FabDigitFabDigit

Diamond-Like Carbon Coating

PVD hard coatings · Vacuum deposition

DLC is a family of black amorphous-carbon coatings used for very low friction and severe sliding wear.

CNC machiningSheet metalHigh cost $$$$Semi-conductive
Quote a part with DLCCompare pvd hard coatings
Diamond-Like Carbon Coating on a machined part

What is DLC?

Typical grades span about 2000–5000 HV, friction about 0.05–0.15, and 1–3 µm thickness.

How it works

PVD or plasma-enhanced vapor deposition forms an sp2/sp3-bonded amorphous-carbon film, usually over metallic adhesion and stress-management layers. The hard carbon surface resists wear while low shear lowers friction. Hydrogenated grades commonly need deposition and service temperatures compatible with about 300–350 °C limits; substrate hardness and polished finish remain essential.

Why specify it

  • About 2000–5000 HV hardness
  • Dry friction commonly 0.05–0.15
  • Only 1–3 µm thick
  • Useful for medical, mould, and engine wear

Where it falls short

  • DLC grades are not interchangeable
  • Typical hydrogenated grades limited to 300–350 °C
  • High internal stress challenges sharp edges
  • Needs hard smooth support

DLC at a glance

DLC is strongest on surface hardness (93 of 100), cosmetic quality (72 of 100) and lubricity (96 of 100), at a high cost.

Corrosion protectionGood55 / 100
Surface hardnessExcellent93 / 100
Cosmetic qualityVery good72 / 100
LubricityExcellent96 / 100
Relative costHigh96 / 100
CorrosionHardnessCosmeticLubricityEconomy

Each score is 0–100 against every finish in this catalog. Corrosion comes from salt-spray life (ASTM B117, log scale) and hardness from the finish layer's Vickers or pencil hardness; cosmetic, lubricity and cost are FabDigit's engineering assessment. Economy on the radar is the inverse of cost.

DLC key numbers

Typical values from the governing specifications and shop practice; bars are this finish against the highest value among pvd hard coatings finishes.

Thickness1–3 µm0.04–0.12 mil
Hardness2,000–5,000 HV
Max service temp.350 °C662 °F
Thickness
1.5–3 µm
Hardness
2,000–5,000 HV — Broad family range; ta-C can differ from hydrogenated DLC.
Electrical
Semi-conductive
Colours
  • black
  • anthracite
Appearance
Smooth black to anthracite, from matte to glossy according to substrate polish.

Where DLC sits among all finishes

Surface hardness (Vickers, log scale) against corrosion protection (salt-spray hours, log scale) for every coating FabDigit offers, one cloud per finish group. DLC is highlighted; hover a dot for its name or open the full map.

