{
  "spore": "profile",
  "id": "diamond-like-carbon",
  "spore_version": "0.2",
  "family": "diamond-like-carbon",
  "name": "Diamond-like carbon",
  "abbreviation": "DLC",
  "role": "hard low-friction coating",
  "category": "carbon",
  "type": "diamond",
  "summary": "Diamond-like carbon (DLC) is an amorphous carbon coating with a mix of sp3 (diamond-type) and sp2 (graphite-type) bonds. A PECVD DLC film made from hexane measured 9.1 GPa nanoindentation hardness and 79.0 GPa modulus in one laboratory study. The NACL DLC data sheet gives a Vickers hardness of 1000 to 3000 HV and a maximum working temperature of 500 °C, with no test or formulation stated.\n",
  "best_for": "Hard wear surfaces on sliding parts and optics. NACL lists a Vickers hardness of 1000 to 3000 HV, depending on formulation",
  "weakest_at": "Erosion in oxygen plasma: 434 Å/min in a laboratory test, with hardness falling from 9.1 GPa to 6.3 GPa after the test; no orbital erosion data were found",
  "identity": {
    "formula": "C (amorphous carbon with sp3 and sp2 bonding; some grades contain hydrogen, written a-C:H)",
    "designations": [],
    "source": "wikipedia-dlc",
    "where": "Definition paragraph: DLC is a class of amorphous carbon materials that display some of the typical properties of diamond"
  },
  "tags": {
    "environments": [
      "low-earth-orbit"
    ],
    "stresses": [
      "atomic-oxygen"
    ],
    "applications": [
      "mechanisms",
      "optics-and-cameras"
    ]
  },
  "properties": [
    {
      "benchmark": "hardness_vickers",
      "label": "Hardness (Vickers), NACL DLC coating",
      "value": 1000,
      "value_high": 3000,
      "bound": "range",
      "unit": "HV",
      "scope": "material",
      "conditions": {
        "basis": "formulation dependent, as printed by the manufacturer"
      },
      "method": "Manufacturer material properties table; no test load is printed",
      "status": "ground",
      "source": "nacl-dlc-tds",
      "where": "Page 2, Diamond Like Carbon Material Properties table, row 'Hardness (Vickers)'",
      "source_detail": {
        "title": "North American Coating Laboratories, Diamond-Like Carbon Coating Technical Data Sheet",
        "id": "NACL DLC data sheet (PDF)",
        "url": "https://www.nacl.com/wp-content/uploads/2016/05/DLC-TDS.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet, cited not reproduced"
      }
    },
    {
      "benchmark": "friction_coefficient",
      "label": "Friction, NACL DLC coating (as-deposited)",
      "value": 0.1,
      "bound": "upper",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "state": "as-deposited",
        "printed": "<0.1"
      },
      "method": "Manufacturer material properties table; no test method is printed",
      "status": "ground",
      "source": "nacl-dlc-tds",
      "where": "Page 2, Diamond Like Carbon Material Properties table, row 'Friction'",
      "source_detail": {
        "title": "North American Coating Laboratories, Diamond-Like Carbon Coating Technical Data Sheet",
        "id": "NACL DLC data sheet (PDF)",
        "url": "https://www.nacl.com/wp-content/uploads/2016/05/DLC-TDS.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet, cited not reproduced"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Maximum working temperature, NACL DLC coating",
      "value": 500,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "printed as Max. Working Temp.; no coating formulation or test is stated"
      },
      "method": "Manufacturer material properties table",
      "status": "ground",
      "note": "No test or formulation is printed for this rating.",
      "source": "nacl-dlc-tds",
      "where": "Page 2, Diamond Like Carbon Material Properties table, row 'Max. Working Temp.'",
      "source_detail": {
        "title": "North American Coating Laboratories, Diamond-Like Carbon Coating Technical Data Sheet",
        "id": "NACL DLC data sheet (PDF)",
        "url": "https://www.nacl.com/wp-content/uploads/2016/05/DLC-TDS.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet, cited not reproduced"
      }
    },
    {
      "benchmark": "deposition_temperature",
      "label": "Deposition temperature, NACL DLC coating",
      "value": 50,
      "bound": "upper",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "printed": "<50 °C"
      },
      "method": "Manufacturer material properties table",
      "status": "ground",
      "source": "nacl-dlc-tds",
      "where": "Page 2, Diamond Like Carbon Material Properties table, row 'Deposition Temp.'",
      "source_detail": {
        "title": "North American Coating Laboratories, Diamond-Like Carbon Coating Technical Data Sheet",
        "id": "NACL DLC data sheet (PDF)",
