Dalian Blackening Surface Treatment Technology - Introduction to Phosphatization

Dalian blackening surface treatment technology. If the steel surface is coated without treatment, the oxide skin, rust, or grease inside the coating will be covered up by the coating, and soon the coating will fall off, causing the sold products to show a rusty appearance and lose their competitiveness in the market. Therefore, the necessity of pre-treatment on the steel surface has attracted the attention of many enterprises.

A basic principle is that phosphating is relatively cheaper than galvanizing, but its corrosion resistance is worse than galvanizing. After phosphating, oil should be applied, and its corrosion resistance is closely related to the performance of the oil applied. For example, after phosphating, applying a general anti rust oil and conducting a neutral salt spray test for only 10-20 hours. Applying high-grade anti rust oil can take up to 72-96 hours. But its price is 2-3 times that of general phosphating oil.

Dalian Blackening Surface Treatment Technology - Introduction to Phosphatization

Phosphatization is a process of chemical and electrochemical reactions to form a phosphate chemical conversion film, which is called a phosphating film.

The main purpose of phosphating is to provide protection for the base metal and to some extent prevent metal corrosion; Used for priming before painting to improve the adhesion and corrosion resistance of the paint film layer; Used for friction reduction and lubrication in metal cold working processes. The application of phosphating treatment technology in industry has a history of over 90 years, which can be roughly divided into three periods: the period of laying the foundation of phosphating technology, the period of rapid development of phosphating technology, and the period of widespread application.

There are two commonly used types of phosphating for fasteners, zinc based phosphating and manganese based phosphating. Zinc based phosphating has better lubrication performance than manganese based phosphating, and manganese based phosphating has better corrosion resistance and wear resistance than zinc plating. It can be used at temperatures ranging from 225 to 400 degrees Fahrenheit (107-204 ℃). Especially for the connection of some important components. For example, connecting rod bolts and nuts of the engine, cylinder head, main bearings, flywheel bolts, wheel bolts and nuts, etc.

The main application of surface alloying technology in mechanical manufacturing is the surface alloying layer or infiltration layer of aluminum, chromium, silicon, vanadium, zinc, etc. The infiltration layer is formed by a chemical reaction between metal halide vapor and the metal surface layer, or by a chemical reaction in the liquid phase.