{
  "spore": "profile",
  "id": "nickel-silver",
  "spore_version": "0.2",
  "family": "copper-alloys",
  "name": "Nickel silver C75200",
  "abbreviation": "C75200",
  "role": "copper-nickel-zinc spring and optical alloy",
  "category": "metals",
  "type": "copper-alloys",
  "summary": "Nickel silver C75200 (UNS C75200, ASTM B122) is a copper-nickel-zinc alloy with a silvery colour. ASTM B122 prints its nominal composition as 65 % copper, 18 % nickel and 17 % zinc. The EN grade CW409J (CuNi18Zn20, DIN 2.0740) is close but not identical: Matthey prints 60.0 to 63.0 % copper for it. Matthey gives a density of 8.7 g/cm3 and a modulus of elasticity of 135 GPa, and its strip tensile strength runs from 370 to 430 MPa soft annealed to 680 MPa minimum extra hard. Fisk gives an electrical conductivity of 6 %IACS when annealed and round-wire tensile strengths from 53.0 to 63.0 ksi annealed to 99.0 to 111 ksi hard. Matthey says the alloy resists atmospheric corrosion and neutral and alkaline saline solutions, is poorly resistant to oxidizing acids, and is much less prone to stress corrosion cracking than brass. Its nickel content is the health concern: PubChem's GHS notifications for nickel include H317 (allergic skin reaction) and H351 (suspected carcinogen).\n",
  "best_for": "Springs, connectors and precision optical or watch parts that need a silver colour, cold-formed strength and corrosion resistance without precious metal",
  "weakest_at": "Machinability (Fisk rates it 1 of 5, Matthey calls it rather poor) and hot working, plus the nickel content, which carries allergy and carcinogen hazard statements",
  "identity": {
    "formula": "Copper-nickel-zinc alloy, nominal Cu 65, Ni 18, Zn 17 (UNS C75200, ASTM B122 nominal table)",
    "designations": [
      {
        "system": "UNS",
        "code": "C75200",
        "source": "astm-b122",
        "where": "Nominal composition table, row C75200; the UNS list in the scope names C75200"
      },
      {
        "system": "EN name",
        "code": "CW409J",
        "source": "matthey-cuni18zn20",
        "where": "Designation row, EN Nr. column, for CuNi18Zn20"
      },
      {
        "system": "EN",
        "code": "2.0740",
        "source": "matthey-cuni18zn20",
        "where": "Designation row, DIN column, for CuNi18Zn20"
      },
      {
        "system": "UNS",
        "code": "C76400",
        "note": "Matthey pairs this UNS number with CuNi18Zn20 (CW409J). ASTM B122 does not list C76400 and gives C75200 for the 65-18-17 nominal, so the two sources conflict; see gaps",
        "source": "matthey-cuni18zn20",
        "where": "Designation row, UNS (ASTM) column"
      },
      {
        "system": "ASTM",
        "code": "B122",
        "note": "copper-nickel-zinc alloy (nickel silver) plate, sheet, strip and rolled bar",
        "source": "fisk-c752",
        "where": "Specifications list"
      },
      {
        "system": "Trade name",
        "code": "Maillechort M18",
        "source": "matthey-cuni18zn20",
        "where": "Page title: CuNi18Zn20, Maillechort M18"
      },
      {
        "system": "Trade name",
        "code": "Nickel Silver 18%",
        "source": "fisk-c752",
        "where": "Page title: C752 Nickel Silver 18% Alloy Wire"
      }
    ],
    "source": "astm-b122",
    "where": "ASTM B122 nominal composition table, row C75200 (Cu 65, Ni 18, Zn 17). Composition limits: Matthey CuNi18Zn20 (CW409J) Cu 60.0 to 63.0, Ni 17.0 to 19.0, Fe up to 0.30, Mn up to 0.50, Pb up to 0.03, Sn up to 0.03, Zn balance. Fisk C752 (C75200 family) Cu 63.0 to 66.5, Ni 16.5 to 19.5, Pb 0.05 max, Fe 0.25 max, Mn 0.50 max, Zn remainder."
