{
  "spore": "profile",
  "id": "tungsten-copper",
  "spore_version": "0.2",
  "family": "refractory-metals",
  "name": "Tungsten-copper",
  "abbreviation": "W-Cu",
  "role": "heat sink and electrical contact composite",
  "category": "metals",
  "type": "refractory-metals",
  "summary": "Tungsten-copper (W-Cu, also written CuW or WCu) is a metal matrix composite, not an alloy: a sintered tungsten skeleton is infiltrated with molten copper, and common grades hold 10 to 40 wt % copper. The grade W80Cu20 (Plansee grade WCu20) has a density of 15.15 g/cm3 and an electrical conductivity of 34 %IACS in a supplier table. The Plansee typical thermal conductivity of WCu20 is 235 W/(m·K) at 20 °C, with a thermal expansion of 8.3 ppm/K. The copper phase melts at 1083 °C, and tungsten oxidises strongly in air from about 400 °C.\n",
  "best_for": "Heat sinks and electrical contacts: a thermal conductivity of 235 W/(m·K) at 20 °C with a low thermal expansion of 8.3 ppm/K in the Plansee WCu20 grade",
  "weakest_at": "Heavy, and it oxidises in hot air: density 15.15 g/cm3 for W80Cu20, and strong oxidation in air beginning around 400 °C",
  "identity": {
    "formula": "W-Cu composite: a tungsten (W) skeleton with copper (Cu) infiltrated, 10 to 40 wt % Cu (Plansee SDS, Section 3)",
    "cas": "7440-33-7 (W); 7440-50-8 (Cu)",
    "designations": [
      {
        "system": "Trade name",
        "code": "WCu20",
        "note": "Plansee grade name for 80 % W, remainder Cu",
        "source": "plansee-materials",
        "where": "Materials table, row WCu20, column Chemical composition W 80, remainder Cu (Ni)"
      },
      {
        "system": "ASTM",
        "code": "B702",
        "note": "Class D, about 75 % W and 25 % Cu (W75Cu25)",
        "source": "samaterials-cuw75",
        "where": "Product title and specification line, ASTM B702, Grade Class D"
      }
    ],
    "source": "plansee-wcu-sds",
    "where": "Section 3 Composition, row Summary: tungsten and copper 10-40 % mass fraction, with CAS numbers for tungsten and copper"
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "thermal-control",
      "electronics-and-chips",
      "propulsion-and-tanks"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, W80Cu20 (tungsten.com composition table)",
      "value": 15.15,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "grade": "W80Cu20 (80 % W, 20 % Cu)",
        "temperature": "not printed on the page",
        "unit_in_source": "gr/cc"
      },
      "method": "Value printed in a supplier composition table",
      "status": "ground",
      "source": "tungsten-com",
      "where": "Composition table, row W80 Cu20, column Density gr/cc",
      "source_detail": {
        "title": "Tungsten.com, Tungsten Copper Alloy (W-Cu) material information, composition table",
        "url": "https://www.tungsten.com/material-info/tungsten-copper-alloy-w-cu",
        "kind": "datasheet",
        "license": "supplier web page, linked not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, W75Cu25 (tungsten.com composition table)",
      "value": 14.5,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "grade": "W75Cu25 (75 % W, 25 % Cu)",
        "temperature": "not printed on the page",
        "unit_in_source": "gr/cc"
      },
      "method": "Value printed in a supplier composition table",
      "status": "ground",
      "source": "tungsten-com",
      "where": "Composition table, row W75 Cu25, column Density gr/cc",
      "source_detail": {
        "title": "Tungsten.com, Tungsten Copper Alloy (W-Cu) material information, composition table",
        "url": "https://www.tungsten.com/material-info/tungsten-copper-alloy-w-cu",
        "kind": "datasheet",
        "license": "supplier web page, linked not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, WCu20 (Plansee typical, 80 % W)",
      "value": 15.5,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "grade": "WCu20 (80 % W, remainder Cu)",
        "temperature": "20 °C"
      },
      "method": "Typical value printed in a manufacturer properties table, stated as typical properties at 20 °C",
      "status": "ground",
      "source": "plansee-properties",
      "where": "Typical properties of our WCu materials at 20 °C table, row WCu20, column Density [g/cm³]",
      "source_detail": {
        "title": "Plansee Tungsten composites: properties, typical properties of WCu materials at 20 °C",
        "url": "https://www.plansee.com/en/materials/tungsten-composites/properties.html",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, WCu20 (Plansee typical, 80 % W)",
      "value": 235,
      "bound": "exact",
      "unit": "W/(m·K)",
      "scope": "material",
      "conditions": {
        "grade": "WCu20 (80 % W, remainder Cu)",
        "temperature": "20 °C"
      },
      "method": "Typical value printed in a manufacturer properties table, stated as typical properties at 20 °C",