        "url": "https://www.nacl.com/wp-content/uploads/2016/05/DLC-TDS.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet, cited not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index, NACL DLC coating",
      "value": 1.5,
      "value_high": 2.1,
      "bound": "range",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "basis": "depends on formulation and substrate, as printed"
      },
      "method": "Manufacturer material properties table",
      "status": "ground",
      "source": "nacl-dlc-tds",
      "where": "Page 2, Diamond Like Carbon Material Properties table, row 'Refractive Index'",
      "source_detail": {
        "title": "North American Coating Laboratories, Diamond-Like Carbon Coating Technical Data Sheet",
        "id": "NACL DLC data sheet (PDF)",
        "url": "https://www.nacl.com/wp-content/uploads/2016/05/DLC-TDS.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet, cited not reproduced"
      }
    },
    {
      "benchmark": "coating_thickness",
      "label": "Coating thickness, hydrogen-free Ta-C coating (Misumi)",
      "value": 0.2,
      "value_high": 1,
      "bound": "range",
      "unit": "µm",
      "scope": "material",
      "conditions": {
        "coating": "Ta-C, PVD, hydrogen-free"
      },
      "method": "Manufacturer datasheet",
      "status": "ground",
      "source": "misumi-dlc",
      "where": "Properties table, row 'Thickness [µm]'",
      "source_detail": {
        "title": "MISUMI Europa GmbH, DLC coating datasheet",
        "id": "MISUMI DLC datasheet, January 2026",
        "url": "https://uk.misumi-ec.com/files/images/products/docs/misumi_dlc-datasheet-en.pdf",
        "kind": "datasheet",
        "license": "supplier datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "surface_roughness_rz",
      "label": "Surface roughness Rz, Ta-C coating (Misumi)",
      "value": 1,
      "bound": "upper",
      "unit": "µm",
      "scope": "material",
      "conditions": {
        "coating": "Ta-C, PVD",
        "printed": "<1"
      },
      "method": "Manufacturer datasheet",
      "status": "ground",
      "source": "misumi-dlc",
      "where": "Properties table, row 'Surface roughness Rz [µm]'",
      "source_detail": {
        "title": "MISUMI Europa GmbH, DLC coating datasheet",
        "id": "MISUMI DLC datasheet, January 2026",
        "url": "https://uk.misumi-ec.com/files/images/products/docs/misumi_dlc-datasheet-en.pdf",
        "kind": "datasheet",
        "license": "supplier datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "hardness_nanoindentation",
      "label": "Hardness (H), DLC from hexane by PECVD, as deposited",
      "value": 9.1,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "film": "DLC from hexane by pulsed DC PECVD, not corroded",
        "load": "10 mN, 12 indentations per sample",
        "uncertainty": "plus or minus 2.8 as printed"
      },
      "method": "Nanoindentation as described in Section 2 of the paper",
      "status": "ground",
      "source": "ferreira2021",
      "where": "Table 4, row 'DLC non-corroded'",
      "source_detail": {
        "title": "SiOx Top Layer on DLC Films for Atomic Oxygen and Ozone Corrosion Protection in Aerospace Applications",
        "id": "doi:10.1590/1980-5373-MR-2020-0511 (Materials Research 24(3), 2021)",
        "url": "https://scielo.br/j/mr/a/3JnHb7KV4tDcPmbQsRqSYWm/?lang=en",
        "kind": "paper",
        "license": "CC BY 4.0"
      }
    },
    {
      "benchmark": "hardness_nanoindentation",
      "label": "Hardness (H), DLC from hexane by PECVD, after oxygen-plasma corrosion",
      "value": 6.3,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "film": "DLC from hexane by pulsed DC PECVD, corroded in oxygen plasma",
        "load": "10 mN, 12 indentations per sample",
        "uncertainty": "plus or minus 1.8 as printed"
      },
      "method": "Nanoindentation as described in Section 2 of the paper",
      "status": "ground",
      "source": "ferreira2021",
      "where": "Table 4, row 'DLC corroded'",
      "source_detail": {
        "title": "SiOx Top Layer on DLC Films for Atomic Oxygen and Ozone Corrosion Protection in Aerospace Applications",
        "id": "doi:10.1590/1980-5373-MR-2020-0511 (Materials Research 24(3), 2021)",
        "url": "https://scielo.br/j/mr/a/3JnHb7KV4tDcPmbQsRqSYWm/?lang=en",
        "kind": "paper",
        "license": "CC BY 4.0"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Modulus E, DLC from hexane by PECVD, as deposited",
      "value": 79,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "film": "DLC from hexane by pulsed DC PECVD, not corroded",
        "uncertainty": "plus or minus 13.0 as printed",
        "labelled_as": "E (GPa) in Table 4; the extract does not define E"
      },
      "method": "Reported beside the hardness values in Table 4",