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "mechanisms",
      "electronics-and-chips",
      "optics-and-cameras"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, CuNi18Zn20 (Matthey)",
      "value": 8.7,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temper": "not stated",
        "temperature": "not stated"
      },
      "method": "Value printed in the physical properties table of a manufacturer's datasheet",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Physical properties table, Density row",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, C752 (Fisk)",
      "value": 0.316,
      "bound": "exact",
      "unit": "lb/in3",
      "scope": "material",
      "conditions": {
        "grade": "C752 (Fisk 18 % nickel silver)",
        "temper": "not stated",
        "temperature": "not stated",
        "unit_in_source": "0.316 lb/in3 (the only density printed)"
      },
      "method": "Value printed in a supplier's physical properties table; the page prints no metric density",
      "status": "ground",
      "source": "fisk-c752",
      "where": "Physical Properties table, Density row",
      "source_detail": {
        "title": "Fisk Alloy Wire: C752 Nickel Silver 18% alloy wire, chemical composition, physical properties, round wire and rolled flat temper tables, fabrication index",
        "url": "https://fiskalloy.com/pdf/c75200/",
        "kind": "datasheet",
        "license": "Supplier datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting range, CuNi18Zn20 (Matthey)",
      "value": 1060,
      "value_high": 1110,
      "bound": "range",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "pressure": "not stated"
      },
      "method": "Range printed in the physical properties table of a manufacturer's datasheet",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Physical properties table, Melting point / Melting range row",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity at 20 °C, CuNi18Zn20 (Matthey)",
      "value": 32,
      "bound": "exact",
      "unit": "W/(m·K)",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temperature": "20 °C",
        "temper": "not stated",
        "unit_in_source": "W/m °K"
      },
      "method": "Value printed in the physical properties table; the unit is printed as W/m °K, the same as W/(m·K)",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Physical properties table, Thermal conductivity at 20 °C row",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cte",
      "label": "Linear coefficient of thermal expansion, CuNi18Zn20 (Matthey)",
      "value": 17.7,
      "bound": "exact",
      "unit": "ppm/K",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temperature": "not stated",
        "unit_in_source": "10^-6 per °C"
      },
      "method": "Printed as 10^-6 per °C; that is the same unit as ppm/K, so the number is copied without conversion",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Physical properties table, Linear dilatation coefficient row",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "electrical_conductivity",
      "label": "Electrical conductivity, CuNi18Zn20 (Matthey)",
      "value": 6,
      "bound": "exact",
      "unit": "%IACS",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temperature": "not stated",
        "temper": "not stated"
      },
      "method": "Value printed in the physical properties table; electrical_conductivity is not in the property canon (see gaps)",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Physical properties table, Electrical conductivity % IACS row",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "electrical_conductivity",
      "label": "Electrical conductivity, annealed C752 (Fisk)",
      "value": 6,
      "bound": "exact",
      "unit": "%IACS",
      "scope": "material",
      "conditions": {
        "grade": "C752 (Fisk 18 % nickel silver)",
        "temper": "annealed",
        "temperature": "68 °F as printed"
      },
      "method": "Value printed in the physical properties table of a supplier's datasheet",
      "status": "ground",
      "source": "fisk-c752",
      "where": "Physical Properties table, Electrical Conductivity (Annealed) row",
      "source_detail": {
        "title": "Fisk Alloy Wire: C752 Nickel Silver 18% alloy wire, chemical composition, physical properties, round wire and rolled flat temper tables, fabrication index",
        "url": "https://fiskalloy.com/pdf/c75200/",
        "kind": "datasheet",
        "license": "Supplier datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Modulus of elasticity, CuNi18Zn20 (Matthey)",
      "value": 135,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temper": "not stated",
        "temperature": "not stated",
        "unit_in_source": "135 kN/mm2"
      },
      "method": "Printed as kN/mm2 in a datasheet table; 1 kN/mm2 equals 1 GPa, so the number is copied without conversion",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Physical properties table, Modulus of elasticity row",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "poissons_ratio",
      "label": "Poisson ratio, CuNi18Zn20 (Matthey)",
      "value": 0.34,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temperature": "not stated",
        "temper": "not stated"
      },
      "method": "Value printed in the physical properties table of a manufacturer's datasheet",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Physical properties table, Poisson ratio row",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "specific_heat",
      "label": "Specific heat at 20 °C, CuNi18Zn20 (Matthey)",
      "value": 380,
      "bound": "exact",
      "unit": "J/(kg·K)",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temperature": "20 °C",
        "unit_in_source": "J/(kg.K)"
      },
      "method": "Value printed in the physical properties table of a manufacturer's datasheet",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Physical properties table, Specific heat at 20 °C row",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, soft annealed H90 strip (R370)",
      "value": 370,
      "value_high": 430,
      "bound": "range",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temper": "H90, soft annealed (R370)",
        "product_form": "strip",
        "unit_in_source": "N/mm2"
      },
