预腐蚀工艺对Gd_(2)Zr_(2)O_(7)陶瓷抗CMAS腐蚀性能的影响

Effect of Pre-corrosion of Gd_(2)Zr_(2)O_(7) at 900-1300 ℃ on Its Hot Corrosion Behavior at 1250 ℃ Beneath Deposites of CaO-MgO-Al_(2)O_(3)-SiO_(2)

对在900、1000、1100、1200和1300℃下预腐蚀0.5 h的Gd_(2)Zr_(2)O_(7)陶瓷进行了1250℃下3 h的CaO-MgO-Al_(2)O_(3)-SiO_(2)(CMAS)热腐蚀实验,利用XRD、SEM以及EDS等手段表征了腐蚀产物和腐蚀深度。实验表明,在1100℃下预腐蚀0.5 h之后的Gd_(2)Zr_(2)O_(7)抗CMAS性能有效提高。1250℃下CMAS腐蚀3 h后,腐蚀深度为39.46μm;CMAS腐蚀10 h后,腐蚀深度为70.49μm。高温下,预腐蚀后的Gd_(2)Zr_(2)O_(7)时与熔融的CMAS相互反应,形成致密的富磷灰石相(Ca_(2)Gd_(8)(SiO_(4))_(6)O_(2))上反应层,能够有效抑制CMAS的进一步渗透。

The Gd_(2)Zr_(2)O_(7)ceramics,as a candidate material for making thermal barrier coating,was subjected firstly to pre-corrosion beneath deposits of CaO-MgO-Al_(2)O_(3)-SiO_(2)(CMAS) powders in temperature range of 900-1300℃ for 0.5 h,afterwards,the pre-corroded Gd_(2)Zr_(2)O_(7)ceramics were subjected to CMAS induced hot corrosion at 1250℃ for 3 h.Then the corroded ceramics were characterized by means of XRD,SEM and EDS in terms of the composition and phase constituent of corrosion products and cross-sectional morphology of the corroded ceramics.Results reveal that after being pre-corroded beneath CMAS deposits at 1100℃,the ceramics present better corrosion resistance rather than the blank ceramics during the post-corrosion beneath CMAS deposits at 1250℃.Which presented corrosion depth of 39.46 and 70.49μm after CMAS induced hot corrosion at 1250℃ for 3 and 10 h respectively.It is proposed that during the pre-corrosion,the Gd_(2)Zr_(2)O_(7)could react with the melt CMAS at 1250℃ to form a dense top reaction scale riched in apatite (Ca_(2)Gd_(8)(SiO_(4))_(6)O_(2)),which can effectively inhibit the further penetration of CMAS during the post corrosion process induced by CMAS deposits.