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采用电弧离子镀技术在镍基单晶高温合金基体上制备了NiCoCrAlYSiB涂层和(NiCoCrAlYSiB+AlSiY)梯度涂层,对比研究了2种涂层退火态的组织结构和在1000,1100和1150℃下的恒温氧化行为.结果表明:退火处理后,NiCoCrAlYSiB涂层是由γ/γ相和弥散其中的点状β-NiAl相构成;(NiCoCrAlYSiB+AlSiY)梯度涂层分为两层,外层以β-NiAl相为主,含有少量的Cr3Si相、内层和NiCoCrAlYSiB涂层的结构相似.NiCoCrAlYSiB涂层在1000℃下有良好的抗氧化性能,在1100和1150℃下因表面生成保护性较差的尖晶石相而快速退化;(NiCoCrAlYSiB+AlSiY)梯度涂层在1000—1150℃下均表现出良好的抗高温氧化性能,1100℃度下氧化300 h后仍有大量的β-NiAl相存在,1150℃下氧化300 h后涂层中Al含量仍在8%(质量分数)以上,少量的β-NiAl相和过饱和的γ/γ相可维持表面Al_2O_3膜的形成和修复.
NiCoCrAlYSiB coating and (NiCoCrAlYSiB + AlSiY) gradient coating were prepared by arc ion plating technique on Ni-based single crystal superalloy substrate. The microstructures of the annealed NiTiCrAlYSiB and NiCoCrAlYSiB + (NiCoCrAlYSiB + AlSiY) gradient coating is divided into two layers, the outer layer of β-NiAl phase is composed of γ / γ phase and dispersed β-NiAl phase; NiCoCrAlYSiB coating is annealed, -NiAl phase, containing a small amount of Cr3Si phase, the inner layer and NiCoCrAlYSiB coating similar structure.NiCoCrAlYSiB coating at 1000 ℃ has good oxidation resistance, due to the surface at 1100 and 1150 ℃ to generate less protective (NiCoCrAlYSiB + AlSiY) gradient coating exhibited good high temperature oxidation resistance at 1000-1150 ℃ .After oxidation for 300 h at 1100 ℃, a large amount of β-NiAl phase still exists, The content of Al in the coating is still above 8% (mass fraction) after being oxidized at 1150 ℃ for 300 h. A small amount of β-NiAl phase and supersaturated γ / γ phase can maintain the surface Al 2 O 3 film formation and repair.