Wickramathilaka Kaveendra Yasas, Valus Joseph, Shuster Seth, Purgay Ryan, Suleiman Yara, Suib Steven L
Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States.
REFINE Center, University of Connecticut, Storrs, Connecticut 06269, United States.
ACS Appl Mater Interfaces. 2024 Oct 23;16(42):57705-57714. doi: 10.1021/acsami.4c13081. Epub 2024 Oct 11.
Ceramic matrix composites (CMCs) have played a significant role in increasing the efficiency of gas turbine engines. CMCs combine the high temperature resistance of ceramics with the high mechanical strength of ceramic fibers into a single unit. Interphase layers are a crucial component in CMCs, as they prevent ceramic fibers from oxidation and introduce strengthening mechanisms into the composite. Hexagonal boron nitride and pyrolytic carbon are the most commonly used interphase layers in the aerospace industry. Other than that, very few materials have been evaluated as interphase layers. In this study, we explore the possibilities of using titanium nitride as an interphase layer in single-tow CMCs (mini composite) representative of a unidirectional composite at a smaller scale. T-300 carbon fibers were coated with TiN by atmospheric pressure chemical vapor infiltration using TiCl, N, and H. The deposition temperature, precursor flow rate ratio, total precursor flow rate, and deposition time were optimized to obtain high-quality coatings. The best coating was produced at 800 °C, 4:1 H [TiCl]/N ratio, 125 standard cubic centimeters per minute (N + H [TiCl]) total flow precursor flow rate, and 2 h of deposition time. At these conditions, the coatings displayed good fiber coverage, good fiber adhesion, minimum fiber linkage, and minimum surface roughness. There was minimum fiber degradation after TiN coating, with a retention of 95% of the initial Young's modulus and 26% of the ultimate tensile strength of the carbon fiber. Adding the TiN interphase coating to the Cf/SiC CMC increased the ultimate tensile strength of the composite by 1122% and Young's modulus by 150%.
陶瓷基复合材料（CMC）在提高燃气轮机发动机效率方面发挥了重要作用。CMC将陶瓷的耐高温性与陶瓷纤维的高机械强度结合在一个单元中。界面层是CMC的关键组成部分，因为它们可防止陶瓷纤维氧化，并将强化机制引入复合材料中。六方氮化硼和热解碳是航空航天工业中最常用的界面层。除此之外，很少有材料被评估用作界面层。在本研究中，我们探索了在较小尺度下将氮化钛用作代表单向复合材料的单丝CMC（微型复合材料）界面层的可能性。使用TiCl、N和H通过常压化学气相渗透法在T-300碳纤维上涂覆TiN。对沉积温度、前驱体流速比、前驱体总流速和沉积时间进行了优化，以获得高质量的涂层。在800℃、H[TiCl]/N比为4:1、前驱体总流速为125标准立方厘米每分钟（N + H[TiCl]）以及沉积时间为2小时的条件下制备出了最佳涂层。在这些条件下，涂层显示出良好的纤维覆盖率、良好的纤维附着力、最小的纤维连接和最小的表面粗糙度。TiN涂层后纤维降解最小，碳纤维的初始杨氏模量保留了95%，极限抗拉强度保留了26%。在Cf/SiC CMC中添加TiN界面涂层使复合材料的极限抗拉强度提高了1122%，杨氏模量提高了150%。
