A modern representation of the behaviour of electrospark alloying of steel by hard alloy

This study is a summary of a series of experimental investigation of electrospark alloying (ESA) by the application of pulse currents with amplitudes and durations ranging from 100 to 1000 angstrom and from 25 to 4000 mu s, respectively. The technological parameters of coating, such as mass transfer, and number of deposition layers till its failure and corresponding properties of coating, such as thickness, roughness and uniformity, etc. were investigated. To prevent the destruction of the already superimposed deposition during ESA, it is necessary to limit the time of processing before the beginning of its fracture. It was experimentally shown that, processing time till fracture could be determined by not only the cross-sectional examination of coating, but simultaneously with some distinctive characteristic of coating parameters, precisely, by the mass transfer coefficient. Since the processing time till the fracture has limit, the amount of mass transferred from treating electrode (anode) to substrate (cathode), that is, the thickness of coating is restricted. The analysis from the thickness point of view was carried out and some approaches to show the possibility to increase it by ESA technique were proposed. (c) 2006 Elsevier B.V. All rights reserved.