Surface Morphology and Wear Behaviour of Chromium Coatings Produced by DC and Pulse Electroplating

Pulse plating processes are widely used in a variety of industrial applications to improve corrosion resistance and mechanical properties of metals and alloys surfaces. In this study chromium plate is deposited on the surface of a st37 steel plate from a standard chromium plating bath using direct and pulse current electroplating method. Among different pulse parameters, duty cycle was optimized to obtain better properties. Surface morphology and coating thickness were investigated using scanning electron and optical microscopes. Wear properties and friction coefficient were investigated using a pin-on-plate reciprocating wear machine. The results showed that the crystal growth and grain size significantly depend on the duty cycle and on/off time ratio. Decreasing duty cycle, cause to uniform and fine grain size, increased resistant to wear and changing morphology of the coating from needle like to cubic structure.