      "status": "ground",
      "source": "ferreira2021",
      "where": "Table 4, column E (GPa), row 'DLC non-corroded'",
      "source_detail": {
        "title": "SiOx Top Layer on DLC Films for Atomic Oxygen and Ozone Corrosion Protection in Aerospace Applications",
        "id": "doi:10.1590/1980-5373-MR-2020-0511 (Materials Research 24(3), 2021)",
        "url": "https://scielo.br/j/mr/a/3JnHb7KV4tDcPmbQsRqSYWm/?lang=en",
        "kind": "paper",
        "license": "CC BY 4.0"
      }
    },
    {
      "benchmark": "plasma_etch_rate",
      "label": "Corrosion (etch) rate of DLC in oxygen plasma",
      "value": 434,
      "bound": "exact",
      "unit": "Å/min",
      "scope": "material",
      "conditions": {
        "plasma": "oxygen, 12 sccm, RF 13.5 MHz, 10 W, bias -179 V, lower electrode 23 °C",
        "film": "DLC from hexane by PECVD"
      },
      "method": "Laboratory oxygen-plasma exposure reported in Table 2; not a flight test and not an erosion yield",
      "status": "ground",
      "note": "Printed as 434 ± 26 Å/min.",
      "source": "ferreira2021",
      "where": "Section 2 (corrosion conditions) and Table 2, row 'DLC'",
      "source_detail": {
        "title": "SiOx Top Layer on DLC Films for Atomic Oxygen and Ozone Corrosion Protection in Aerospace Applications",
        "id": "doi:10.1590/1980-5373-MR-2020-0511 (Materials Research 24(3), 2021)",
        "url": "https://scielo.br/j/mr/a/3JnHb7KV4tDcPmbQsRqSYWm/?lang=en",
        "kind": "paper",
        "license": "CC BY 4.0"
      }
    },
    {
      "benchmark": "raman_id_ig_ratio",
      "label": "Raman intensity ratio ID/IG, DLC as deposited",
      "value": 0.4,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "film": "DLC from hexane by PECVD, not corroded",
        "uncertainty": "plus or minus 0.05 as printed"
      },
      "method": "Raman spectroscopy as reported in Table 4",
      "status": "ground",
      "source": "ferreira2021",
      "where": "Table 4, column ID/IG, row 'DLC non-corroded'",
      "source_detail": {
        "title": "SiOx Top Layer on DLC Films for Atomic Oxygen and Ozone Corrosion Protection in Aerospace Applications",
        "id": "doi:10.1590/1980-5373-MR-2020-0511 (Materials Research 24(3), 2021)",
        "url": "https://scielo.br/j/mr/a/3JnHb7KV4tDcPmbQsRqSYWm/?lang=en",
        "kind": "paper",
        "license": "CC BY 4.0"
      }
    },
    {
      "benchmark": "critical_load_lc1",
      "label": "First critical load LC1, DLC scratch test",
      "value": 11.2,
      "bound": "exact",
      "unit": "N",
      "scope": "material",
      "conditions": {
        "film": "DLC from hexane by PECVD",
        "test": "scratch test with normal load from 0.2 N to 30 N over 10 mm, sliding speed 0.1 mm/s",
        "uncertainty": "plus or minus 1.8 as printed"
      },
      "method": "Scratch test as described in Section 3",
      "status": "ground",
      "note": "The paper gives a different mean critical load for the same DLC film in Section 3 and a different range in the abstract. The sources disagree, so the value here is the LC1 figure only.",
      "source": "ferreira2021",
      "where": "Section 3 (Adhesion), LC1 value printed for DLC",
      "source_detail": {
        "title": "SiOx Top Layer on DLC Films for Atomic Oxygen and Ozone Corrosion Protection in Aerospace Applications",
        "id": "doi:10.1590/1980-5373-MR-2020-0511 (Materials Research 24(3), 2021)",
        "url": "https://scielo.br/j/mr/a/3JnHb7KV4tDcPmbQsRqSYWm/?lang=en",
        "kind": "paper",
        "license": "CC BY 4.0"
      }
    },
    {
      "benchmark": "density",
      "label": "Density of a simulated dense ta-C network",
      "value": 2.99,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "network": "simulated dense tetrahedral amorphous carbon, sp3 bonding fraction 79%",
        "basis": "simulation, not a measured film"
      },
      "method": "Tight-binding molecular dynamics and Monte Carlo simulation, per the abstract",
      "status": "calculated",
      "note": "Printed as 2.99 gcm−3 in the paper. No measured bulk density for a DLC film was recorded in this run.",
      "source": "fyta2006",
      "where": "Results, description of Fig. 1(a)",
      "source_detail": {
        "title": "Structure, stability and stress properties of amorphous and nanostructured carbon films",
        "id": "arXiv cond-mat/0605381",
        "url": "https://arxiv.org/pdf/cond-mat/0605381",
        "kind": "paper",
        "license": "arXiv preprint, licence as listed on arXiv"
      }
    },
    {
      "benchmark": "sp3_fraction",
      "label": "sp3 bonding fraction of the same simulated network",
      "value": 79,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "network": "simulated dense ta-C, density 2.99 g/cm3"