      "method": "Range printed in the mechanical properties table of strip; the N/mm2 value is copied as printed, which equals MPa",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Mechanical properties of strips table, row R370 H90 soft annealed, column Rm (N/mm2)",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, half-hard H120 strip (R430)",
      "value": 430,
      "value_high": 520,
      "bound": "range",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temper": "H120, half hard (R430)",
        "product_form": "strip",
        "unit_in_source": "N/mm2"
      },
      "method": "Range printed in the mechanical properties table of strip",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Mechanical properties of strips table, row R430 H120 half hard, column Rm (N/mm2)",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, three-quarter hard H150 strip (R520)",
      "value": 520,
      "value_high": 610,
      "bound": "range",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temper": "H150, three-quarter hard (R520)",
        "product_form": "strip",
        "unit_in_source": "N/mm2"
      },
      "method": "Range printed in the mechanical properties table of strip",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Mechanical properties of strips table, row R520 H150 three-quarter hard, column Rm (N/mm2)",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, hard H185 strip (R610)",
      "value": 610,
      "value_high": 700,
      "bound": "range",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temper": "H185, hard (R610)",
        "product_form": "strip",
        "unit_in_source": "N/mm2"
      },
      "method": "Range printed in the mechanical properties table of strip",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Mechanical properties of strips table, row R610 H185 hard, column Rm (N/mm2)",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, extra hard H200 strip (R680, minimum)",
      "value": 680,
      "bound": "lower",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temper": "H200, extra hard (R680)",
        "product_form": "strip",
        "measure": "minimum",
        "unit_in_source": "N/mm2"
      },
      "method": "Minimum value printed in the mechanical properties table of strip",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Mechanical properties of strips table, row R680 H200 extra hard, column Rm (N/mm2)",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation A50mm, soft annealed H90 strip",
      "value": 40,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temper": "H90, soft annealed",
        "product_form": "strip",
        "gauge_length": "A50mm"
      },
      "method": "Value printed in the mechanical properties table of strip",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Mechanical properties of strips table, row R370 H90, column A50mm (%)",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation A50mm, half-hard H120 strip",
      "value": 22,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temper": "H120, half hard",
        "product_form": "strip",
        "gauge_length": "A50mm"
      },
      "method": "Value printed in the mechanical properties table of strip",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Mechanical properties of strips table, row R430 H120, column A50mm (%)",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation A50mm, three-quarter hard H150 strip",
      "value": 6,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temper": "H150, three-quarter hard",
        "product_form": "strip",
        "gauge_length": "A50mm"
      },
      "method": "Value printed in the mechanical properties table of strip",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Mechanical properties of strips table, row R520 H150, column A50mm (%)",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation A50mm, hard H185 strip",
      "value": 2,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temper": "H185, hard",
        "product_form": "strip",
        "gauge_length": "A50mm"
      },
      "method": "Value printed in the mechanical properties table of strip",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Mechanical properties of strips table, row R610 H185, column A50mm (%)",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "hardness_vickers",
      "label": "Hardness HV, soft annealed H90 strip",
      "value": 90,
      "value_high": 125,
      "bound": "range",
      "unit": "HV",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temper": "H90, soft annealed",
        "product_form": "strip"
      },
      "method": "Range printed in the mechanical properties table of strip; hardness_vickers is not in the property canon (see gaps)",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Mechanical properties of strips table, row R370 H90, column Hardness HV",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "hardness_vickers",
      "label": "Hardness HV, half-hard H120 strip",
      "value": 120,
      "value_high": 155,
      "bound": "range",
      "unit": "HV",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temper": "H120, half hard",
        "product_form": "strip"
      },
      "method": "Range printed in the mechanical properties table of strip",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Mechanical properties of strips table, row R430 H120, column Hardness HV",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "hardness_vickers",
      "label": "Hardness HV, hard H185 strip",
      "value": 185,
      "value_high": 210,
      "bound": "range",
      "unit": "HV",
      "scope": "material",
      "conditions": {
        "grade": "CuNi18Zn20 (CW409J)",
        "temper": "H185, hard",
        "product_form": "strip"
      },
      "method": "Range printed in the mechanical properties table of strip",
      "status": "ground",
      "source": "matthey-cuni18zn20",
      "where": "Mechanical properties of strips table, row R610 H185, column Hardness HV",
      "source_detail": {
        "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, annealed C752 round wire (minimum)",
      "value": 53,
      "value_high": 63,
      "bound": "range",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "grade": "C752 (Fisk 18 % nickel silver)",
        "temper": "annealed",
        "product_form": "round wire",
        "unit_in_source": "53.0 to 63.0 ksi"
      },
