Abstract
The authors of this paper have attempted to improve the quality of surface layers applied to steel elements of machine parts constituting friction couples. The main goal of the research was to investigate an electrospark alloying method process for obtaining abrasion-resistant tribological coatings containing molybdenum disulfide on a steel surface. A substance in the form of sulfur ointment with a sulfur content of 33.3% was applied on the surfaces of C22 and C40 steel specimens. In order to determine the influence of the energy parameters of ESA equipment on the quality parameters of coatings, the ESA process was carried out using a molybdenum electrode with discharge energies Wp = 0.13; Wp = 0.55; Wp = 3.4 J. The following tests were carried out on specimens with such coatings: metallographic analysis, microhardness tests, surface roughness, and local X-ray diffraction microanalysis. The experiments revealed that sulfomolybdenum coatings consist of four zones with different mechanical properties. Depending on the discharge energy and the substrate material, the hardness of these zones varies from approx. 1100 to over 10,000 MPa. Differences in the distribution of, among others, sulfur and molybdenum in the obtained coatings, as well as differences in the microstructure of the observed coatings, were observed.
Highlights
Wear of contact joint parts, in particular of antifriction purpose, is a cause of unbalance of machine units due to changes in the sizes of the worn parts thereof, which results in equipment operation instability, loss of productivity, and reduced product quality [1,2]
Despite the fact that the chemical heat treatment (CHT) method significantly improves the quality of the machine parts’ surface layers, the above method has a number of disadvantages:
We have proposed a method for sulfomolybdenum metal surfaces, which include materials coated with a substance in the form of a sulfur ointment and electrospark alloying with a molybdenum electrode
Summary
Wear of contact joint parts, in particular of antifriction purpose, is a cause of unbalance of machine units due to changes in the sizes of the worn parts thereof, which results in equipment operation instability, loss of productivity, and reduced product quality [1,2]. Wear of metal surfaces in the places of interactions of main component parts of machines and mechanisms is an urgent problem of modern science and technology. Just molybdenum disulfide is an effective lubricant in the air under light-duty or reasonable operating conditions of parts [7]. It is well known that to increase the wear resistance of machine parts, oils and lubricants laced with antifriction additives are used.
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