spore: profile
id: zirconium-nitride
spore_version: 0.2
family: carbide-nitride-boride-ceramics
name: Zirconium nitride
abbreviation: ZrN
role: hard, yellow nitride ceramic used as a protective and diffusion-barrier coating
category: ceramics
type: nitrides
summary: |
  Zirconium nitride is a yellow, hard rock-salt ceramic. WebElements lists a density of 7090 kg m-3 (7.09 g/cm3) and a melting point of 2960 degC. First-principles calculations by Krasnenko and Brik (arXiv, 2013) give a bulk modulus of 268.16 GPa with the LDA method and 226.14 GPa with GGA for the rock-salt phase, and an experimental lattice constant of 4.575 Angstrom. Magnetron-sputtered ZrN films on 316L stainless steel reached nanohardness values of 26.3 to 39.3 GPa as the substrate bias rose from 0 V to -100 V (Journal of Electrical Engineering, 2019). In Hank's solution the -100 V film corroded at 0.0026 mpy, against 0.0244 mpy for uncoated steel in the same test, while the 0 V film corroded faster than uncoated steel at 0.0451 mpy.
best_for: Hard protective coatings on steel for wear and corrosion tests, where a high melting point and a hard surface both matter
weakest_at: Oxidation in air. No readable source in this run gives an oxidation onset temperature for ZrN, so the limit in hot air is unverified
identity:
  formula: ZrN
  cas: 25658-42-8
  crystal_system: cubic
  space_group: Fm-3m
  source: krasnenko-arxiv-2013
  where: Text on the neat carbides and nitrides (ZrN included, all crystallize in the Fm-3m space group), and Table 1, ZrN row; CAS from the PubChem record for CID 94359
tags:
  environments: []
  stresses: []
  applications:
    - mechanisms
    - electronics-and-chips
properties:
  - benchmark: density
    label: Density of ZrN
    value: 7090
    unit: kg m-3
    scope: material
    conditions:
      basis: single figure given for the compound; no temperature stated
    method: Database entry for the compound; the page gives no measurement method
    status: ground
    source: webelements-zrn
    where: Properties table, Density row (printed as 7090 kg m-3)
  - benchmark: melting_point
    label: Melting point of ZrN
    value: 2960
    unit: degC
    scope: material
    conditions:
      basis: single figure given for the compound; no atmosphere or pressure stated
    method: Database entry for the compound; the page gives no measurement method
    status: ground
    source: webelements-zrn
    where: Properties table, Melting point row (printed as 2960°C)
  - benchmark: lattice_constant
    label: Lattice constant, rock-salt ZrN (experimental value quoted)
    value: 4.575
    unit: Å
    scope: material
    conditions:
      basis: experimental value listed in the Exp. column, from the reference the paper calls e
    method: Experimental value quoted in the paper's comparison column
    status: ground
    source: krasnenko-arxiv-2013
    where: Table 1, ZrN row, Exp. column
  - benchmark: bulk_modulus
    label: Bulk modulus, ZrN (calculated, LDA)
    value: 268.16
    unit: GPa
    scope: material
    conditions:
      basis: rock-salt ZrN, first-principles LDA result from this work
    method: First-principles calculation (LDA) in an arXiv preprint; a calculated value, not a measurement
    status: calculated
    source: krasnenko-arxiv-2013
    where: Table 2, ZrN row, LDA column (calculated, this work)
  - benchmark: bulk_modulus
    label: Bulk modulus, ZrN (calculated, GGA)
    value: 226.14
    unit: GPa
    scope: material
    conditions:
      basis: rock-salt ZrN, first-principles GGA result from this work
    method: First-principles calculation (GGA) in an arXiv preprint; a calculated value, not a measurement
    status: calculated
    source: krasnenko-arxiv-2013
    where: Table 2, ZrN row, GGA column (calculated, this work)
  - benchmark: elastic_constant_c11
    label: Elastic constant C11, ZrN (calculated, LDA)
    value: 605.99
    unit: GPa
    scope: material
    conditions:
      basis: rock-salt ZrN, first-principles LDA result from this work
    method: First-principles calculation (LDA) in an arXiv preprint; a calculated value, not a measurement
