Various Ytterbium-Silicate-Mullite composites were successfully fabricated by adding Yb SiO into mullite ceramics and then using pressureless sintering at 1550 °C. The influence of Yb SiO addition on the microstructure, mechanical properties, and thermal conductivity of ytterbium-silicate-mullite composites was investigated. Results show that the composites mainly consisted of a mullite matrix and some in situ formed Yb Si O and Al O phases. By the addition of Yb SiO , the Vickers hardness of composites reached ~9.0 at an additive concentration of 5 mol %. Fracture toughness increased to ~2.7 MPa·m at the additive concentration of 15 mol %, owing to the trans-granular fracture and crack deflection of the pinning effect of the Al O phase in the composites. With the increase of the Al O phase in the composite, the thermal conductivity for the 15YbAM reached around 4.0 W/(m·K) at 1200 °C. Although the thermal conductivity increased, it is still acceptable for such composites to be used as environmental barrier coatings.
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机译：通过将Yb SiO添加到莫来石陶瓷中，然后在1550°C下进行无压烧结，成功地制造了各种硅酸锂-硅藻土-M石复合材料。研究了Yb SiO添加对-硅酸盐-莫来石复合材料的微观结构，力学性能和热导率的影响。结果表明，复合材料主要由莫来石基体和一些原位形成的Yb Si O和Al O相组成。通过添加Yb SiO，在5 mol％的添加剂浓度下，复合材料的维氏硬度达到〜9.0。由于在复合物中Al O相的钉扎作用发生了穿晶断裂和裂纹偏转，在添加浓度为15 mol％时，断裂韧性增加到〜2.7 MPa·m。随着复合物中Al O相的增加，15YbAM在1200°C时的热导率达到4.0 W /（m·K）左右。尽管导热率增加了，但仍可以将这种复合材料用作环境隔离涂层。
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