Institute of Fundamental Technological Research

The article describes a new method of forming the protective coatings of steel parts operating under conditions of abrasive wear both in general mechanical engineering, the composition of which is of 90% ВК6 + 10% 1М, and in industries, where there may be radiation exposure and the composition of 1М (70% Ni, 20% Cr, 5% Si, 5% B), by applying them by the method of electrospark alloying (ESA) with compact electrodes-tools made of nichrome wire X20Н80 and ВК6 hard alloy and using special technological media (STM), which include the necessary alloying elements. As a result of these research, it is established that the surface layers of the 45 and Р6M5 steels after applying wear-resistant coatings have a structure that consists of three areas: the ‘white layer’, the transition zone below, and the base metal. When the discharge energy (Wp) increases from 0.52 to 2.6 J, the thicknesses of the ‘white layer’ and the transition zone, their microhardness and surface roughness increase, but the integrity of the applied coating decreases. The highest microhardness of 9750-12800 and 14250-14600 MPa corresponds to the coating formed on steel 45 and Р6M5, respectively, during ESA by means of both the compact electrodes-tools made of hard alloy ВК6 and the STM with the composition of 0.5% Si + 0.5% B + 2% Cr + 7% Ni + 90% Vaseline.

electrospark alloying, electrode tool, coating, white layer, microhardness, roughness, continuity

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