微阴极电弧推力器导电薄膜状态实验研究

In order to make up for the lack of evaluation methods for conductive films of Micro Cathode Arc Thruster（μCAT）and in-depth study the degradation of film，a state characterization method of the conductive film was established，based on the four-probe resistivity test theory and size effect fitting model. This method is used to investigate the variation of the conductive film parameters of μCAT under different discharge times. The research shows that with the increase of the number of discharges，the resistivity of the film increases，the charac⁃ teristic thickness of the film decreases. Influenced by the changes of the two factors，the resistance of the film in⁃ creases exponentially，and the influence of the thickness is greater than that of the resistivity. For Ti films，the di⁃ viding line between the bulk resistance region and the size effect region is about 2μm. When the thickness is greater than 5μm，the thruster will fail due to short circuit. When the thickness is between 0.012μm and 2μm，it is the stable discharge region of the thruster，which is in the size effect region and the resistance continues to rise. When the thickness is less than 0.012μm，the film resistance exceeds 1000Ω and rises sharply until the thruster fails due to open circuit. The state evaluation method of conductive film is to calculate the parameters of conduc⁃ tive film by combining experimental measurement data and theoretical model，and the validity of the method is verified by experiments. This method can provide technical support for the future evaluation of the lifetime of μCAT by the state characterization of the conductive film.