Nickel–tungsten alloy brush plating for engineering applications
Nickel–tungsten alloy brush plating for engineering applications
复制标题
DOI：
10.1016/j.surfcoat.2013.12.059
复制
发表时间：
2014-02
影响因子：
5.4
通讯作者：
Z. Zhong;S. Clouser
中科院分区：
文献类型：
--
作者：
Z. Zhong;S. Clouser
硬涂层可以改善材料的表面性能，超过基材的能力。长期以来，由于提高了耐磨性，硬镍、硬铬、硬质合金和硬质复合材料等涂层被开发用于工程应用。新开发的镍钨电刷镀工艺具有替代电镀硬铬的工程应用潜力，镍钨电刷镀液是基于氨性柠檬酸盐镀液，可以像刷镀其他金属或合金一样方便地进行刷镀。另一方面，硬铬由于暴露在超过职业安全与健康管理局（OSHA）限制的有害六价铬中而无法刷镀。镍钨合金镀层已被开发用于工程应用。它具有纳米晶结构（约2 nm微晶尺寸），具有优异的硬度和耐磨性。涂层是60%的镍，40%的钨重量。由于合金中钨含量高，因此具有热稳定性。适度升高的温度（200-500 °C）不会像大多数其他硬质涂层（如硬铬、镍磷）那样导致晶粒尺寸增长和软化。实际上，镍钨合金涂层可以通过暴露在200-500 °C的高温下短时间进一步硬化。除了硬度和磨损性能外，还通过XRD、电子和光学显微镜、氢脆、盐雾腐蚀、摩擦学、轴向疲劳和其他测试对涂层进行了进一步表征。
Hard coating can improve the surface properties of a material beyond the capability of the substrate. For a long time, coatings such as hard nickel, hard chromium, hard alloys and hard composites have been developed for engineering applications due to the improved wear resistance. A newly-developed nickel–tungsten brush plating process has the potential as an alternative of electroplating of hard chromium for engineering application.The nickel–tungsten solution is based on the ammoniacal citrate bath, which can be conveniently brush plated just as brush plating of other metals or alloys. On the other side, hard chromium cannot be brush plated due to the exposure of hazardous hexavalent chromium exceeding the Occupational Safety and Health Administration (OSHA) limits.The nickel–tungsten alloy coating has been developed for engineering application. It is of nanocrystalline structure (~ 2 nm crystallite size) and demonstrates excellent hardness and wear resistance. The coating is 60% nickel, 40% tungsten by weight. Due to high tungsten content in the alloy, it is thermally stable. Moderately elevated temperatures (200–500 °C) do not cause grain size growth and softening as the case of most other hard coatings (such as hard chromium, nickel phosphorus). Actually, the nickel–tungsten alloy coating can be further hardened by exposure to high temperature of 200–500 °C for a short period of time. Beyond the hardness and wear properties, the coating has been further characterized by XRD, electronic and optical microscopy, hydrogen embrittlement, salt spray corrosion, tribology, axial fatigue, and other testing.