      "method": "Range printed in the round wire temper table of a supplier's datasheet; ksi is copied as printed",
      "status": "ground",
      "source": "fisk-c752",
      "where": "Round Wire table, Annealed row, Tensile strength (ksi) Min and Max",
      "source_detail": {
        "title": "Fisk Alloy Wire: C752 Nickel Silver 18% alloy wire, chemical composition, physical properties, round wire and rolled flat temper tables, fabrication index",
        "url": "https://fiskalloy.com/pdf/c75200/",
        "kind": "datasheet",
        "license": "Supplier datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, hard H04 C752 round wire (minimum)",
      "value": 99,
      "value_high": 111,
      "bound": "range",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "grade": "C752 (Fisk 18 % nickel silver)",
        "temper": "H04, hard",
        "product_form": "round wire"
      },
      "method": "Range printed in the round wire temper table of a supplier's datasheet",
      "status": "ground",
      "source": "fisk-c752",
      "where": "Round Wire table, Hard H04 row, Tensile strength (ksi) Min and Max",
      "source_detail": {
        "title": "Fisk Alloy Wire: C752 Nickel Silver 18% alloy wire, chemical composition, physical properties, round wire and rolled flat temper tables, fabrication index",
        "url": "https://fiskalloy.com/pdf/c75200/",
        "kind": "datasheet",
        "license": "Supplier datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, spring H08 C752 round wire (minimum)",
      "value": 105,
      "bound": "lower",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "grade": "C752 (Fisk 18 % nickel silver)",
        "temper": "H08, spring",
        "product_form": "round wire",
        "measure": "minimum"
      },
      "method": "Minimum value printed in the round wire temper table of a supplier's datasheet",
      "status": "ground",
      "source": "fisk-c752",
      "where": "Round Wire table, Spring H08 row, Tensile strength (ksi) Min",
      "source_detail": {
        "title": "Fisk Alloy Wire: C752 Nickel Silver 18% alloy wire, chemical composition, physical properties, round wire and rolled flat temper tables, fabrication index",
        "url": "https://fiskalloy.com/pdf/c75200/",
        "kind": "datasheet",
        "license": "Supplier datasheet (cited, not reproduced)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Atmosphere, organic compounds, and neutral or alkaline saline solutions",
      "headline": "Nickel silver has good resistance to atmospheric corrosion and to neutral or alkaline saline solutions.",
      "effect": "Matthey says the CuNi18Zn20 grade has good resistance to atmospheric corrosion, organic compounds and neutral and alkaline saline solutions. Fisk says the C752 alloy combines corrosion resistance with strength and a lustrous silver colour. No exposure time, corrosion rate or test is printed in either source.",
      "rating": "low",
      "conditions": {
        "basis": "qualitative statements in datasheets; no rate, exposure time or test standard is printed",
        "grade": "CuNi18Zn20 (CW409J) for the Matthey statement"
      },
      "source": "matthey-cuni18zn20",
      "where": "Main technical properties and features, first paragraph"
    },
    {
      "environment": "Oxidizing acids",
      "headline": "Nickel silver is poorly resistant to oxidizing acids.",
      "effect": "Matthey says the alloy is poorly resistant to oxidizing acids. The datasheet names no acid, concentration or temperature.",
      "rating": "moderate",
      "conditions": {
        "basis": "qualitative statement; no acid, concentration or temperature is named",
        "grade": "CuNi18Zn20 (CW409J)"
      },
      "source": "matthey-cuni18zn20",
      "where": "Main technical properties and features, first paragraph"
    },
    {
      "environment": "Ammonia or amine atmospheres with tensile stress (stress corrosion cracking)",
      "headline": "Stress corrosion cracking sensitivity is much lower than for brass.",
      "effect": "Matthey says the sensitivity of CuNi18Zn20 to stress corrosion cracking is much lower than that of brass. No threshold stress, time to crack or test environment is printed for nickel silver.",
      "rating": "low",
      "conditions": {
        "basis": "qualitative comparison with brass; no threshold stress or time to crack is printed",
        "grade": "CuNi18Zn20 (CW409J)"
      },
      "source": "matthey-cuni18zn20",
      "where": "Main technical properties and features, first paragraph"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "PubChem's GHS notifications for nickel (CID 935) include H317 May cause an allergic skin reaction (99.9 % of notifications) and H351 Suspected of causing cancer (72.9 %), H350 May cause cancer (22.5 %), and also list H334, H372 and H360F in some notifications. No SDS for the alloy itself was read.",
        "ghs": [],
        "source": "pubchem-nickel",
        "where": "Safety and Hazards, GHS Classification, CID 935 (ECHA aggregated notifications)"
      },
      {
        "text": "Nickel is 17.0 to 19.0 % of the CuNi18Zn20 grade (Matthey) and 16.5 to 19.5 % of the C752 grade (Fisk), so nickel is the main hazard element. ASTM B122 nominal for C75200 is 18 % nickel.",
        "ghs": [],
        "source": "matthey-cuni18zn20",
        "where": "Chemical composition table, Ni row"
      },
      {
        "text": "Lead is an impurity: Matthey gives 0.03 % maximum and Fisk gives 0.05 % maximum. The sources read do not add lead to this grade.",
        "ghs": [],
        "source": "fisk-c752",
        "where": "Chemical Composition Limits, Pb row"
      }
    ],
    "failure_risks": [
      {
        "mode": "Softening after heating above the annealing range",
        "trigger": "Heating a cold-worked part above the annealing range printed by Fisk (1100 to 1400 °F)",
        "consequence": "The temper is lost and the part falls back toward the annealed strength (53.0 to 63.0 ksi round wire, Fisk). The softening consequence is an inference from the printed ranges.",
        "severity": "moderate",
        "source": "fisk-c752",
        "where": "Physical Properties table, Annealing Range rows; Round Wire table, Annealed row"
      },
      {
        "mode": "Cracking when hard tempers are bent or formed",
