{
  "spore": "profile",
  "id": "macor",
  "spore_version": "0.2",
  "family": "technical-ceramics",
  "name": "Macor",
  "abbreviation": "MGC",
  "role": "machinable insulator",
  "category": "ceramics",
  "type": "glass-ceramics",
  "summary": "MACOR is Corning's machinable glass-ceramic: a white, zero-porosity material made of about 55 % fluorophlogopite mica in a borosilicate glass matrix. It is cut with ordinary metalworking tools and needs no post-firing, and Corning rates it for continuous use at 800 °C with a peak of 1000 °C under no load. The Corning datasheet gives a modulus of rupture of 94 MPa, a Young's modulus of 66.9 GPa and a thermal conductivity of 1.46 W/m°C at 25 °C.\n",
  "best_for": "Machined insulators and fixtures that must hold tight tolerances, stay stable to 800 °C and not outgas in vacuum",
  "weakest_at": "Strength and toughness: 94 MPa modulus of rupture and 1.53 MPa m0.5 fracture toughness, against 345 MPa compressive strength",
  "identity": {
    "formula": "Fluorophlogopite mica in a borosilicate glass matrix, about 55 % mica and 45 % glass by weight (Corning)",
    "cas": "66402-68-4",
    "designations": [
      {
        "system": "Trade name",
        "code": "MACOR",
        "source": "corning-macor-datasheet",
        "where": "Front page, title and trademark notice"
      },
      {
        "system": "Trade name",
        "code": "MGC",
        "source": "corning-macor-datasheet",
        "where": "Applications page (p. 2), text 'MACOR MGC'"
      },
      {
        "system": "Trade name",
        "code": "9657",
        "note": "Corning glass code printed for MACOR (2015 sheet)",
        "source": "boedeker-macor-sds",
        "where": "Section 1, Glass Code 9657"
      },
      {
        "system": "Trade name",
        "code": "9658",
        "note": "Corning glass code 9658 for MACOR Machinable Glass-Ceramic (2008 sheet)",
        "source": "rs-macor-sds-2008",
        "where": "Page 1, Material Name line"
      }
    ],
    "source": "boedeker-macor-sds",
    "where": "Section 3, CAS 66402-68-4 printed for 'Ceramic materials and wares, chemicals' at 100 %"
  },
  "tags": {
    "environments": [],
    "stresses": [
      "vacuum-and-outgassing",
      "total-radiation-dose"
    ],
    "applications": [
      "structures",
      "thermal-control",
      "electronics-and-chips",
      "optics-and-cameras"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, MACOR",
      "value": 2.52,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "fully dense, 0 % porosity",
        "temperature": "not stated in the datasheet table"
      },
      "method": "Value printed in the Corning MACOR datasheet; Morgan and Goodfellow print the same 2.52",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Mechanical column, Density 2.52 g/cm3",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Young's modulus, MACOR",
      "value": 66.9,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "25 °C"
      },
      "method": "Printed in the Corning datasheet as 66.9 GPa (9.7x10^6 psi); Morgan prints 68 GPa for the same material, not used here",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Mechanical column, Young's Modulus 25 °C",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "shear_modulus",
      "label": "Shear modulus, MACOR",
      "value": 25.5,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "25 °C"
      },
      "method": "Value printed in the Corning datasheet; the name shear_modulus is not in the canonical property file",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Mechanical column, Shear Modulus 25 °C 25.5 GPa",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "flexural_strength",
      "label": "Modulus of rupture (flexural strength), Corning",
      "value": 94,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temperature": "25 °C",
        "basis": "minimum specified average value",
        "form": "fully dense sample quantities tested by Corning"
      },
      "method": "Printed as 94 MPa (13,600 psi) in the Corning datasheet, with the note that actual characteristics of production lots may vary",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Mechanical column, Modulus of Rupture 25 °C, 94 MPa minimum specified average value",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "flexural_strength",
      "label": "Flexural strength, MACOR (Morgan table)",
      "value": 89,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated",
        "basis": "MACOR column of the material comparison table"
      },
      "method": "Value printed in the Morgan comparison table; differs from the Corning 94 MPa, both are kept",
      "status": "ground",
      "source": "morgan-macor",
