621.762Some classes of sintered antifriction materials that form the basis for the development of new materials are discussed. Metal-and nonmetal-based materials with high wear resistance, low friction coefficient, and maximum lifetime are described. They differ in composition, structure (microheterogeneous, macroheterogeneous, layered, fibrous), carrying capacity, and potential for operation under various loads, at sliding rates, and in various conditions (high and low temperatures, corrosive and aggressive media, i.e., in water, acids, alkalis, melted metals, burning-hot gases, with and without lubrication, under high vacuum), in different friction modes (light, medium, heavy, and extremely heavy). The above materials are intended for application in the aviation, motorcar, chemical, oil, metallurgical, transportation, nuclear, textile, and food industries, in cryogenic, rocket, missile, and turbine engineering.The general advance in mechanical engineering, transportation, communications, and other industries, associated with higher rates, pressure, power, operating temperatures of machines and mechanisms, and in space, nuclear, and cryogenic engineering are impossible without new materials. Of them, antifriction materials with high wear resistance, low friction coefficient, and maximum lifetime hold the lead. They are used to produce sliding bearings (cylindrical and ball bearings, thrust bearings, inserts, guides, end and side seals, etc.) for friction units of most contemporary machines and mechanisms.Along with conventional cast antifriction materials, sintered powder materials are taking a leading role since they are long-run, can be operated in various conditions, and their mechanical and tribotechnical properties and economic indicators often surpass those of cast alloys. The long-term experience of applying sintered antifriction materials in various engineering areas shows that they increase the wear resistance of friction units by a factor of 1.5 to 3.0 as compared with cast materials, lubricant supply being limited.Powder metallurgy methods make it possible to produce materials from components that have different melting temperatures or show liquid immiscibility, to obtain a homogenous material of desired porosity, to control the grain size by varying the reduction ratio of the initial components, and to develop composites by combining a high-strength component (which has high fracture toughness under friction and forms the load-bearing matrix of the material) and antifriction components (which form secondary structures on rubbing surfaces to prevent seizure). These methods result in sintered antifriction materials with ample solid and liquid lubricants of virtually any structure, composition, and
