一步法制备含扩散阻挡层的多层体系及其界面结合强度

ONE-STEP DEPOSITION AND INTERFACIAL ADHESIVE STRENGTH OF THE MULTILAYER SYSTEM WITH A DIFFUSION BARRIER

为抑制合金元素的互扩散,在Ni-Cr-Al-Y-Si涂层和DSM11基体间通过电弧离子镀技术一步制备了含扩散阻挡层(DB)和黏结层(BC)的多层体系Ni-Cr-Al-Y-Si/DB/BC/DSM11.由恒温氧化、循环氧化和粘胶拉伸实验考察了涂层的抗氧化性、DB阻挡元素扩散能力和体系的界面结合强度.结果表明,含扩散阻挡层的多层能很好地保护基体材料,经过1050℃恒温氧化100 h后,试样表面形成连续致密的Al_2O_3膜,外层中仅检测到微量的来自基体的合金元素;经过1050℃(?)室温(RT)循环氧化100 cyc后,DB与两侧材料的结合保持良好.退火多层体系的界面结合强度达到63.6 MPa,比不连续法制备的Ni-Cr-Al-Y/Cr-O-N/DSM11体系提高了约20 MPa.一步法制备能提高含扩散阻挡层多层体系的界面结合强度,DB在恒温和循环氧化过程中能保持很好的抑制元素扩散的能力.

M-Cr-Al-Y（M=Ni and/or Co） coatings with the good comprehensive property among anti-oxidation,anti corrosion and mechanical properties have been widely used for the protection for the gas turbine components.However,after a long-term thermal exposure to high temperature atmosphere in service,the coatings are rapidly degraded.The main cause is ascribed to the intensive element interdiffusion between the coating and the substrate.To suppress the interdiffusion,addition of a diffusion barrier（DB） is required at the interface of the overlayer and the substrate.However,M-Cr-Al-Y coating system with a ceramic diffusion barrier prepared by a conventional two-step arc ion plating（AIP） on the superalloy substrate would reduce the interfacial adhesive strength.In this paper,the multilayer system of Ni-Cr-Al-Y-Si overlayer with a DB and a bond coat（BC） was deposited on the DSM11 substrate by one-step AIP. The anti-oxidation property,the anti-diffusion ability of the barrier and the interfacial adhesive strength of the multilayer system were investigated.The results indicate that the multilayer can provide more effective protection for the DSM11 substrate than the single coating at high temperature. After 100 h thermal exposure at 1050℃,the surface Al_2O_3 scales are continuous,dense,and only very little amounts of alloy elements diffused from the substrate is detected in the overlayer.After 100 cyc cycles between 1050℃and room temperature（RT）,the barrier layer has still well adhesive to the overlayer and the substrate.The tensile adhesion test shows that the interfacial adhesive strength is 63.6 MPa for the annealed multilayer system,which is about 20 MPa higher than that of the coating system with a DB on the DSM11 substrate deposited by the two-step AIP.The one-step AIP method can increase the interfacial adhesive strength and improve the anti-oxidation performance of the multilayer with DB.