Application of Electrospark Deposition Process and Modified SHS Electrode Materials to Improve the Endurance of Hot Mill Rolls. Part 1. Features of Coating Formation on SPHN-60 White Cast Iron Substrates

Resumo

Electrospark deposition on samples made of SPHN-60 white cast iron is carried out in two stages. During the first stage, a barrier sublayer was applied, and during the second stage, a multifunctional protective coating was applied. Two materials for the electrodes, Ni and Cr, were chosen to form a sublayer according to the calculations of Palatnik’s criterion. The impact of a sublayer on the features of the formation of electrospark coatings is studied using hard-metal electrodes of SHIM-40NАОKn (TiC–NiAl + \({\text{ZrO}}_{2}^{{{\text{nano}}}})\) and SHIM-11ОKn (TiB₂–NiAl + \({\text{ZrO}}_{2}^{{{\text{nano}}}})\). The phase composition and the surface roughness of the formed coatings are studied. It is found that deposition of a sublayer contributes to an increase in the fraction of refractory phases in coatings. The surface roughness (R_a) varies from 3.37 to 8.20 μm. The adhesion strength of the two-layer electrospark coatings to the substrate exceeds 100 N.