (CASTEP, density functional theory)",
      "status": "calculated",
      "source": "paper",
      "where": "Table 2, Cr3C2 row, E/GPa column",
      "source_detail": {
        "title": "First Principles Investigation of Binary Chromium Carbides Cr7C3, Cr3C2 and Cr23C6: Electronic Structures, Mechanical Properties and Thermodynamic Properties under Pressure",
        "id": "doi:10.3390/ma15020558 (Materials 15(2), 558; PMC8779879)",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC8779879/",
        "year": 2022,
        "kind": "paper",
        "license": "open access (licence as listed by the journal; not checked in this run)"
      }
    },
    {
      "benchmark": "poissons_ratio",
      "value": 0.28,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "basis": "zero pressure; calculated from the Voigt-Reuss-Hill averages"
      },
      "method": "Calculated in a first-principles study (CASTEP, density functional theory)",
      "status": "calculated",
      "source": "paper",
      "where": "Table 2, Cr3C2 row, v column",
      "source_detail": {
        "title": "First Principles Investigation of Binary Chromium Carbides Cr7C3, Cr3C2 and Cr23C6: Electronic Structures, Mechanical Properties and Thermodynamic Properties under Pressure",
        "id": "doi:10.3390/ma15020558 (Materials 15(2), 558; PMC8779879)",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC8779879/",
        "year": 2022,
        "kind": "paper",
        "license": "open access (licence as listed by the journal; not checked in this run)"
      }
    },
    {
      "benchmark": "lattice_parameter_a",
      "label": "Lattice parameter a, calculated at zero pressure",
      "value": 5.48,
      "bound": "exact",
      "unit": "Å",
      "scope": "material",
      "conditions": {
        "basis": "zero pressure, orthorhombic cell"
      },
      "method": "Calculated in a first-principles study; the table lists experimental values beside it, which are not used here",
      "status": "calculated",
      "source": "paper",
      "where": "Table 1, Cr3C2 row, a column",
      "source_detail": {
        "title": "First Principles Investigation of Binary Chromium Carbides Cr7C3, Cr3C2 and Cr23C6: Electronic Structures, Mechanical Properties and Thermodynamic Properties under Pressure",
        "id": "doi:10.3390/ma15020558 (Materials 15(2), 558; PMC8779879)",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC8779879/",
        "year": 2022,
        "kind": "paper",
        "license": "open access (licence as listed by the journal; not checked in this run)"
      }
    },
    {
      "benchmark": "lattice_parameter_b",
      "label": "Lattice parameter b, calculated at zero pressure",
      "value": 2.79,
      "bound": "exact",
      "unit": "Å",
      "scope": "material",
      "conditions": {
        "basis": "zero pressure, orthorhombic cell"
      },
      "method": "Calculated in a first-principles study",
      "status": "calculated",
      "source": "paper",
      "where": "Table 1, Cr3C2 row, b column",
      "source_detail": {
        "title": "First Principles Investigation of Binary Chromium Carbides Cr7C3, Cr3C2 and Cr23C6: Electronic Structures, Mechanical Properties and Thermodynamic Properties under Pressure",
        "id": "doi:10.3390/ma15020558 (Materials 15(2), 558; PMC8779879)",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC8779879/",
        "year": 2022,
        "kind": "paper",
        "license": "open access (licence as listed by the journal; not checked in this run)"
      }
    },
    {
      "benchmark": "lattice_parameter_c",
      "label": "Lattice parameter c, calculated at zero pressure",
      "value": 11.47,
      "bound": "exact",
      "unit": "Å",
      "scope": "material",
      "conditions": {
        "basis": "zero pressure, orthorhombic cell"
      },
      "method": "Calculated in a first-principles study",
      "status": "calculated",
      "source": "paper",
      "where": "Table 1, Cr3C2 row, c column",
      "source_detail": {
        "title": "First Principles Investigation of Binary Chromium Carbides Cr7C3, Cr3C2 and Cr23C6: Electronic Structures, Mechanical Properties and Thermodynamic Properties under Pressure",
        "id": "doi:10.3390/ma15020558 (Materials 15(2), 558; PMC8779879)",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC8779879/",
        "year": 2022,
        "kind": "paper",