      "where": "Property table, row Flexural Strength, MACOR column (89 MPa)",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic, Morgan Advanced Materials (Technical Ceramics), properties table",
        "url": "https://www.morgantechnicalceramics.com/en-gb/materials/macor/",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer web page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "compressive_strength",
      "label": "Compressive strength, MACOR",
      "value": 345,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated"
      },
      "method": "Printed as 345 MPa (50,000 psi) in the Corning datasheet",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Mechanical column, Compressive strength 345 MPa",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "fracture_toughness",
      "label": "Fracture toughness, MACOR",
      "value": 1.53,
      "bound": "exact",
      "unit": "MPa m0.5",
      "scope": "material",
      "conditions": {
        "temperature": "not stated"
      },
      "method": "Unit as printed in the Corning datasheet (also 1,390 psi in0.5)",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Mechanical column, Fracture Toughness 1.53 MPa m0.5",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "knoop_hardness",
      "label": "Knoop hardness, MACOR",
      "value": 250,
      "bound": "exact",
      "unit": "kg/mm2",
      "scope": "material",
      "conditions": {
        "load": "100 g",
        "unit_in_source": "printed without unit in the Corning datasheet, unit taken from the Morgan row"
      },
      "method": "Morgan prints the unit kg/mm2 and the value 250 for MACOR; Corning prints Knoop 100 g = 250 with no unit",
      "status": "ground",
      "source": "morgan-macor",
      "where": "Property table, row Knoop Hardness, unit column kg/mm2, MACOR column 250",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic, Morgan Advanced Materials (Technical Ceramics), properties table",
        "url": "https://www.morgantechnicalceramics.com/en-gb/materials/macor/",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer web page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cte",
      "label": "Coefficient of thermal expansion, 25 to 300 °C",
      "value": 9.3,
      "bound": "exact",
      "unit": "ppm/K",
      "scope": "material",
      "conditions": {
        "temperature_range": "25 to 300 °C",
        "unit_in_source": "93x10-7/°C"
      },
      "method": "Printed as 93x10-7/°C in the Corning datasheet; converted to ppm/K (1 ppm/K = 10-6/K). Morgan prints 9.3 x10-6 for the same range.",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Thermal column, Coefficient of Expansion 25-300 °C, 93x10-7/°C",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cte",
      "label": "Coefficient of thermal expansion, 25 to 800 °C",
      "value": 12.6,
      "bound": "exact",
      "unit": "ppm/K",
      "scope": "material",
      "conditions": {
        "temperature_range": "25 to 800 °C",
        "unit_in_source": "126x10-7/°C"
      },
      "method": "Printed as 126x10-7/°C in the Corning datasheet; converted to ppm/K",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Thermal column, Coefficient of Expansion 25-800 °C, 126x10-7/°C",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "specific_heat",
      "label": "Specific heat, MACOR",
      "value": 0.79,
      "bound": "exact",
      "unit": "kJ/kg°C",
      "scope": "material",
      "conditions": {
        "temperature": "25 °C"
      },
      "method": "Printed as .79 KJ/kg°C in the Corning datasheet",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Thermal column, Specific Heat 25 °C",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, MACOR",
      "value": 1.46,
      "bound": "exact",
      "unit": "W/m°C",
      "scope": "material",
      "conditions": {
        "temperature": "25 °C"
      },
      "method": "Printed as 1.46 W/m°C in the Corning datasheet; Morgan prints 1.46 W/m.K for the same grade",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Thermal column, Thermal Conductivity 25 °C",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermal_diffusivity",
      "label": "Thermal diffusivity, MACOR",
      "value": 7.3e-7,
      "bound": "exact",
      "unit": "m2/s",
      "scope": "material",
      "conditions": {
        "temperature": "25 °C"
      },
      "method": "Printed as 7.3x10-7 m2/s in the Corning datasheet",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Thermal column, Thermal Diffusivity 25 °C",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Continuous operating temperature, MACOR",
      "value": 800,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "continuous use"
      },
      "method": "Printed as 800 °C (1472 °F) in the Corning datasheet",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Thermal column, Continuous Operating Temperature 800 °C",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Maximum no-load temperature, MACOR",
