Electroerosive Powders Research Articles

Investigation into the properties of electroerosive powders and hard alloy fabricated from them by isostatic pressing and sintering

Results of an investigation into the properties of the hard alloy fabricated by isostatic pressing and sintering of powders prepared by the electric discharge dispersal (EDD) of tungsten-containing waste of the T15K6 alloy in distilled water and burning kerosene are presented. An original installation developed and patented by the authors was used for the EDD of conductive materials. Isostatic pressing of the powder was performed using an EPSI press (Belgium) at a pressure of 300 MPa, and sintering was performed in a Nabertherm high-temperature furnace (Germany) in vacuum at 1500°C for 2 h. The content of main elements (W, Ti, Co), both in the powder and in the hard alloy fabricated from it, was established using electron probe microanalysis. The microhardness of the powder and alloy is investigated and it is shown that powder prepared by EDD in kerosene and the alloy made of it has increased HV compared with the samples fabricated using water as the working liquid.

Defectiveness of the crystal structure of electroerosion powders

The fine structure and defectiveness of metal powder crystal lattices produced by electroerosion dispersion were examined. Dispersion was performed on granulated aluminum, Armco iron, carbon steels, and tungsten. The fine structure was examined by x-ray diffraction. Harmonic analysis was performed using a computer and a program which calculates not only the expansion coefficients of the functions into a Fourier series but also the microdistortions and the dimensions of the mosaic blocks. Electroerosion powders were found to have higher density of crystal lattice defects which can increase their chemical and catalytic activity, improve the metallic electroerosion powder passivation, and increase their corrosion resistance.