采用两步包埋渗的方法在钼基体表面制备了不同CeO 2掺杂量的Si-B复合涂层,通过XRD、EDS和SEM分析了CeO 2掺杂对Si-B复合涂层在1150℃氧化前后表面物相和截面形貌的影响,并采用失重法研究了CeO 2掺杂前后Si-B复合涂层在1150℃下氧化160 h的氧化动力学行为。结果表明:适量CeO 2的掺杂对Si具有一定的催渗效果,当CeO 2掺杂量为1%(质量分数)时,所制备的Si-B复合涂层的厚度最大且均匀致密,但随着CeO 2掺杂量的增加,涂层厚度有所减小。CeO 2掺杂Si-B复合涂层在1150℃下氧化前70 h的氧化速率常数值(1.48×10-4 mg 2/(cm 4·h))较未掺杂时明显降低,这表明CeO 2掺杂Si-B复合涂层的高温抗氧化性能较好。
The Si-B composite coatings with different doping amount of CeO 2 were prepared on the surface of molybdenum substrate by two-step pack cementation methods.The effect of CeO 2 doping on phase structure and cross-section morphology of Si-B composite coatings before and after oxidation at 1150℃were analyzed by XRD,EDS and SEM.The oxidation kinetics of Si-B composite coatings before and after CeO 2 doping oxidized at 1150℃for 160 h were studied by mass-loss method.The results showed that appropriate doping amount of CeO 2 had certain per-meation effect on Si element in pack cementation process.The Si-B composite coatings with thick,uniform and dense structure were obtained when the doping amount of CeO 2 was fixed at 1wt%.However,the thickness of Si-B composite coatings decreased with the further increase of CeO 2 doping amount.The oxidation rate constant(1.48×10-4 mg 2/(cm 4·h))of the doped Si-B composite coating oxidized at 1150℃for 70 h was significantly lower than that without CeO 2 doping,which indicated that the Si-B composite coating doped with CeO 2 has better high temperature oxidation resistance.
two-step pack cementation
Si-B composite coating
CeO 2 doping