Interface and Wear Resistance of SiC Ceramic Column Grid Array Reinforced High-Chromium Cast Iron Composite Pretreated with TiH2

利用TiH2粉末膏剂涂覆和在真空下1000或1400℃保温20 min的预处理工艺对反应烧结SiC陶瓷柱进行了表面预处理,再将预处理好的SiC陶瓷柱固定在石墨板上,随后采用金属浇铸工艺制备了一种具有高度陶瓷增强体宏观均匀性、可靠性和可设计性的SiC陶瓷柱阵列增强高铬铸铁复合材料。陶瓷涂层和复合材料界面分析表明:1400℃为较优的SiC表面预处理温度,预处理后SiC表面形成一层可靠的金属性复合层。该复合层在高温浇注过程中不会被溶解,可有效抑制高铬铸铁与SiC陶瓷的界面反应,从而形成无脱层、优良的复合材料陶瓷/金属磨损界面。与该复合材料的金属基体相比,由于SiC陶瓷柱的有效添加,经表面处理后不同陶瓷含量的SiC/高铬铸铁复合材料的耐磨性能均显著提高。

Interface and Wear Resistance of SiC Ceramic Column Grid Array Reinforced High-Chromium Cast Iron Composite Pretreated with TiH2

Reaction-bonded SiC ceramic columns were coated by titanium hydride (TiH2) powder paste firstly, and then pretreated in a vacuum at 1000 or 1400 oC for 20 min. After that, the pretreated SiC ceramic columns were fixed on a graphite plate. Subsequently, a kind of SiC ceramic column grid array reinforced high-chromium cast iron composites, with high macro-uniformity, reliability and designability of the ceramic reinforcements, were fabricated by metal casting. The microstructure analysis on the ceramic coating and the ceramic/metal interface of the SiC/iron composite reveals that a reliable metallic composite coating can be formed on the SiC surface after the pretreatment at 1400 oC which was proved to be a better pretreatment temperature. The as-formed coating would not be dissolved during the metal casting process, and the interfacial reactions between SiC and iron were also restrained effectively, resulting in an excellent ceramic/metal interface without delamination after wear testing. Moreover, the wear resistances of the SiC/iron composites with different SiC ceramic contents are improved markedly in comparison with that of the metal matrix due to the effective additions of SiC ceramic columns.