LaMeAl11O19(Me=Cu,Zn)陶瓷体材料的抗CMAS性能研究

随着燃气涡轮机的应用温度不断提升,陶瓷材料的抗CaO-MgO-Al₂O₃-SiO₂(CMAS)性能越来越重要。通过X射线衍射(XRD)、扫描电镜(SEM)等测试方法,研究了LaMeAl₁₁O₁₉(Me=Cu,Zn)陶瓷体材料在不同温度和时间条件下的抗CMAS腐蚀行为。结果表明,LaZnAl₁₁O₁₉(LZA)和LaCuAl₁₁O₁₉(LCA)体材料的腐蚀产物都包括透辉石(Ca(Mg,Al)(Si,Al)O₇)和钙长石(CaAl₂Si₂O₈)。随着腐蚀温度的提高和时间的延长,腐蚀深度增加,Ca(Mg,Al)(Si,Al)O₇逐渐转变为CaAl₂Si₂O₈。LZA和LCA体材料的CMAS腐蚀可以用“溶解-析出”机制解释。体材料逐渐溶解到CMAS中,形成Ca(Mg,Al)(Si,Al)O₇,进而逐渐转变为CaAl₂Si₂O₈,使难以结晶的透辉石相转变为易结晶的钙长石相。La原子为析晶的晶核,CMAS玻璃相与体材料之间存在界面能,这些因素共同促进了CaAl₂Si₂O₈在CMAS内部以及两者的界面处析出厚板状晶体。

Study on CMAS Resistance of LaMeAl11O19(Me=Cu,Zn) Ceramic Bulk Materials

With the increasing application temperature of gas turbine, the CMAS resistance of ceramic materials is becoming more and more important. In this paper, theCaO-MgO-Al₂O₃-SiO₂ (CMAS) corrosion resistance behavior of LaMeAl₁₁O₁₉ (Me=Cu,Zn) ceramic bulk materials under different temperatures and time was studied by X-ray diffraction (XRD), scanning electron microscope (SEM) and so on. The results show that the corrosion products of both LaZnAl₁₁O₁₉(LZA) and LaCuAl₁₁O₁₉ (LCA) bulk materials include diopside (Ca(Mg,Al)(Si,Al)O₇) andanorthite (CaAl₂Si₂O₈). With the increase of corrosion temperature and time, the corrosion depth increases, and Ca(Mg,Al)(Si,Al)O₇ gradually transforms into CaAl₂Si₂O₈. The CMAS corrosion of LZA and LCA bulk materials can be explained by “dissolution-precipitation” mechanism. The bulk materials gradually dissolve into the CMAS, forming Ca(Mg,Al)(Si,Al)O₇, and then gradually transform into CaAl₂Si₂O₈, so that the diopside phase which is difficult to crystallize is transformed into the anorthite phase which is easy to crystallize. La atom is the crystal nucleus of devitrification, and the interfacial energy exists between the CMAS glass phase and the bulk materials. These factors together promote the precipitation of thick plate-like crystals of CaAl₂Si₂O₈ inside CMAS and at the interface of CaAl₂Si₂O₈ and CMAS.