Study On The Effect Of Interface Structure On Interface Bonding Strength Of Remanufacturing Coating

Remanufacturing industry as the emerging industries that aims to repair and reform waste products and restore their use value,has a great role in solving the problems of resource waste and environmental pollution in China.As an important part of remanufacturing technology,thermal spraying technology can not only repair surface damage,but also make a better surface performance by preparing coatings with different material properties on device surface.As a typical thermal spraying coating,thermal barrier coating is not easy to explore its interface strength through experiments because of its thin thickness.So it is very meaningful to explore the influencing factors of its interface strength through simulation for improving the life of thermal barrier coating.In this paper,different thermal barrier coatings models are established by using finite element method.Firstly,the effect of interface roughness on the residual stress of thermal barrier coatings after cooling was investigated.Then,the cohesion element was used to simulate the TBC/BC interface,and the effect of interface roughness of thermal barrier coatings on the interfacial bonding strength was investigated.Its main contents and achievements are as follows:1.Three models of thermal barrier coatings with different interfacial roughness were established.And the model was cooled to room temperature of 20? after a temperature load of 1000? was applied to the model.By comparing the difference of residual stress distribution among different roughness models,the results show that:With the increase of the roughness of the coating interface,the maximum residual stress increases in the coating increases,the minimum residual stress decreases and the distribution of residual stress becomes more inhomogeneous.By comparing the TBC/TGO interface and the TGO/BC interface of the same model,the results show that:The maximum stress at the interface of TBC/TGO is higher than that at the interface of TGO/BC.The maximum concentrated stress at the upper layer of thermal oxide(TGO),near the ceramic layer,is higher than that at the lower layer of thermal oxide(TGO).By comparing the residual stresses of wave peak and valley at the same interface,the results show that :The concentrated stress at the interface valley is much larger than that at the interface peak.The larger the interface stress,the smaller the local deformation.The difference of thickness and material between ceramic layer and matrix may be the reason for the difference of the stress concentration between the interface peak and the valley.2.The TGO layer of thermal barrier coating is set as cohesion unit,and the interfacial roughness of thermal barrier coating model is controlled by changing its amplitude.Three models of thermal barrier coatings with different interfacial roughness were established,and displacement loads were applied to the model.The process and results of interfacial fracture of coatings were observed and recorded,and the influencing factors on interfacial bonding strength of coatings were explored.By comparing the fracture time and displacement of different interface roughness models,the results show that:The greater roughness of the interface of the thermal barrier coating model,the longer tearing time of the interface,the greater the total displacement of the loading point of the model,and the greater of the interface strength.By recording the fracture stress of the coating interface from the beginning of simulation to the complete tearing of the thermal barrier coating interface,it can be found that : the greater surface roughness of thermal barrier coatings,the more inhomogeneous distribution of interfacial fracture stress and the greater maximum interfacial fracture stress.The average stress of TBC/TGO interface is obviously larger than TGO/BC interface.