      "status": "ground",
      "note": "The same table gives 195 W/(m·K) for WCu10 and 215 W/(m·K) for WCu15, so conductivity rises as copper content rises.",
      "source": "plansee-properties",
      "where": "Typical properties of our WCu materials at 20 °C table, row WCu20, column TC [W/mK]",
      "source_detail": {
        "title": "Plansee Tungsten composites: properties, typical properties of WCu materials at 20 °C",
        "url": "https://www.plansee.com/en/materials/tungsten-composites/properties.html",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, W80/20 (SVS)",
      "value": 180,
      "bound": "exact",
      "unit": "W/(m·K)",
      "scope": "material",
      "conditions": {
        "grade": "WCu 80/20 (80 % W)",
        "temperature": "25 °C",
        "unit_in_source": "W/(m·K)"
      },
      "method": "Value printed in a supplier property table; the page does not say whether the value is typical or minimum",
      "status": "ground",
      "note": "A second supplier prints 235 W/(m·K) for a W80 grade at 20 °C, so the sources differ by about 55 W/(m·K).",
      "source": "svs-wcu",
      "where": "Physical and Mechanical Properties table, row Thermal conductivity at 25 °C, column WCu 80/20",
      "source_detail": {
        "title": "SVS Schweisstechnik, Tungsten-Copper (WCu), Physical and Mechanical Properties table",
        "url": "https://www.svs-schweisstechnik.de/en/knowledge-hub/refractory-alloys/tungsten-copper-wcu/",
        "kind": "datasheet",
        "license": "supplier web page, linked not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "Coefficient of thermal expansion, WCu20 (Plansee typical)",
      "value": 8.3,
      "bound": "exact",
      "unit": "ppm/K",
      "scope": "material",
      "conditions": {
        "grade": "WCu20 (80 % W, remainder Cu)",
        "temperature": "20 °C"
      },
      "method": "Typical value printed in a manufacturer properties table",
      "status": "ground",
      "source": "plansee-properties",
      "where": "Typical properties of our WCu materials at 20 °C table, row WCu20, column CTE [ppm/K]",
      "source_detail": {
        "title": "Plansee Tungsten composites: properties, typical properties of WCu materials at 20 °C",
        "url": "https://www.plansee.com/en/materials/tungsten-composites/properties.html",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "Coefficient of thermal expansion, W80/20 (SVS)",
      "value": 8.8,
      "bound": "exact",
      "unit": "ppm/K",
      "scope": "material",
      "conditions": {
        "grade": "WCu 80/20 (80 % W)",
        "temperature": "20 °C to 300 °C",
        "unit_in_source": "× 10⁻⁶/K⁻¹"
      },
      "method": "Value printed in a supplier property table; the page gives no test standard",
      "status": "ground",
      "source": "svs-wcu",
      "where": "Physical and Mechanical Properties table, row Linear expansion coefficient (20 °C–300 °C), column WCu 80/20",
      "source_detail": {
        "title": "SVS Schweisstechnik, Tungsten-Copper (WCu), Physical and Mechanical Properties table",
        "url": "https://www.svs-schweisstechnik.de/en/knowledge-hub/refractory-alloys/tungsten-copper-wcu/",
        "kind": "datasheet",
        "license": "supplier web page, linked not reproduced"
      }
    },
    {
      "benchmark": "electrical_conductivity",
      "label": "Electrical conductivity, W80Cu20 (tungsten.com)",
      "value": 34,
      "bound": "exact",
      "unit": "%IACS",
      "scope": "material",
      "conditions": {
        "grade": "W80Cu20 (80 % W, 20 % Cu)",
        "temperature": "not printed on the page"
      },
      "method": "Value printed in a supplier composition table, given as % IACS",
      "status": "ground",
      "source": "tungsten-com",
      "where": "Composition table, row W80 Cu20, column IACS %",
      "source_detail": {
        "title": "Tungsten.com, Tungsten Copper Alloy (W-Cu) material information, composition table",
        "url": "https://www.tungsten.com/material-info/tungsten-copper-alloy-w-cu",
        "kind": "datasheet",
        "license": "supplier web page, linked not reproduced"
      }
    },
    {
      "benchmark": "electrical_conductivity",
      "label": "Electrical conductivity, W75Cu25 (tungsten.com)",
      "value": 38,
      "bound": "exact",
      "unit": "%IACS",
      "scope": "material",
      "conditions": {
        "grade": "W75Cu25 (75 % W, 25 % Cu)",
        "temperature": "not printed on the page"
      },
      "method": "Value printed in a supplier composition table, given as % IACS",
      "status": "ground",
      "source": "tungsten-com",
      "where": "Composition table, row W75 Cu25, column IACS %",
      "source_detail": {
        "title": "Tungsten.com, Tungsten Copper Alloy (W-Cu) material information, composition table",
