Manufacture and properties of composite coatings: An introduction

Composite layers are capable of varying surface properties of parts over wi de ranges. The galvanic route and thermal spraying are predestined to creat e composite layers. Wear resistance can be realized by a metallic matrix an d nonmetallic reinforcing component that serves as a disperse phase. The go al of this article is to report on experimental results gained from samples produced galvanically, Improved wear resistance and hardness of the compos ite layers are main topics. The thermal spray process requires more sophisticated processing techniques if the desired components cannot be supplied by individual injectors or me chanically premixed. In cases where pneumatic material feed (e.g., carbon s hort fibers) is not possible, the material supply must be achieved by agglo merated powders containing the second phase as a constituent, Suitable aggl omerated powders allow a control of thermal decomposition of the sprayed ma terials by using additives as admixture to the agglomerate. practical examp les are outlined in the article.