      },
      "method": "Tight-binding molecular dynamics and Monte Carlo simulation, per the abstract",
      "status": "calculated",
      "source": "fyta2006",
      "where": "Results, description of Fig. 1(a)",
      "source_detail": {
        "title": "Structure, stability and stress properties of amorphous and nanostructured carbon films",
        "id": "arXiv cond-mat/0605381",
        "url": "https://arxiv.org/pdf/cond-mat/0605381",
        "kind": "paper",
        "license": "arXiv preprint, licence as listed on arXiv"
      }
    },
    {
      "benchmark": "friction_coefficient",
      "label": "Steady-state friction coefficient, ion-beam DLC on silicon, ultrahigh vacuum",
      "value": 0.1,
      "bound": "upper",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "film": "ion-beam-deposited DLC from an argon and CH4 mixture at 1500 or 700 eV ion energy",
        "environment": "ultrahigh vacuum; the report also tests humid air, dry nitrogen and water",
        "test": "unidirectional rotating sliding at room temperature"
      },
      "method": "Sliding friction test; the report prints the value as a bound",
      "status": "ground",
      "note": "The abstract prints low steady-state coefficients of friction (<0.1) for DLC in every environment tested.",
      "source": "miyoshi1997",
      "where": "Abstract; Coefficients of Friction and Wear Rates section",
      "source_detail": {
        "title": "Lubrication by Diamond and Diamondlike Carbon Coatings (NASA Lewis, report E-10462)",
        "id": "NTRS 19970025138",
        "url": "https://ntrs.nasa.gov/citations/19970025138",
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "coating_thickness",
      "label": "Thickness, ion-beam DLC films on silicon",
      "value": 520,
      "value_high": 660,
      "bound": "range",
      "unit": "nm",
      "scope": "material",
      "conditions": {
        "film": "ion-beam-deposited DLC, argon and CH4 in a 3:17 mixture",
        "note_source": "the report cites Wu et al. (1995) for this range"
      },
      "method": "Stated in the DLC deposition description of the report",
      "status": "ground",
      "source": "miyoshi1997",
      "where": "Experimental section, DLC deposition paragraph",
      "source_detail": {
        "title": "Lubrication by Diamond and Diamondlike Carbon Coatings (NASA Lewis, report E-10462)",
        "id": "NTRS 19970025138",
        "url": "https://ntrs.nasa.gov/citations/19970025138",
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "surface_roughness_rms",
      "label": "Mean surface roughness (rms), ion-beam DLC at 1500 eV",
      "value": 22,
      "bound": "exact",
      "unit": "nm",
      "scope": "material",
      "conditions": {
        "film": "ion-beam-deposited DLC at 1500 eV ion energy"
      },
      "method": "Surface characterisation as reported",
      "status": "ground",
      "note": "The 700 eV film is 14 nm rms in the same section.",
      "source": "miyoshi1997",
      "where": "Results, DLC film characterisation paragraph",
      "source_detail": {
        "title": "Lubrication by Diamond and Diamondlike Carbon Coatings (NASA Lewis, report E-10462)",
        "id": "NTRS 19970025138",
        "url": "https://ntrs.nasa.gov/citations/19970025138",
        "kind": "report",
        "license": "public domain (NASA)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Oxygen plasma (laboratory), which the paper links to atomic-oxygen erosion in orbit",
      "headline": "In a short oxygen-plasma test, the hexane-deposited DLC film was etched and lost hardness.",
      "effect": "The paper reports a corrosion rate of 434 ± 26 Å/min for DLC and a fall in hardness from 9.1 GPa to 6.3 GPa after exposure. The paper's aim, from its title, is protection by a silicon-oxide top layer (SiOx-DLC) on the DLC film.",
      "rating": "moderate",
      "conditions": {
        "exposure": "oxygen plasma, 12 sccm, RF 13.5 MHz, 10 W, bias -179 V, 22 min",
        "film": "DLC from hexane by PECVD",
        "test": "laboratory plasma only; no flight result"
      },
      "source": "ferreira2021",
      "where": "Section 2 (corrosion conditions), Table 2 and Table 4"
    },
    {
      "environment": "Air at high temperature (maximum temperature rated by NACL)",
      "headline": "NACL rates its DLC at a maximum working temperature of 500 °C, but prints no test.",
      "effect": "The NACL sheet gives 500 °C as the maximum working temperature, with no test or formulation stated. No oxidation onset or ageing data were found in the sources held for this run.",
      "rating": "unknown",
      "conditions": {
        "basis": "manufacturer rating, not measured in these sources"
      },
      "source": "nacl-dlc-tds",
      "where": "Page 2, row 'Max. Working Temp.'"
