ELECTROSPARK COATING PROCESSING WITH METHOD OF ULTRASONIC PLASTIC DEFORMATION
In the paper there are shown results on roughness parameter decrease on the electrospark coatings of 20H13 and 30 steel surfaces by means of smoothing with the use of the plant for non-abrasive ultrasonic finishing (NUF). For the coating formation there were used Ni, Cu and an intermetallic alloy based on Ni3Al phase. At the NUF increase of coatings formed with the use of Cu there is a roughness growth caused with material “pickup” upon an indenter. It is determined that for smoothing the surfaces with electrospark coating with the assurance of roughness considerable decrease a six-fold NUF processing is required. A microstructure of the coating obtained with the use of anode material based on the Ni3Al alloy consists of columnar crystal grains the cross-section dimensions of which change from some mkm to several tens of nm. Crystal grains are directed mainly normally regarding a cathode surface. By means of micro-X-ray spectrum analysis there is defined an elementary composition of columnar crystal grains corresponding to the alloy of the Nix-Aly-Fez system which is alloyed with Cr and contains admixtures of Si and Mn. By means of the microstructure investigation of the coating smoothed surface in a number of areas there are revealed crystal grains with the signs of plastic deformation.