        "license": "open access (licence as listed by the journal; not checked in this run)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Moisture and water contact",
      "headline": "The supplier safety data sheet says Cr3C2 reacts with moisture to form methane gas.",
      "effect": "The 2012 SDS states that the powder reacts with moisture to form methane gas, and it lists moisture among the materials to avoid. The sheet gives no reaction rate, temperature or test.",
      "rating": "moderate",
      "conditions": {
        "basis": "supplier statement, no test conditions"
      },
      "source": "sam-msds",
      "where": "Section V (Incompatibility) and Section VII (handling paragraph)"
    },
    {
      "environment": "Strong oxidizing agents, acids and bases",
      "headline": "The supplier SDS lists strong oxidizing agents, acids and bases as materials to avoid.",
      "effect": "The SDS gives this as an incompatibility statement without concentrations, times or test results.",
      "rating": "low",
      "conditions": {
        "basis": "incompatibility list, no test data"
      },
      "source": "sam-msds",
      "where": "Section V (Incompatibility - materials to avoid)"
    },
    {
      "environment": "High-temperature air",
      "headline": "The 2022 paper describes outstanding oxidation resistance at high temperature, without a figure.",
      "effect": "The paper's introduction describes 'outstanding oxidation resistance under a high temperature environment' for the binary chromium carbides. It gives no oxidation onset temperature, exposure time or test method, so this is a general statement only.",
      "rating": "unknown",
      "conditions": {
        "basis": "general statement in the introduction; no test"
      },
      "source": "paper",
      "where": "Introduction, paragraph 1"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "PubChem's hazards summary for the chromium carbide record reads 'May be harmful after ingestion, inhalation, or skin contact; May damage eyes'.",
        "ghs": [],
        "source": "pubchem-cr3c2",
        "where": "Safety and Hazards, Hazards Identification, Hazards Summary (CID 3650773)"
      },
      {
        "text": "The supplier product page lists the hazard statement 'Flammable solid' with the signal word 'Warning'.",
        "ghs": [],
        "source": "sam-product",
        "where": "Safety information block"
      }
    ],
    "failure_risks": [
      {
        "mode": "Methane release on contact with moisture",
        "trigger": "Contact with moisture or water",
        "consequence": "The SDS says the powder reacts with moisture to form methane gas.",
        "severity": "moderate",
        "source": "sam-msds",
        "where": "Section V (Hazardous decomposition or byproducts) and Section VII"
      }
    ],
    "side_effects": [
      {
        "text": "The SDS says 'Chromium carbide may emit toxic fumes if involved in a fire'.",
        "affects": "Firefighters and people near a fire",
        "source": "sam-msds",
        "where": "Section IV, Unusual fire and explosion hazards"
      },
      {
        "text": "PubChem notes that trivalent chromium 'may be oxidized to hexavalent chromium, a known carcinogen'.",
        "affects": "Workers handling heated or oxidized material",
        "source": "pubchem-cr3c2",
        "where": "Toxicity, Health Effects"
      }
    ],
    "handling": [
      {
        "text": "Store in a cool, dry area, in a tightly sealed container, under an inert gas such as argon, as the SDS directs.",
        "source": "sam-msds",
        "where": "Section VII and Section VIII (Other)"
      },
      {
        "text": "Keep the powder away from moisture, strong oxidizing agents, acids and bases, which the SDS lists as materials to avoid.",
        "source": "sam-msds",
        "where": "Section V"
      },
      {
        "text": "Take care not to raise dust, and use a NIOSH-approved dust respirator where the SDS requires it.",
        "source": "sam-msds",
        "where": "Section VII and Section VIII (Respiratory)"
      },
      {
        "text": "PubChem prints the PEL and the TLV as '0.5 [mg/m3], as Cr'. The SDS prints '0.5 mg/m3' and '1 mg/m3' under the headings ACGIH-TLV and OSHA PEL, so the two sources do not agree on the PEL.",
        "source": "pubchem-cr3c2",
        "where": "Exposure Control and Personal Protection (PEL and TLV); the SDS figures are in Section II"
      }
    ],
    "mitigations": []
  },