    },
    {
      "environment": "Humidity and salt spray (military test methods listed by NACL)",
      "headline": "NACL says its DLC is approved against named military test methods but prints no results.",
      "effect": "The NACL data sheet lists humidity, salt spray and adhesion tests under military specifications. It gives no numbers for those tests, so no corrosion rating is assigned from this source.",
      "rating": "unknown",
      "conditions": {
        "basis": "manufacturer statement; no results printed"
      },
      "source": "nacl-dlc-tds",
      "where": "Page 1, text on military specifications; page 2 test list"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "PubChem's element record for carbon lists 'H319 (55.1%): Causes serious eye irritation' and 'H335 (51.1%): May cause respiratory irritation', both from company notifications. PubChem does not say which carbon form each notification describes, so this is a proxy for DLC and not a classification of the coating.",
        "ghs": [
          "H319",
          "H335"
        ],
        "source": "pubchem-carbon",
        "where": "Safety and Hazards, GHS Classification and Hazard Classes and Categories (CID 5462310)"
      },
      {
        "text": "PubChem's carbon record also states that the chemical 'does not meet GHS hazard criteria' for a share of reports. Toxicity data for DLC coatings were not found in any source held for this run.",
        "ghs": [],
        "source": "pubchem-carbon",
        "where": "Safety and Hazards, GHS Classification note"
      }
    ],
    "failure_risks": [
      {
        "mode": "Adhesion loss (delamination) under scratch loading",
        "trigger": "Scratch test with normal load rising from 0.2 N to 30 N",
        "consequence": "The paper's first critical load LC1 for the hexane-deposited DLC film is 11.2 N (printed as 11.2 ± 1.8 N).",
        "severity": "moderate",
        "source": "ferreira2021",
        "where": "Section 3 (Adhesion)"
      },
      {
        "mode": "Friction rise after oxygen corrosion",
        "trigger": "Oxygen-plasma corrosion of DLC, as cited by Ferreira et al. from Tagawa et al.",
        "consequence": "The paper quotes 'the DLC films present a high friction coefficient (0.38)' after oxygen corrosion, and says friction later returned to 0.05.",
        "severity": "moderate",
        "source": "ferreira2021",
        "where": "Section 3, values from other cited work"
      },
      {
        "mode": "Erosion in oxygen plasma, which the paper links to atomic oxygen",
        "trigger": "Oxygen plasma exposure, 22 min in the laboratory test",
        "consequence": "The DLC film was etched at 434 ± 26 Å/min and its hardness fell to 6.3 GPa (printed 6.3 ± 1.8 GPa).",
        "severity": "moderate",
        "source": "ferreira2021",
        "where": "Table 2 and Table 4"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "No DLC-specific safety data sheet was found. The hazard entries above use the carbon element record, which PubChem aggregates from notifiers.",
        "source": "pubchem-carbon",
        "where": "Safety and Hazards (CID 5462310)"
      }
    ],
    "mitigations": [
      {
        "text": "The paper's answer to oxygen-plasma erosion is a silicon-oxide top layer (SiOx-DLC) on the DLC film, which the title describes as protection against atomic oxygen and ozone. This was not tested in orbit.",
        "source": "ferreira2021",
        "where": "Title; Sections 1 and 4"
      }
    ]
  },
  "uses": [
    {
      "application": "mechanisms",
      "device": "Engine components such as fuel injection systems, valve trains and pistons",
      "example": "Oerlikon says its DLC coating provides excellent protection against abrasion, tribo-oxidation and adhesive wear and gives low friction losses in high-speed sliding.",
      "source": "oerlikon-balinit-product",
      "where": "BALINIT DLC product page, application and performance text"
    },
    {
      "application": "mechanisms",
      "device": "Locating and positioning pins for aluminium die-cast body parts",
      "example": "Misumi's DLC locating pin datasheet gives a body-shell test on aluminium die-cast parts, with a cycle count printed in its test results table.",
      "source": "misumi-dlc",
      "where": "Test results section (installation location Body in White)"
    },
    {
      "application": "optics-and-cameras",
      "device": "Barcode scanner windows, laser optics, optical mirrors and infrared windows",
      "example": "NACL lists these as typical applications for its DLC coating, which it says is deposited at or near room temperature.",
      "source": "nacl-dlc-tds",
      "where": "Page 1, 'Ideal Diamond-Like Carbon Applications' and deposition text"
    }
  ],
  "supply": [
    {
      "subject": "Graphite (carbon context; not the DLC precursor)",
      "producers": [
        {
          "country": "China",
          "share_percent": 82,
          "year": 2025
        }
      ],
      "critical_lists": [
        {
          "list": "USGS 2025 List of Critical Minerals (page lists 'Graphite')",
          "listed": true
        }
      ],
      "recycling": "USGS: the abundance of graphite in the world market inhibits increased recycling efforts; information on recycled quantity was not available.",
      "substitutes": [
        "USGS: molybdenum disulfide competes as a dry lubricant but is more sensitive to oxidizing conditions."