    status: calculated
    source: krasnenko-arxiv-2013
    where: Table 3, ZrN row, LDA C11 column
  - benchmark: elastic_constant_c12
    label: Elastic constant C12, ZrN (calculated, LDA)
    value: 99.25
    unit: GPa
    scope: material
    conditions:
      basis: rock-salt ZrN, first-principles LDA result from this work
    method: First-principles calculation (LDA) in an arXiv preprint; a calculated value, not a measurement
    status: calculated
    source: krasnenko-arxiv-2013
    where: Table 3, ZrN row, LDA C12 column
  - benchmark: elastic_constant_c44
    label: Elastic constant C44, ZrN (calculated, LDA)
    value: 128.06
    unit: GPa
    scope: material
    conditions:
      basis: rock-salt ZrN, first-principles LDA result from this work
    method: First-principles calculation (LDA) in an arXiv preprint; a calculated value, not a measurement
    status: calculated
    source: krasnenko-arxiv-2013
    where: Table 3, ZrN row, LDA C44 column
  - benchmark: hardness
    label: Nanohardness of sputtered ZrN films on 316L, bias 0 V to -100 V
    value: 26.3
    value_high: 39.3
    unit: GPa
    scope: material
    conditions:
      form: ZrN film, RF magnetron sputtered from a 99.99 % zirconium target onto 316L stainless steel, 1.43 to 2.0 um thick (Table 2)
      substrate_bias: 0 V (26.3 GPa) to -100 V (39.3 GPa)
      method_of_measurement: nanoindentation with a Berkovich diamond tip, average of ten measurements, depth about 10 % of film thickness
    method: Nanoindentation of the sputtered film, loading and unloading curves
    status: ground
    source: jee-2019-zrn
    where: Section 3 text on nanohardness (26.3 to 39.3 GPa as bias increases); Table 2 (thickness)
  - benchmark: hardness
    label: Hardness of magnetron-sputtered ZrN coating, text range
    value: 23
    value_high: 30
    unit: GPa
    scope: material
    conditions:
      form: magnetron-sputtered ZrN coating on stainless steel, 2 to 3 um thick series
      method_of_measurement: nanoindentation at 10 mN and 20 mN
    method: Nanoindentation; the paper states the range in its discussion and does not give a separate value per load
    status: ground
    source: ul-hamid-jar-2020
    where: Nanoindentation discussion (Fig. 9a text) and Conclusions; text reads ZrN showed the highest values of hardness (23-30 GPa)
  - benchmark: corrosion_rate
    label: Corrosion rate in Hank's solution, ZrN film at -100 V bias
    value: 0.0026
    unit: mpy
    scope: material
    conditions:
      electrolyte: Hank's solution, a simulated physiological medium
      form: ZrN film on 316L stainless steel, sample S3, 1.61 um thick (Table 2)
      method_of_measurement: potentiodynamic polarisation, Tafel extrapolation, PARSTAT 400 potentiostat
    method: Electrochemical test, corrosion rate from Tafel extrapolation
    status: ground
    source: jee-2019-zrn
    where: Table 3, S3 column (-100 V), Corrosion Rate Cr (mpy)
  - benchmark: corrosion_rate
    label: Corrosion rate in Hank's solution, uncoated stainless steel
    value: 0.0244
    unit: mpy
    scope: material
    conditions:
      electrolyte: Hank's solution, a simulated physiological medium
      form: uncoated stainless steel substrate (316L)
      method_of_measurement: potentiodynamic polarisation, Tafel extrapolation, PARSTAT 400 potentiostat
    method: Electrochemical test, corrosion rate from Tafel extrapolation
    status: ground
    source: jee-2019-zrn
    where: Table 3, Uncoated Steel column, Corrosion Rate Cr (mpy)
  - benchmark: corrosion_rate
    label: Corrosion rate in Hank's solution, ZrN film at 0 V bias
    value: 0.0451
    unit: mpy
    scope: material
    conditions:
      electrolyte: Hank's solution, a simulated physiological medium
      form: ZrN film on 316L stainless steel, sample S1, 2.0 um thick (Table 2)
      method_of_measurement: potentiodynamic polarisation, Tafel extrapolation, PARSTAT 400 potentiostat
    method: Electrochemical test, corrosion rate from Tafel extrapolation
    status: ground
    note: The unbiased film corroded faster than the uncoated steel in this test.
