Thermal cycling resistance of ZrB2-SiC coatings with MgO additive on SiC coated graphite

摘要

To improve the thermal cycling resistance of ZrB2-SiC/SiC dual layer coating, MgO was added into the pack powders used to prepare ZrB2-SiC outer coating by pack cementation. The composition, microstructure and thermal cycling resistance of these coatings were studied. The results show that as-received coatings were mainly composed of SiC, ZrB2 and Si. ZrB2-SiC outer coating contained 5 wt%, 7 wt%, 9 wt% MgO additive showed better thermal cycling resistance with 97.6%, 98.8% and 96.5% weight retention after 15 thermal shock cycles between 1500 degrees C and room temperature.