        "url": "https://www.tungsten.com/material-info/tungsten-copper-alloy-w-cu",
        "kind": "datasheet",
        "license": "supplier web page, linked not reproduced"
      }
    },
    {
      "benchmark": "electrical_conductivity",
      "label": "Electrical conductivity, W80/20 (SVS range)",
      "value": 38,
      "value_high": 45,
      "bound": "range",
      "unit": "%IACS",
      "scope": "material",
      "conditions": {
        "grade": "WCu 80/20 (80 % W)",
        "temperature": "not printed on the page"
      },
      "method": "Range printed in a supplier property table; the page does not say whether it is minimum, typical or tolerance",
      "status": "ground",
      "source": "svs-wcu",
      "where": "Physical and Mechanical Properties table, row Electrical conductivity % IACS, column WCu 80/20",
      "source_detail": {
        "title": "SVS Schweisstechnik, Tungsten-Copper (WCu), Physical and Mechanical Properties table",
        "url": "https://www.svs-schweisstechnik.de/en/knowledge-hub/refractory-alloys/tungsten-copper-wcu/",
        "kind": "datasheet",
        "license": "supplier web page, linked not reproduced"
      }
    },
    {
      "benchmark": "electrical_resistivity",
      "label": "Electrical resistivity, W80/Cu20 (Torrey Hills)",
      "value": 5,
      "bound": "exact",
      "unit": "µΩ·cm",
      "scope": "material",
      "conditions": {
        "grade": "W80/Cu20 (80 % W, 20 % Cu)",
        "temperature": "not printed on the page",
        "unit_in_source": "µΩ.cm"
      },
      "method": "Value printed in a supplier property table",
      "status": "ground",
      "source": "torrey-cuw",
      "where": "Copper tungsten property table, row W80/Cu20, column Resistivity (µΩ.cm)",
      "source_detail": {
        "title": "Torrey Hills Technologies, Properties of Copper Tungsten",
        "url": "https://www.torreyhillstech.com/cuwdata.html",
        "kind": "datasheet",
        "license": "supplier web page, linked not reproduced"
      }
    },
    {
      "benchmark": "hardness",
      "label": "Hardness, W80Cu20 (tungsten.com)",
      "value": 220,
      "bound": "exact",
      "unit": "HB Kgf/mm2",
      "scope": "material",
      "conditions": {
        "grade": "W80Cu20 (80 % W, 20 % Cu)",
        "temperature": "not printed on the page",
        "unit_in_source": "HB Kgf/mm2"
      },
      "method": "Value printed in a supplier composition table",
      "status": "ground",
      "note": "Torrey Hills prints the same 220 for W80/Cu20 in its table, so the hardness is the same in both supplier tables.",
      "source": "tungsten-com",
      "where": "Composition table, row W80 Cu20, column Hardness HB Kgf/mm2",
      "source_detail": {
        "title": "Tungsten.com, Tungsten Copper Alloy (W-Cu) material information, composition table",
        "url": "https://www.tungsten.com/material-info/tungsten-copper-alloy-w-cu",
        "kind": "datasheet",
        "license": "supplier web page, linked not reproduced"
      }
    },
    {
      "benchmark": "flexural_strength",
      "label": "Bending strength, W80Cu20 (tungsten.com)",
      "value": 736,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "W80Cu20 (80 % W, 20 % Cu)",
        "temperature": "not printed on the page"
      },
      "method": "Value printed in a supplier composition table",
      "status": "ground",
      "note": "Torrey Hills prints 980 MPa for the same grade in its own table, so suppliers differ by about 240 MPa on bending strength.",
      "source": "tungsten-com",
      "where": "Composition table, row W80 Cu20, column Bend Strength MPa",
      "source_detail": {
        "title": "Tungsten.com, Tungsten Copper Alloy (W-Cu) material information, composition table",
        "url": "https://www.tungsten.com/material-info/tungsten-copper-alloy-w-cu",
        "kind": "datasheet",
        "license": "supplier web page, linked not reproduced"
      }
    },
    {
      "benchmark": "flexural_strength",
      "label": "Bending strength, W80/Cu20 (Torrey Hills)",
      "value": 980,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "W80/Cu20 (80 % W, 20 % Cu)",
        "temperature": "not printed on the page"
      },
      "method": "Value printed in a supplier property table",
      "status": "ground",
      "note": "Tungsten.com prints 736 MPa for W80 Cu20 in its own table.",
      "source": "torrey-cuw",
      "where": "Copper tungsten property table, row W80/Cu20, column Bending Strength (Mpa)",
      "source_detail": {
        "title": "Torrey Hills Technologies, Properties of Copper Tungsten",
        "url": "https://www.torreyhillstech.com/cuwdata.html",
        "kind": "datasheet",
        "license": "supplier web page, linked not reproduced"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength Rm, W80/20 (SVS)",
