等离子喷涂炭/炭复合材料Cr-Al-Si涂层显微结构及高温抗氧化性能

采用等离子喷涂法在涂覆SiC内涂层的炭/炭复合材料表面制备了Cr-Al-Si外涂层。采用XRD和SEM分析了涂层的物相组成及微观结构, 并测试了复合涂层炭/炭复合材料试样在1500℃静态空气中的抗氧化性能。结果表明: 合金外涂层主要由Al_3.21Si_0.47、 Cr₃Si及Al₂O₃组成, 厚度约为120μm, 无穿透性裂纹; 多孔结构单一β-SiC内涂层的防氧化能力较差, 氧化10h后涂层试样的氧化失重就接近10%, 外加Cr-Al-Si涂层后, 涂层试样的氧化性能显著提高, 氧化61 h后试样的失重仅为5.3%。 

Investigation on microstructure and oxidation resistance of Cr-Al-Si coating for carbon/carbon composites by plasma spraying

Cr-Al-Si coating was prepared on the surface of SiC coated C/C composites by the plasma spraying method. The phase composition and microstructure of Cr-Al-Si coating were studied by XRD and SEM. The isothermal oxidation test at 1500℃ was carried out in air. The XRD results show that the outer Cr-Al-Si alloy coating consists of Al3.21Si0.47, Cr3Si and Al2O3. The thickness of the coating was about 120μm, and no penetrable crack was observed in the cross-sectional SEM morphologies of the coating. The oxidation resistance of the single porous β-SiC coating is poor, which can only protect C/C composites from oxidation for 10 h with a mass loss of 10%. After adding the Cr-Al-Si alloy outer coating, the double-layer Cr-Al-Si and SiC show a better oxidation protective ability and 5.3% mass loss of the coated sample after oxidation for 61h.