The bright black treatment on the surface of 304 stainless steel can be achieved through various methods, including chemical oxidation, electrolytic oxidation, physical vapor deposition, and chemical black nickel plating. These methods each have their own advantages and disadvantages, and the selection should be based on a comprehensive consideration of usage requirements, costs, and production scale.
1.Nature And Human HeaChemical oxidation method
- Principle: A black oxide film is generated on the surface of stainless steel through a chemical reaction. It is generally achieved by using oxidants to undergo oxidation-reduction reactions with metal elements on the surface of stainless steel, forming stable black oxides on the metal surface.
- Operation process: Pre treat the surface of stainless steel (remove oil and rust), then immerse the workpiece in a prepared oxidation solution and perform oxidation reaction under certain temperature and time conditions. Finally, perform post-treatment such as cleaning and passivation.
- Advantages: Simple operation, low cost, able to handle complex shaped workpieces, obtain uniform black appearance, and the oxide film has certain corrosion resistance and wear resistance.
- Disadvantages: The thickness of the oxide film is limited, and the wear resistance and corrosion resistance are relatively limited
2.Electrolytic oxidation method
- Principle: Stainless steel workpieces are used as anodes, placed in a specific electrolyte, and subjected to an external current to cause oxidation reactions on the surface of the stainless steel, forming a black oxide film.
- Operation process: After pre-treatment of the stainless steel surface, place it in an electrolytic cell, apply a certain voltage and current density, and control the electrolysis time and temperature. After electrolysis, post-treatment such as cleaning and passivation should be carried out.
- Advantages: It can accurately control the thickness and properties of the oxide film, with strong adhesion between the oxide film and the substrate, and good corrosion resistance, wear resistance, and heat resistance.
- Disadvantages: Complex operation and high cost
3.Physical vapor deposition and chemical black nickel plating method
- Physical vapor deposition: Deposition of a black metal or ceramic film on the surface of stainless steel using physical vapor deposition technology.
- Chemical black nickel plating method: a layer of black nickel is deposited on the surface of stainless steel through a chemical reaction.
- Advantages: It can achieve a uniform black appearance and has good corrosion resistance and wear resistance.
- Disadvantages: Complex operation and high cost