CAJ | 학술논문

用空气缓冷和水快冷方式对加热至1050℃的NiCrAlY单一涂层及含CrON扩散阻挡层的复合涂层冷却至室温,由此研究其抗循环氧化能力.结果表明:在缓冷情况下,经过200次循环氧化,无扩散阻挡层的NiCrAlY涂层明显退化,表面膜呈疏松多孔结构,以混合氧化物相为主,在涂层与基体界面附近出现Kirkendall孔穴;有扩散阻挡层的试样表面则以Al2O3膜为主,扩散阻挡层保持连续,无明显涂层退化或破坏现象,说明扩散阻挡层能明显提高NiCrAlY涂层的缓冷抗循环氧化能力.在快冷情况下,有或无扩散阻挡层的试样的表面涂层均较快发生破坏.40次循环氧化后,单一涂层表面出现鼓包突起;45次循环氧化后,鼓包处涂层脱落.而有扩散阻挡层的试样经40次循环氧化后于扩散阻挡层界面处开裂;45次循环氧化后,包覆涂层部分断落.利用Oxx公式能很好地解释涂层/基体或涂层/扩散阻挡层界面的破坏;对于快冷循环氧化,还要考虑在循环过程中的热应力累积效应.
용공기완랭화수쾌랭방식대가열지1050℃적NiCrAlY단일도층급함CrON확산조당층적복합도층냉각지실온,유차연구기항순배양화능력.결과표명:재완랭정황하,경과200차순배양화,무확산조당층적NiCrAlY도층명현퇴화,표면막정소송다공결구,이혼합양화물상위주,재도층여기체계면부근출현Kirkendall공혈;유확산조당층적시양표면칙이Al2O3막위주,확산조당층보지련속,무명현도층퇴화혹파배현상,설명확산조당층능명현제고NiCrAlY도층적완랭항순배양화능력.재쾌랭정황하,유혹무확산조당층적시양적표면도층균교쾌발생파배.40차순배양화후,단일도층표면출현고포돌기;45차순배양화후,고포처도층탈락.이유확산조당층적시양경40차순배양화후우확산조당층계면처개렬;45차순배양화후,포복도층부분단락.이용Oxx공식능흔호지해석도층/기체혹도층/확산조당층계면적파배;대우쾌랭순배양화,환요고필재순배과정중적열응력루적효응.
@@@@The cycled oxidation resistance abilities of single NiCrAlY coated sample and NiCrAlY/CrON duplex coating sample were studied by cooling from 1 050 ℃to room temperature in air and water quenching. The results show that during slow cooling, the single NiCrAlY coating degrades after 200 cycles, with mixed-oxides of Al2O3, NiCr2O4 and TiO2 on the surface and Kirkendall voids formed closing to the NiCrAlY/DSM11 interface. On the surface of duplex coating sample with the diffusion barrier layer, an adhered Al2O3 scale is formed and no damage is detected at the coating/substrate interface. In the case of fast cooling, the two coating samples are fast damaged only after some cycles. After 40 cycles, some bulges are found on the single coating surface, and the interfacial delamination occurs in the duplex coating sample. After 45 cycles, the coatings in the bulge zone are spalled off from the single coated sample, while part of the overlayer is fractured in the duplex coating sample. By Oxx formula, the thermal stress formed during cycled oxidations can be used to explain the interfacial damage or coating failure, and the cumulative effects of stress should be considered during rapid cooling in water quenching.