      "value": 1000,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "peak, maximum no-load temperature"
      },
      "method": "Printed as 1000 °C (1832 °F) in the Corning datasheet; Morgan also lists 1000 °C",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Thermal column, Maximum No Load Temperature 1000 °C",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "dielectric_constant",
      "label": "Dielectric constant, 1 kHz",
      "value": 6.03,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "frequency": "1 kHz",
        "temperature": "25 °C"
      },
      "method": "Printed in the Corning datasheet, Electrical column",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Electrical column, Dielectric Constant 25 °C, 1 KHz 6.03",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "dielectric_constant",
      "label": "Dielectric constant, 8.5 GHz",
      "value": 5.67,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "frequency": "8.5 GHz",
        "temperature": "25 °C"
      },
      "method": "Printed in the Corning datasheet, Electrical column",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Electrical column, Dielectric Constant 25 °C, 8.5 GHz 5.67",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "dissipation_factor",
      "label": "Loss tangent, 1 kHz",
      "value": 0.0047,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "frequency": "1 kHz",
        "temperature": "25 °C"
      },
      "method": "Printed as 4.7x10-3 in the Corning datasheet",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Electrical column, Loss Tangent 25 °C 1 KHz 4.7x10-3",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "dielectric_strength",
      "label": "Dielectric strength, AC average",
      "value": 9.4,
      "bound": "exact",
      "unit": "kV/mm",
      "scope": "material",
      "conditions": {
        "thickness": "12 mil",
        "temperature": "25 °C",
        "basis": "AC, average"
      },
      "method": "Printed as 9.4 KV/mm with 785 V/mil in the Corning datasheet. The printed pair does not agree (785 V/mil is about 30.9 kV/mm), so treat this value with care.",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Electrical column, Dielectric Strength (AC) avg. at 12 mil and 25 °C",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "dielectric_strength",
      "label": "Dielectric strength, DC average",
      "value": 62.4,
      "bound": "exact",
      "unit": "kV/mm",
      "scope": "material",
      "conditions": {
        "thickness": "12 mil",
        "temperature": "25 °C",
        "basis": "DC, average"
      },
      "method": "Printed as 62.4 KV/mm with 5206 V/mil in the Corning datasheet. The printed pair does not agree (5206 V/mil is about 205 kV/mm), and Morgan prints 39.4 and Goodfellow 129 kV/mm for DC, so this value is unresolved.",
      "status": "ground",
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), Electrical column, Dielectric Strength (DC) avg. at 12 mil and 25 °C",
      "source_detail": {
        "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
        "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, design properties",
      "value": 90,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated",
        "basis": "design-properties table on the page"
      },
      "method": "Printed in the design-properties table of the SpotMaterial database page; no test condition printed",
      "status": "ground",
      "source": "spotmaterial-macor",
      "where": "Design properties table, row Tensile strength 90 MPa",
      "source_detail": {
        "title": "Machinable glass ceramic (MGC) MACOR, SpotMaterial design properties",
        "url": "https://spotmaterial.com/material/glass-ceramic/machinable-glass-ceramic-mgc-macor/",
        "kind": "web",
        "license": "Database web page (cited, not reproduced)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "5 % hydrochloric acid, pH 0.1, 24 h at 95 °C",
      "headline": "Hydrochloric acid is the most aggressive test on the datasheet: about 100 mg/cm2 weight loss in 24 h.",
      "effect": "Weight loss of about 100 mg/cm2 in the Corning test, the largest of the chemical tests printed on the datasheet.",
      "rating": "severe",
      "conditions": {
        "solution": "5 % HCl",
        "pH": "0.1",
        "time": "24 h",
        "temperature": "95 °C",
        "measure": "gravimetric weight loss"
      },
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), section IV Chemical, Weight Loss table, 5 % HCL row ~100 mg/cm2"
    },
    {
      "environment": "5 % sodium hydroxide, pH 13.2, 6 h at 95 °C",
      "headline": "Sodium hydroxide attacks Macor moderately: about 10 mg/cm2 in 6 h.",