        "trigger": "Forming or bending strip in the hard H185 or extra hard H200 temper",
        "consequence": "Elongation falls to 2 % in hard H185 strip (A50mm), against 40 % soft annealed. Matthey prints no forming limit.",
        "severity": "moderate",
        "source": "matthey-cuni18zn20",
        "where": "Mechanical properties of strips table, rows R370 H90 and R610 H185, column A50mm (%)"
      },
      {
        "mode": "Poor machinability and hot working",
        "trigger": "Machining or hot forming the alloy",
        "consequence": "Fisk rates machinability 1 of 5 (poor) and hot working 1 of 5 (poor). Matthey says machinability is rather poor and hot formability is limited.",
        "severity": "low",
        "source": "fisk-c752",
        "where": "Fabrication Index table, Machinability and Hot Worked rows"
      }
    ],
    "side_effects": [
      {
        "text": "Matthey says the alloy can be brazed or welded, but its weldability by laser is not good.",
        "affects": "Laser-welded assemblies",
        "source": "matthey-cuni18zn20",
        "where": "Main technical properties and features, paragraph on joining"
      }
    ],
    "handling": [
      {
        "text": "Anneal at 620 to 700 °C (Matthey) or within the 1100 to 1400 °F range (Fisk).",
        "source": "matthey-cuni18zn20",
        "where": "Main technical properties and features, annealing sentence"
      },
      {
        "text": "Stress-relieve at 300 to 350 °C after cold forming to reduce internal stress (Matthey).",
        "source": "matthey-cuni18zn20",
        "where": "Main technical properties and features, last sentence"
      },
      {
        "text": "Pick the temper from the strip table: soft annealed H90 gives 370 to 430 MPa, half-hard H120 430 to 520 MPa, three-quarter hard H150 520 to 610 MPa, hard H185 610 to 700 MPa, extra hard H200 680 MPa minimum (Matthey).",
        "source": "matthey-cuni18zn20",
        "where": "Mechanical properties of strips table"
      },
      {
        "text": "Lead is an impurity limit only. Chips and dust should be handled as nickel-containing material; this handling advice is an inference from the nickel hazard statements, not a printed instruction.",
        "source": "pubchem-nickel",
        "where": "Safety and Hazards, GHS Classification, CID 935"
      }
    ],
    "mitigations": [
      {
        "text": "Matthey recommends a leaded nickel silver, CuNi12Zn25Pb1 (B420), where good machinability is needed.",
        "source": "matthey-cuni18zn20",
        "where": "Main technical properties and features, machinability sentence"
      },
      {
        "text": "Use the stress-relief heat treatment at 300 to 350 °C after cold work to decrease internal stress (Matthey).",
        "source": "matthey-cuni18zn20",
        "where": "Main technical properties and features, last sentence"
      }
    ]
  },
  "uses": [
    {
      "application": "mechanisms",
      "device": "Relay springs and hinges for glasses",
      "example": "Matthey lists relay springs and hinges for glasses as typical uses; Fisk lists springs among its applications.",
      "source": "matthey-cuni18zn20",
      "where": "Typical uses paragraph"
    },
    {
      "application": "electronics-and-chips",
      "device": "Connectors, resistors and electrical contacts",
      "example": "Matthey lists connectors and parts for precision and electronic instruments; Fisk lists resistors and contacts.",
      "source": "fisk-c752",
      "where": "Introduction, Applications sentence"
    },
    {
      "application": "optics-and-cameras",
      "device": "Optical frames and parts",
      "example": "Fisk lists optical frames and parts first among its applications; Matthey lists optical instruments and watch-making parts.",
      "source": "fisk-c752",
      "where": "Introduction, Applications sentence"
    }
  ],
  "supply": [
    {
      "subject": "Copper (mine production, copper content, 2025e), about 60 to 66 % of the alloy",
      "producers": [
        {
          "country": "Chile",
          "share_percent": 23,
          "year": 2025
        },
        {
          "country": "Congo (Kinshasa)",
          "share_percent": 13.9,
          "year": 2025
        },
        {
          "country": "Peru",
          "share_percent": 11.7,
          "year": 2025
        },
        {
          "country": "China",
          "share_percent": 7.8,
          "year": 2025
        },
        {
          "country": "Russia",
          "share_percent": 5.7,
          "year": 2025
        }
      ],
      "critical_lists": [
        {
          "list": "U.S. Final 2025 List of Critical Minerals (copper added, per the USGS copper summary)",
          "listed": true
        }
      ],
      "recycling": "USGS: brass and wire-rod mills accounted for approximately 80% of the total copper recovered from scrap, and copper recovered from scrap contributed about 30% of the U.S. copper supply.",
      "substitutes": [],
      "source": "usgs-mcs2026-copper",
      "where": "World Mine and Refinery Production and Reserves table, mine production 2025e (world total 23,000 thousand t; shares calculated by Space Mushroom from the printed values 5,300, 3,200, 2,700, 1,800 and 1,300 thousand t); Recycling paragraph; Critical minerals paragraph"
    },
    {
      "subject": "Nickel (mine production, nickel content, 2025e), 16.5 to 19.5 % of the alloy",
      "producers": [
        {
          "country": "Indonesia",
          "share_percent": 66.7,
          "year": 2025
        },
        {
          "country": "Philippines",
          "share_percent": 6.9,
          "year": 2025
        },
        {
          "country": "Russia",
          "share_percent": 5.1,
          "year": 2025
        },
        {
          "country": "Canada",
          "share_percent": 3.6,
          "year": 2025
        },
        {
          "country": "New Caledonia",
          "share_percent": 3.6,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "USGS: nickel recovered from scrap accounted for approximately 60% of apparent consumption in 2025, and most secondary nickel was stainless-steel scrap.",
      "substitutes": [
        "USGS: low-nickel, duplex, or ultrahigh-chromium stainless steels have been substituted for austenitic grades in construction; titanium alloys can substitute for nickel or nickel-base alloys in corrosive environments."