    source: jee-2019-zrn
    where: Table 3, S1 column (0 V), Corrosion Rate Cr (mpy)
  - benchmark: corrosion_rate
    label: Corrosion rate in Hank's solution, ZrN film at -50 V bias
    value: 0.0244
    unit: mpy
    scope: material
    conditions:
      electrolyte: Hank's solution, a simulated physiological medium
      form: ZrN film on 316L stainless steel, sample S2, 1.43 um thick (Table 2)
      method_of_measurement: potentiodynamic polarisation, Tafel extrapolation, PARSTAT 400 potentiostat
    method: Electrochemical test, corrosion rate from Tafel extrapolation
    status: ground
    source: jee-2019-zrn
    where: Table 3, S2 column (-50 V), Corrosion Rate Cr (mpy)
corrosion:
  - environment: Hank's solution (simulated physiological medium), ZrN films on 316L stainless steel
    headline: A ZrN film made at -100 V bias corroded about nine times more slowly than uncoated steel in the same solution.
    effect: Potentiodynamic tests gave a corrosion rate of 0.0026 mpy for the -100 V film, against 0.0244 mpy for uncoated steel, 0.0244 mpy for the -50 V film and 0.0451 mpy for the 0 V film. The -100 V film also had the highest polarisation resistance of the set (12.155 MOhm).
    rating: low
    conditions:
      exposure: electrochemical polarisation in Hank's solution; no long-term immersion reported
      film: reactive RF magnetron sputtering of ZrN on 316L, bias 0 V to -100 V
    source: jee-2019-zrn
    where: Table 3 (electrochemical parameters, all sample columns)
risks:
  hazards:
    - text: PubChem's GHS record for zirconium nitride is based on 7 reports. It says 14.3 % (1 of 7) of those reports do not meet GHS hazard criteria.
      ghs:
        - 'H228 (71.4 % of reports): Flammable solid'
        - 'H315 (85.7 % of reports): Causes skin irritation'
        - 'H319 (85.7 % of reports): Causes serious eye irritation'
        - 'H335 (85.7 % of reports): May cause respiratory irritation'
      source: pubchem-zrn
      where: Safety and Hazards, GHS Classification (CID 94359 record); signal word Danger, pictograms GHS02 and GHS07
  failure_risks: []
  handling:
    - text: PubChem lists precautionary codes P210, P240, P241, P261, P264, P271, P280 and P405 for this compound, but the statement text was not read in this run. Check the supplier's safety data sheet for powder or target stock.
      source: pubchem-zrn
      where: Safety and Hazards, Precautionary Statement Codes (CID 94359 record)
  mitigations:
    - text: Applying a -100 V substrate bias during sputtering gave the lowest corrosion rate of the set (0.0026 mpy in Hank's solution) and the highest nanohardness (39.3 GPa), against 0.0451 mpy for the film made at 0 V.
      source: jee-2019-zrn
      where: Table 3 and Section 3 (nanohardness text)
uses:
  - application: mechanisms
    device: Wear-resistant coating for sliding parts (tribological use, terrestrial)
    example: The 2020 paper says Zr-nitride coatings have been evaluated for hardness and wear resistance in tribological applications. Its conclusion calls them potential candidates for tribological applications. No flight or wear test of ZrN in space is reported.
    source: ul-hamid-jar-2020
    where: Introduction; Conclusions
  - application: electronics-and-chips
    device: Barrier layer in integrated circuits (terrestrial)
    example: The same paper names Zr-nitride as a barrier material in integrated circuits. This is a statement about the material class, not a test of ZrN in a device.
