1. Hot galvanizing
, also known as hot-dip galvanizing and hot-dip zinc, is an effective metal corrosion protection, mainly used in various of metal structures. Dip the rust steel in the 500 degrees melting zinc solution, so that the steel surface can attach to the zinc layer, which achieves the purpose of anti-corrosion.
2. Cold galvanizing
Cold galvanizing, also called electro-galvanizing, electrolysis equipment will be put in zinc salt solution after degreasing, pickling, and connect the negative electrolytic equipment, place zinc plate in the opposite of pipe fitting, connect to the positive pole. Make use of the current that moves from the positive pole to the negative pole. The layer of zinc will deposit on the tube. The cold-plated pipe is galvanized after processing.
3. Weak acid potassium chloride galvanizing
Advantages: no cyanide, simple composition, stable, low cost, high current efficiency, saving energy, fast deposition speed, high production efficiency, suitable for cast iron parts, high carbon steel parts. The coating is bright, delicate and smooth.
Disadvantages: galvanizing solution can corrode steel equipment.
4. Cyanide galvanizing
Advantages: fine crystal coating, good capability of dispersion and cover, no corrosion to steel equipment.
Disadvantages: galvanizing solution contains highly toxic cyanide, the waste water and waste gas are harmful to the environment, corrosive to steel equipment.
5. Alkaline zincate galvanizing
Advantages: no cyanide, no corrosion to steel equipment, passivation film is not easy to get black in hot and humid atmosphere.
Disadvantages: inferior to zinc cyanide galvanizing compared to the coating of binding force and brittleness.
6. Sulfate galvanizing
Advantages: low cost, stable plating, high current efficiency, high allowable cathode current density, high deposition rate.
Disadvantages: inferior capability of plating, the coating is thicker, only for the simple shape of the parts, corrosive to steel equipment.
Zinc coating can greatly improve its protective and decorative performance by passive treatment, dyeing or coating protective agent. In recent years, with the development of galvanizing process, galvanizing has entered the protective and decorative applications from the simple protection.