Comparative Wear Tests of Different Types of Coatings on Steels

Abstract

AbstractDifferent coatings were formed by galvanical deposition, thermochemical treatment, CVD, PVD or plasma spraying. Their wear behaviour was tested under various conditions so that adhesive and abrasive wear mechanisms predominated. The resistance of the coatings to adhesive failure and wear was examined with the pin and disc system under conditions of boundary lubrication. The discs were protected by different coatings while the pins were made of tool steel or alumina. For abrasive wear tests a grinding apparatus with grinding papers of flint, alumina or silicon carbide was used. From the resultsthe following conclusions can be drawn: -Thermochemically treated steels and nickel-phosphorus coatings have a high resistance to galling if the counterbody consists of steel or alumina. The couples plasma sprayed molybdenum against steel and tungsten carbide against alumina also have a high resistance against galling.-The wear of most coatings is low if the counterbody is made of steel. By analumina counterbody the wear of the coatings isincreased. Alumina is worn less by the coatings than steel.-The hard CVD- and PVD-coatings, the thermochemically formed iron boride andvanadium carbide coatings and the electroless nickel-phosphorus-diamond coatings have a high abrasive wear resistance.