  "uses": [
    {
      "application": "mechanisms",
      "device": "Cutting tools, drilling bits and wear parts",
      "example": "The supplier says Chromium Carbide Powder is commonly used in the production of cutting tools, drilling bits, wear-resistant parts, molds, and coatings for turbine components.",
      "source": "sam-product",
      "where": "Chromium Carbide Powder Applications section"
    },
    {
      "application": "structures",
      "device": "Coatings for turbine components and thermal spray",
      "example": "The same supplier page lists coatings for turbine components, and its FAQ names thermal spray coatings for wear protection.",
      "source": "sam-product",
      "where": "Chromium Carbide Powder Applications section; FAQs"
    },
    {
      "application": "mechanisms",
      "device": "Grain refinement agent in cemented carbide",
      "example": "The 2022 paper says chromium carbides can be used as grain refinement agents in cemented carbide and other wear-resistance components.",
      "source": "paper",
      "where": "Introduction, paragraph 1"
    }
  ],
  "supply": [
    {
      "subject": "Chromium (the metal in Cr3C2; the carbon supply is not covered by any source read in this run)",
      "producers": [
        {
          "country": "South Africa",
          "share_percent": 45.1,
          "year": 2025
        },
        {
          "country": "Turkey",
          "share_percent": 17.6,
          "year": 2025
        },
        {
          "country": "Kazakhstan",
          "share_percent": 13.7,
          "year": 2025
        },
        {
          "country": "India",
          "share_percent": 5.9,
          "year": 2025
        }
      ],
      "critical_lists": [
        {
          "list": "USGS 2025 List of Critical Minerals (the page lists Chromium, used in stainless steel)",
          "listed": true
        }
      ],
      "recycling": "USGS: 'In 2025, recycled chromium (contained in reported stainless-steel scrap receipts) accounted for 21% of apparent consumption.'",
      "substitutes": [
        "USGS: 'Chromium has no substitute in stainless steel, the leading end use, or in superalloys, the major strategic end use.'"
      ],
      "source": "usgs-mcs2026-chromium",
      "where": "World Mine Production and Reserves table, 2025e column (chromium content in thousand metric tons; world total 51,000 rounded; shares calculated by Space Mushroom against that total); Recycling; Substitutes. Critical list: USGS 2025 critical minerals page (usgs-crit2025)."
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Material Safety Data Sheet: Chromium carbide, Cr3C2 (Stanford Advanced Materials, 2012)",
      "type": "sds",
      "url": "https://www.sputtertargets.net/Public/pdf/chromium-carbide-msds.pdf",
      "year": 2012
    },
    {
      "title": "Chromium Carbide (Cr3C2) Powder product page (Stanford Advanced Materials)",
      "type": "datasheet",
      "url": "https://www.samaterials.com/chromium/1314-chromium-carbide-cr3c2-powder.html",
      "year": 2026
    },
    {
      "title": "First Principles Investigation of Binary Chromium Carbides Cr7C3, Cr3C2 and Cr23C6 (Materials 15(2), 558, 2022)",
      "type": "paper",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC8779879/",
      "year": 2022
    },
    {
      "title": "Mineral Commodity Summaries 2026, Chromium",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf",
      "year": 2026
    },
    {
      "title": "PubChem: chromium carbide (CID 3650773), hazards and toxicity sections",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/3650773",
      "year": 2026
    }
  ],
  "gaps": [
    "Oxidation onset in air for dense Cr3C2 was not found in any source read in this run. A search snippet for the powder was not opened and is not used.",
    "No thermal conductivity, coefficient of thermal expansion, specific heat or band gap for Cr3C2 was found in any source read.",
    "No bulk or tap density was found in a fetched source. The American Elements pages were blocked by a browser check, and search snippets are not used.",
    "The PubChem web page was blocked by a browser check. The PubChem REST record was read instead; it gives a hazards summary and exposure limits but no GHS hazard statements, so the GHS field is empty.",
    "No UNS, EN, ASTM or other designation for Cr3C2 was printed in a source read in this run. Identity uses the CAS number printed on the supplier product page and SDS.",