02550751000255075100Corrosion protection (0–100)Surface hardness (HV, log scale, 0–100)Plating — 19 finishesHard coatings — 17 finishesAnodize & conversion — 8 finishesPaint & powder — 7 finisheshard, low corrosion protectionhard and protectiveprotective, softsoft, little protectionType II anodize — corrosion 71, hardness 54BSA anodize — corrosion 71, hardness 52Type I anodize — corrosion 71, hardness 49Hard anodize — corrosion 71, hardness 61PTFE hard anodize — corrosion 71, hardness 61Nitriding — corrosion 55, hardness 73PEO — corrosion 70, hardness 74Sherardizing — corrosion 83, hardness 56Brass plate — corrosion 35, hardness 44Bronze plate — corrosion 40, hardness 49Cadmium plate — corrosion 70, hardness 26Copper plate — corrosion 32, hardness 39Decorative chrome — corrosion 64, hardness 71Electroless copper — corrosion 20, hardness 41Electroless nickel — corrosion 70, hardness 68Nickel plate — corrosion 51, hardness 55Gold plate — corrosion 68, hardness 39Hard chrome — corrosion 40, hardness 73Hot-dip zinc — corrosion 90, hardness 42Nickel-PTFE — corrosion 72, hardness 57Silver plate — corrosion 55, hardness 39Solder plate — corrosion 42, hardness 9Tin plate — corrosion 34, hardness 0Zinc plate — corrosion 60, hardness 30Zinc-nickel — corrosion 86, hardness 60Cerakote — corrosion 83, hardness 27E-coat — corrosion 83, hardness 15Epoxy coat — corrosion 83, hardness 15Powder coat — corrosion 83, hardness 14Wet paint — corrosion 59, hardness 10AlCrN PVD — corrosion 58, hardness 93AlTiN PVD — corrosion 52, hardness 94CrN PVD — corrosion 62, hardness 83MoS2 PVD — corrosion 20, hardness 26TiAlN PVD — corrosion 50, hardness 93TiCN PVD — corrosion 40, hardness 92TiB2 PVD — corrosion 40, hardness 94TiN PVD — corrosion 45, hardness 87WC/C PVD — corrosion 48, hardness 77ZrN PVD — corrosion 52, hardness 90CVD alumina — corrosion 70, hardness 85CVD TiCN — corrosion 38, hardness 92CVD TiN — corrosion 45, hardness 87Multilayer CVD — corrosion 62, hardness 88HVOF coating — corrosion 78, hardness 77Plasma spray — corrosion 60, hardness 68Plastic chrome — corrosion 72, hardness 71Electroless plastic — corrosion 58, hardness 39Clear coat — corrosion 20, hardness 12Soft-touch — corrosion 20, hardness 5PLATINGHARD COATINGSANODIZE & CONVERSIONPAINT & POWDERWC/C PVDMoS2 PVDType II anodizePowder coatZinc plateZinc-nickelHard chromeTiN PVDTin plateCadmium plateE-coatCerakoteWet paintHot-dip zincNitridingHVOF coatingDLC — corrosion 55, hardness 93DLC
02550751000255075100Corrosion protection (0–100)Surface hardness (HV, log scale, 0–100)Plating — 19 finishesHard coatings — 17 finishesAnodize & conversion — 8 finishesPaint & powder — 7 finishesType II anodize — corrosion 71, hardness 54BSA anodize — corrosion 71, hardness 52Type I anodize — corrosion 71, hardness 49Hard anodize — corrosion 71, hardness 61PTFE hard anodize — corrosion 71, hardness 61Nitriding — corrosion 55, hardness 73PEO — corrosion 70, hardness 74Sherardizing — corrosion 83, hardness 56Brass plate — corrosion 35, hardness 44Bronze plate — corrosion 40, hardness 49Cadmium plate — corrosion 70, hardness 26Copper plate — corrosion 32, hardness 39Decorative chrome — corrosion 64, hardness 71Electroless copper — corrosion 20, hardness 41Electroless nickel — corrosion 70, hardness 68Nickel plate — corrosion 51, hardness 55Gold plate — corrosion 68, hardness 39Hard chrome — corrosion 40, hardness 73Hot-dip zinc — corrosion 90, hardness 42Nickel-PTFE — corrosion 72, hardness 57Silver plate — corrosion 55, hardness 39Solder plate — corrosion 42, hardness 9Tin plate — corrosion 34, hardness 0Zinc plate — corrosion 60, hardness 30Zinc-nickel — corrosion 86, hardness 60Cerakote — corrosion 83, hardness 27E-coat — corrosion 83, hardness 15Epoxy coat — corrosion 83, hardness 15Powder coat — corrosion 83, hardness 14Wet paint — corrosion 59, hardness 10AlCrN PVD — corrosion 58, hardness 93AlTiN PVD — corrosion 52, hardness 94CrN PVD — corrosion 62, hardness 83MoS2 PVD — corrosion 20, hardness 26TiAlN PVD — corrosion 50, hardness 93TiCN PVD — corrosion 40, hardness 92TiB2 PVD — corrosion 40, hardness 94TiN PVD — corrosion 45, hardness 87WC/C PVD — corrosion 48, hardness 77ZrN PVD — corrosion 52, hardness 90CVD alumina — corrosion 70, hardness 85CVD TiCN — corrosion 38, hardness 92CVD TiN — corrosion 45, hardness 87Multilayer CVD — corrosion 62, hardness 88HVOF coating — corrosion 78, hardness 77Plasma spray — corrosion 60, hardness 68Plastic chrome — corrosion 72, hardness 71Electroless plastic — corrosion 58, hardness 39Clear coat — corrosion 20, hardness 12Soft-touch — corrosion 20, hardness 5PLATINGHARD COATINGSANODIZE & CONVERSIONPAINT & POWDERWC/C PVDMoS2 PVDPowder coatZinc plateDLC — corrosion 55, hardness 93DLC
Anodize & conversionPlatingPaint & powderHard coatings

Specifications for DLC

The documents a drawing cites to define this finish, with the Type / Class rows that apply. Each links to a page explaining the standard.

Drawing call-out

APPLY DLC (a-C:H) TO DESIGNATED SLIDING SURFACES, 2–3 µm TOTAL THICKNESS, HARDNESS 2000 HV MIN, DRY FRICTION 0.15 MAX AGAINST POLISHED STEEL; MAX SERVICE 300 °C; MASK FITS

Which materials take DLC?

