Ni-B_4C复合镀层的氩气保护预热处理

Study on Argon Protecting Pre-treatment for Ni-B_4C Electrocomposite Plating Parts

经过氩气保护预热处理，Ni-B4C复合镀层在800℃下抗高温氧化的能力较未经预热处理的镀层强。预热处理可使镀层B4C颗粒发生分解，并促使B元素向镀层表面扩散，生成富集于镀层外侧的新相Ni3B，并呈“岛状”分布。在高温氧化过程中，新相Ni3B优先转化为Ni3B2O6。未经预热处理的镀层，表面氧化膜则为NiO和NiaB2O6的多相结构。均相的Ni3B2O6。氧化膜要比多相的NiO和Ni3B2O6。的致密性好，能更有效地防止或延缓高温下氧对金属Ni的侵蚀，因此经预热处理镀层的抗氧化能力必然优于未经预热处理的镀层。

By pre-treating at 900℃ in argon atmosphere,Ni-B4C Composite plating had better characteristics ofanti-oxidation than that of the plating without pre-treatment. The pre-treatment promoted the dissociation of B4Cparticles in the plating and made B element diffused toward the surface of the plating, then formed new phaseNi3B' The new phase gathered at the surface of the plating, presented in island-like distribution. In the process ofhigh temperature oxidation, first of all, Ni3B was transformed into Ni3B2O6 But without the pre-treatment, theoxidation film of the surface is multiphase construction,which was formed by NiO and Ni3B2O6. Comparatively,the homogeneous phase film of Ni3B2O6 has better compact features and more effectively corrosion resistance ofNi against oxygen in high temperature than that of the multiphase of NiO and Ni3B2O6.