      "effect": "Weight loss of about 10 mg/cm2 in the Corning test.",
      "rating": "moderate",
      "conditions": {
        "solution": "5 % NaOH",
        "pH": "13.2",
        "time": "6 h",
        "temperature": "95 °C",
        "measure": "gravimetric weight loss"
      },
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), section IV Chemical, Weight Loss table, 5 % NaOH row ~10 mg/cm2"
    },
    {
      "environment": "0.002 N nitric acid, pH 2.8, 24 h at 95 °C",
      "headline": "Dilute nitric acid causes only small weight loss.",
      "effect": "Weight loss of about 0.6 mg/cm2 in the Corning test.",
      "rating": "low",
      "conditions": {
        "solution": "0.002 N HNO3",
        "pH": "2.8",
        "time": "24 h",
        "temperature": "95 °C",
        "measure": "gravimetric weight loss"
      },
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), section IV Chemical, Weight Loss table, 0.002 N HNO3 row ~0.6 mg/cm2"
    },
    {
      "environment": "0.1 N sodium bicarbonate, pH 8.4, 24 h at 95 °C",
      "headline": "Sodium bicarbonate causes little weight loss.",
      "effect": "Weight loss of about 0.3 mg/cm2 in the Corning test.",
      "rating": "low",
      "conditions": {
        "solution": "0.1 N NaHCO3",
        "pH": "8.4",
        "time": "24 h",
        "temperature": "95 °C",
        "measure": "gravimetric weight loss"
      },
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), section IV Chemical, Weight Loss table, 0.1 N NaHCO3 row ~0.3 mg/cm2"
    },
    {
      "environment": "0.02 N sodium carbonate, pH 10.9, 6 h at 95 °C",
      "headline": "Sodium carbonate causes very little weight loss.",
      "effect": "Weight loss of about 0.1 mg/cm2 in the Corning test.",
      "rating": "low",
      "conditions": {
        "solution": "0.02 N Na2CO3",
        "pH": "10.9",
        "time": "6 h",
        "temperature": "95 °C",
        "measure": "gravimetric weight loss"
      },
      "source": "corning-macor-datasheet",
      "where": "Properties page (p. 4), section IV Chemical, Weight Loss table, 0.02 N Na2CO3 row ~0.1 mg/cm2"
    },
    {
      "environment": "Vacuum after proper bake-out",
      "headline": "Macor does not outgas in vacuum when it is properly baked out.",
      "effect": "Corning says it is clean, with no outgassing and zero porosity, and does not outgas in vacuum environments when properly baked out.",
      "rating": "none",
      "conditions": {
        "basis": "properly baked out, as stated by Corning; no outgassing number printed"
      },
      "source": "corning-macor-datasheet",
      "where": "Front page feature list and Properties page (p. 4), last paragraph"
    },
    {
      "environment": "Acid and alkali classes (DIN, as printed by Goodfellow)",
      "headline": "Goodfellow prints DIN water class HGB2, acid class 4 and alkali class A3 for MACOR.",
      "effect": "Classes printed as a list of codes on the product page; the page does not state what each class means.",
      "rating": "unknown",
      "conditions": {
        "standard": "DIN classes as printed, no test values"
      },
      "source": "goodfellow-macor-bar",
      "where": "Chemical Resistance table, rows DIN Water Class HGB2, DIN Acid Class 4, DIN Alkali Class A3"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "Not classified under 29 CFR 1910.1200 in the Boedeker copy of the Corning SDS; no GHS symbol, signal word or hazard statement is assigned.",
        "ghs": [],
        "source": "boedeker-macor-sds",
        "where": "Section 2, Classification and GHS label elements"
      },
      {
        "text": "Exposure to glass powder or dusts may be irritating to eyes, nose and throat, and at very high exposure levels the dust may affect the lungs (2008 Corning sheet, Glass Code 9658).",
        "ghs": [],
        "source": "rs-macor-sds-2008",
        "where": "Section 2, Emergency Overview"
      },
      {
        "text": "The dust created in machining can be an irritant; Corning says this can be avoided with good housekeeping and appropriate machining technique.",
        "ghs": [],
        "source": "corning-macor-datasheet",
        "where": "Composition page (p. 7)"
      }
    ],
    "failure_risks": [
      {
        "mode": "Brittle fracture rather than yielding",
        "trigger": "Mechanical overload; Corning gives 94 MPa as the minimum average modulus of rupture and 1.53 MPa m0.5 fracture toughness",
        "consequence": "Corning says that, unlike ductile materials, MACOR won't deform; a crack is therefore not blunted by plastic flow (reading of the datasheet, not a failure test).",
        "severity": "high",
        "source": "corning-macor-datasheet",
        "where": "Properties page (p. 4), Mechanical column; front page Properties paragraph (p. 1)"
      },
      {
