Example of a black oxide part
Black oxidation treatment is a commonly used method of chemical surface treatment. Its principle is to form an oxide film on the metal surface to isolate it from air and achieve the purpose of rust prevention. When the appearance requirements are not high, blackening treatment can be adopted. The blackening treatment of the surface of steel parts is also called bluing. Black oxidation treatment, as it can eliminate reflection, refers to a commonly used surface coating treatment method.
| Surface preparation | Colors | Applicable materials | Cosmetic availability | Thickness** Visual appearance |
| As machined (Ra 3.2μm / Ra 126μin) | Steel,Stainless Steel, Copper | Steel,Stainless Steel, Copper | No | 0-30um/0-1181μin Smooth black matte |
To enhance the anti-rust ability of steel parts, a strong oxidant is used to oxidize the surface of the steel parts into a dense and smooth form of iron (III) oxide. This thin layer of iron (III) oxide can effectively protect the interior of steel parts from oxidation. The iron (III) oxide oxidized at high temperatures (about 550℃) appears sky blue, thus it is called bluing treatment. Iron (III) oxide formed at low temperatures (about 350 ℃) appears dark black, thus it is called blackening treatment. In industrial production, blackening treatment is commonly used.
Black oxide is a conversion coating, compatible with steel, stainless steel and copper, that provides a black appearance and mildly improves resistance to corrosion of parts.
run parts through machining and deburring.
Clean parts using alkaline solutions.
Rinse in water.
Black oxidizing. Immerse the part in the hot (135-145oC) alkaline bath for a period of 5 to 40 minutes depending on the size of the part
Rinse in water Seal the oxide surface with oil, lacquer or wax.
This imparts the desired aesthetic appearance and improves the corrosion resistance of the component.
The process of black iron oxide forming ferrous metals and other types of materials is often called black oxides. The ferrous oxide process is a chemical conversion coating for ferrous metal materials, stainless steel, copper and copper-based alloys, zinc, powder metals and silver solder. This is done to improve corrosion resistance, enhance appearance and minimize light reflection.
Black oxidation coatings, also known as blackening treatment, are ideal for coating iron materials, stainless steel, copper-based alloys, copper, zinc and silver solder. It imparts corrosion resistance to metals, reduces light reflections, and improves aesthetics. Unlike black anodizing, black oxidation coatings form coatings on the material through chemical conversion. Depending on the temperature used, there are three methods for black oxidation coating: high temperature, medium temperature and low temperature. Black anodization, on the other hand, is an electrochemical process that helps improve the aesthetics and durability of aluminum.
After the CNC is processed, it generally needs to be surface-treated to enhance certain features of the parts, such as functionality, corrosion resistance, or brightly colored appearance;
Common surface treatment processes for CNC machining parts:
Anodizing
Electroplating Normal plating Galvanized Tin plating Copper plating Nickel plating Chrome blue/black Phosphate Passivation
Sandblasting
Powder spraying
polishing
Silk printing
Laser marking
Brushed
Paint, etc.
We usually define surface treatment requirements based on different material properties.