Pre-treatment and electroless Ni–P deposition for surface-modification of tungsten fibres

Abstract

In order to improve the surface activity of tungsten fibres (W_f) for subsequent sintering with adjacent powders of W and Cu, autocatalytic Ni–P coatings on W_f were fabricated via electroless deposition in this work. Before electroless deposition, optimal pre-treatment of W_f was determined to increase their surface activity without destroying their internal structure. Afterwards, the deposition rate, microstructure and phase constituents of the plated Ni–P coatings at bath pH values of 5, 6, 7, 8 and 9 were studied systematically. SEM observations showed the presence of uniform and compact grains in the coating and XRD analysis revealed their amorphous or partially crystalline structure. Further sintering of W_f with powders of W and Cu demonstrated the superior interfacial bonding state due to the Ni–P coatings on the W_f surface.

Keywords:

• Electroless deposition
• Ni–P
• W–Cu alloys
• tungsten fibres
• Interface

Acknowledgements

The authors would like to acknowledge the financial support of the National Natural Science Foundation of China (51371139 and 51604223), 863 Program (2015AA034304), the Science and Technique Innovation Program of Shaanxi Province (2012KTCQ01-14), the Pivot Innovation Team of Shaanxi Electric Materials and the Infiltration Technique (2012KCT-25), the Science and Technology Project of Shaanxi Province (2016JQ5025), Key Laboratory Foundation of Shaanxi Provincial Department of Education (16JS064) and Shaanxi Provincial Project of Special Foundation of Key Disciplines for this research.