Silicoaluminum carbonitride with anomalously high resistance to oxidation and hot corrosion

In this communication we report for the first time that amorphous silicoaluminum carbonitride (SiAlCN) ceramics possess anomalously high resistance to oxidation and hot-corrosion. The materials were synthesized by thermal decomposition of polymer precursors.[18] The oxidation kinetics of the materials was determined at 1 200°C in dry air by measuring the thickness of the oxide scale as a function of annealing times up to 200 h. The hot-corrosion behavior was studied by scanning electron microscopy (SEM) observation on the surfaces of the materials that were annealed in either NaCl or water vapor environments at 1 200°C for 50 h. The experiments were performed on two SiAlCN ceramics with different aluminum content (see table 1); the hot-corrosion experiments were also performed on SiCN without aluminum for comparison. A mechanism underlying the observed phenomena is discussed.