Electroless Ni-P coating on W-Cu alloy via potential activation process

摘要

Electroless Ni-P coating was deposited on W-Cu alloy via potential activation at -0.8 V. The coating was characterised for its morphology, structure, microhardness and the corrosion resistance. Scanning electron microscopy observation showed the presence of smooth and compact crystals in the coating. X-ray diffraction analysis showed that the Ni-P coating was amorphous in structure. The adhesion between Ni-P coating and W-Cu alloy was qualified. Heat treatment can improve the microhardness of Ni-P coating. Both the porosity test and immersion test in 10 vol.- percent H_2SO_4 solution revealed that the Ni-P coating exhibited good corrosion resistance properties in protecting the W-Cu alloy.