Thermodiffusion zinc-plating
The thermodiffusion zinc (TDZ) coating which is deposited in powder mixtures can be used for protection of steel products, tubes and fasteners from corrosion in the atmosphere and corrosive media and for improvement of exploitation parameters of parts.
The method for TDZ coating deposition is virtually waste-free and provides a uniform coating on the whole surface of products. The coating is rough and is light-gray. It consists mainly of the iron-zinc d-phase containing 7 to 10% of iron. The corrosion resistance is 2-4 times higher than that of galvanized and hot-dip galvanized coatings.
The technology is characterized by the following parameters:
- the coating is deposited on products made of common-quality carbon steel, quality constructional carbon steel, low-alloyed steel or cast iron;
- the plating time necessary to obtain a layer 15-30 mm thick is 1 hour at temperatures 390-4300С;
- the corrosion resistance of zinc-plated products with thickness of 30 mm is 25 years;
- thermodiffusion plating of products is implemented into periodic action installations under industrial conditions.
Advantages:
- The use of a superfine zinc powder for thermodiffusion zinc-plating of threaded parts improves the quality of galvanization and allows decreasing the consumption of the zinc powder (as compared to the consumption of ПЦ-1 – ПЦ-4 zinc powders).
- Raw materials are used in a closed cycle. Free of gas and dust emissions into atmosphere.
- With respect to the relevant British standard, the technology provides a 2-fold reduction in the consumption of the zinc powder for coatings 30 mm thick.
