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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。
The powders of Er 2 Si 2 O 7 and LaMgAl 11 O 19 were synthesized by solid-state reaction at high temperature. The surface of the carbon fiber reinforced silicon carbide composites (Cf / SiC) was characterized by atmospheric plasma spraying (APS) The anti-oxidation coatings of LMA / Er_2Si_2O_7 and LMA / Er_2Si_2O_7 / Si were prepared by preparing Si or Er_2Si_2O_7 and LMA coatings. The chemical compatibility of LMA and Er_2Si_2O_7 at elevated temperatures was also investigated. Anti-oxidation protection. The results show that both coatings have good anti-oxidant protection on the matrix. The Si coating can seal the pores of the matrix and reduce the oxygen permeability. Therefore, the performance ratio of LMA / Er_2Si_2O_7 / Si coating LMA / Er_2Si_2O_7 is better; Er_2Si_2O_7 and LMA begin to undergo a slight chemical reaction above 1200 ℃, which leads to the decrease of the stability of the coating, the decrease of the oxidation resistance of the coating, the rapid reaction of more than 1400 ℃ and the stability of the coating Also rapidly declined. APS technology prepared coating, its structure is uniform and good combination with the substrate. With the increase of temperature, the cracks of the coating gradually increased after heat shock for 10 times, but no peeling occurred, and the high temperature oxidation resistance of C_f / SiC composites was significantly improved.