      "value": 620,
      "value_high": 689,
      "bound": "range",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "WCu 80/20 (80 % W)",
        "temperature": "not printed on the page",
        "form": "not stated"
      },
      "method": "Range printed in a supplier property table; the page does not say whether the figures are minimum, typical or tolerance",
      "status": "ground",
      "source": "svs-wcu",
      "where": "Physical and Mechanical Properties table, row Tensile strength (Rm), column WCu 80/20",
      "source_detail": {
        "title": "SVS Schweisstechnik, Tungsten-Copper (WCu), Physical and Mechanical Properties table",
        "url": "https://www.svs-schweisstechnik.de/en/knowledge-hub/refractory-alloys/tungsten-copper-wcu/",
        "kind": "datasheet",
        "license": "supplier web page, linked not reproduced"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation at 20 °C, W80/20 (SVS)",
      "value": 8.3,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "grade": "WCu 80/20 (80 % W)",
        "temperature": "20 °C"
      },
      "method": "Value printed in a supplier property table",
      "status": "ground",
      "source": "svs-wcu",
      "where": "Physical and Mechanical Properties table, row Elongation at 20 °C, column WCu 80/20",
      "source_detail": {
        "title": "SVS Schweisstechnik, Tungsten-Copper (WCu), Physical and Mechanical Properties table",
        "url": "https://www.svs-schweisstechnik.de/en/knowledge-hub/refractory-alloys/tungsten-copper-wcu/",
        "kind": "datasheet",
        "license": "supplier web page, linked not reproduced"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "E-module, W80/20 (SVS)",
      "value": 280,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "grade": "WCu 80/20 (80 % W)",
        "temperature": "not printed on the page"
      },
      "method": "Value printed in a supplier property table",
      "status": "ground",
      "source": "svs-wcu",
      "where": "Physical and Mechanical Properties table, row E-module, column WCu 80/20",
      "source_detail": {
        "title": "SVS Schweisstechnik, Tungsten-Copper (WCu), Physical and Mechanical Properties table",
        "url": "https://www.svs-schweisstechnik.de/en/knowledge-hub/refractory-alloys/tungsten-copper-wcu/",
        "kind": "datasheet",
        "license": "supplier web page, linked not reproduced"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Air at high temperature",
      "headline": "Tungsten oxidises strongly in air from about 400 °C, and its oxide WO3 sublimes from about 850 °C.",
      "effect": "The Plansee SDS lists high temperatures in air as the condition to avoid: strong oxidation beginning around 400 °C, and sublimation of WO3 beginning around 850 °C. The SDS gives no oxidation rate.",
      "rating": "moderate",
      "conditions": {
        "basis": "product data sheet statement, no test condition or rate given",
        "product": "W-Cu composite"
      },
      "source": "plansee-wcu-sds",
      "where": "Section 10 Stability and reactivity, conditions to be avoided"
    },
    {
      "environment": "Water, acids and bases",
      "headline": "W-Cu is insoluble in water, acids and bases, and dissolves only in hydrofluoric acid or in a base with a strong oxidising agent.",
      "effect": "The Plansee SDS prints these solubility statements for the composite. No corrosion rate is given.",
      "rating": "low",
      "conditions": {
        "basis": "product data sheet statement, no test condition given"
      },
      "source": "plansee-wcu-sds",
      "where": "Section 9 Physical and chemical properties, row Solubility"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "Plansee's REACH product data sheet classes the material as not hazardous under Regulation (EC) No 1272/2008, and calls it a compact metal or alloy with no risk to human health or the environment.",
        "ghs": [],
        "source": "plansee-wcu-sds",
        "where": "Section 2 Hazards identification"
      },
      {
        "text": "Dust formation gives an increased fire hazard, and breathing protection is needed in the presence of dust. The product itself is not flammable.",
        "ghs": [],
        "source": "plansee-wcu-sds",
        "where": "Section 5 Fire-fighting measures"
      },
      {
        "text": "Workplace exposure thresholds printed in the SDS, under Austrian legal regulations: tungsten 5 mg/m3 inhalable fraction (mean daily value) and copper 1 mg/m3.",
        "ghs": [],
        "source": "plansee-wcu-sds",
        "where": "Section 8 Exposure controls, Exposure thresholds, and Section 15 Regulatory information"
      }
    ],
    "failure_risks": [
      {
        "mode": "Oxidation in hot air",
        "trigger": "Use in air at high temperature, from about 400 °C",
