自蔓延高温合成碳化铬金属陶瓷熔覆层

An Investigation on Deposition of Chromium Carbide by SHS Ablation

利用自蔓延高温合成（ＳＨＳ）熔铸技术，将碳化铬的高温熔体铺展在平面样品的钢表面上，从而形成厚度为几毫米的熔覆层。为克服碳化铬与底材的润湿问题，采用与Ｆｅ有良好互溶性的Ｃｒ作为润湿功能层，在此基础上，使Ｃｒ－Ｃ合金层中的碳作阶梯改变，从而获得了梯度熔覆层结构。来用Ｎ２加压（＜２０ＭＰａ）和预热工艺（≤３００℃）等措施，控制反应燃烧温度，改善熔体流动性，增大熔渣分离速度，有利于提高熔覆层表面平滑程度。研究认为，良好的结合强度来源于界面间强烈的冶金作用以及梯度成分分布。

levated temperature melt of chromium carbide was spread out on a plane shape substrate of carbon steel and resulted in a deposition layer about 1.8mm in thickness by self propagation high temperature synthesis(SHS).In order to surmount an obstacle of wet between the chromium carbide and the steel substrate,mettalic Cr, which had good dissolubility with Fe,was selected as a wetting functional component.Among the followed Cr-C coatings, carbon content was two-steply increased so that a gradient composition ablation could be obtained. In addition,two other messurements were adapted.i.e.high pressure N2(<20M Pa)and preheating process(≤300℃)which were comfirmed to be effective no rasing combustion temperature.A 950 ℃ repeated thermal quenching test used to evaluate the kinetic adhesion revealed that there was no sighs of peeling off even if the cycle number had exceeded to 40.AnalySis indicated that the nice bond strength was due to an intense metallurgy interaction and gradient composition at the ablation root.