The Relationship Between The Composition Of The Bonding Layer And The Interface Electron Structure Of The Thermal Barrier Coatings

This paper based on the Yu's "the empirical electron theory in solid and molecule (EET)" and Cheng's improved Thomas-Fermi-Dirac (TFD) theory, combining the interface valence electron structure parameters - phase structure factor and interface conjunction factor brought forward by Liu Zhilin and his colleagues, and in view of the valence electron structure and interface electron structure of the crystal, analyzed the valence electron structure of three kinds of different phase structure of ZrO2 in the ceramic thermal barrier coatings, calculated the interface conjunction factor between the bonding layer and ceramic layer of the thermal barrier coatings of different content of Co, Cr, Y. The results are as following.Calculated the phase structure factor of three different kinds of ceramic structure, and explained the phase transformation order of ceramics in view of valence electron structure that from the monocline phase of high temperature to tetragonal phase and final to cubic phase of low temperature. It completely coincides with experiment fact.No matter what orientation of the bonding layer in, the addition of Co can be in favor of the release of interface stress and keep the continuity of the interface electron density. While the orientation of the bonding layer is (110), the increasing of Co content can enhance the interface conjunction. However when the orientation is (100) or (111), the content of Co almost has no effect.When the orientation of the bonding layer is (100) or (111), the addition of Cr can improve the interface conjunction of the interface between the ceramic layer and the bonding layer. While the orientation is (110), a content of Cr less than 10-wt% can improve the interface conjunction. Otherwise Cr can damage the interface conjunction. Thereby, in the situation when the texture in the bonding layer is controlled with difficulty, considering the interface conjunction, the content of Cr of Ni based bonding layer should be reduced as low as possible.When the orientation of the bonding layer is (100) and (111), the addition of Y can improve the interface conjunction. But the effect is not obvious. While the orientation is (110), a content of Y more than 0.4-wt% can improve the interface conjunction. So the addition of Y greater than 0.4-wt% is suitable.