High-speed wear behaviors of CrSiN coatings for the industrial applications of water hydraulics

To develop environmentally friendly hydraulic systems that utilize environmentally compatible fluids such as tap water as transmitting media, the high friction between rotating parts must be reduced. In this study, CrSiN coatings with optimum coating properties were deposited on the rotating surface of cylinder barrel of an hydraulic pump and their tribological behavior under various lubrication conditions investigated by using a custom-built high speed wear tester. Cylinder barrels coated with Cr–9.8 at.% Si–N composition, which shows the maximum hardness value of approximately 24 GPa, were produced and the coating wear properties were compared with those of a plasma-nitrided barrel. Although a reduction in the friction coefficient to below 0.13 is still needed for optimization or commercialization of the CrSiN coated cylinder barrel for water hydraulics, much improved friction behavior up to 1600 rpm obtained in a tap water environment, without delamination or surface cracking of the coating. This improvement was accompanied by an abrasive wear mode.