Verdict per material family, with the grades that behave differently. Each family links to its datasheets in the material library.

Material familyVerdictNotes
Stainless Steel
YesSuitable with adhesion layers on hardened or work-hardened stainless.
Steel
YesHardened polished steel is preferred.
Titanium
YesCommon tribological and medical substrate after a qualified adhesion system.
Aluminum
LimitedLow-temperature cycle and adequate support hardness are required.
Brass
LimitedSoft zinc-bearing alloy; decorative PVD is possible, not a wear-tool substrate.
Copper Alloy
LimitedSoft copper alloys do not support a hard nitride; decorative films need a qualified adhesion layer.
Magnesium Alloy
NoMelting point and reactivity exclude conventional PVD tool-coating cycles.
Polymer
NoOrdinary functional DLC requires a conductive, load-bearing substrate.
Zinc Alloy
NoMelting point is below typical PVD process temperature.

How DLC is applied, and what it does to the part

  1. 1Polish and clean
  2. 2Ion etch
  3. 3Deposit adhesion and stress-control layers
  4. 4Deposit DLC
  5. 5Inspect adhesion, thickness, and tribology
DimensionsA 2 µm DLC film adds about 2 µm per side and 4 µm to an outside diameter.
Build-up per side1–3 µm — Allow full film thickness per coated side.
MaskingUsually needed. Mask fits, threads, electrical contacts, and bonding surfaces.
ElectricalSemi-conductive
Temperature limit350 °C (662 °F) continuous
AppearanceSmooth black to anthracite, from matte to glossy according to substrate polish.
Added lead time7–14 working days on top of the bare part

Design rules for DLC

What to decide on the drawing before the part goes to the finisher.

  1. Name the DLC family.a-C:H and ta-C have different properties.
  2. Use a hard polished substrate.DLC follows roughness and cannot bridge substrate deformation.
  3. Avoid unsupported sharp edges.Internal stress can promote chipping.
  4. Define counterface and lubrication.Friction values are system-specific.

DLC versus the alternatives

Finishes engineers weigh against DLC, and when each wins.

FinishCorrosionHardnessCosmeticCostThicknessChoose it when
DLC
this page
559372$$$$1–3 µm—
Tungsten Carbide Carbon PVD
DLC vs Tungsten Carbide Carbon PVD →
487750$$$$1–5 µma tougher tungsten-doped carbon system is preferred
Molybdenum Disulfide PVD
DLC vs Molybdenum Disulfide PVD →
202635$$$$1–3 µmlowest friction in high vacuum is primary
CorrosionHardnessCosmeticLubricityEconomy
DLCTungsten Carbide Carbon PVD

The radar overlays DLC with Tungsten Carbide Carbon PVD, its most common alternative — chosen a tougher tungsten-doped carbon system is preferred. Scores in the table are 0–100 across every finish in the catalog.

Cost, lead time and compliance

Relative cost

Diamond-Like Carbon Coating is a high-cost finish ($$$$): more expensive than about 98 % of the finishes FabDigit quotes.

Finishing is priced per part with a lot minimum, from FabDigit's own China-side rates cross-checked against US job-shop pricing. The exact figure appears on the instant quote once the part is uploaded.

Lead time and compliance

Added lead time7–14 working days
RoHSCompliant
NotesCarbon films are generally RoHS-compliant; medical use requires process-specific biocompatibility evidence.

What DLC is used for

  • Engine valve train parts
  • Medical instruments
  • Precision bearings
  • Injection mould components

DLC — frequently asked

How thick is DLC coating?

DLC is commonly 1–3 µm thick, often 1.5–3 µm. A 2 µm film adds 4 µm to a fully coated outside diameter.

How hard is DLC coating?

Typical engineering DLC spans about 2000–5000 HV. Exact hardness depends on whether it is hydrogenated DLC, ta-C, or a doped architecture.

What is the friction coefficient of DLC?

Dry values commonly fall around 0.05–0.15 against a suitable polished counterface. Load, humidity, lubricant, and DLC type must be stated.

What temperature can DLC withstand?

Many hydrogenated grades are limited to about 300–350 °C. Specialized hydrogen-free grades may differ and require supplier data.

Can aluminum be DLC coated?

Yes with low-temperature deposition and an adhesion system, but soft aluminum may not support the hard film. Hard anodize or a hardened interlayer may be needed.