Comparison of Physical and Mechanical Properties in Ceramics Composites Si3N4–CTR–AlN and Si3N4–Y2O3–AlN

Abstract

The important factor to consider for successful ceramics composites development is the need of matching the whiskers and matrix characteristics, taking into account the chemical compatibility of the sintering aids utilized. The purpose of this work was to analyze and compare use of rare earth concentrate (CTR) and yttrium oxide, as sintering aids, and its influence in the densification and physical/mechanical properties of hot pressed and sintered Si3N4-SiC(w). The CTR powder materials present high yttrium oxide percentage and its production is cheaper than the additives usually used in ceramic materials, such as Y2O3. For physical and mechanical properties evaluation, specific mass, crystalline phases, micrographs analysis, microhardness and fracture toughness were measured, showing similar results between the two sintering aids. Therefore, this study shows the possibility of obtaining low processing cost products with the use of rare earth concentrate. Meanwhile, more characterization steps are necessary for analyzing its behavior at elevated temperatures.