    source: ul-hamid-jar-2020
    where: Introduction
media: []
documents:
  - title: PubChem compound record CID 94359 (zirconium nitride), GHS classification
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/94359/JSON
    year: 2026
  - title: USGS Mineral Commodity Summaries 2026, Zirconium and Hafnium
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-zirconium-hafnium.pdf
    year: 2026
  - title: WebElements, Zirconium nitride properties table
    type: database
    url: https://winter.group.shef.ac.uk/webelements/compounds/zirconium/zirconium_nitride.html
    year: 2026
  - title: First-principles calculations of the structural, elastic and electronic properties of MNxC1-x carbonitrides (arXiv 1306.3139)
    type: paper
    url: https://arxiv.org/pdf/1306.3139
    year: 2013
  - title: The influence of substrate bias voltage on the electrochemical properties of ZrN thin films deposited by radio-frequency magnetron sputtering (J. Electrical Engineering 70, 2019)
    type: paper
    url: https://reference-global.com/download/article/10.2478/jee-2019-0051.pdf
    year: 2019
  - title: Synthesis, microstructural characterization and nanoindentation of Zr, Zr-nitride and Zr-carbonitride coatings (J. Adv. Res. 2020)
    type: paper
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC8020350
    year: 2020
  - title: Deposition, microstructure and nanoindentation of multilayer Zr nitride and carbonitride nanostructured coatings (Sci. Rep. 2022)
    type: paper
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC8979963
    year: 2022
  - title: Thermodynamic properties of zirconium nitride in the condensed state (Physics-Uspekhi 67, 2024)
    type: paper
    url: https://ufn.ru/en/articles/accepted/39655
    year: 2024
supply:
  - subject: Zirconium (zircon and zirconium mineral concentrates)
    abundance: not read in this run
    producers:
      - country: Australia
        share_percent: 33.3
        year: 2025
      - country: South Africa
        share_percent: 22.5
        year: 2025
      - country: Mozambique
        share_percent: 13.3
        year: 2025
      - country: China
        share_percent: 8.3
        year: 2025
      - country: Senegal
        share_percent: 5.8
        year: 2025
      - country: Indonesia
        share_percent: 4.3
        year: 2025
    critical_lists: []
    recycling: 'USGS: companies in Oregon and Utah recycle zirconium from new scrap and from post-commercial old scrap. Zircon foundry mold cores and spent or rejected zirconia refractories are often recycled but could not be quantified.'
    substitutes:
      - 'USGS: chromite and olivine can substitute for zircon in some foundry applications (the chapter''s substitute list is for zircon, not for zirconium nitride).'
    source: usgs-mcs2026-zirconium-hafnium
    where: 'World Mine Production and Reserves table, zirconium mineral concentrates, 2025 (thousand metric tons, gross weight; shares calculated by Space Mushroom against the printed world total of 1,200 thousand t). Import Sources (2021 to 2024): zirconium ores and concentrates, South Africa 48%, Australia 35%, Senegal 15%. Recycling; Substitutes.'
gaps:
  - No oxidation onset temperature for ZrN in air was read on a fetched page. The Coatings 2020 paper (10(2):149) returned HTTP 403, so no value from it is used here.
  - No electrical resistivity value for ZrN was read in a fetched page. A National Tsing Hua University thesis reports 56 with no readable unit, so it is not used.
  - Thermal conductivity, coefficient of thermal expansion and specific heat were not found in a readable source. The 2024 Physics-Uspekhi review (Aristova et al.) gives a heat-capacity equation for crystalline ZrN, but its coefficients were not printed in the text read.
  - Young's modulus for ZrN films is only shown in a figure in the 2019 paper, and the 2020 and 2022 Ul-Hamid papers report modulus values for multilayers or with bar charts. No single-value modulus for ZrN films is used.
  - Hardness values come from different loads and substrates (nanoindentation on 316L in the 2019 paper; a 23-30 GPa range in the 2020 paper). They are not one standard test and are not a Vickers value.
  - Calculated bulk and elastic constants are first-principles values, not measurements. The paper's experimental bulk modulus values for ZrN were not printed in its ZrN row.
  - The melting point and density come from one database page (WebElements) that gives no method and no reference per value. Other sites give slightly different melting points (search results only, not read).
  - Atomic weights of zirconium and nitrogen were not read in a fetched page, so the recipe parts have no atomic_weight.
  - Zirconium abundance in the crust and nitrogen supply were not read in this run; supply covers the zirconium component only.
  - Critical-minerals status (USGS 2025 list and EU CRM list) was not stated in the zirconium chapter text read, so critical_lists is left empty.
  - No space, vacuum, radiation or flight test of ZrN was found. The nuclear inert-matrix use (fast-reactor fuels) is in the story only, because no allowed application in the schema fits it.
  - 'Property names used here that are not in spores/property-canon.yaml: hardness, lattice_constant, elastic_constant_c11, elastic_constant_c12, elastic_constant_c44, corrosion_rate.'
  - Failure risks were not found in a readable source for ZrN beyond the corrosion test, so failure_risks is empty.
  - Some PubChem hazard figures were read through a summarising fetch rather than the raw record text, so the verify step should confirm them. The Hazards Summary section was not in the part of the page read.
