Black Zinc Treatment and its Importance in Die Casting

Black zinc refers to a zinc plate treatment used in die casting that provides the product or component surface with aesthetic as well as functional qualities. It is a type of zinc plating intended to provide functional characteristics to a product or service such as resistance from corrosion or rust. There are different types of zinc plating such as zinc gold passivate, blue or clear zinc, and acid zinc. Each of this plating is used to provide a certain aesthetic and functional qualities to the components such as its color.

What is Black Zinc Treatment?

Black zinc treatment refers to the process by which the casted product or component is coated with a thick black phosphate. This will alter the color of the entire product and acts as a shield against humidity and corrosion. Black zinc treatment is carried out by first applying zinc plating and then subjecting it to black chromate conversion plating. This will result in the surface to appear uniform with a coating that confers numerous benefits to the product or component surface.

Different Methods of Black Zinc

Various methods are used to carry out black zinc in a product or component surface. Some of them are:

  • Zinc plating and black passivation – In this method, a zinc layer measuring about eight microns thick is deposited on the product or component surface by means of galvanizing. This is preceded by carrying out a black passivation on the zinc layer. The passivation process does not require considering any additional microns.
  • Zinc-iron plating and black or gray passivation – This method involves coating the first layer using an alloy of ZnFe. A black or gray passivation is performed on the product surface after this is done. An additional organic coating is also required for the black passivation to have more resistant features.
  • Zinc-nickel and black or gray passivation – The first layer of alloy used in this method is ZnNi.

Advantages of Black Zinc Treatment

Black zinc treatment has numerous advantages for the zinc die casting process. A key advantage is in the appearance of the product as it can provide a matte or shiny look. The finish will remain on the component surface permanently and stays even when certain abrasions occur.

Black zinc treatment has the advantage of providing additional protection to the product or components in the form of corrosion resistance, improved aesthetic appearance, and preventing abrasions. The components subjected to black zinc treatment will have better lubrication characteristics making it perfect for use in running parts.