随着重型燃气轮机不断升级，燃气轮机透平的进气温度不断提高，传统YSZ涂层已无法满足高于1200 ℃的服役温度。通过大气等离子喷涂技术制备新型热障涂层LaMgAl₁₁O₁₉（LMA）和YSZ涂层，在1100 ℃和1300 ℃进行静态氧化实验，采用SEM和XRD技术对比分析了不同烧结温度和时长下的孔隙率、微观组织和相变过程。结果表明：LMA涂层在1100 ℃和1300 ℃下，孔隙率随烧结时间的延长而增大，YSZ涂层则随烧结时间延长孔隙率明显下降。LMA涂层在高温下短时间内发生相变，断口中可观察到细小的针状晶，随烧结时间的延长，结晶相长大成条状和片状结构，有利于提高涂层的抗烧结性。Rietveld精修结果表明，在1300 ℃下烧结1000 h，YSZ涂层中T′相含量从82.67%下降至27.69%，C相含量从初始1.50%增加到46.84%，M相含量从0.19%增加到15.39%。此相变过程引起体积转变，产生较大的残余应力，导致涂层脱落。

With the development of heavy-duty gas turbines， its gas inlet temperature keeps increasing， and the traditional YSZ coatings could not service above 1200 ℃. The LaMgAl₁₁O₁₉（LMA） and YSZ coatings are fabricated byair plasma spray method， and the static oxidation tests are carried out at 1100 ℃ and 1300 ℃. The porosity， microstructure， and phase transformation process are investigated comparatively by SEM and XRD. The results show that the porosity of LMA coatings increases with the sintering time increasing at 1100 ℃ and 1300 ℃， while the porosity of YSZ coatings decreases obviously. The amorphous phase of LMA coatings is transformed rapidly at high temperatures. The needle-like grain at LMA coating fracture is formed， and the grain growth becomes platelet-shaped grains with the sintering time increasing， which improves the sintering resistance of LMA coatings. The results of YSZ coatings Rietveld refinement show that the content of the T′ phase decreases from 82.67% to 27.69% with the sintering time increasing to 1000 h at 1300 ℃. Meanwhile， the content of the C phase rises from 1.50% to 46.84%， and the M phase increases from 0.19% to 15.39%. This phase transformation causes volume transformation， which generates large residual stress，leading to the coating falling off.