PROTECTIVE COATINGS OBTAINED BY PYROLYSIS OF METALLOORGANIC CHROMIUM COMPOUNDS.

The authors investigated the possibility of obtaining protective coatings by the method of low-temperature thermochemical treatment (TCT) using metalloorganic compounds (MOC). Coatings obtained from MOC are usually highly corrosion and wear resistant, and in many cases they are also very hard. Potentially useful are processes of deposition of metallic and metallike coatings from the vapor phase in thermal decomposition of MOC. In addition to the basic reaction of decomposition with the emergence of chromium atoms there occur subsidiary reactions of fission of the organic part of the molecules leading to the precipitation of carbon into the solid phase, the amount of carbon depending on the conditions of thermal decomposition. Depending on the regime of deposition, coatings with different structure and phase composition may be obtained: practically amorphous homogeneous deposits in the kinetic region, horizontally laminated ones in the intermediate region, columnar and dendritic coatings based on chromium and its carbides in the diffusion region.