    "Crystal structure is printed as Rhombohedral on two supplier pages. The paper gives orthorhombic, space group Pnma, and that is what identity records.",
    "Melting point conflicts: the product page gives 1890 °C and the 2012 SDS gives 1980.0 °C. Wikipedia gives a different melting value, which is not used. Wikipedia is cited for production routes only.",
    "The 2012 SDS boiling point is not confirmed by any other source read in this run.",
    "Exposure limits differ between PubChem and the SDS, as shown in risks.handling. Carcinogen labels also differ: the SDS calls chromium a confirmed human carcinogen, while PubChem gives a carcinogen classification (see the PubChem record).",
    "Atomic weights of chromium and carbon were not read in a fetched page, so story.recipe.parts has no atomic_weight.",
    "The paper's other quoted Vickers hardness ranges for Cr3C2 are not recorded as separate rows; the paper gives them without measurement details.",
    "Property names not in spores/property-canon.yaml: vickers_hardness (used for microhardness and the quoted range), theoretical_hardness, lattice_parameter_a, lattice_parameter_b and lattice_parameter_c.",
    "The paper's elastic, bulk, shear and lattice values are first-principles results at zero pressure, marked status calculated. They are not measured values.",
    "Supply covers chromium only. The EU critical raw materials list was not opened in this run, so no EU listing is recorded.",
    "No space, vacuum, radiation or atomic-oxygen results for Cr3C2 were found.",
    "The IPEN paper on attrition-milled Cr3C2 refused the connection and was not read.",
    "No media images were added."
  ],
  "story": {
    "why": "Chromium carbide (Cr3C2) is a hard ceramic powder made of chromium and carbon. Its supplier calls it a hard, durable coating material for protection against wear, corrosion and high temperatures, and lists it for cutting tools, drilling bits, wear-resistant parts and molds. It is supplied as a grey-black powder, and the supplier names thermal spray as a use. Its hardness and stiffness are the main reasons it is used. Its melting values disagree between two supplier sheets, and no measured high-temperature oxidation figure was found in the sources read.",
    "uses": [
      {
        "where": "Cutting tools, drilling bits and molds",
        "line": "The supplier says the powder is commonly used in cutting tools, drilling bits, wear-resistant parts and molds."
      },
      {
        "where": "Turbine coatings and thermal spray",
        "line": "The supplier lists coatings for turbine components, and its FAQ names thermal spray coatings for wear protection. These are supplier statements; no field test was found."
      },
      {
        "where": "Grain refiner in cemented carbide",
        "line": "The 2022 paper says chromium carbides can be used as grain refinement agents in cemented carbide and other wear-resistance components."
      }
    ],
    "can_do": [
      {
        "label": "Hardness",
        "line": "The supplier gives a microhardness of 2280 kg/mm2 with no test method stated. The paper quotes a Vickers hardness of 15.1 to 18.9 GPa for Cr3C2 from earlier studies, and calculates a theoretical hardness of 18.2 GPa.",
        "benchmark": "vickers_hardness",
        "scope": "material",
        "value": "2280 kg/mm2"
      },
      {
        "label": "Stiffness",
        "line": "The 2022 paper calculates a Young's modulus of 423.7 GPa and a Poisson's ratio of 0.28 at zero pressure. These are calculated values, not measurements.",
        "benchmark": "elastic_modulus",
        "scope": "material",
        "value": "423.7 GPa"
      },
      {
        "label": "Density",
        "line": "Two suppliers print a density of 6.68: one in gm/cc in a 2012 safety data sheet, and one in g/cm3 on a product page.",
        "benchmark": "density",
        "scope": "material",
        "value": "6.68 g/cm3"
      },
      {
        "label": "Melting point",
        "line": "The supplier product page gives a melting point of 1890 °C, and its 2012 safety data sheet gives 1980.0 °C. The two supplier values differ, and neither prints a method.",
        "benchmark": "melting_point",
        "scope": "material",
        "value": "1890 °C"
      }
    ],