  - No media images were added.
sources:
  pubchem-zrn:
    title: PubChem compound record CID 94359 (zirconium nitride, azanylidynezirconium), GHS and safety sections
    id: CID 94359
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/94359/JSON
    year: 2026
    kind: database
    license: public domain (NCBI)
  usgs-mcs2026-zirconium-hafnium:
    title: Mineral Commodity Summaries 2026, Zirconium and Hafnium
    id: USGS MCS 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-zirconium-hafnium.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  webelements-zrn:
    title: WebElements, Zirconium nitride (compound properties table)
    id: WebElements, Sheffield
    url: https://winter.group.shef.ac.uk/webelements/compounds/zirconium/zirconium_nitride.html
    year: 2026
    kind: database
    license: not stated on the page read
  krasnenko-arxiv-2013:
    title: First-principles calculations of the structural, elastic and electronic properties of MNxC1-x (M=Ti, Zr, Hf) carbonitrides at ambient and elevated hydrostatic pressure (Krasnenko and Brik)
    id: arXiv:1306.3139
    url: https://arxiv.org/pdf/1306.3139
    year: 2013
    kind: paper
    license: arXiv preprint (author license as listed on arXiv)
  jee-2019-zrn:
    title: The influence of substrate bias voltage on the electrochemical properties of ZrN thin films deposited by radio-frequency magnetron sputtering (Journal of Electrical Engineering 70, no. 7S, 2019, pp. 112-116)
    id: doi:10.2478/jee-2019-0051
    url: https://reference-global.com/download/article/10.2478/jee-2019-0051.pdf
    year: 2019
    kind: paper
    license: not stated on the copy read
  ul-hamid-jar-2020:
    title: Synthesis, microstructural characterization and nanoindentation of Zr, Zr-nitride and Zr-carbonitride coatings deposited using magnetron sputtering (Journal of Advanced Research 29, 2020, 107-119)
    id: doi:10.1016/j.jare.2020.11.010
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC8020350
    year: 2020
    kind: paper
    license: CC BY-NC-ND 4.0 (per the article page)
  ul-hamid-sr-2022:
    title: Deposition, microstructure and nanoindentation of multilayer Zr nitride and carbonitride nanostructured coatings (Scientific Reports 12, 5591)
    id: doi:10.1038/s41598-022-09449-6
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC8979963
    year: 2022
    kind: paper
    license: CC BY 4.0 (per the article page)
  aristova-ufn-2024:
    title: Thermodynamic properties of zirconium nitride in the condensed state (Physics-Uspekhi 67, 2024, 1022-1033)
    id: Aristova, Onufriev, Savvatimskiy
    url: https://ufn.ru/en/articles/accepted/39655
    year: 2024
    kind: paper
    license: not stated; page says reproduction needs publisher permission
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 14
  unreachable: 3
  caveats: 3
  note: Written by an AI assistant on 2026-10-26 from pages read in this run. Three open sources returned HTTP 403 or an access-denied page (MDPI Coatings 10(2):149, RSC Materials Advances 2020 d0ma00233j, Sheffield HiPIMS ZrN paper). Some PubChem and WebElements figures were read through a summarising fetch. Calculated values are first-principles results, not measurements.
story:
  recipe:
    line: Zirconium nitride is one zirconium atom bonded to one nitrogen atom in a rock-salt crystal (space group Fm-3m). It is made as a thin film by reactive magnetron sputtering of a pure zirconium target in a mix of argon and nitrogen gas, as in the 2019 study.
    parts:
      - name: Zirconium
        symbol: Zr
        role: The metal that gives the film its hardness. The sputtering target is 99.99 % pure zirconium.
      - name: Nitrogen
        symbol: 'N'
        role: Reacts with the sputtered zirconium in the gas mix to form the rock-salt nitride. The nitrogen share of the gas controls the film's composition.
  risk_groups:
    - title: For people
      level: 0
      verdict: Most reports list hazards; check the SDS
      lead: PubChem's GHS record for zirconium nitride is based on 7 reports. Six of the seven carry hazard statements, so the powder should be handled as a hazardous solid until the supplier's sheet says otherwise.
      points:
        - label: The notifications
          line: The record gives a signal word of Danger and pictograms for flammable material and irritation. H228 (flammable solid) appears in 71.4 % of reports. H315, H319 and H335 (skin, eye and respiratory irritation) each appear in 85.7 %.
