Institute of Fundamental Technological Research

In article we present the results of studies of the local x-ray spectral analysis of coatings formed by the electrospark alloying (ESA) method at the discharge energy Wp = 0.13, 0.52 and 0.9 J by anodes from nickel and stainless steel X10CrNiTi18-10 on the cathode surface from X10CrNiTi18-10 steel. During ESA by stainless steel X10CrNiTi18-10 anode with an increase Wp in characteristic points and from the entire investigated surface of the coating, the quantitative elemental composition is not changed. The analysis of elements distribution over the depth of the formed layer is showed that when using the electrode tool from steel X10CrNiTi18-10 with an increase in Wp, there are a slight decrease in chromium and an increase in nickel and titanium in the surface layer. When steel X10CrNiTi18-10 is replaced by nickel with an increase in Wp, the concentration of nickel on the coating surface decreases from 95.38 to 89.04%. As the recession deepens from the coating surface, the concentration of nickel gradually decreases, respectively, at Wp = 0.13, 0.52 and 0.9 J from 96.29, 90.29 and 89.04% on the surface to 9.0, 10.30 and 9.9% at depth: 120, 165 and 240 μm. At the same time, the concentration of chromium, titanium and iron gradually increases.

electrospark alloying, nickel, steel, x-ray spectral analysis, scan step, topography, spectrum

The article substantiates the importance and relevance of increasing problem of the performance and service life of babbitt sliding bearings (SB), which are the rotors supports of a large number of centrifugal pumps, compressors, turbines and other dynamic equipment operating at high operating parameters (speeds, loads and temperatures), as well as in conditions of corrosive, abrasive and other types of working environment’s influence. The analysis of the babbitt SBs production technology and operating conditions showed that the reason for the decrease in their durability are factors that are formed both at the stage of manufacture and during operation. SB failure under normal operating conditions is a consequence of wear various types: cavitation, abrasive wear, damage due to plastic deformations, fatigue damage, etc. The antifriction layer wear resistance depends on the mode of operation and design of the bearing, the physical properties of the connection between the layer and the base, the rigidity of the shaft and the bed under the bearings. As established, the bearing anti-friction layer quality must be evaluated according to the following criteria: adhesion strength of the coating to the base, cohesive strength of the anti-friction layer, porosity, and homogeneity of the structure. As established, during the production of SBs, the formation by the method of electrospark alloying (ESA) of a copper intermediate layer, firmly bonded with steel substrate, and tin layer (formation of solid substitution solutions) and babbitt provides a stronger (by 35%) of adhesion, compared to traditional technology (steel 20 + babbitt), steel substrate with babbitt, as well as more intensive removal of heat from the friction zone. As determined, a new technology in which all operations are carried out by the ESA method can be a reserve for improving the babbitt coatings formation quality, which significantly affects the durability of the SB. As determined, in order to determine a more rational technology for applying babbitt coatings, it is necessary to develop a physically based mathematical model that relates the wear of a certain amount of babbitt to the frictional work spent on it.

sliding bearing, babbitt, coating, wear, structure, transition layer, adhesion strength, electrospark alloying, mathematical model