    "compare": "Chromium carbide sits among the hard refractory carbides. Its supplier microhardness of 2280 kg/mm2 and its calculated theoretical hardness of 18.2 GPa are both high. The sources read here give no direct side-by-side comparison with the other carbides in this collection. The two supplier melting values, 1890 °C and 1980.0 °C, disagree and are shown side by side. Oxidation in air is not quantified in the sources read. The hardness values are not directly comparable: the supplier figure has no test method, and the paper's figures are calculated or quoted from other studies.",
    "compare_rows": [
      {
        "label": "Microhardness (supplier)",
        "benchmark": "vickers_hardness",
        "scope": "material"
      },
      {
        "label": "Melting point (supplier)",
        "benchmark": "melting_point",
        "scope": "material"
      },
      {
        "label": "Young's modulus (calculated)",
        "benchmark": "elastic_modulus",
        "scope": "material"
      }
    ],
    "handling": [
      "Store in a cool, dry area, in a tightly sealed container, under an inert gas such as argon, as the SDS directs.",
      "Keep the powder away from moisture, strong oxidizing agents, acids and bases, which the SDS lists as materials to avoid.",
      "Take care not to raise dust, and use a NIOSH-approved dust respirator where the SDS requires it.",
      "Check the supplier's current SDS for your grade, because the 2012 SDS and the product pages disagree on melting point and on exposure limits."
    ],
    "good_for": [
      "Hard wear parts. The supplier says it is used in cutting tools, drilling bits, wear-resistant parts and molds.",
      "Thermal spray coatings. The supplier FAQ lists thermal spray coatings for wear protection.",
      "Stiff hard coatings in design studies. The paper's calculated Young's modulus of 423.7 GPa is a theoretical value."
    ],
    "watch_out": [
      "Moisture reaction. The SDS says the powder reacts with moisture to form methane gas.",
      "Conflicting melting values. The product page gives 1890 °C and the 2012 SDS gives 1980.0 °C.",
      "Oxidation in air is not quantified. The paper says 'outstanding oxidation resistance under a high temperature environment' without a figure.",
      "Crystal structure is printed two ways. Two supplier pages say Rhombohedral; the paper gives orthorhombic, space group Pnma."
    ],
    "verdict": "Chromium carbide is a hard wear-resistant powder for coatings and tool parts. Its hardness data are stronger than its melting and oxidation data, and the supplier figures should be checked against a current SDS before use.",
    "recipe": {
      "line": "Chromium carbide (Cr3C2) is a binary compound of chromium and carbon with an orthorhombic crystal structure. The 2022 paper lists Cr3C2 among the stable binary chromium carbides at ambient pressure, alongside the other two carbides it studies. Wikipedia describes two production routes: mechanical alloying of chromium and graphite followed by hot isostatic pressing under argon, and a self-propagating exothermic reaction that uses chromium oxide, aluminum and graphite.",
      "parts": [
        {
          "name": "Chromium",
          "symbol": "Cr",
          "role": "The metal in the compound. The paper says metallic bonding runs between neighbouring chromium atoms, and the chromium-carbon bonds give the hardness it reports."
        },
        {
          "name": "Carbon",
          "symbol": "C",
          "role": "Bonds covalently to chromium in the paper's bonding analysis; the Cr-C bond strength is the basis of its theoretical hardness."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "PubChem's hazards summary says the material may be harmful after ingestion, inhalation or skin contact, and may damage eyes. The supplier SDS calls chromium a confirmed human carcinogen. These are supplier and database summaries, not incident records.",
        "points": [
          {
            "label": "Summary",
            "line": "PubChem's hazards summary reads 'May be harmful after ingestion, inhalation, or skin contact; May damage eyes'."
          },
          {
            "label": "Carcinogen labels differ",
            "line": "The 2012 SDS calls chromium a 'Confirmed human carcinogen'. PubChem's carcinogen classification reads '3, not classifiable as to its carcinogenicity to humans.'"
          },
          {
            "label": "Flammability",
            "line": "The supplier product page lists the hazard statement 'Flammable solid' with the signal word 'Warning'."