      ],
      "source": "usgs-mcs2026-nickel",
      "where": "World Mine Production and Reserves table, 2025e (world total rounded 3,900,000 t; shares calculated by Space Mushroom from the printed values 2,600,000, 270,000, 200,000 and 140,000 t, the last two each for Canada and New Caledonia); Domestic Production and Use, Recycling and Substitutes paragraphs"
    },
    {
      "subject": "Zinc (mine production, zinc content, 2025e), about 17 % of the alloy",
      "producers": [
        {
          "country": "China",
          "share_percent": 31.5,
          "year": 2025
        },
        {
          "country": "Peru",
          "share_percent": 11.5,
          "year": 2025
        },
        {
          "country": "Australia",
          "share_percent": 8.5,
          "year": 2025
        },
        {
          "country": "India",
          "share_percent": 6.7,
          "year": 2025
        },
        {
          "country": "Mexico",
          "share_percent": 6,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "USGS: refined zinc produced in the United States was recovered from secondary materials, including galvanizing residues and crude zinc oxide from electric arc furnace dust.",
      "substitutes": [
        "USGS: aluminum and plastics substitute for galvanized sheet in automobiles; many elements are substitutes for zinc in chemical, electronic and pigment uses. The summary names no substitute for zinc in nickel silver."
      ],
      "source": "usgs-mcs2026-zinc",
      "where": "World Mine Production and Reserves table, 2025e (world total rounded 13,000 thousand t; shares calculated by Space Mushroom from the printed values 4,100, 1,500, 1,100, 870 and 780 thousand t); Recycling and Substitutes paragraphs"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Lamineries Matthey: CuNi18Zn20 (Maillechort M18) technical datasheet",
      "type": "datasheet",
      "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf"
    },
    {
      "title": "Fisk Alloy Wire: C752 Nickel Silver 18% alloy wire datasheet",
      "type": "datasheet",
      "url": "https://fiskalloy.com/pdf/c75200/"
    },
    {
      "title": "ASTM B122/B122M: copper-nickel-zinc alloy (nickel silver) plate, sheet, strip and rolled bar, UNS list and nominal composition",
      "type": "standard",
      "url": "https://store.astm.org/b0122_b0122m-16.html",
      "year": 2016
    },
    {
      "title": "Wikipedia: Nickel silver (composition and history only)",
      "type": "database",
      "url": "https://en.wikipedia.org/wiki/Nickel_silver"
    },
    {
      "title": "PubChem: Nickel (CID 935), Safety and Hazards, GHS classification",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/Nickel"
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Copper",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Zinc",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-zinc.pdf",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Nickel",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf",
      "year": 2026
    }
  ],
  "gaps": [
    "Designations conflict: Matthey prints UNS C76400 for CuNi18Zn20 (CW409J, Cu 60.0 to 63.0), but ASTM B122 does not list C76400 and prints C75200 for the 65-18-17 nominal (Cu 65, Ni 18, Zn 17). The profile lists both as printed and does not treat C76400 as the same grade as C75200. Someone should check which UNS number the EN CW409J grade maps to before the two are linked in search.",
    "Composition: the EN grade CW409J (Cu 60.0 to 63.0) and C75200 (Cu 63.0 to 66.5 per Fisk) are close but not the same range. The profile keeps both and does not average them.",
    "Fisk prints a nominal zinc of 35 in its nominal composition column next to Cu 65 and Ni 18, which does not fit the zinc remainder in its limits. The nominal zinc is not used.",
    "Fisk prints a modulus of elasticity of 18 ksi, which is about 1000 times too low for a copper alloy and is treated as a units error. It is not recorded. Matthey's 135 GPa is used instead.",
    "Matthey prints an electrical resistivity of 28.7 with the unit 'cm', which cannot be read reliably as a unit (the superscript was lost). It is not recorded; Matthey's 3.3 MS/m is also not used because the %IACS value is recorded.",
    "No yield strength (0.2 % offset or 0.5 % extension) is printed in any source read, for strip or for round wire.",
    "No copper.org (CDA) alloy page and no MakeItFrom page could be read: copper.org returned 403 and MakeItFrom returned 403 to the fetcher. Their values are not used.",
    "Hardness is in HV for strip only (Matthey). The property name hardness_vickers is not in the property canon. Fisk gives no hardness.",
    "electrical_conductivity is not in the property canon; the name is used as a snake_case placeholder (see the brass profile for the same case).",
    "Thermal conductivity and thermal expansion are from Matthey only. Fisk prints them in imperial units (19 Btu per ft2 per ft per hour per degree F, 9 per degree F over 68 to 572 F) and they are not converted or recorded.",
    "Nickel critical-mineral status is not read in this run (the nickel summary read has no critical-list statement), so critical_lists is empty for nickel. Zinc's status is also not read.",
    "Hazards: the GHS codes are for nickel (PubChem CID 935), not for the alloy. ATSDR's nickel ToxFAQ could not be read (the fetched page was the portal landing page), so the carcinogen and allergy statements rest on PubChem's GHS notifications and not on ATSDR.",
    "No occupational exposure limit for nickel or nickel silver was read.",
    "No corrosion rate, test time or threshold stress for nickel silver was printed in the sources read, and no dezincification data was read.",
    "No space-environment data (outgassing, atomic oxygen, cold welding, radiation) was read, so tags.environments is empty and the habitats-and-suits application is not used.",
    "No CAS number is recorded: the alloy is identified by its UNS number, and no source read gives a CAS number for the alloy.",
    "No media (images) were added to this profile; no image was fetched or checked in this run.",
    "Wikipedia was used for the composition formulation (60 % copper, 20 % nickel, 20 % zinc) and history only, as the brief requires; its use statements were not used.",
    "Specific heat is from Matthey at 20 °C only; the temperature dependence and the Poisson ratio at temperature were not read."
