中文摘要：

采用高温固相反应法合成Er_2Si_2O_7和LaMgAl_（11）O_（19）（LMA）粉末,用大气等离子喷涂（atmospheric plasma spraying,APS）方法在碳纤维增强的碳化硅复合材料（Cf/SiC）基体表面依次制备Si或Er_2Si_2O_7和LMA涂层,形成LMA/Er_2Si_2O_7和LMA/Er_2Si_2O_7/Si两种结构的抗氧化涂层,探索了LMA和Er_2Si_2O_7在高温下的化学相容性以及涂层在静态空气中对基体的抗氧化保护性能。研究结果表明,两种涂层对基体都有良好的抗氧化保护作用;Si涂层对基体表面的微孔起密封作用,降低了氧气的渗透率,因此LMA/Er_2Si_2O_7/Si涂层的性能比LMA/Er_2Si_2O_7更好;Er_2Si_2O_7和LMA在1 200℃以上开始发生轻微的化学反应而使涂层的稳定性降低,涂层的抗氧化性能也下降,1 400℃以上反应迅速,涂层的稳定性也迅速下降。APS技术制备的涂层,其结构均匀且与基体结合良好。随着温度的升高,循环热震10次后,涂层的裂纹逐渐增多,但均未出现脱落,显著提高了C_f/SiC复合材料的高温抗氧化性能。

英文摘要：

Er_2Si_2O_7 and LaMgAl_（11）O_（19）（LMA）powders were synthesized by the solid-state reaction,and these powders were deposited onto carbon fiber reinforced composite substrates（C_f/SiC）by atmospheric plasma spraying（APS）to fabricate LMA/Er_2Si_2O_7 coatings with or without Si bond layer.The chemical compatibility of Er_2Si_2O_7 and LMA,and oxidation protection performance of coatings at high temperatures were investigated.The experimental results indicate that both LMA/Er_2Si_2O_7 and LMA/Er_2Si_2O_7/Si coatings behave good for the oxidation-resistance of composite substrates.Si bond layer could effectively cover micro-pores in the surface layer of substrates,leading to the reduction of oxygen diffusion into substrates at high temperatures,and therefore the coating LMA/Er_2Si_2O_7/Si has a better oxidation-resistance than LMA/Er_2Si_2O_7.The partial reaction between Er_2Si_2O_7 and LMA occurred above 1 200 ℃,giving rise to the instability and reduction of oxidation-resistance of coatings.Coatings made by APS exhibit a homogeneous structure and bond well to the substrate.With the increase of temperature,cracks in coatings increased gradually after 10 cycles of thermal shock.The oxidation-resistance of composite substrates at high temperature was significantly improved by the coatings.