          }
        ],
        "level": 0,
        "verdict": "Harmful by inhalation or ingestion, per PubChem"
      },
      {
        "title": "If the powder is heated or burns",
        "lead": "These statements come from supplier sheets and database summaries, not from field incidents.",
        "points": [
          {
            "label": "Fire",
            "line": "The SDS says the material 'may emit toxic fumes if involved in a fire', and it calls for full face, self-contained breathing apparatus for firefighters."
          },
          {
            "label": "Oxidized chromium",
            "line": "PubChem says trivalent chromium 'may be oxidized to hexavalent chromium, a known carcinogen'."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Moisture",
            "line": "The SDS says the powder 'reacts with moisture to form methane gas'. It asks for storage in a cool, dry area in a tightly sealed container, under an inert gas such as argon."
          },
          {
            "label": "Exposure limits",
            "line": "PubChem prints '0.5 [mg/m3], as Cr' for both the PEL and the TLV. The SDS prints '0.5 mg/m3' and '1 mg/m3' under the headings ACGIH-TLV and OSHA PEL."
          }
        ]
      }
    ]
  },
  "updated": "2026-11-01",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 15,
    "unreachable": 2,
    "caveats": 3,
    "note": "Written by an AI assistant on 2026-11-01 from pages read in this run. Unreachable as web pages: the American Elements pages (browser check) and the PubChem web page (browser check; the PubChem REST record was read instead). Calculated values are first-principles results, not measurements."
  },
  "sources": {
    "sam-product": {
      "title": "Chromium Carbide (Cr3C2) Powder product page, Stanford Advanced Materials (specification, description, applications, safety and FAQ sections)",
      "id": "CAS 12012-35-0; catalog CR1314",
      "url": "https://www.samaterials.com/chromium/1314-chromium-carbide-cr3c2-powder.html",
      "kind": "web",
      "license": "supplier page (cited, not reproduced)"
    },
    "sam-msds": {
      "title": "Material Safety Data Sheet: Chromium carbide, Cr3C2 (Stanford Advanced Materials, version 2.0, revision 5 September 2012), hosted by Sputter Targets",
      "id": "CAS 12012-35-0",
      "url": "https://www.sputtertargets.net/Public/pdf/chromium-carbide-msds.pdf",
      "year": 2012,
      "kind": "datasheet",
      "license": "supplier document (cited, not reproduced)"
    },
    "sputter-cr3c2": {
      "title": "Chromium Carbide Powder product page, Sputter Targets (Cr3C2 specifications)",
      "url": "https://www.sputtertargets.net/chromium-carbide-powder/",
      "kind": "web",
      "license": "supplier page (cited, not reproduced)"
    },
    "paper": {
      "title": "First Principles Investigation of Binary Chromium Carbides Cr7C3, Cr3C2 and Cr23C6: Electronic Structures, Mechanical Properties and Thermodynamic Properties under Pressure",
      "id": "doi:10.3390/ma15020558 (Materials 15(2), 558; PMC8779879)",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC8779879/",
      "year": 2022,
      "kind": "paper",
      "license": "open access (licence as listed by the journal; not checked in this run)"
    },
    "usgs-mcs2026-chromium": {
      "title": "Mineral Commodity Summaries 2026, Chromium",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-crit2025": {
      "title": "About the 2025 List of Critical Minerals (USGS, final list of 60 minerals)",
      "id": "Final 2025 List of Critical Minerals, November 2025",
      "url": "https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals",
      "year": 2025,
      "kind": "web",
      "license": "public domain (USGS)"
    },
    "pubchem-cr3c2": {
      "title": "PubChem compound record CID 3650773, chromium carbide (Cr3C2, CAS 12012-35-0): hazards summary, exposure limits, toxicity",
      "id": "CID 3650773",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/3650773",
      "year": 2026,
      "kind": "database",
      "license": "public domain (NCBI)"
    },
    "wiki-cr3c2": {
      "title": "Wikipedia, Chromium(II) carbide (composition and production routes only; numbers not used)",
      "url": "https://en.wikipedia.org/wiki/Chromium(II)_carbide",
      "kind": "web",
      "license": "CC BY-SA"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/chromium-carbide/"
}