Influence of Sintering on the Structure and Properties of Ceramics from Silica Nanopowders

Abstract

In this paper the ceramics obtained from various silica powders investigated. Two different methods for ceramics receiving (with consecutive pressing and sintering, and the method of hot-pressing (spark plasma sintering)) were tested. For ceramics obtained by different methods the microhardness, ultimate compression strength and grain size were compared. At a classical method of powders sintering the microhardness and durability growth is observed at reduction of the initial particles size though the observed size of grains in ceramics is approximately identical for all types of powders. It is received that vitrification of samples of ceramics created by the SPS method, happens at much smaller temperature (1100°C), than the corresponding temperature at consecutive operations of pressing and sintering (1550°C). Values of microhardness of the ceramics received by two various methods, were similar (~ 2 GPa). Ultimate compression strength value (0,25 GPa) for the samples received by a method of spark plasma sintering, only slightly exceeds the value of ultimate compression strength for the samples created in the traditional way (0,23 GPa). If at consecutive operations of pressing and sintering the ceramics with a micron size of grain turns out, at the SPS method the grains of received ceramics have the size about 300 nm. It speaks about prospects of nanopowders sintering by the method of spark plasma sintering at which nanostructural parameters of powder in the consolidated material remain