Y2O3掺杂ZrB2-SiC基超高温陶瓷的抗烧蚀性能

为改善ZrB2-SiC基超高温陶瓷的抗氧化和抗烧蚀性能,在制备过程中加入Y2O3。用氧乙炔火焰法来考察ZrB2-SiC-Y2O3的抗氧化和抗烧蚀性能。采用SEM和XRD分析烧蚀前后形貌及物相。材料在加热和冷却过程中没有出现开裂现象,说明其具有良好的抗热冲击性能。微观组织分析表明,氧化层主要由4层组成,且氧化层与基体层没有明显的剥离。结果表明:Y2O3的添加可以将氧化产物中的高温稳定相稳定到室温,减少由于相变发生的体积膨胀,改善氧化层与基体层的粘结性能。

Ablation Resistance Behavior of ZrB2-SiC Ultra-High Temperature Ceramics with Y2O3 Addition

In order to improve the oxidation resistance and ablation resistance of ZrB2-SiC ultra-high temperature ceramics (UHTCs), Y2O3 particles were introduced during the fabrication process of the ZrB2 based UHTCs. The oxidation-resistance and ablation-resistance of ZrB2-SiC-Y2O3 UHTCs were investigated using oxyacetylene torch test. The microstructures and phases of ZrB2-SiC-Y2O3 before and after ablation were studied by SEM and XRD. No cracks are found on the ablated surface during the process of heating and cooling, indicating that ZrB2-SiC-Y2O3 UHTCs have good thermal shock resistance. Microstructure analysis shows that the oxidation layer is composed of 4 layers and there is no obvious exfoliation between the oxidation layer and the substrate layer. The results show that high temperature stable phase t-ZrO2 in the oxidation product can be kept at low temperature by the addition of Y2O3, thus reducing the volume expansion owing to transformation and improving coherent properties of oxidation layers