Electrodeposition and properties of an amorphous Ni-W-B alloy before and after heat treatment

Abstract

To strengthen the properties of Ni-W alloy, dimethylamine borane (DMAB) was added to an alloy Ni-W electrolyte solution and a ternary Ni-W-B alloy was electrodeposited. The electrodeposition, crystallographic structure, surface morphology, heat treatment and corrosion resistance, of the alloy were studied by DSC, XRD, SEM and electrochemical techniques. The results showed that the structure of the alloy was greatly affected by the cooperation of boron compound. DSC experiment combined with X-ray diffractometry indicated that the obtained Ni-W-B alloy was still in amorphous structure although W content in the alloy was decreased by the addition of DMAB. After heat treatment at 400 degrees C for 1 h, the microhardness was increased from 612 to 947 kg*mm(-2) that was comparative to Cr coating. The appearance of the as-plated coating was in fine and slice grains and kept almost no change after heat treatment. In w=0.03 NaCl solution the as-plated coating presented very good corrosion resistance. After the coating was heat-treated its corrosion resistance was enhanced.