  ],
  "story": {
    "why": "Nickel silver is chosen for its silver colour, cold-forming strength and corrosion resistance, without precious metal. Matthey names relay springs, connectors and watch-industry parts, and Fisk names springs, optical frames and resistors. Matthey rates cold forming as excellent and hot forming as limited. The density is 8.7 g/cm3 and the electrical conductivity is 6 %IACS when annealed.",
    "uses": [
      {
        "where": "Relay springs and glasses hinges",
        "line": "Matthey lists relay springs, hinges for glasses, connectors, watch-industry components and pressure membranes as typical uses. Fisk lists springs among its applications."
      },
      {
        "where": "Connectors, resistors and contacts",
        "line": "Fisk lists resistors and contacts; Matthey lists connectors and parts for precision and electronic instruments."
      },
      {
        "where": "Optical frames and parts",
        "line": "Fisk lists optical frames and parts first among its applications, and Matthey names optical instruments."
      }
    ],
    "can_do": [
      {
        "label": "Spring",
        "line": "Extra hard H200 strip has a minimum tensile strength of 680 MPa (Matthey). Round wire spring temper H08 is 105 ksi minimum (Fisk).",
        "benchmark": "ultimate_tensile_strength",
        "scope": "material",
        "value": "680 MPa minimum"
      },
      {
        "label": "Carry current",
        "line": "Electrical conductivity is 6 %IACS in Matthey's table and 6 %IACS annealed in Fisk's table.",
        "benchmark": "electrical_conductivity",
        "scope": "material",
        "value": "6 %IACS"
      },
      {
        "label": "Carry heat",
        "line": "Thermal conductivity is 32 W/m °K at 20 °C (Matthey).",
        "benchmark": "thermal_conductivity",
        "scope": "material",
        "value": "32 W/(m·K)"
      },
      {
        "label": "Weight",
        "line": "Density is 8.7 g/cm3 (Matthey). Fisk prints 0.316 lb/in3.",
        "benchmark": "density",
        "scope": "material",
        "value": "8.7 g/cm3"
      },
      {
        "label": "Melting",
        "line": "The melting range is 1060 to 1110 °C (Matthey).",
        "benchmark": "melting_point",
        "scope": "material",
        "value": "1060 to 1110 °C"
      }
    ],
    "compare": "The copper profile at /profiles/copper/ covers the pure metal. Within this profile, the two suppliers print strength in different units (MPa for strip, ksi for round wire), and the strip table gives 680 MPa minimum at its hardest temper while round wire reaches 111 ksi, so the two tables should not be compared number to number.",
    "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 temper: strip runs from 370 MPa soft annealed to 680 MPa minimum extra hard (Matthey); round wire runs from 53.0 ksi annealed to 111 ksi hard (Fisk).",
      "Anneal at 620 to 700 °C (Matthey) and stress-relieve at 300 to 350 °C after cold forming.",
      "Lead is an impurity limit only (0.03 % maximum by Matthey, 0.05 % by Fisk). Chips and dust should be handled as nickel-containing material, which is an inference from the nickel hazard statements."
    ],
    "good_for": [
      "Springs, relay parts and hinges where a silver colour and a spring temper are both needed.",
      "Connectors and precision optical or watch parts stamped, folded or bent from strip (Matthey).",
      "Brazed or soldered assemblies: Fisk rates soldering and brazing as excellent (5 of 5)."
    ],
    "watch_out": [
      "Machining is poor (Fisk 1 of 5, Matthey rather poor). Matthey recommends a leaded nickel silver for good machinability.",
      "The hard tempers have little elongation: 2 % in H185 strip.",
      "Nickel content gives allergy and cancer hazard statements; handle chips and dust with that in mind.",
      "Oxidizing acids attack the alloy (Matthey poorly resistant). No corrosion rate is printed."
    ],
    "verdict": "Nickel silver C75200 is a silvery copper-nickel-zinc alloy with good atmospheric and saline corrosion resistance, a 6 %IACS conductivity and spring-grade tempers up to 680 MPa minimum in strip. Its machinability is poor and its nickel content carries allergy and carcinogen hazard statements. The C75200 nominal (Cu 65, Ni 18, Zn 17) and the EN CW409J grade (Cu 60.0 to 63.0) are close but not the same, and the Matthey UNS number for CW409J (C76400) conflicts with ASTM B122. No yield strength, corrosion rate or space-environment result was found in the sources read.",
    "recipe": {
      "line": "Nickel silver is a copper-nickel-zinc alloy with a single alpha phase (Matthey). Wikipedia gives the usual formulation as 60 % copper, 20 % nickel and 20 % zinc, and the C75200 nominal in ASTM B122 is 65 % copper, 18 % nickel and 17 % zinc.",
      "parts": [
        {
          "name": "Copper",
          "symbol": "Cu",
          "role": "The matrix metal. It sets the colour base and most of the conductivity."
        },
        {
          "name": "Nickel",
          "symbol": "Ni",
          "role": "Gives the silvery, greyer colour (Matthey) and the corrosion resistance (Fisk and Matthey). It is also the source of the nickel hazard statements."
