| Abstract Scope |
Hard coating can improve the surface properties of a material beyond the capability of the substrate. Hard chromium and other coatings are used for functional applications due to their greater hardness and wear resistance. Nickel-tungsten brush plating has the potential as an alternative of electroplating of hard chromium.The nickel-tungsten alloy is of nanocrystalline structure and demonstrates excellent hardness and wear resistance. The coating is 60% nickel, 40% tungsten by weight. Moderately elevated temperatures do not cause grain size growth and softening. Actually, the nickel-tungsten alloy coating is further hardened by exposure to 200 ~ 500 °C. Both abrasive Taber wear and pin-on-disk sliding wear of the coating have been investigated. Beyond the hardness and wear properties, the coating has been further characterize by XRD, scanning electron and optical microscopy, hydrogen embrittlement, salt spray corrosion, tribology, axial fatigue, NACE corrosion, and other testing. |