Thermal shock cycling behavior of NiCoCrAlYSiB coatings on Ni-base superalloys: I. Accelerated oxidation attack
Thermal shock cycling behavior of NiCoCrAlYSiB coatings on Ni-base superalloys: I. Accelerated oxidation attack
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DOI：
10.1016/j.msea.2005.06.028
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发表时间：
2005-10
期刊：
影响因子：
6.4
通讯作者：
Qisheng Wang;Yizhe Tang;M. Guo;P. Ke;J. Gong;Congting Sun;L. Wen
中科院分区：
文献类型：
--
作者：
Qisheng Wang;Yizhe Tang;M. Guo;P. Ke;J. Gong;Congting Sun;L. Wen
采用电弧离子镀技术在镍基定向凝固高温合金表面制备了NiCoCrAlYSiB涂层。通过在高温（900、1000和1050℃）和室温（强制水淬）之间循环，研究了裸露和涂层试样的抗热震性。采用重力、XRD、SEM、EDS等方法对热冲击循环过程中的经历冲击进行了研究。结果表明，在热冲击循环条件下，裸合金和涂层试样的氧化加剧。在热冲击循环条件下，涂层试样表现出良好的抗热冲击性能，对高温合金具有足够的保护作用。研究了涂层的加速氧化机理及裂纹的形成和扩展。氧化加速是由于氧化物在高温下生长和冷却时的热失配导致氧化物中的压应力积累，从而加速了氧化物的形成和分解。涂层中裂纹的形成和扩展可归因于金属涂层中不可逆循环蠕变积累所产生的氧化物中的拉应力和突出到涂层中的氧化物的“楔入”效应。
NiCoCrAlYSiB coatings were obtained using an arc ion plating technique on a directionally solidified Ni-base superalloy. Thermal shock resistance of the bare and coated specimens were investigated by cycling between high temperature (900, 1000 and 1050°C) and room temperature (forced water quenching). The experienced attack during thermal shock cycling was studied by gravimetry, XRD, SEM and EDS. The results showed that bare alloys and coated specimens experienced aggravating oxidation under thermal shock cycling conditions. The coated specimens exhibited excellent thermal shock resistance and provided enough protective effect on the superalloys under thermal shock cycling conditions. The accelerated oxidation mechanism and crack formation and propagation in the coatings were also investigated. The accelerated oxidation can be attributed to the accelerating oxide formation and breakdown due to compressive stresses accumulation in the oxides due to oxide growth at high temperature and thermal mismatch during cooling. The formation and propagation of cracks formed in coatings can be attributed to tensile stresses in oxides generated by irreversible cyclic creep accumulation in the metallic coatings and the “wedging” effect of oxide protruded into the coatings.