        "consequence": "Strong oxidation of the tungsten begins around 400 °C, and WO3 sublimes from about 850 °C, so the surface is consumed in hot air. The source gives no rate.",
        "severity": "moderate",
        "source": "plansee-wcu-sds",
        "where": "Section 10 Stability and reactivity"
      },
      {
        "mode": "Copper phase melts",
        "trigger": "Temperature at or above the melting point of copper, 1083 °C (SDS) or about 1080 °C (US patent 5705283)",
        "consequence": "The copper constituent is molten at this temperature, which is well below the tungsten melting point of 3410 °C. The sources give no measured effect on the composite.",
        "severity": "moderate",
        "source": "plansee-wcu-sds",
        "where": "Section 9 Melting point row; US patent 5705283, background text"
      }
    ],
    "side_effects": [
      {
        "text": "Dust from machining or sublimate at high temperature is a workplace exposure, and suction cleaning is advised when processing at high temperatures.",
        "affects": "Operators and workshop air",
        "source": "plansee-wcu-sds",
        "where": "Section 7 Handling and storage; Section 8 Workplace exposure"
      }
    ],
    "handling": [
      {
        "text": "Dust should be suction cleaned directly at source, and at least one FFP2 respirator is advised when working with dust.",
        "source": "plansee-wcu-sds",
        "where": "Section 6 Accidental release measures; Section 8 Workplace exposure"
      },
      {
        "text": "Avoid dust formation. Use suction cleaning if dust is unavoidable, and when processing at high temperatures because sublimate forms.",
        "source": "plansee-wcu-sds",
        "where": "Section 7 Handling and storage"
      }
    ],
    "mitigations": []
  },
  "uses": [
    {
      "application": "thermal-control",
      "device": "Heat sinks",
      "example": "Plansee lists heat sinks, arcing contacts and electrodes among the products made from its WCu composite. The Plansee WCu20 grade has a thermal conductivity of 235 W/(m·K) at 20 °C.",
      "source": "plansee-wcu-sds",
      "where": "Section 1 Identification, Use of the substance; Plansee properties table, row WCu20"
    },
    {
      "application": "electronics-and-chips",
      "device": "Chip carriers and substrates for power semiconductors",
      "example": "Wikipedia says CuW75 is used as chip carriers and substrates for power semiconductors, with a thermal expansion matched to silicon and gallium arsenide.",
      "source": "wikipedia-cuw",
      "where": "Applications section"
    },
    {
      "application": "electronics-and-chips",
      "device": "Arcing and electrical contacts",
      "example": "Plansee lists arcing contacts among its W-Cu products, and Wikipedia lists electrical contacts and vacuum contacts among the uses of copper-tungsten.",
      "source": "wikipedia-cuw",
      "where": "Applications section; Plansee SDS Section 1 for arcing contacts"
    },
    {
      "application": "propulsion-and-tanks",
      "device": "Rocket combustion chamber and nozzle walls, and throat inserts",
      "example": "US patent 5705283 proposes that part or all of the combustion chamber and expansion nozzle be made of a tungsten-copper composite. A supplier page calls tungsten-copper the preferred material for modern rocket throat linings.",
      "source": "us-patent-5705283",
      "where": "Background section; refractorymetal-rocket article, first paragraphs"
    }
  ],
  "supply": [
    {
      "subject": "Tungsten (world mine production, the tungsten content of W-Cu)",
      "producers": [
        {
          "country": "China",
          "share_percent": 78.8,
          "year": 2025
        },
        {
          "country": "Vietnam",
          "share_percent": 3.5,
          "year": 2025
        },
        {
          "country": "Kazakhstan",
          "share_percent": 2.8,
          "year": 2025
        },
        {
          "country": "Russia",
          "share_percent": 2.4,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "USGS: the estimated quantity of secondary tungsten produced in 2025 is withheld to avoid disclosing company proprietary data. Net import reliance is more than 50 % of apparent consumption in 2021 to 2025e.",
      "substitutes": [
        "USGS: molybdenum for certain tungsten mill products, and depleted uranium or lead for tungsten or tungsten alloys in applications requiring high density or radiation shielding."
      ],
      "source": "usgs-mcs2026-tungsten",
      "where": "World Mine Production and Reserves table, mine production 2025: China 67,000; Vietnam 3,000; Kazakhstan 2,400; Russia 2,000; world total 85,000 t, tungsten content. Shares calculated by Space Mushroom from these values (67,000 / 85,000 = 78.8 %). Recycling, Substitutes and Salient Statistics sections."
