Rubber
Rubber proves successful for bearings working in heavily polluted water or corrosive solutions. The lining must have through slots and it must always be flooded, otherwise the bearings easily break. The maximum specific load is 0.35 MPa for a sliding speed of 0.5 m/sec, the maximum sliding speed is 5 m/sec, and the maximum temperature is 65° C. Bearings for pumps, hydraulic turbines, ship shafts, and some chemical equipment are obtained by vulcanizing rubber into steel bushings.
Carbon materials, Graphite
Carbon materials and graphite have small impact strength, small thermal expansivity, great thermal conductivity, they can carry thermal shocks and they are inert against a majority of chemicals. Carbon materials are suitable for bearings working without lubrication (a certain environment humidity is necessary), for a water environment and at low and high temperatures. They have a friction factor from 0.15 to 0.25 without lubrication, for limiting lubrication the factor is from 0.05 to 0.1. The range of operating temperatures is from -200 C to +500 C.
The shaft material can be a gray cast iron, hardened chromatic or nitridated steel, glass, ceramics, and so on. Aluminum alloys are not convenient. The sum of surface textures of sliding faces should not exceed 0.6 micron. Shafts operating without lubrication are used as a solution for sliding mountings in chemical, food, and nuclear industry.