      ],
      "source": "usgs-mcs2026-graphite",
      "where": "Text on China's production share, Recycling and Substitutes sections; World Mine Production table (2025e)"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "North American Coating Laboratories, Diamond-Like Carbon Coating Technical Data Sheet",
      "type": "datasheet",
      "url": "https://www.nacl.com/wp-content/uploads/2016/05/DLC-TDS.pdf"
    },
    {
      "title": "MISUMI DLC coating datasheet (January 2026)",
      "type": "datasheet",
      "url": "https://uk.misumi-ec.com/files/images/products/docs/misumi_dlc-datasheet-en.pdf",
      "year": 2026
    },
    {
      "title": "SiOx Top Layer on DLC Films for Atomic Oxygen and Ozone Corrosion Protection in Aerospace Applications (Materials Research, open access)",
      "type": "paper",
      "url": "https://scielo.br/j/mr/a/3JnHb7KV4tDcPmbQsRqSYWm/?lang=en",
      "year": 2021
    },
    {
      "title": "Structure, stability and stress properties of amorphous and nanostructured carbon films (arXiv cond-mat/0605381)",
      "type": "paper",
      "url": "https://arxiv.org/pdf/cond-mat/0605381",
      "year": 2006
    },
    {
      "title": "NASA: Lubrication by Diamond and Diamondlike Carbon Coatings (E-10462)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/citations/19970025138",
      "year": 1997
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Graphite (Natural)",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-graphite.pdf",
      "year": 2026
    },
    {
      "title": "PubChem compound record: Carbon (CID 5462310), Safety and Hazards",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/5462310",
      "year": 2026
    }
  ],
  "gaps": [
    "No flight, vacuum-exposure or outgassing result for DLC was found in this run. The only space-related source is the 1997 NASA ultrahigh-vacuum friction study on laboratory films, and it gives no mass-loss or outgassing data.",
    "No orbital atomic-oxygen erosion yield for DLC was found. The corrosion rate recorded above is from a laboratory oxygen plasma and is not comparable to an orbital yield.",
    "Wear rates in the NASA report are printed with exponents, so they are left out.",
    "The density recorded is a simulation result (Fyta et al.). No measured bulk density for a ta-C or a-C:H film was found in an open source in this run.",
    "The Oerlikon BALINIT DLC specification table (hardness HIT, dry friction, maximum service and process temperature) was read in this run, but the cited page's raw text does not contain it, so those rows are left out of the file. No second source for that grade was found.",
    "Misumi prints the hardness as '~ 2.000' with a dot as thousands separator, and prints the friction range as '0.15 - 2'. Neither can be recorded as a checked number, so both are left out.",
    "The NACL refractive index and hardness are ranges that depend on formulation; no single value is recorded.",
    "Hydrogen content printed as H (%) in Table 4 of the Ferreira paper is not defined in the extract, so it is left out.",
    "The supply row is graphite, shown as carbon context. The hydrocarbon precursors actually used (methane in the NASA report, hexane in the Ferreira paper) were not sourced for supply in this run.",
    "The EU critical raw materials list was not checked for graphite in this run.",
    "Property names for hardness, friction, coating thickness, roughness, deposition and process temperature are not in spores/property-canon.yaml; snake_case names are used.",
    "No DLC-specific safety data sheet was found. Hazard entries use PubChem's carbon element record, which does not name the carbon form.",
    "The Ferreira paper's abstract and Section 3 give different critical loads for the same DLC film. Only the LC1 value from Section 3 is recorded.",
    "Wikipedia is cited for the definition and history only; no numbers were taken from it."
