ZrC/SiC composites from functionalised ZrC combining preceramic precursors and SPS

Abstract

ZrC/SiC composites were obtained in situ using Spark Plasma Sintering (SPS), with a previous organic functionalisation of ZrC particles (ZrCf). It used the direct ceramisation/sintering of ZrCf/polycarbosilane mixture without any previous crosslinking steps. The prior functionalisation did not have an effect on either the relative density of the materials or the mechanical properties. However, larger SiC domains were observed around the functionalised ZrC particles, probably due to the hydrosilylation reaction between pendant alkene groups and Si-H from the commercial polycarbosilane. In addition, TEM analyses showed different features such as the presence of inter- and intra-granular SiC, and of a double layer at the grain boundaries between the ZrC and SiC phases, when avoiding functionalisation. The oxidation behaviour was also tested, and the prior functionalisation improved the properties of the final samples.