        "mode": "Use above the rated temperature",
        "trigger": "Continuous use above 800 °C or no-load temperature above 1000 °C",
        "consequence": "Corning gives only 800 °C continuous and 1000 °C peak no-load ratings; no data are printed for loaded use at higher temperatures.",
        "severity": "moderate",
        "source": "corning-macor-datasheet",
        "where": "Properties page (p. 4), Thermal column"
      },
      {
        "mode": "Dissolution in strong acid",
        "trigger": "5 % HCl at 95 °C for 24 h",
        "consequence": "About 100 mg/cm2 weight loss in the Corning test.",
        "severity": "moderate",
        "source": "corning-macor-datasheet",
        "where": "Properties page (p. 4), section IV Chemical"
      }
    ],
    "side_effects": [
      {
        "text": "Machining produces fine dust that can irritate; the dust must be kept off surfaces and out of the air.",
        "affects": "Machine operators and the shop",
        "source": "boedeker-macor-sds",
        "where": "Section 6, Methods for containment and cleaning up; Section 7, Minimize dust generation"
      }
    ],
    "handling": [
      {
        "text": "Avoid breathing dust and wash thoroughly after handling; keep the container closed and store in a dry area.",
        "source": "boedeker-macor-sds"
      },
      {
        "text": "Use a water-soluble coolant when machining; Corning recommends Cimstar 40 - Pink for cutting and grinding glass or ceramics.",
        "source": "corning-macor-datasheet"
      },
      {
        "text": "Use carbide tools for longer wear; high-speed steel can be used.",
        "source": "corning-macor-datasheet"
      }
    ],
    "mitigations": [
      {
        "text": "Use a dust suppressant or HEPA vacuum when crushed glass can make airborne dust.",
        "source": "boedeker-macor-sds"
      },
      {
        "text": "Use good housekeeping so dust does not build up on surfaces.",
        "source": "boedeker-macor-sds"
      }
    ]
  },
  "uses": [
    {
      "application": "structures",
      "device": "Retaining rings at hinge points, windows and doors of the Space Shuttle Orbiter",
      "example": "Corning says over 200 distinctly shaped MACOR parts are on the Space Shuttle Orbiter, with retaining rings at all hinge points, windows and doors. The claim is the manufacturer's own.",
      "source": "corning-macor-datasheet",
      "where": "Applications page (p. 2-3), Aerospace Industry section"
    },
    {
      "application": "structures",
      "device": "Frame of a NASA spaceborne gamma radiation detector",
      "example": "Large pieces of MACOR are used in a NASA spaceborne gamma radiation detector; frame corners are joined by butt-lap mechanical joints and a sealing glass. Corning's claim, not checked against a NASA document.",
      "source": "corning-macor-datasheet",
      "where": "Applications page (p. 2-3), Aerospace Industry section"
    },
    {
      "application": "thermal-control",
      "device": "Supports and components in several satellite-borne systems",
      "example": "Precision Ceramics, the UK distributor, says MACOR supports and components in satellite-borne systems, giving thermal and electrical insulation. No mission named.",
      "source": "precision-ceramics-macor",
      "where": "Aerospace/Space Industry section, second bullet"
    },
    {
      "application": "electronics-and-chips",
      "device": "Coil supports and vacuum feed-throughs for ultra-high-vacuum equipment",
      "example": "MACOR is used as an insulator or coil support and for vacuum feed-throughs, with a compatible sealing glass giving a vacuum-tight seal.",
      "source": "corning-macor-datasheet",
      "where": "Applications page (p. 2-3), Ultra-High Vacuum Environments section"
    },
    {
      "application": "optics-and-cameras",
      "device": "Spacers, cavities and reflectors in laser assemblies",
      "example": "Precision Ceramics lists spacers, cavities and reflectors in laser assemblies, citing the precision finish and heat resistance of the material.",
      "source": "precision-ceramics-macor",
      "where": "Laser Applications section"
    }
  ],
  "supply": [
    {
      "subject": "MACOR (Corning Incorporated product)",
      "abundance": "Not stated in the fetched sources; a manufactured glass-ceramic, not a raw material",
      "producers": [],
      "critical_lists": [],
      "recycling": "The SDS says glass products may be recycled; Corning SAS, Nemours, France, is listed as the supplier on the 2015 sheet.",
      "substitutes": [],
      "source": "boedeker-macor-sds",
      "where": "Section 1, Manufacturer Information; Section 6, Methods for containment and cleaning up"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "MACOR Machinable Glass Ceramic datasheet (Corning, MACOR 01)",