  ],
  "story": {
    "why": "Diamond-like carbon (DLC) is a coating, not a bulk material, and it is chosen for hardness and low friction on sliding parts and optics. The grades in these sources are made and rated differently, so the numbers are not interchangeable: a PECVD film measured in one lab study, and a manufacturer optical DLC data sheet that rates the coating for 500 °C.",
    "uses": [
      {
        "where": "Engine and sliding parts",
        "line": "Oerlikon says its BALINIT DLC coating suits engine components such as fuel injection systems, valve trains and pistons, where it protects against abrasion and adhesive wear."
      },
      {
        "where": "Locating pins for aluminium parts",
        "line": "Misumi sells a DLC-coated locating pin for positioning aluminium die-cast body parts. Its datasheet prints a cycle count from a body-shell test."
      },
      {
        "where": "Optics",
        "line": "NACL lists barcode scanner windows, laser optics, optical mirrors and infrared windows as typical DLC applications."
      }
    ],
    "can_do": [
      {
        "label": "Hardness",
        "line": "Resist abrasion on sliding parts. NACL rates its DLC at a Vickers hardness of 1000 to 3000 HV, depending on formulation.",
        "scope": "material"
      },
      {
        "label": "Friction",
        "line": "Keep friction low. NACL lists the as-deposited DLC at a friction below 0.1, with no test method printed.",
        "scope": "material"
      },
      {
        "label": "Temperature",
        "line": "Run at up to 500 °C by NACL's rating. No test is printed for that figure.",
        "scope": "material"
      },
      {
        "label": "Deposition",
        "line": "Coat without heating the part much. NACL says its DLC is deposited below 50 °C.",
        "scope": "material"
      }
    ],
    "compare": "DLC is a thin, hard, low-friction film on a part, not a bulk material. The NACL sheet rates hardness at 1000 to 3000 HV and friction below 0.1 for the as-deposited film, with a maximum working temperature of 500 °C. The laboratory PECVD film measured 9.1 GPa hardness and a 79 GPa modulus, and its erosion in oxygen plasma (434 Å/min) is the weak point in the lab data. The compare rows use the three properties that the sources report for DLC.",
    "compare_rows": [
      {
        "label": "Hardness (Vickers) of the NACL DLC coating",
        "benchmark": "hardness_vickers",
        "scope": "material"
      },
      {
        "label": "Friction coefficient of the NACL DLC coating (as-deposited)",
        "benchmark": "friction_coefficient",
        "scope": "material"
      },
      {
        "label": "Maximum working temperature of the NACL DLC coating",
        "benchmark": "max_service_temp",
        "scope": "material"
      }
    ],
    "handling": [
      "No DLC-specific safety data sheet was found. The carbon element record lists eye and respiratory irritation from company notifications.",
      "The sources do not give a cleaning or handling method for coated parts."
    ],
    "good_for": [
      "Hard sliding surfaces. NACL rates its DLC at 1000 to 3000 HV, depending on formulation.",
      "Coating parts without much heat. NACL deposits its DLC below 50 °C.",
      "Optical windows and mirrors that need a scratch-resistant, low-friction surface, as NACL describes its coating."
    ],
    "watch_out": [
      "Oxygen plasma erodes the film. The PECVD DLC etched at 434 ± 26 Å/min in the laboratory and lost hardness.",
      "The 500 °C maximum temperature rests on one manufacturer rating with no test printed. Check it for the grade you buy.",
      "No orbital erosion or outgassing data were found. The only space-related study is a 1997 ultrahigh-vacuum friction test on laboratory films."
    ],
    "verdict": "Diamond-like carbon is a hard, low-friction coating for sliding parts and optics. The NACL data sheet rates its hardness at 1000 to 3000 HV and its maximum working temperature at 500 °C, but no test is printed. The laboratory PECVD film has 9.1 GPa hardness and erodes in oxygen plasma, and no orbital erosion or outgassing data were found.",
    "recipe": {
      "line": "Diamond-like carbon is made of carbon alone in most grades, and some grades add hydrogen. The atoms form a disordered network with a mix of diamond-type sp3 bonds and graphite-type sp2 bonds. It is deposited as a thin film by physical vapour deposition (PVD) or by plasma-enhanced chemical vapour deposition (PECVD) from a hydrocarbon gas or liquid.",
      "parts": [
        {
          "name": "Carbon",
          "symbol": "C",
          "role": "The whole film. Its sp3 bonds give the hardness, and its sp2 bonds give a softer, graphite-like part of the network."
        },
        {
          "name": "Hydrogen",
          "symbol": "H",
          "role": "Present in hydrogenated grades (a-C:H). Misumi lists its Ta-C coating as hydrogen-free."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "No DLC-specific safety data sheet was found. The hazard entries come from PubChem's record for the element carbon, which lists eye and respiratory irritation from company notifications.",
        "points": [
          {
            "label": "Eye and airway",
            "line": "PubChem's carbon record lists 'H319 (55.1%): Causes serious eye irritation' and 'H335 (51.1%): May cause respiratory irritation'. These come from company notifications, not from a test of a DLC coating."
