Black Oxide + Oil
Finish
Deep Matte Black
Effect
1045 Steel
Material
System upgrade reminder, Homepage update.
Xmake provides black oxide finishing for CNC machined steel, stainless steel, and copper parts. The coating adds less than 1 μm to the surface, preserving your original tolerances while delivering a uniform matte black appearance - from single prototypes to production volumes.
Function
Applicable Materials
Coating Thickness
Dimensional Change
Color
Post-Treatment
Masking
Black oxide is a chemical conversion coating that reacts with the metal surface to form a thin layer of black iron oxide (Fe₃O₄). Unlike paint or plating, it becomes part of the metal itself - it will not chip, peel, or flake. The coating adds less than 1 μm to the surface, so it preserves the part's original dimensions and tight tolerances. This makes black oxide one of the few finishing options that will not affect fit or function on precision CNC components.
On its own, black oxide provides mild corrosion resistance. For better protection, we apply an oil, wax, or lacquer sealant after coating. The sealed finish also reduces friction and eliminates light reflection, which is why it is widely used on tooling, firearms components, fasteners, and optical equipment.
Tip: Black oxide does not build up on the surface like plating or paint - no masking is needed for most precision features. If specific areas must remain completely untreated, mark them on your drawing.
We blacken steel, stainless steel, and copper alloys. Black oxide is not suitable for aluminum - for a black finish on aluminum, consider black anodizing.
Carbon Steel / Alloy Steel
Applications
Fasteners · Shafts · Gears · Tooling · Brackets
Notes: The most common substrate for black oxide. Produces a deep, uniform black finish.
Carbon Steel / Alloy Steel
Applications
Fasteners · Shafts · Gears · Tooling · Brackets
Notes: The most common substrate for black oxide. Produces a deep, uniform black finish.
Before and after comparison of our black oxide work on real parts.
All three produce a black finish, but they work differently and suit different applications.
| Feature | Black Oxide | Black Anodizing | Black Powder Coating |
|---|---|---|---|
| Substrate | Steel · Stainless steel · Copper | Aluminum only | Most metals |
| Thickness | Less than 1 μm | 5-25 μm | 60-120 μm |
| Dimensional Impact | Virtually zero | Minimal | Moderate |
| Corrosion Resistance | Mild (improved with sealant) | Good to excellent | Excellent |
| Hardness | No change | Up to 600 HV (Type III) | Low-moderate |
| Appearance | Matte black · Non-reflective | Matte or satin black | Matte or gloss black |
| Cost | Lowest | Moderate | Moderate |
| Best For | Precision steel parts · Tooling · Fasteners | Aluminum housings · Consumer products | Outdoor enclosures · Industrial parts |
Choose black oxide when you need a black finish on steel parts without affecting dimensions or tolerances. Choose black anodizing for aluminum parts. Choose black powder coating when maximum corrosion protection matters more than dimensional precision.
Contact usXmake integrates black oxide finishing with CNC machining and other surface treatments in one streamlined workflow.
Black oxide adds less than 1 μm. Your CNC tolerances stay intact, and we inspect critical dimensions before and after coating to confirm conformance.
Parts move directly from machining to black oxide on a coordinated schedule, with turnaround as fast as 5 business days.
400+ CNC machines with integrated finishing capabilities, managed under ISO 9001 and ISO 13485 standards. NDA available upon request.
400+
CNC Machines
ISO 9001
Certified
27+
Years Experience
100%
Inspection Coverage
Have more questions? Our engineering team is ready to help.
Building A, Jinsheng Finance Building, No. 217 Nanhuan Road, Bao'an District.
MAKE DIRECT HOLDINGS LIMITED Unit 1111, 11/F, Hollywood Plaza, 610 Nathan Road, Mong Kok, Kowloon, Hong Kong