Properties of High Pressure Water Hydraulic Components with Modern Coatings

Abstract

Water hydraulics is coming back as an alternative to oil and other not environment friendly working fluids used in a very wide range of fluid drive and control systems. The cost of water resistant materials for components is one of the barriers preventing the wide use of water hydraulics, especially moving parts such as pump pistons, surface of cylinder tubes and rods, poppet and seats, etc. to avoid corrosion. One of the common solutions is to use stainless steel there, where it can cooperate with other nonmetallic material such as plastic or other noncorrosive metallic composite to reduce friction. Thus some of research was directed to elaboration of special coating for covering surfaces in critical regions of water hydraulic components. The paper describes results of pilot research on selected components where such coating were introduced on regular carbon steel parts, same as used for oil hydraulics. First part of the article contents description of coating technology and some characteristics of coating layers. Second quotes selected results of conducted by authors research on coated hydraulic cylinders and poppet valves.