          }
        ],
        "level": 0,
        "verdict": "No DLC data sheet found; carbon record flags irritation"
      },
      {
        "title": "In a plasma or a fire",
        "lead": "Oxygen plasma is a process hazard for the film, not for people.",
        "points": [
          {
            "label": "Erosion",
            "line": "In a laboratory oxygen plasma, the hexane-deposited DLC film etched at 434 ± 26 Å/min. This shows how the film wears in reactive oxygen, but it is not a flight result."
          }
        ],
        "level": 0,
        "verdict": "Oxygen plasma etches the film in the lab"
      }
    ]
  },
  "updated": "2026-11-01",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 18,
    "unreachable": 1,
    "caveats": 3,
    "note": "Read by an AI assistant on 2026-11-01 from the pages and PDFs named in each entry. Unreachable: the PMC review (PMC7878482) returned a verification page and could not be read. Caveats: the NACL maximum temperature has no test; the Fyta density is a simulation; the Ferreira critical loads differ between abstract and text. The Oerlikon BALINIT DLC table was read but is not in the file because the cited raw page does not contain it."
  },
  "sources": {
    "oerlikon-balinit-product": {
      "title": "BALINIT DLC product page (Oerlikon Balzers)",
      "id": "Oerlikon Balzers BALINIT DLC",
      "url": "https://oerlikon.com/balzers/be/en/portfolio/balzers-surface-solutions/pvd-and-pacvd-based-coating-solutions/balinit/carbon-dlc-based/balinit-dlc",
      "kind": "web",
      "license": "manufacturer web page, cited not reproduced"
    },
    "nacl-dlc-tds": {
      "title": "North American Coating Laboratories, Diamond-Like Carbon Coating Technical Data Sheet",
      "id": "NACL DLC data sheet (PDF)",
      "url": "https://www.nacl.com/wp-content/uploads/2016/05/DLC-TDS.pdf",
      "kind": "datasheet",
      "license": "manufacturer data sheet, cited not reproduced"
    },
    "misumi-dlc": {
      "title": "MISUMI Europa GmbH, DLC coating datasheet",
      "id": "MISUMI DLC datasheet, January 2026",
      "url": "https://uk.misumi-ec.com/files/images/products/docs/misumi_dlc-datasheet-en.pdf",
      "kind": "datasheet",
      "license": "supplier datasheet, cited not reproduced"
    },
    "ferreira2021": {
      "title": "SiOx Top Layer on DLC Films for Atomic Oxygen and Ozone Corrosion Protection in Aerospace Applications",
      "id": "doi:10.1590/1980-5373-MR-2020-0511 (Materials Research 24(3), 2021)",
      "url": "https://scielo.br/j/mr/a/3JnHb7KV4tDcPmbQsRqSYWm/?lang=en",
      "kind": "paper",
      "license": "CC BY 4.0"
    },
    "fyta2006": {
      "title": "Structure, stability and stress properties of amorphous and nanostructured carbon films",
      "id": "arXiv cond-mat/0605381",
      "url": "https://arxiv.org/pdf/cond-mat/0605381",
      "kind": "paper",
      "license": "arXiv preprint, licence as listed on arXiv"
    },
    "miyoshi1997": {
      "title": "Lubrication by Diamond and Diamondlike Carbon Coatings (NASA Lewis, report E-10462)",
      "id": "NTRS 19970025138",
      "url": "https://ntrs.nasa.gov/citations/19970025138",
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "usgs-mcs2026-graphite": {
      "title": "Mineral Commodity Summaries 2026, Graphite (Natural)",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-graphite.pdf",
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-crit2025": {
      "title": "About the 2025 List of Critical Minerals (USGS)",
      "id": "Final 2025 List of Critical Minerals",
      "url": "https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals",
      "kind": "web",
      "license": "public domain (USGS)"
    },
    "pubchem-carbon": {
      "title": "PubChem compound record, Carbon (CID 5462310)",
      "id": "CID 5462310",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/5462310",
      "kind": "database",
      "license": "public domain (NCBI)"
    },
    "wikipedia-dlc": {
      "title": "Wikipedia: Diamond-like carbon (definition and history only)",
      "id": "en.wikipedia.org",
      "url": "https://en.wikipedia.org/wiki/Diamond-like_carbon",
      "kind": "web",
      "license": "CC BY-SA 4.0"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/diamond-like-carbon/"
}