Zhou Jianyu, Almansour Amjad S, Chase George G, Morscher Gregory N
Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH, USA.
Department of Mechanical Engineering, The University of Akron, Akron, OH, USA.
J Eur Ceram Soc. 2017 Aug;37(10):3241-3253. doi: 10.1016/j.jeurceramsoc.2017.03.065.
SiC based composite materials commonly have protective silica surface in air. Under humid environments at high temperatures, like occur in jet engines, the silica surface layer reacts with water molecules to form volatile silicon hydroxide (Si(OH)) and the protection is reduced which cause jet engine degradation. An alternative approach to protect SiC based composites would be to infiltrate the SiC matrix via slurry with an oxide material that is resistant to the high-temperature and humid environment. As proof of concept, aqueous based mullite particle slurries were infiltrated by pressurized flow and by capillarity of the wetting slurry on the external surface of the porous SiC matrix of single-fiber-tow SiC/SiC minicomposites. Minicomposites were precracked at room temperature during tensile tests then tested in tensile creep in air at 1200 °C to study the degree of protection that the infiltrated mullite provided at high temperatures. Next, fracture surfaces were examined using SEM.
基于碳化硅的复合材料在空气中通常具有保护性的二氧化硅表面。在高温潮湿环境下，比如喷气发动机中出现的情况，二氧化硅表面层会与水分子反应形成挥发性的硅氢氧化物（Si(OH)），从而降低保护作用，导致喷气发动机性能下降。保护基于碳化硅的复合材料的另一种方法是通过浆料将一种耐高温且耐潮湿环境的氧化物材料渗入碳化硅基体中。作为概念验证，通过加压流动以及利用润湿浆料在单纤维束碳化硅/碳化硅微型复合材料的多孔碳化硅基体外表面的毛细作用，将水基莫来石颗粒浆料渗入其中。微型复合材料在室温下拉伸试验期间进行预裂纹处理，然后在1200℃空气中进行拉伸蠕变试验，以研究渗入的莫来石在高温下提供的保护程度。接下来，使用扫描电子显微镜检查断裂表面。
