WHAT IS ZINC PLATING?
Zinc: The Greener Solution
According to NASA, the cost of corrosion-related losses to United States industries totals approximately $276 billion dollars annually. For decades, the preferred solution for these costs was cadmium electroplating. As it turns out, cadmium is a highly toxic material that has adverse effects on the environment, humans, and other animals. To combat this, zinc was used to replace cadmium and its use became widespread in the 1980s.
The Zinc Plating Process
A TSP employee operating the bead blaster.
"Rack #5" where parts are racked to be plated.
These parts have been plated, cleaned, and are ready for shipment.
Parts received must be thoroughly cleaned before plating to ensure the zinc can properly adhere to the surface. Some parts require bead blasting, a process that projects fine glass beads against the metal in order to give a more uniform finish without compromising the dimensions of the part. We also use an alkaline detergent to clean the surface of the part before "pickling" the part in an acid bath to remove any surface rust.
The part then goes into a zinc electrolyte solution. This solution contains a zinc metal ionic solution and other chemicals to assist the zinc with adhesion. We use an acid zinc solution because it provides a higher covering ability, higher efficiency, and faster deposition rate when compared to its alkaline counterpart.
Depending on the size and the shape of the part, it may be plated by using either barrel plating or rack plating. The chemical process remains the same for both methods, but one may be chosen over the other to enable the geometry of the part to work with the solution to produce the most evenly-coated product possible.
The process of electroplating (or electrodeposition) is the use of an electrical current to deposit metal ions on a surface. The metal part is used as the cathode while a direct current originating at the zinc (the anode in our case) flows through the solution, onto the part, and back to the anode to complete the circuit. This is the step in which your part actually gets plated.
Chromate is used to give the zinc (and your part) extra protection as well as give the metal a shiny, more impressive finish.
Upon customer request, your part is treated with an organic chemical sealer that protects your part even more. The addition of chromate and sealer does not add any dimension to the part.
After plating, the parts are rinsed thoroughly to remove any contaminants, then dried before being packed for shipping.
Additional Benefits When Choosing Zinc
- Inexpensive - When compared to
- Increased Strength of Material - Although lightweight and applied as a thin coating, zinc does slightly increase the strength of the part.
- Range of Application and Aesthetics - Zinc can be used to in a wide range of chemical baths, giving the customer a good selection of options when it comes to the look of the finished part. Additionally, with the use of barrel and rack plating, zinc can be used in a great range of applications.
- The Green Solution - As outlined above, zinc is the safer choice when it comes to our loved ones and the environment.