AR-15 Finish and Coating Guide
Hardness, thickness, max operating temperature, salt spray resistance, and cost for every common AR-15 coating. Sourced from mil-spec documents, ASTM standards, and vendor technical data sheets.
Interactive Comparison
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| Coating▲ | Hardness | Max temp | Salt spray | Cost | Thickness | Lubricity | Colors | Standard |
|---|---|---|---|---|---|---|---|---|
| Cerakote (ceramic polymer) | 6H to 9H pencil hardness | 500 to 1800 F by series | 1,000 to 3,000+ hr | $$ | 25 microns typical | Moderate | Hundreds of colors | NIC Industries published data |
| DLC (Diamond-Like Carbon) | 2,000 to 9,000 HV | 650 F (a-C:H) | 500 to 1,000 hr | $$$$ | 1 to 5 microns | Extremely low friction (μ 0.05 to 0.10) | Deep black | ISO 20523 (a-C:H and ta-C variants) |
| Hard Chrome | 900 to 1,100 HV (66 to 72 HRC) | 800 F | 200 to 500 hr | $$ | 10 to 25 microns | Low friction (μ 0.16) | Bright silver | AMS-QQ-C-320B |
| Nickel Boron (NiB) | 800 to 900 HV (65 to 70 HRC) | 750 F | 350 to 500 hr | $$$ | 10 to 25 microns | Very low friction, self-lubricating | Silver/white | ASTM B607 (Ni-B electroless) |
| Nitride / Melonite / QPQ | 900 to 1,200 HV (65 to 72 HRC) | 1000 F | 500 to 1,000 hr | $$ | 10 to 30 micron diffusion layer | Low friction, very smooth | Satin black | Ferritic Nitrocarburizing (ASM HB Vol 4) |
| Phosphate (Manganese) | Substrate HRC (coating itself is soft) | 450 F | 96 to 200 hr (oiled) | $ (baseline) | 5 to 15 microns | Holds oil well, porous. Baseline friction. | Matte black/gray | MIL-DTL-16232 Type M Class 4 |
| TiN (Titanium Nitride) | 2,000 to 2,400 HV | 1100 F | varies by substrate | $$$ | 2 to 5 microns | Moderate (μ 0.4 to 0.5 dry, low wet) | Gold | PVD deposited (ISO 4957) |
| Type III Hard Anodize | 500 to 600 HV (60 to 70 HRC) | 2000 F (melts aluminum first) | 336 hr (MIL-A-8625 min) | $ | 25 to 50 microns | Moderate, porous dyes improve | Black (mil-spec), bronze, gray | MIL-A-8625 Type III Class 2 |
Hardness shown in Vickers (HV) where published; HRC equivalents provided. Salt spray tested per ASTM B117 neutral salt fog. Sources: MIL-DTL-16232, MIL-A-8625, AMS-QQ-C-320B, ASTM B607, ISO 20523, NIC Industries Cerakote product data sheets (H / C / Elite series), and Oerlikon Balzers / UCT published DLC and TiN data.
Coating Details
Mil-spec Phosphate (MIL-DTL-16232)
Heavy manganese phosphate conversion coating applied per MIL-DTL-16232 Type M Class 4. The coating itself is soft (around 250 HV) but its porous structure retains oil, which provides the actual corrosion and wear protection. Must be kept oiled to perform as rated.
Nitride / Melonite / QPQ (Ferritic Nitrocarburizing)
A thermochemical case-hardening process that diffuses nitrogen and carbon into the steel surface at roughly 1000 F. Not a coating in the traditional sense: it transforms the outer 10 to 30 microns of the substrate itself. Melonite and QPQ are branded versions of the same underlying process. Produces surface hardness of 900 to 1,200 HV with excellent corrosion resistance.
Nickel Boron (NiB)
Electroless nickel deposited with boron co-deposition per ASTM B607. Self-lubricating with friction coefficients around 0.05 to 0.08. Easy to clean because carbon fouling does not bond well to the surface. Bright silver appearance.
DLC (Diamond-Like Carbon)
PVD-deposited amorphous carbon coating. Two main variants: hydrogenated a-C:H (softer, cheaper, 2,000 to 3,500 HV) and tetrahedral ta-C (harder, up to 9,000 HV). Extremely low friction, excellent wear and corrosion resistance, but thin (1 to 5 microns) so substrate hardness matters.
TiN (Titanium Nitride)
Gold-colored PVD ceramic coating, around 2,000 to 2,400 HV. Common on drill bits and BCGs. Handles high temperatures well but dry friction is higher than DLC or NiB. Best used with proper lubrication.
Cerakote (ceramic polymer)
A thin-film ceramic-filled polymer finish from NIC Industries. Typically 25 microns thick, pencil hardness 6H to 9H depending on series (H Series, C Series, Elite Series). Max temp ranges from around 500 F up to 1800 F for high-temp series. Available in hundreds of colors. Sacrifices intrinsic surface hardness for aesthetics and corrosion resistance.
Hard Chrome
Electroplated chromium per AMS-QQ-C-320B. Used on mil-spec barrel bores (MIL-B-11595E) and occasionally BCGs. 900 to 1,100 HV, good corrosion resistance, classic bright silver appearance. Cracks under extreme heat cycling, which is why it is rarely used on external BCG surfaces anymore.
Type III Hard Anodize (MIL-A-8625)
The only option on this list for aluminum receivers. Grows an integral aluminum oxide layer 25 to 50 microns thick, with a hardness approaching glass. Class 2 (dyed black) is the mil-spec choice. Must meet 336 hour salt spray per ASTM B117 and abrasion resistance per Taber test.
Disclaimer: Specifications are sourced from published military technical data packages, SAAMI standards, and manufacturer data sheets. Always verify critical dimensions with calibrated measuring tools.