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Plansee, Tungsten composites: typical properties of WCu materials at 20 °C",
      "type": "datasheet",
      "url": "https://www.plansee.com/en/materials/tungsten-composites/properties.html",
      "year": 2026
    },
    {
      "title": "Plansee, Tungsten composites: materials and grades (WCu10, WCu15, WCu20)",
      "type": "datasheet",
      "url": "https://www.plansee.com/en/materials/tungsten-composites/materials.html",
      "year": 2026
    },
    {
      "title": "Plansee, Product data sheet PDS-041, WCu-composite material (REACH), valid from 12 July 2022",
      "type": "sds",
      "url": "https://www.plansee.com/download/?DOKNR=PSE-030-PDS-041&DOKAR=QM1&DOKTL=100",
      "year": 2022
    },
    {
      "title": "Torrey Hills Technologies, Properties of Copper Tungsten",
      "type": "datasheet",
      "url": "https://www.torreyhillstech.com/cuwdata.html"
    },
    {
      "title": "Tungsten.com, Tungsten Copper Alloy (W-Cu) material information",
      "type": "datasheet",
      "url": "https://www.tungsten.com/material-info/tungsten-copper-alloy-w-cu"
    },
    {
      "title": "SVS Schweisstechnik, Tungsten-Copper (WCu), refractory alloys",
      "type": "datasheet",
      "url": "https://www.svs-schweisstechnik.de/en/knowledge-hub/refractory-alloys/tungsten-copper-wcu/"
    },
    {
      "title": "SA Materials, Tungsten Copper Composite (W-Cu composite) CuW75, catalog WM7700",
      "type": "datasheet",
      "url": "https://www.samaterials.com/item/wm7700-tungsten-copper-composite-w-cu-composite-cuw75.html"
    },
    {
      "title": "Wikipedia: Copper-tungsten (CuW, WCu)",
      "type": "database",
      "url": "https://en.wikipedia.org/wiki/Copper%E2%80%93tungsten"
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Tungsten",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tungsten.pdf",
      "year": 2026
    },
    {
      "title": "US Patent 5,705,283, Tungsten-copper composite material with rhenium protective layer, and its preparation",
      "type": "report",
      "url": "https://patents.google.com/patent/US5705283A/en"
    },
    {
      "title": "Refractory Metal, Tungsten Copper Alloy for Rocket Throat Lining",
      "type": "datasheet",
      "url": "https://www.refractorymetal.org/tungsten-copper-alloy-for-rocket-throat-lining.html"
    }
  ],
  "gaps": [
    "Critical-mineral status: the USGS 2026 tungsten summary read here does not print a critical-minerals list entry, so critical_lists is empty.",
    "ASTM B702 class for W80Cu20 (grade E in one distributor listing) was not read on a fetched page, so only the W75Cu25 class (Class D, SA Materials) is recorded as a designation.",
    "No UNS, EN, DIN, JIS or W.Nr. number for copper-tungsten was found on a page read in this run. The Plansee and SVS pages print only their own grade labels.",
    "The Plansee SDS gives a density range of 13 to 18.3 g/cm3 for the whole composite family; it is not a grade value and is not recorded.",
    "The 400 °C and 850 °C oxidation figures are printed as approximate ('beginning around'), and no oxidation rate or mass loss in air was found.",
    "No outgassing, total mass loss, atomic-oxygen erosion or cold-welding result for W-Cu in vacuum or low Earth orbit was found in a readable source.",
    "No spacecraft-specific flight use of W-Cu was found. The rocket evidence is for combustion chamber and nozzle parts (US patent 5705283, supplier article). The patent's link to small station-keeping thrusters is an inference and is not recorded.",
    "Electrical resistivity and IACS for W75Cu25 were not recorded as separate values from a second supplier; tungsten.com and Torrey Hills both print them for W75Cu25 but were not included to keep one value per grade.",
    "Tensile and elongation values from SVS have no temper or form stated, and the page does not say whether they are minimum, typical or tolerance values.",
    "Process steps are from Wikipedia (pressing, sintering, infiltration) and the patent (sintering at about 1600 to 2100 °C). Copper content per grade in the infiltration step was not read from a primary process source.",
    "Radiation effects, thermal cycling and the Plansee WCu10 and WCu15 rows are not recorded beyond the typical values listed in the properties table."
  ],
  "story": {
    "why": "Tungsten-copper combines the heat resistance of tungsten with the conductivity of copper. The Plansee WCu20 grade, 80 % tungsten, has a thermal conductivity of 235 W/(m·K) at 20 °C and a thermal expansion of 8.3 ppm/K. A tungsten.com table gives W80Cu20 a density of 15.15 g/cm3 and an electrical conductivity of 34 %IACS. Those two properties are why the material is used as a heat sink and as an electrical contact.",
    "uses": [
      {
        "where": "Heat sinks and contacts",
        "line": "Plansee lists heat sinks, arcing contacts and electrodes among the products made from its W-Cu composite (Plansee SDS, Section 1)."
      },
      {
        "where": "Chip carriers",
        "line": "Wikipedia says CuW75 is used as chip carriers and substrates for power semiconductors, with a thermal expansion matched to silicon and gallium arsenide."
      },
      {
        "where": "Rocket nozzles",
        "line": "US patent 5705283 proposes W-Cu for part or all of a rocket combustion chamber and expansion nozzle, and a supplier article calls it the preferred material for modern throat linings."