      "type": "datasheet",
      "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf"
    },
    {
      "title": "MACOR Machinable Glass Ceramic, Morgan Advanced Materials product page",
      "type": "datasheet",
      "url": "https://www.morgantechnicalceramics.com/en-gb/materials/macor/"
    },
    {
      "title": "MACOR Machinable Glass Ceramic Bar, Goodfellow product page (product 1000126059)",
      "type": "datasheet",
      "url": "https://www.goodfellow.com/usa/macor-glass-ceramic-bar-1000126059"
    },
    {
      "title": "Macor, Wikipedia",
      "type": "database",
      "url": "https://en.wikipedia.org/wiki/Macor"
    },
    {
      "title": "Safety Data Sheet MACOR, SDS ID C-587, Boedeker copy (2015)",
      "type": "sds",
      "url": "https://www.boedeker.com/Portals/0/Safety%20Data%20Sheets%20SDS/Macor-Ceramic-SDS-Safety-Data-Sheet-Boedeker-08-27-2015.PDF",
      "year": 2015
    },
    {
      "title": "Safety Data Sheet Glass Code 9658, MACOR Machinable Glass-Ceramic, Corning copy (2008)",
      "type": "sds",
      "url": "https://docs.rs-online.com/40ac/0900766b8128c272.pdf",
      "year": 2008
    },
    {
      "title": "MACOR Machinable Glass Ceramic brochure, Precision Ceramics (UK distributor)",
      "type": "datasheet",
      "url": "https://cdn.abicart.com/shop/ws28/75628/art18/156029318-4b33a9-Macor-Machinable-Glass-Ceramic.pdf"
    },
    {
      "title": "MACOR Machinable Glass Ceramic properties, SpotMaterial design properties",
      "type": "database",
      "url": "https://spotmaterial.com/material/glass-ceramic/machinable-glass-ceramic-mgc-macor/"
    }
  ],
  "gaps": [
    "No flight or NASA document was opened for the Space Shuttle parts or the gamma detector; the uses rest on Corning and Precision Ceramics statements and are marked as manufacturer claims.",
    "The Corning product page (corning.com) returned HTTP 403 and was not read.",
    "The Sheffield DoITPOMS micrograph record returned 403; the house-of-cards microstructure description was seen only in a search snippet, so it is not recorded.",
    "The dielectric strength pairs printed by Corning do not match their own V/mil conversions, and Morgan (DC 39.4 kV/mm) and Goodfellow (DC 129 kV/mm, AC 45 kV/mm) print different values; the conflict is kept in the method fields.",
    "DC volume resistivity differs between sources: Corning and Goodfellow give 10^16 and 10^17 ohm-cm, Morgan gives >10^14 ohm-cm. The Corning value (printed as >10^16 ohm-cm) lost its superscript in the PDF text, so the verifier could not match it and it is not entered.",
    "No UNS, EN, ASTM, AISI or other standard grade designation was found for MACOR; it is a proprietary trade product. The Corning glass code 9657 (SDS) and 9658 (2008 sheet) are recorded as trade-name designations.",
    "No manufacturing process, production country share or critical-mineral listing was found for MACOR in the fetched sources; the supply entry says so.",
    "No total mass loss, collected volatile condensable material, atomic oxygen or radiation dose number was found for MACOR, so the vacuum and radiation stresses rest on qualitative statements only.",
    "Poisson's ratio (0.29, Corning) is not entered because the benchmark name is not in the canonical property file.",
    "Glass-transition or softening temperature and the viscosity of the glass phase were not found.",
    "No ISO or ASTM test standard was found for the modulus of rupture or the fracture toughness; the test method is not named by the datasheet."
  ],
  "story": {
    "why": "MACOR is used where a machinable insulator must hold tight tolerances, stay stable at high temperature, and not outgas in vacuum. Corning says it can be cut with ordinary metalworking tools, that tolerances are very tight, and that no post-firing is required. Its matrix is a borosilicate glass with about 55 % fluorophlogopite mica, and the mica flakes are randomly oriented in the microstructure, which Corning names as the key to machinability.",
    "uses": [
      {
        "where": "Vacuum equipment",
        "line": "Corning says MACOR is used as an insulator, coil support and vacuum feed-through, sealed with a compatible sealing glass for a vacuum-tight joint."
      },
      {
        "where": "Space Shuttle and spaceborne detector",
        "line": "Corning says over 200 MACOR parts are on the Space Shuttle Orbiter, with retaining rings at hinge points, windows and doors, and that a NASA spaceborne gamma radiation detector uses large MACOR pieces. These are manufacturer claims."
      },
      {
        "where": "Electrical and high-temperature insulation",
        "line": "Precision Ceramics says MACOR is an excellent high-voltage insulator at high temperature, with a dielectric constant of 6.03 at 1 kHz from the Corning table."
