The most extensively used corrosion resistant finish, zinc plating has for many years been the most cost effective method of protecting steel components. It gives a sacrificial protection to the base material which means that it will corrode in preference to the ferrous substrate. As this happens the zinc will form a layer of white zinc oxide powder and it is not until all the zinc has been converted to this powder that red rust will appear.

At E C Williams we have extensive barrel and jig facilities for zinc plating. Our plant sizes are such that we can process very small batches right up to tons per week. Our jig department specialises in high tolerance precision engineered parts.

To further enhance the protection offered by zinc plating it is usual to passivate the zinc. This passivate film protects the zinc from corroding which itself protects the base metal from rusting. There are many various passivates available, some of which will contain hexavalent chromium which is a banned substance under the EEC End of Life Vehicle directive and the Waste Electrical and Electronic Equipment directive.

The relative corrosion performance is assessed using a Neutral Salt Spray Test (ASTM B117) and typical results for an 8µms deposit are as follows:

A colour dye can be added to some of these passivates to further extend the range of colours for additional identification purposes.

Corrosion resistance can be further enhanced by the use of an additional leach and seal process JS500.

During electroplating, hydrogen is evolved at the surface of the components and can embrittle hardened steel components. To counteract this we offer a de-embrittling service.