Corrosion Resistance of Zinc Plating

 

Zinc Electroplating offers a low cost but highly effective way in which to protect ferrous metals against a range of Corrosion sources. So what is Zinc, what can it be used for?

 

What is Zinc?

 

Zinc is a naturally occurring element that is abundant in the earth’s crust and is the 4th most widely consumed metal in the world. Zinc in its metallic state has been produced since the 13th century, but today is most popular for use in metal finishing.

 

What Can It Be Used For?

 

If you’ve ever seen a rusty gate, you’ve seen the effects of Oxidation. When Iron reacts with oxygen it forms Hydrated Iron Oxide which we see as rust, this is a corrosive substance that will deteriorate the metal given time. Zinc Plating offers a good level of corrosion resistance to combat the effects of oxygen and moisture. When we refer to Zinc Plating we are actually referring to two processes that work together; Zinc Plating and Passivation.

 

Zinc Plating is an electro-plating technique in which components are placed into a vat containing an electrolytic solution, and a current is run into the bath promoting the build-up of Zinc onto the part. You cannot however simply add Zinc onto your part to protect it. Zinc reacts with Oxygen to form Zinc Oxide, which is soft and porous and would do nothing to protect the component. In order to be effective the component is Passivated after plating. This Passivation process converts the surface of the part into a complex mixture of Chromium compounds which will oxidise into a barrier layer. When coupled with the Zinc this provides the desirable corrosion and wear protection. In essence the Zinc protects the base metal, and the Passivation protects the Zinc.

 

Zinc Plating provides a good level of protection against oxidation and low levels of abrasion, but will not perform well in chemically corrosive or high wear environments. It is sacrificial in nature, Zinc is less noble and more active than Iron and so dissolves in an anodic reaction. The electrons given up by the dissolved Zinc flow to the protected part, acting as a cathode and preventing its corrosion.

 

What Silchrome Offer

 

Silchrome Plating offer Zinc Plating with a range of passivated finishes including, Clear, Yellow, Black,Oliver Drab and Trivalent. We are fully ISO 9001 and 14001 certified and carry out a wide range of metal finishing processes all from our modern facility in Leeds.