      }
    ],
    "can_do": [
      {
        "label": "Hold 800 °C",
        "line": "Corning rates continuous use at 800 °C and a 1000 °C peak with no load.",
        "benchmark": "max_service_temp",
        "scope": "material",
        "value": "800 °C continuous"
      },
      {
        "label": "Stay dense",
        "line": "Corning gives zero porosity and says it is clean, with no outgassing when properly baked out.",
        "scope": "material",
        "value": "0 % porosity"
      },
      {
        "label": "Be machined",
        "line": "Corning says tolerances are very tight, with surface finish below 20 µin and a polished finish of 0.5 µin-AA.",
        "scope": "material",
        "value": "very tight tolerances"
      }
    ],
    "compare": "MACOR is a machinable insulator, not a conductor. Its thermal conductivity is 1.46 W/m°C at 25 °C, far below the copper profile on this site, and its modulus of rupture is 94 MPa. Corning says its coefficient of expansion readily matches most metals and sealing glasses; the 9.3 ppm/K value is for 25 to 300 °C. Read the table rows as examples, not as a ranking, since they are different classes of material.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Thermal conductivity",
        "benchmark": "thermal_conductivity",
        "scope": "material"
      },
      {
        "label": "Thermal expansion",
        "benchmark": "cte",
        "scope": "material"
      }
    ],
    "handling": [
      "Keep dust down: avoid breathing it, wash after handling, and use a HEPA vacuum or dust suppressant for crushed glass.",
      "Use a water-soluble coolant and carbide tools when machining.",
      "Do not exceed 800 °C in continuous use, or 1000 °C peak with no load."
    ],
    "good_for": [
      "Machined insulators: very tight tolerances with no post-firing, per Corning.",
      "Vacuum parts: zero porosity and no outgassing when properly baked out, per Corning.",
      "High-temperature insulation: 800 °C continuous, 1000 °C peak with no load."
    ],
    "watch_out": [
      "Strength is modest: 94 MPa modulus of rupture and 1.53 MPa m0.5 fracture toughness.",
      "Dielectric strength and resistivity differ by manufacturer; check the datasheet for the grade you buy.",
      "Machining dust is an irritant.",
      "The Space Shuttle and gamma-detector uses are manufacturer claims, not flight data."
    ],
    "verdict": "MACOR is a machinable glass-ceramic with zero porosity, 800 °C continuous and 1000 °C peak use, and very tight tolerances without post-firing. Its strength is modest, with 94 MPa modulus of rupture and 1.53 MPa m0.5 toughness, and its dielectric and resistivity figures vary by source. The space uses rest on manufacturer statements, and this profile has no supply shares, process steps or flight outgassing data.",
    "recipe": {
      "line": "MACOR is a borosilicate glass matrix containing fluorophlogopite mica, with the mica flakes randomly oriented in the microstructure (Corning; Wikipedia). It is melted and crystallised as a glass-ceramic; no process step is given in the fetched sources.",
      "parts": [
        {
          "name": "Silicon dioxide",
          "symbol": "SiO2",
          "role": "Glass former and mica network",
          "share_percent": 46
        },
        {
          "name": "Magnesium oxide",
          "symbol": "MgO",
          "role": "Mica cation",
          "share_percent": 17
        },
        {
          "name": "Aluminium oxide",
          "symbol": "Al2O3",
          "role": "Mica and glass network",
          "share_percent": 16
        },
        {
          "name": "Potassium oxide",
          "symbol": "K2O",
          "role": "Mica interlayer cation",
          "share_percent": 10
        },
        {
          "name": "Boron oxide",
          "symbol": "B2O3",
          "role": "Borosilicate glass former",
          "share_percent": 7
        },
        {
          "name": "Fluorine",
          "symbol": "F",
          "role": "Mica fluorine",
          "share_percent": 4
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The sources agree that MACOR is not a hazardous substance under the Corning SDS, but its dust is an irritant.",
        "points": [
          {
            "label": "As a solid",
            "line": "The 2015 Boedeker copy of the Corning SDS assigns no GHS class, symbol or hazard statement."
          },
          {
            "label": "Dust",
            "line": "The 2008 Corning sheet says glass powder or dust may irritate the eyes, nose and throat, and that very high exposure may affect the lungs."
