Zinc Barrel Electroplating (Trivalent)
Process
Zinc Barrel Electroplating is the electrodeposition of dissolved zinc onto the surface of metal parts. This process uses a cathode (the metal part) and anode (the zinc to be deposited on the parts) and the reaction takes place by the connection of both to an external supply of direct current (the rectifier). The rate at which the anode is dissolved is equal to the rate at which the cathode is plated. The solution in which the reaction takes place consists of a controlled mixture of zinc chloride, potassium chloride, boric acid; a zinc carrier and zinc brightener.
The process is called acid zinc electroplating
Prior to electroplating the metal parts are cleaned in an electrically charged alkaline washing solution; a second still washing solution and immersed in a weak solution of hydrochloric acid to remove any residues of surface contaminants and prepare the work for the electroplating process. The cleanliness of the surfaces of the components to be plated is a key determinant in the quality of the finished product. An inhibitor is used in the hydrochloric solution to minimise the risk of hydrogen entering the surface of the metal.
Following electroplating the components are dipped into trivalent chromate solutions with an end colour of clear (silver) or yellow (gold). Black trivalent chromating is carried out in a separate process off line.
Processing Equipment
At AMTS we have a six barrel capacity integrated electroplating line with an overhead gantry. All process information is held in our ITMS job information system to ensure product repeatability. All process information for each individual job is logged for traceability through both the electroplating line and hydrogen de-embrittlement oven
Quality Assurance & Customer Service
Our processes are accredited to General Motors Worldwide Standard GMW3044 and Ford CQ-11.
Plating depths are checked and regular salt spray checks confirm the salt spray requirements. Our process regularly achieves 120 hrs salt spray to white rust and 240 hrs to red rust minimum.