Application of Electrospark Deposition and Modified SHS Electrode Materials to Improve the Endurance of Hot Mill Rolls. Part 2. Structure and Properties of the Formed Coatings

Resumo

The electrospark deposition of coatings onto SPKhN–60 white cast iron samples has been undertaken in two stages. A barrier sublayer has been deposited at the first stage, using chromium and nickel electrodes, and a multifunctional protective coating was deposited at the second stage. The effect of the sublayer on coating properties upon application of STIM–40NAOKn (TiC–NiAl + \({\text{ZrO}}_{2}^{{{\text{nano}}}}\)) and STIM-11OKn (TiB₂–NiAl + \({\text{ZrO}}_{2}^{{{\text{nano}}}}\)) electrodes is studied. The coating structures are investigated. The grain size of the refractory phase is found to be smaller than 100 nm. The application of double-layer coatings increased the wear and heat resistances of white cast iron samples. Pre-deposition of a nickel sublayer enhanced the heat resistance of STIM-11OKn coating over eightfold. The full-scale tests of the rolls strengthened using SHS electrodes were carried out and positive results were obtained.