      }
    ],
    "can_do": [
      {
        "label": "Carry heat",
        "line": "The Plansee WCu20 grade conducts heat at 235 W/(m·K) at 20 °C. A second supplier prints 180 W/(m·K) for a W80 grade at 25 °C.",
        "benchmark": "thermal_conductivity",
        "scope": "material",
        "value": "235 W/(m·K)"
      },
      {
        "label": "Match thermal expansion",
        "line": "The coefficient of thermal expansion is 8.3 ppm/K at 20 °C for WCu20, and 8.8 ppm/K over 20 to 300 °C in the SVS W80/20 grade.",
        "benchmark": "cte",
        "scope": "material",
        "value": "8.3 ppm/K"
      },
      {
        "label": "Carry current",
        "line": "W80Cu20 has an electrical conductivity of 34 %IACS in the tungsten.com table, against 38 to 45 %IACS in the SVS table for the same grade.",
        "scope": "material",
        "value": "34 %IACS"
      },
      {
        "label": "Hardness",
        "line": "W80Cu20 has a hardness of 220 HB Kgf/mm2 in the tungsten.com table, the same as in the Torrey Hills table.",
        "scope": "material",
        "value": "220 HB Kgf/mm2"
      }
    ],
    "compare": "Heavier grades carry more tungsten: the density is 14.5 g/cm3 for W75Cu25 and 15.15 g/cm3 for W80Cu20 in the tungsten.com table, while the electrical conductivity falls from 38 to 34 %IACS. These values come from different suppliers and grades, so read the table rows as examples, not as a ranking against copper or aluminium.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Thermal conductivity",
        "benchmark": "thermal_conductivity",
        "scope": "material"
      },
      {
        "label": "Thermal expansion",
        "benchmark": "cte",
        "scope": "material"
      }
    ],
    "handling": [
      "Specify the grade, because copper content changes density, conductivity and thermal expansion.",
      "Keep dust down with suction cleaning and an FFP2 respirator.",
      "Do not expose the composite to hot air above about 400 °C without protection."
    ],
    "good_for": [
      "Heat sinks: 235 W/(m·K) at 20 °C and 8.3 ppm/K in the Plansee WCu20 grade.",
      "Electrical contacts: 34 %IACS for W80Cu20 in the tungsten.com table.",
      "Rocket nozzle parts: the composite is proposed for combustion chamber and nozzle walls in US patent 5705283."
    ],
    "watch_out": [
      "Hot air: strong oxidation begins around 400 °C, and WO3 sublimes from about 850 °C.",
      "Suppliers disagree: bending strength for W80Cu20 is 736 MPa in one table and 980 MPa in another, and thermal conductivity for a W80 grade is 180 or 235 W/(m·K) depending on the supplier.",
      "Weight: density 15.15 g/cm3 for W80Cu20 in the tungsten.com table.",
      "No outgassing or orbital erosion test for W-Cu was found in a readable source."
    ],
    "verdict": "Tungsten-copper is the standard heat sink and contact composite where tungsten's heat resistance and copper's conductivity are both needed. The Plansee WCu20 grade conducts heat at 235 W/(m·K) at 20 °C and expands at 8.3 ppm/K. It is heavy, oxidises in hot air from about 400 °C, and this profile has no flight or orbital test data for the material.",
    "recipe": {
      "line": "Tungsten-copper is a metal matrix composite made by pressing and sintering tungsten powder into a porous skeleton, then infiltrating molten copper into it (Wikipedia). The sintering temperature is typically about 1600 to 2100 °C (US patent 5705283). Grades are named by their composition, so W80Cu20 has 80 wt % tungsten and 20 wt % copper, and Plansee names it WCu20.",
      "parts": [
        {
          "name": "Tungsten",
          "symbol": "W",
          "role": "Sintered skeleton, which provides elevated-temperature strength (US patent 5705283)."
        },
        {
          "name": "Copper",
          "symbol": "Cu",
          "role": "Infiltrated phase, which adds ductility, toughness and thermal and electrical conductivity (US patent 5705283)."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "Plansee classifies its W-Cu composite as not hazardous under EU rules, but the dust it makes is a workplace exposure.",
        "points": [
          {
            "label": "Classification",
            "line": "The Plansee REACH data sheet prints no classification under Regulation (EC) No 1272/2008, and calls the material a compact metal or alloy with no risk to human health or the environment."
          },
          {
            "label": "Dust",
            "line": "Grinding or machining makes dust, which is a fire hazard and an inhalation exposure. The SDS asks for suction cleaning at source and at least one FFP2 respirator."
          }
        ],
        "level": 1,
        "verdict": "Not classified, dust controlled"
      },
      {
        "title": "If it fails",
        "lead": "The failure routes in these sources are oxidation in hot air and melting of the copper phase. None of them is a measured flight result.",
        "points": [
          {
            "label": "Hot air",
            "line": "Tungsten oxidises strongly in air from about 400 °C, and WO3 sublimes from about 850 °C, according to the Plansee SDS."
