What are the different types of Phosphating processes?

The phosphating process is implemented for converting a steel surface into iron phosphate, which is a pretreatment method merged with another method for corrosion protection. The phosphate coating generally involves iron, zinc, or manganese crystals. Phosphating is typically applied to cast iron, carbon steel, and low-alloy steel. This coating is mainly prepared with a solution of iron, manganese, or zinc phosphate salts in phosphoric acid.

Then it is applied by either dipping the substrate into the solution or by spraying it onto the substrate. As the iron or steel parts are put in the phosphoric acid, the reaction causes hydronium ion to deplete, and the pH range rises, causing the salt to dissolve and fall out of the solution and get precipitated on the surface. The process is also known as phosphate conversion coating or phosphating. Here is an elaborative detail about different types of phosphating.

·         Iron Phosphating

Iron Phosphating offers an increase in paint adherence and resistance impact to protect against oxidation. Since this phosphating offers the least corrosion resistance, it is available at a low cost in the market. This is most often used in indoor equipment which is not subjected to a high level of wear and corrosion. The deposition colour can range from pale blue to grey according to the weight ranging from light to heavy.

·         Manganese phosphating

The manganese phosphating process is known to be the most absorbent of all other phosphating. One of the most general applications of Manganese phosphating is serving as an undercoat for paints and lubricants. This phosphating solution is abundantly used for preventing metal-on-metal contact.

Although this process offers high wear resistance, it does not offer higher corrosion resistance than zinc phosphating. The process helps with preventing galling without affecting the coating. Thus, it is highly utilised in the automotive industry. Manganese phosphate’s colour is generally dark grey, almost similar to black.

·         Zinc Phosphating

The most preferred choice of coating for resisting corrosion of ferrous metals would be zinc phosphating, which is suitable for tough weather applications. Zinc phosphating is also profusely used in the automotive industry, just as manganese. The zinc phosphating process can increase lubricity and act as a carrier for oils, paint, or waxes. It can come in a dark shade of grey; however, it can be dyed to make a matte black finish.

Even though there are different types of phosphate treatment temperatures available on the market, the most promising process would be medium-temperature phosphating. They are highly applicable for large-area applications. If you are looking for a quality phosphating solution for any specific use, find the suitable ones in the collection of A-Gas Electronic Materials at an affordable price range.