Cross-group finish comparison
Diamond-Like Carbon Coating vs Nitriding and QPQ
Diamond-Like Carbon Coating (pvd hard coatings) and Nitriding and QPQ (anodizing & conversion coatings) solve the same problem by different routes; dLC is the harder surface (2,000–5,000 HV vs 700–1,200 HV).
Diamond-Like Carbon Coating
PVD hard coatings · $$$$ · instant quote
DLC is a family of black amorphous-carbon coatings used for very low friction and severe sliding wear.
Nitriding and QPQ
Anodizing & conversion coatings · $$$$
Nitriding diffuses nitrogen into steel to create a hard wear-resistant case without depositing a conventional coating.
When to choose which
Choose DLC
Choose DLC when lower friction with only micrometre buildup is required.
- About 2000–5000 HV hardness
- Dry friction commonly 0.05–0.15
- Only 1–3 µm thick
Choose Nitriding
Nitriding is the pick when its strengths below matter more than DLC's.
- Surface hardness commonly 700–1200 HV
- Case depth about 0.1–0.7 mm
- Low distortion compared with carburizing
What the numbers say
- DLC is the harder surface (2,000–5,000 HV vs 700–1,200 HV).
- Nitriding is the lower-cost option ($$$$).
- DLC is the thinner coating (1–3 µm), so it disturbs tight fits less.
- DLC is semi-conductive; Nitriding is unchanged.
- Nitriding tolerates more heat (500 °C continuous).
Scores side by side
Each score is 0–100 against every finish in this catalog. Corrosion is derived from salt-spray test duration and surface hardness from the finish layer's Vickers hardness where a measured figure exists; a finish that leaves the base metal's own surface is not rated for hardness. Cosmetic, lubricity and cost are FabDigit's engineering assessment. Scores and typical figures are screening data, not matched side-by-side tests or service-life rankings; ASTM B117 is a controlled salt-fog method, not a field-life prediction.
| Score | DLC | Nitriding |
|---|---|---|
| Corrosion resistance | 55 Good | 55 Good |
| Surface hardness / wear | 93 Excellent | 73 Very good |
| Cosmetic quality | 72 Very good | 55 Good |
| Lubricity | 96 Excellent | 58 Good |
| Cost | 96 $$$$ | 72 $$$$ |
Key numbers
| Property | DLC | Nitriding |
|---|---|---|
| Thickness | 1–3 µm | 5–20 µm |
| Surface hardness | 2,000–5,000 HV | 700–1,200 HV |
| Max service temperature | 350 °C | 500 °C |
| Electrical | Semi-conductive | Unchanged |
| Colours | black, anthracite | silver-grey, black QPQ |
| Relative cost | High ($$$$) | High ($$$$) |
| Added lead time | 7–14 working days | 7–15 working days |
| RoHS | Compliant | Compliant |
| Instant quote | Yes | On request |
Bold marks the side that is ahead on a row where more (or less, for cost and lead time) is better. Ranges are the typical specification window; the drawing call-out fixes the class.
Which materials take each finish
| Material family | DLC | Nitriding |
|---|---|---|
| Stainless Steel | Yes | With care |
| Steel | Yes | Yes |
| Titanium | Yes | Limited |
| DMLS / SLM | — | With care |
| Aluminum | Limited | No |
| Brass | Limited | No |
| Copper Alloy | Limited | No |
DLC vs Nitriding — frequently asked
What is the difference between DLC and Nitriding?
Diamond-Like Carbon Coating (pvd hard coatings) and Nitriding and QPQ (anodizing & conversion coatings) solve the same problem by different routes; dLC is the harder surface (2,000–5,000 HV vs 700–1,200 HV). Nitriding is the lower-cost option ($$$$). DLC is the thinner coating (1–3 µm), so it disturbs tight fits less.
When should I use DLC instead of Nitriding?
Choose DLC when lower friction with only micrometre buildup is required.
Is DLC or Nitriding cheaper?
Nitriding is the lower-cost finish ($$$$ against $$$$ for DLC) among the finishes FabDigit quotes. Both are priced per part with a lot minimum; the exact figure appears on the instant quote once the part is uploaded.