    - title: Handling
      points:
        - label: Storage
          line: The PubChem record read gives no storage advice. The supplier's safety data sheet is the source for storage and for the target or powder you use.
  why: Zirconium nitride is a rock-salt nitride of zirconium. The 2022 study describes it as a refractory ceramic with a high melting point. The 2019 paper describes it as a material with high hardness, thermal and chemical stability, and low electrical resistivity. Those properties follow from the strong metal-nitrogen bonding in the rock-salt structure, which the calculations here model with DFT. The sputtering data show that bias voltage changes both the hardness and the corrosion resistance of the same film.
  uses:
    - where: Wear-resistant coatings on sliding parts
      line: A 2020 paper on Zr-nitride coatings says they have been evaluated for hardness and wear resistance in tribological applications and calls them potential candidates for tribological use.
    - where: Barrier layer in integrated circuits
      line: The same 2020 paper names Zr-nitride as a barrier material in integrated circuits. It is a statement about the material class, not a device test of ZrN.
    - where: Biomedical coating on stainless steel (laboratory study)
      line: The 2019 paper studies ZrN films on 316L stainless steel for biomedical use and tests their corrosion in a simulated body fluid.
    - where: Inert matrix in fast-reactor nuclear fuel
      line: A 2024 review of ZrN in the condensed state describes it as an inert matrix for mixed nitride fuels in fast neutron reactors. It gives no numbers in the text read.
  can_do:
    - label: Hardness
      benchmark: hardness
      value: 26.3 to 39.3 GPa
      line: Sputtered films on 316L reached 26.3 GPa unbiased and 39.3 GPa at -100 V bias, measured by nanoindentation. The 2020 paper gives 23 to 30 GPa for its own ZrN coatings.
    - label: Stiffness
      benchmark: bulk_modulus
      value: 268.16 GPa
      line: First-principles calculations give a bulk modulus of 268.16 GPa (LDA) and 226.14 GPa (GGA) for rock-salt ZrN. These are calculated values, not measurements.
    - label: Melting
      benchmark: melting_point
      value: 2960 degC
      line: The WebElements compound table gives a melting point of 2960 degC. The table does not give a method.
    - label: Corrosion in body fluid
      benchmark: corrosion_rate
      value: 0.0026 mpy
      line: A film made at -100 V bias corroded at 0.0026 mpy in Hank's solution, against 0.0244 mpy for uncoated stainless steel. A film made at 0 V corroded faster than the uncoated steel.
  compare: Zirconium nitride is a hard, high-melting nitride. The sources read here give a calculated bulk modulus, a hardness range and a body-fluid corrosion test, but no oxidation onset or electrical resistivity value. Its hardness and modulus can be set beside those of other hard nitrides in this collection, but the oxidation comparison cannot be made from the sources read in this run.
  compare_rows:
    - label: Melting point
      benchmark: melting_point
    - label: Density
      benchmark: density
    - label: Bulk modulus
      benchmark: bulk_modulus
  handling:
    - The PubChem record gives precautionary codes but no storage advice. Read the supplier's safety data sheet for powder or target stock.
    - Keep powder away from heat sources, since most PubChem reports list it as a flammable solid.
    - Set the substrate bias during sputtering. In the 2019 test, a 0 V film corroded faster than uncoated steel, while a -100 V film corroded about nine times more slowly.
  good_for:
    - Hard coatings on steel. Sputtered ZrN reached 26.3 to 39.3 GPa nanohardness on 316L in the 2019 study.
    - Corrosion protection in a body-fluid test. The -100 V film corroded at 0.0026 mpy against 0.0244 mpy for uncoated steel.
  watch_out:
    - Oxidation in air. No readable source in this run gives an onset temperature for ZrN.
    - Bias voltage matters a great deal. The 0 V film corroded faster than uncoated steel in the same test.
    - The calculated moduli are first-principles values, and the hardness figures come from lab films on one substrate, not from flight or service tests.
  verdict: Zirconium nitride is a hard, high-melting, yellow nitride that protected 316L steel in one body-fluid test when it was biased at -100 V. Its oxidation limit in air and its behaviour in space are not sourced yet, so treat it as a lab-stage candidate until those are read.