In-situ Synthesis Of Functional Coating By Electro-deoxidation Method

Electro-deoxidation is a new method to prepare the functional alloy coating. Compared with the traditional technology, it has a lot of advantages, such as environmental protection, energy conservation, high product purity, simple operation and so on, so the project enioys promising prospect.Mo-Si-Ti alloy coating was successfully prepared by using electrochemical method with the Mo substrate, SiO₂ sol and TiO₂ as raw material. The TiO₂ and borax mixed oxides were regarded as material to synthesis TiB alloy by the electrochemical deoxidation. Making use of TiO₂ and carbon as primary stuff, undergoing mixing and tabletting, the Ti-C alloy was successfully prepared by electrolying. Some key parameters, e.g. electrolytic voltage, electrolytic time, were studied in detail, and the products were detected by XRD and SEM.The function of Mo-Si-Ti coating preparation: In the electrolysis process, SiO₂ reacted with CaCl₂ to form Ca₂SiO₄, Ca₂ SiO₄ was formed of MoSi₂ on the Mo base surface by electrolysis reaction, TiO₂ was generated of Ti by deoxidation and Ti and Si were alloyed to generate TiSi₂, then its leaded to form a functional coating. Electric deoxidation reaction and electrolysis efficiency were promoted by increasing electrolysis voltage, Ti/Si molar ratio of 1:9, at 2.8 V in the 900 oC molten salt electrolyed for 3 h are the best conditions for preparing Mo-Si-Ti alloy coating.The preparation of Ti C: Results showed that TiO₂ reacted with CaCl₂ to form CaTiO₃, then the intermediate product of CaTiO₃ reacted with C to form Ti C, so as to obtain the desired product. During the experiment, prolonging the reaction time, its conducive to complete reaction and improve the purity of the product. Ti/C mole ratio of 1:2, at 2.8 V in the 900 oC molten salt electrolyed for 3h are the best conditions.The preparation of Ti-B alloy: Firstly, Na₂B4O₇ reacted with CaCl₂ to form CaB₂O₄, then TiO₂ and CaB₂O₄ reaction of Ti B, Ti₃B₄ and TiB₂ alloy. In the process of electrolysis, improve the temperature of the molten salt leaded to enhanced liquidity and improve the electrolysis efficiency.Ti/B mole ratio of 1:2, at 3.2 V in the 700 oC molten salt?NaCl+CaCl₂? electrolyed for 7 h are the best conditions.