CAJ | 학술논문

在传统的热障涂层(TBCs)制备工艺的基础上,在制备热障涂层陶瓷层前,采用超音速微粒轰击技术(SFPB)改变粘结层的表面状态.采用X射线衍射分析仪(XRD)、扫描电子显微镜(SEM)、能谱仪(EDS)、透射电子显微镜(TEM)和微区Cr3+荧光光谱研究粘结层的表面结构及其1000℃时的高温氧化相变.粘结层表面位错密度大幅度增加,形成了大量的原子扩散通道；在高温氧化初期,粘结层中Al原子扩散速度的增快保证了优先形成一层稳定的α-Al2O3相；在高温氧化瞬态阶段,大量Cr3+通过SFPB产生的扩散通道,形成过渡相(Al0.9Cr0.1)2O3,该过渡相间接促进了γ→θ→α相变.在高温氧化初期,热障涂层TGO中的残余应力先急剧增大然后减小:与高温氧化26 h的0.93 GPa相比,高温氧化310h的残余应力降低至0.63 GPa.在热障涂层的TGO层中获得了单一、连续、致密的具有抗高温氧化能力的主相α-Al2O3,这利于进一步延长其使用寿命.
재전통적열장도층(TBCs)제비공예적기출상,재제비열장도층도자층전,채용초음속미립굉격기술(SFPB)개변점결층적표면상태.채용X사선연사분석의(XRD)、소묘전자현미경(SEM)、능보의(EDS)、투사전자현미경(TEM)화미구Cr3+형광광보연구점결층적표면결구급기1000℃시적고온양화상변.점결층표면위착밀도대폭도증가,형성료대량적원자확산통도；재고온양화초기,점결층중Al원자확산속도적증쾌보증료우선형성일층은정적α-Al2O3상；재고온양화순태계단,대량Cr3+통과SFPB산생적확산통도,형성과도상(Al0.9Cr0.1)2O3,해과도상간접촉진료γ→θ→α상변.재고온양화초기,열장도층TGO중적잔여응력선급극증대연후감소:여고온양화26 h적0.93 GPa상비,고온양화310h적잔여응력강저지0.63 GPa.재열장도층적TGO층중획득료단일、련속、치밀적구유항고온양화능력적주상α-Al2O3,저리우진일보연장기사용수명.
This work was attempted to modify the current technology for thermal barrier coatings (TBCs) by adding an additional step of surface modification,namely,supersonic fine particles bombarding (SFPB) process,on bond coat before applying the topcoat.After isothermal oxidation at 1000 ℃ for different time,the surface state of the bond coat and its phase transformation were investigated using X-ray diffraction (XRD),scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectrometry (EDS),transmission electron microscopy (TEM) and Cr3+ luminescence spectroscopy.The dislocation density significantly increases after SFPB process,which can generate a large number of diffusion channels in the area of the surface of the bond coat.At the initial stage of isothermal oxidation,the diffusion velocity of Al in the bond coat significantly increases,leading to the formation of a layer of stable α-Al2O3 phase.A great number of Cr3+ positive ions can diffuse via diffusion channels during the transient state of isothermal oxidation,which can lead to the presence of (Al0.9Cr0.1)2O3 phase and accelerate the γ→θ→α phase transformation.Cr3+ luminescence spectroscopy measurement shows that the residual stress increases at the initial stage of isothermal oxidation and then decreases.The residual stress after isothermal oxidation for 310 h reduces to 0.63 GPa compared with 0.93 GPa after isothermal oxidation for 26 h.In order to prolong the lifespan of TBCs,a layer of continuous,dense and pure α-Al2O3 with high oxidation resistance at the interface between topcoat and bond coat can be obtained due to additional SFPB process.