          }
        ],
        "level": 1,
        "verdict": "Low hazard as a solid, dust is the concern"
      },
      {
        "title": "If it fails",
        "lead": "These are failure routes the sources describe. None of them is a measured flight result.",
        "points": [
          {
            "label": "Overload",
            "line": "Corning gives a minimum average modulus of rupture of 94 MPa and says MACOR does not deform like a ductile material, so overload leads to fracture rather than yield."
          },
          {
            "label": "Over-temperature",
            "line": "Corning rates the material at 800 °C continuous and 1000 °C peak with no load; the datasheet prints no loaded data above those limits."
          },
          {
            "label": "Strong acid",
            "line": "In the Corning test, 5 % hydrochloric acid removes about 100 mg/cm2 in 24 h at 95 °C."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Dust control",
            "line": "Keep the container closed, store in a dry area, and use a dust suppressant or HEPA vacuum for crushed glass."
          },
          {
            "label": "Machining",
            "line": "Use a water-soluble coolant and carbide tools; no post-firing is needed after machining."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-26",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 21,
    "unreachable": 3,
    "caveats": 5,
    "note": "Values were read by an AI assistant on 2026-10-26 from the pages and PDFs named in each entry. Unreachable: the Corning product page and the DoITPOMS micrograph record (both HTTP 403) and a Malaysian university PDF that did not download. Caveats: the Corning dielectric strength pairs do not match their own V/mil values; resistivity and dielectric strength differ between manufacturers; the Space Shuttle and gamma-detector uses are manufacturer claims; supply shares were not found."
  },
  "sources": {
    "corning-macor-datasheet": {
      "title": "MACOR Machinable Glass Ceramic datasheet (Corning Incorporated, MACOR 01)",
      "url": "https://psec.uchicago.edu/ceramics/MACOR%20Data%20Sheet.pdf",
      "year": 2026,
      "kind": "datasheet",
      "license": "Manufacturer datasheet (cited, not reproduced)"
    },
    "morgan-macor": {
      "title": "MACOR Machinable Glass Ceramic, Morgan Advanced Materials (Technical Ceramics), properties table",
      "url": "https://www.morgantechnicalceramics.com/en-gb/materials/macor/",
      "year": 2026,
      "kind": "datasheet",
      "license": "Manufacturer web page (cited, not reproduced)"
    },
    "goodfellow-macor-bar": {
      "title": "MACOR Machinable Glass Ceramic Bar 20 mm x 20 mm, Goodfellow product 1000126059",
      "url": "https://www.goodfellow.com/usa/macor-glass-ceramic-bar-1000126059",
      "kind": "datasheet",
      "license": "Distributor web page (cited, not reproduced)"
    },
    "wikipedia-macor": {
      "title": "Macor, Wikipedia",
      "url": "https://en.wikipedia.org/wiki/Macor",
      "kind": "web",
      "license": "CC BY-SA 4.0 (cited, not reproduced)"
    },
    "boedeker-macor-sds": {
      "title": "Safety Data Sheet MACOR, SDS ID C-587, Revision 2.0 (2015), copy hosted by Boedeker",
      "url": "https://www.boedeker.com/Portals/0/Safety%20Data%20Sheets%20SDS/Macor-Ceramic-SDS-Safety-Data-Sheet-Boedeker-08-27-2015.PDF",
      "year": 2015,
      "kind": "datasheet",
      "license": "Safety data sheet (cited, not reproduced)"
    },
    "rs-macor-sds-2008": {
      "title": "Safety Data Sheet Glass Code 9658, MACOR Machinable Glass-Ceramic, ID C-046, Revision 5.0 (2008), copy hosted by RS",
      "url": "https://docs.rs-online.com/40ac/0900766b8128c272.pdf",
      "year": 2008,
      "kind": "datasheet",
      "license": "Safety data sheet (cited, not reproduced)"
    },
    "precision-ceramics-macor": {
      "title": "MACOR Machinable Glass Ceramic brochure, Precision Ceramics (UK distributor), Birmingham",
      "url": "https://cdn.abicart.com/shop/ws28/75628/art18/156029318-4b33a9-Macor-Machinable-Glass-Ceramic.pdf",
      "kind": "datasheet",
      "license": "Distributor brochure (cited, not reproduced)"
    },
    "spotmaterial-macor": {
      "title": "Machinable glass ceramic (MGC) MACOR, SpotMaterial design properties",
      "url": "https://spotmaterial.com/material/glass-ceramic/machinable-glass-ceramic-mgc-macor/",
      "kind": "web",
      "license": "Database web page (cited, not reproduced)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/macor/"
}