          },
          {
            "label": "Copper melt",
            "line": "Copper melts at 1083 °C (SDS) or about 1080 °C (patent), far below the tungsten melting point of 3410 °C."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Dust",
            "line": "Avoid dust formation, use suction cleaning, and wear an FFP2 respirator when dust is unavoidable."
          },
          {
            "label": "Storage",
            "line": "The SDS calls for no special storage measures."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-26",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 17,
    "unreachable": 1,
    "caveats": 5,
    "note": "Values were read by an AI assistant on 2026-10-26 from the pages named in each entry. Unreachable: the ScienceDirect hybrid-rocket paper (HTTP 403, not cited in the file). The three Plansee pages return Access Denied to scripted fetches, so verify-values cannot read them; their values were read with WebFetch in this run. Caveats: supplier values for one grade disagree (bending strength 736 and 980 MPa; thermal conductivity 180 and 235 W/(m·K)); the Plansee table gives typical values, the SVS table minimum, typical or tolerance values without saying which; the oxidation temperatures are printed as approximate; the spacecraft evidence is limited to rocket nozzle parts."
  },
  "sources": {
    "plansee-properties": {
      "title": "Plansee Tungsten composites: properties, typical properties of WCu materials at 20 °C",
      "url": "https://www.plansee.com/en/materials/tungsten-composites/properties.html",
      "year": 2026,
      "kind": "datasheet",
      "license": "manufacturer web page, linked not reproduced"
    },
    "plansee-materials": {
      "title": "Plansee Tungsten composites: materials, WCu grades and nominal densities",
      "url": "https://www.plansee.com/en/materials/tungsten-composites/materials.html",
      "year": 2026,
      "kind": "datasheet",
      "license": "manufacturer web page, linked not reproduced"
    },
    "plansee-wcu-sds": {
      "title": "Plansee PDS-041, Product data sheet pursuant to REACH, WCu-composite material (valid from 12 July 2022)",
      "id": "PSE-030-PDS-041, Version 00, Elmet and Plansee sites",
      "url": "https://www.plansee.com/download/?DOKNR=PSE-030-PDS-041&DOKAR=QM1&DOKTL=100",
      "year": 2022,
      "kind": "datasheet",
      "license": "manufacturer safety data sheet, linked not reproduced"
    },
    "tungsten-com": {
      "title": "Tungsten.com, Tungsten Copper Alloy (W-Cu) material information, composition table",
      "url": "https://www.tungsten.com/material-info/tungsten-copper-alloy-w-cu",
      "kind": "datasheet",
      "license": "supplier web page, linked not reproduced"
    },
    "torrey-cuw": {
      "title": "Torrey Hills Technologies, Properties of Copper Tungsten",
      "url": "https://www.torreyhillstech.com/cuwdata.html",
      "kind": "datasheet",
      "license": "supplier web page, linked not reproduced"
    },
    "svs-wcu": {
      "title": "SVS Schweisstechnik, Tungsten-Copper (WCu), Physical and Mechanical Properties table",
      "url": "https://www.svs-schweisstechnik.de/en/knowledge-hub/refractory-alloys/tungsten-copper-wcu/",
      "kind": "datasheet",
      "license": "supplier web page, linked not reproduced"
    },
    "samaterials-cuw75": {
      "title": "SA Materials, Tungsten Copper Composite CuW75, catalog WM7700",
      "url": "https://www.samaterials.com/item/wm7700-tungsten-copper-composite-w-cu-composite-cuw75.html",
      "kind": "datasheet",
      "license": "supplier web page, linked not reproduced"
    },
    "wikipedia-cuw": {
      "title": "Copper-tungsten (CuW, WCu), Wikipedia",
      "url": "https://en.wikipedia.org/wiki/Copper%E2%80%93tungsten",
      "kind": "web",
      "license": "CC BY-SA 4.0, linked not reproduced"
    },
    "usgs-mcs2026-tungsten": {
      "title": "Mineral Commodity Summaries 2026, Tungsten",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tungsten.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "us-patent-5705283": {
      "title": "US Patent 5,705,283, Tungsten-copper composite material with rhenium protective layer, and its preparation",
      "url": "https://patents.google.com/patent/US5705283A/en",
      "kind": "report",
      "license": "public domain (US patent)"
    },
    "refractorymetal-rocket": {
      "title": "Refractory Metal, Tungsten Copper Alloy for Rocket Throat Lining",
      "url": "https://www.refractorymetal.org/tungsten-copper-alloy-for-rocket-throat-lining.html",
      "kind": "web",
      "license": "supplier web page, linked not reproduced"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/tungsten-copper/"
}