Self lubricating solid coating of tungsten carbide with cobalt for covering a friction surface of a turbomachine part e.g. sleeve, comprises a cobalt matrix and a phase of cobalt-tungsten-carbide compound inserted in the matrix

摘要

The self lubricating solid coating (15) of tungsten carbide with cobalt (17%) for covering a friction surface of a turbomachine part e.g. sleeve (11), comprises a cobalt matrix and a phase of cobalt-tungsten-carbide compound inserted in the matrix. The cobalt-tungsten-carbide compound includes a single phase hexagonal tungsten carbide (= 85 vol.%), which is uniformly distributed at an interior zone having a surface of = 100mu m 2. The single phase hexagonal tungsten carbide occupies 55% of the surface of the zone. The self lubricating solid coating (15) of tungsten carbide with cobalt (17%) for covering a friction surface of a turbomachine part e.g. sleeve (11), comprises a cobalt matrix and a phase of cobalt-tungsten-carbide compound inserted in the matrix. The cobalt-tungsten-carbide compound includes a single phase hexagonal tungsten carbide (= 85 vol.%), which is uniformly distributed at an interior zone having a surface of = 100mu m 2. The single phase hexagonal tungsten carbide occupies 55% of the surface of the zone. The cobalt-tungsten-carbide compound is expressed as Co yW zC x, where y= 0, z= 1 and z= x. An independent claim is included for a turbomachine.