Structural and Tribological Properties of Multicomponent Coatings on 45 and 210Cr12 Steels Obtained by Electrospark Deposition with WC-B4C-TiB2-Ni-Cr-Co-B-Si Electrodes

Abstract

In the present work, a new type of wear-resistant coatings obtained on steels by contactless electro-spark deposition using a rotating electrode and by electrical discharge deposition with a vibrating electrode has been studied. Electrodes have been obtained by pressing and sintering multi-component powder mixtures of hard metal WC-Co with additives of super-hard and refractory compounds of B₄C and TiB₂ and semi-self-fluxing alloys Ni-Cr-B-Si. High density coatings, with a thickness up to 80 μm and micro hardness up to 17.0 GPa, have been obtained. The roughness, thickness, composition, and structure of the coatings thus obtained have been studied by X-ray diffraction, scanning electron microscopy, and electro-spark deposition. The influence of micro-geometric parameters, composition and structure of coatings on their tribological properties and wear resistance were studied by comparative tests of friction and abrasion wear. The friction tests showed that the wear of the coated steel surfaces is up to 5 times lower compared to the uncoated those. On the base of the experimental data, a comparative analysis of the coatings obtained by the two methods have been made. Appropriate regimes and conditions for deposition of coatings with optimal properties have been defined.