        },
        {
          "name": "Zinc",
          "symbol": "Zn",
          "role": "The balance element that completes the alloy. The Fisk nominal print of zinc 35 does not match its limits and is not used."
        },
        {
          "name": "Lead",
          "symbol": "Pb",
          "role": "Impurity limit only. Matthey says leaded grades such as CuNi12Zn25Pb1 are separate products for machinability."
        },
        {
          "name": "Iron",
          "symbol": "Fe",
          "role": "Impurity limit printed by both datasheets."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The nickel in this alloy is the main health concern in the sources. PubChem gives the nickel hazard statements, and the Matthey and Fisk limits show how much nickel the alloy holds.",
        "points": [
          {
            "label": "Allergy",
            "line": "PubChem's GHS notifications for nickel include H317, May cause an allergic skin reaction (99.9 % of notifications), and H334 for respiratory allergy in some notifications."
          },
          {
            "label": "Cancer",
            "line": "PubChem's GHS notifications list H351, Suspected of causing cancer (72.9 %), and H350 (22.5 %) in some. The alloy itself is not classified in the sources read."
          },
          {
            "label": "Nickel content",
            "line": "The CuNi18Zn20 grade holds 17.0 to 19.0 % nickel (Matthey) and the C752 grade 16.5 to 19.5 % (Fisk). ASTM B122 gives 18 % nominal for C75200."
          }
        ],
        "level": 2,
        "verdict": "Nickel-containing alloy"
      },
      {
        "title": "If it fails",
        "lead": "The failure routes in these sources are heat that removes the temper, forming of the hard tempers, and the machining limits.",
        "points": [
          {
            "label": "Heat softening",
            "line": "Heating above the Fisk annealing range (1100 to 1400 °F) removes cold-work strength, so the part falls back toward the annealed value."
          },
          {
            "label": "Hard temper",
            "line": "Hard H185 strip stretches only 2 % (A50mm) against 40 % soft annealed, so bending needs a softer temper."
          },
          {
            "label": "Machining",
            "line": "Fisk rates machinability 1 of 5 and Matthey calls it rather poor, so high-volume machining is a poor fit."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Pick the temper",
            "line": "Strip tempers run from 370 to 430 MPa soft annealed to 680 MPa minimum extra hard (Matthey). Round wire runs from 53.0 to 63.0 ksi annealed to 99.0 to 111 ksi hard (Fisk)."
          },
          {
            "label": "Stress relief",
            "line": "Stress-relieve at 300 to 350 °C after cold forming to reduce internal stress, as Matthey advises."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-26",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 25,
    "unreachable": 4,
    "caveats": 6,
    "note": "Values were read by an AI assistant on 2026-10-26 from the pages and PDFs named in each entry. Unreachable to the fetcher: copper.org (403, CDA alloy page and nickel silver page), MakeItFrom (403), suppliersonline (503), ATSDR nickel ToxFAQ (landing page only, no nickel content). Caveats: the C75200 and CW409J composition ranges differ, and the Matthey UNS number for CW409J (C76400) is not in ASTM B122; the Fisk modulus (18 ksi) is a units error and is not recorded; the Fisk nominal zinc (35) does not fit its own limits; hazard statements are for nickel from PubChem and not from an SDS for the alloy; no yield strengths or corrosion rates were read."
  },
  "sources": {
    "astm-b122": {
      "title": "ASTM B122/B122M: copper-nickel-zinc alloy (nickel silver) plate, sheet, strip and rolled bar; UNS list and nominal composition table",
      "url": "https://store.astm.org/b0122_b0122m-16.html",
      "kind": "standard",
      "license": "Standard listing page (cited, not reproduced)"
    },
    "matthey-cuni18zn20": {
      "title": "Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table",
      "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf",
      "kind": "datasheet",
      "license": "Manufacturer datasheet (cited, not reproduced)"
    },
    "fisk-c752": {
      "title": "Fisk Alloy Wire: C752 Nickel Silver 18% alloy wire, chemical composition, physical properties, round wire and rolled flat temper tables, fabrication index",
      "url": "https://fiskalloy.com/pdf/c75200/",
      "kind": "datasheet",
      "license": "Supplier datasheet (cited, not reproduced)"
    },
    "wiki-nickel-silver": {
      "title": "Wikipedia: Nickel silver (composition and history only)",
      "url": "https://en.wikipedia.org/wiki/Nickel_silver",
      "kind": "web",
      "license": "CC BY-SA 4.0 (cited, not reproduced)"
    },
    "pubchem-nickel": {
      "title": "PubChem: Nickel, CID 935, Safety and Hazards, GHS classification (ECHA aggregated notifications)",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/Nickel",
      "kind": "database",
      "license": "PubChem public database (cited, not reproduced)"
    },
    "usgs-mcs2026-copper": {
      "title": "Mineral Commodity Summaries 2026: Copper",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-mcs2026-zinc": {
      "title": "Mineral Commodity Summaries 2026: Zinc",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-zinc.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-mcs2026-nickel": {
      "title": "Mineral Commodity Summaries 2026: Nickel",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/nickel-silver/"
}