Preparation of YAM Coating on the ZrB2 Composites and their Ablation Resistance

The YAM coatings on the ZrB2 composites surface were prepared by co-precipitation technique and with Al (NO3)3 and Y(NO3)3 solutions acting as precursor. The effect of matrix surface treating conditions, dipping times and calcination temperature was investigated. Phase compostion, coating morphology and interface between matrix and coating were analyzed by XRD and SEM. The results indicated that the YAM coating was formed after calcined at 1250°C in vaccum. The thickness of coating was increased with the dipping times, the smoothest coating was obtained by two dipping times, and matrix surface coarsing was beneficial for improving the adhension between matrix and coating. The ablative teste was evaluated at 2000°C by oxy-acetylene flame, the ablative properties was obviously improved by coating compared with uncoated composites.