Zirconium Diboride Waste Recycling by Grinding and Recurrent Spark Plasma Sintering

An economically viable and environmentally friendly method is proposed for recycling the wastes from electrical discharge cutting of the blanks obtained by the spark plasma sintering of a powdered composition based on zirconium diboride with the addition of silicon carbide, lanthanum and yttrium oxides. The wastes are ground in a flow-type centrifugal mill TsEM-7-1, and the product of milling is further consolidated by spark plasma sintering. The microstructure and phase composition of the sintered materials made from initial powder composition and the powder obtained by grinding the ceramic wastes from final machining of finished products are investigated. It is shown that the largest pieces in the wastes that cannot be ground in the mill are to be crushed preliminarily to enhance the yield of ground powder. The absence of differences in the phase composition of initial and processed powder mixtures and blanks made of them has been revealed, which demonstrates the possibility of repeated use of the wastes for spark plasma sintering of the materials formed from ceramic powders based on zirconium diboride, for the purpose of decreasing the consumption of initial components.