POROSITY OF A HEAT-RESISTANT ALLOY MADE BY SPARK PLASMA SINTERING OF NICKEL POWDER OBTAINED BY ELECTRODISPERSING THE ZHS6U ALLOY IN WATER

Abstract

Metallographic studies are required to expand the scope of practical application of powder materials obtained from waste of the ZhS6U alloy. The purpose of this work was to study the porosity of a heat-resistant alloy produced by spark plasma sintering of nickel powder obtained by electrodispersing the LC6U alloy in water. The work is based on the task of obtaining a heat-resistant nickel alloy with improved physical and mechanical properties and low cost. The alloy under study is obtained by spark plasma sputtering of nickel powders obtained by electroerosive dispersion of waste of the alloy ZhS6U in distilled water. The waste of heat-resistant alloy of the brand ZhS6U was used in the work, which was crushed by the method of electroerosive dispersion in distilled water at the original installation. Parameters of the installation during the disposal of waste ZhS6U: voltage at the electrodes 190–210 V; capacitance of the condenses 55–60 UF; pulse repetition frequency 180–200 Hz. As a result of local exposure to short-term electrical discharges between the electrodes, the alloy waste was destroyed with the formation of heat-resistant nickel powder particles. Sintering of heat-resistant nickel powder was carried out in the SPS 25-10 "Thermal Technology" system (USA) at a temperature of 1300 °C, a pressure of 40 MPa and a holding time of 10 min. It has been experimentally established that new heat-resistant alloys produced by spark plasma sintering of an electroerosive charge have a porosity of about 0.52 %. The practically nonporous structure of heat-resistant alloys is explained by the presence of particles of different fractions in the electroerosion charge, which ensures tight packing and the so-called "spark discharge plasma effect" during spark plasma fusion.