CrO_3对SHS重力法制备薄壁管内衬涂层质量的影响

采用SHS重力法,以Al-Fe_2O_3为反应体系,SiO_2、CrO_3为添加剂,对小直径薄壁陶瓷内衬管的制备工艺进行了研究。结果表明:在没有添加CrO_3情况下,陶瓷层中含有Al2O3、Al6Si2O13、Fe Al_2O_4和Fe_2SiO_4等相;添加CrO_3以后,FeAl_2O_4和Fe_2SiO_4衍射峰消失。当CrO_3的添加质量分数为6%时,基体表面出现微熔,与陶瓷层结合最为紧密,涂层与基体的结合界面属于"机械锚固",此时显气孔率出现极小值,致密度最高;而后,随着CrO_3添加量增加,显气孔率逐渐升高,体积密度逐渐下降,当CrO_3添加质量分数为10%时,钢管发生了局部熔穿,获得的涂层气孔较多,结构疏松,质量较差。

Effect of CrO3 on the quality of thin wall pipe lining coating prepared by SHS gravity method

Using SHS gravity method,Al-Fe2O3 as reaction system,SiO2 and CrO3 as additives,the preparation of small diameter thin wall ceramic lined pipe was studied.The results show the ceramic layer contains Al2O3,Al6Si2O13,FeAl2O4 and Fe2SiO4 phases without adding CrO3,while the diffraction peaks of FeAl2O4 and Fe2SiO4 disappear after adding CrO3.When the mass percent of CrO3 is 6％,the surface of the substrate is slightly fused,which is the most closely combined with the ceramic layer,the coating and substrate interface are mechanical anchoring,the apparent porosity is the minimum and the volume density is the highest.With the increase of CrO3 content,the apparent porosity increases and the volume density decreases gradually.When the mass percent of CrO3 is 10％,the steel pipe has partial melting;the coating with more pores,loose structure and poor quality is obtained.