PRODUCTION OF COMPOSITE CERAMIC MATERIAL FOR THERMAL SPRAYING

A composite ceramic material has been developed for thermal spraying that permits to increase wear resistance due to introduction of high-chromium steel and molybdenum in its structure, to obtain optimum porosity in the starting charge material while synthesizing FeCrMo – MoS2/CaF2/С – TiC compositions, to improve technological parameters of powders and thereby increase coefficient of powder usage in spraying, to reduce cost of wear-resistant coating technology. The paper presents characteristics and parameters of the developed material and coating which is based on it. Methodology is based on complex metallographical, X-ray diffraction and electron microscopy investigations of structural elements of composite plasma coatings. Main components of composite particles are solid solutions based on iron, titanium carbides, solid lubricant inclusions in the form of molybdenum disulfide, calcium fluoride, carbon. Presence of such powder particles predetermines obtaining wear-resistant coatings which are rather efficient in case of molecular and mechanical and abrasive wear-out under disadvantageous friction conditions (boundary lubrication or absence of lubrication material, elevated temperature actions). The contemplated powders are characterized by complex geometric shape and developed surface relief of particles. There has been observed a stable distribution of hard carbide phase in volumes of deposited materials and absence of superficial zone with deficit of TiC inclusions that positively influence on working capacity of the investigated wear-resistant coatings. Plasma coatings which have been deposited with the help of FeCrMo – MoS2 – TiC powders in accordance with the technology developed by authors have better wear resistance in case of dry friction in a steel 45 (coating wear-out is less by 1.2-fold; scoring load is higher by 1.2-fold) than a coating which has been obtained with the help of Ni80Cr20 – 12 % MoS2 – 50 % TiC powder. In such a case coating adhesive strength is increased by 1.23-fold and and powder cost lower is decreased by 1.5-fold. Thus plasma wear-resistant coatings obtained while using FeCrMo – MoS2/CaF2/carbon – TiC composite powders are considered as prospective for restoration and hardening of steel parts which are operating under disadvantageous friction conditions.