| Funded by the National Basic Research Program Of China (973 project) and the National High Technology Research and Development Program (863project), with the aim of developing satisfactory inert wettable cathode material for aluminum electrolysis, TiB2/Al203 composite cathode is taken as the research object. In order to improve the properties of composite cathode, the effects of solid content,glacial acetic acid mass fraction,peptization temperature on the viscosity,granularity,stability of colloidal alumina were investigated. The relationship between electrical resistivity,compressive strength,bending strength,relative density and colloidal mass fraction,colloidal solid content,alumina mass fraction,carbon fiber mass fraction,sintering temperature,sintering time,sintering atmosphere was studied. The main work and achievements are as follows:(1) With the increase of solid content and glacial acetic acid mass fraction, the viscosity of colloidal alumina increased; with the increase of peptization temperature, the viscosity of colloidal alumina first increased and then decreased. Particle size distribution curve of the sol with 5% solid content has the highest peak and minimum span, particle size distribution curves of the sol with 10% and 15% solid content appeared multimodal, span relatively large, particle size less concentrated. Particle size distribution curve of the sol with 1%,2%,4% and 5% glacial acetic acid mass fraction appeared multimodal, span relatively large, particle size less concentrated, particle size distribution curve of the sol with 3% glacial acetic acid mass fraction has the highest peak and minimum span. Particle size distribution curve of the sol with 45℃,65℃and 125℃peptization temperature appeared multimodal, span relatively large, particle size less concentrated, particle size distribution curve of the sol with 85℃and 105℃peptization temperature had the highest peak and minimum span, in addition, particle size distribution curve of the sol with 85℃was better than that with 105℃. Zeta potential of the sol with 5%,10% and 15% solid content were more than 30mv.they were all steady. With the increase of glacial acetic acid mass fraction and peptization temperature, the Zeta potential of colloidal alumina increased.(2) With the increase of colloidal solid content,and alumina mass fraction, the electrical resistivity and compressive strength increased. When the mass fraction of alumina powder increases from 0 to 25%, the relative density decreased from 93.43% to 92.06%, the electrical resistivity increased from 1.47μΩ·m to 2.45μΩ·m, the compressive strength decreased from 41.39MPa to 16.41MPa. When the mass fraction of alumina powder was 10%, the composite cathode had very good electrical resistivity (1.75μΩ·m) and compressive strength (39.55MPa). When the mass fraction of carbon fiber increases from 0.2% to 1.0%, the electrical resistivity decreased from 1.24μΩ·m to 0.49μΩ·m, the compressive strength increased from 35.24MPa to 46.30MPa, the bending strength increased from 17.51 MPa to 24.73MPa; when the mass fraction of carbon fiber increases from 1.0% to 3.0%, the electrical resistivity increased from 0.49μΩ·m to 1.13μΩ·m, the compressive strength decreased from 46.30MPa to 13.19MPa, the bending strength decreased from 24.73MPa to 8.28MPa. When the mass fraction of carbon fiber was 1%, the composite cathode had very good electrical resistivity (0.49μΩ·m),compressive strength (46.30MPa) and bending strength (24.73MPa).(3) Effect of sintering temperature(1300℃,1350℃,1400℃) and sintering time (1h,3h,5h,7h,9h) on the material structure and property of TiB2/Al2O3 composite cathode was analyzed. The results show that The composite cathode prepared by mixing TiB2 with colloidal alumina(15% solid content and 25% mass fraction), sintered at 1400℃for 3h, has a electrical resistivity of 1.47μΩ·m and a compressive strength of 41.39MPa. Effect of sintering atmosphere(vacuo and reducing atmosphere) on the material structure and property of TiB2/Al2O3 composite cathode show that the composite cathode prepared by mixing TiB2 with colloidal alumina(15% solid content and 25% mass fraction), sintered in vacuo at 1400℃for 3h, had a electrical resistivity of 1.47μΩ·m, a compressive strength of 41.39MPa and a bending strength of 19.44MPa; while sintered in reducing atmosphere at 1400℃for 3h, had a electrical resistivity of 4.10μΩ·m, a compressive strength of 83.768MPa and a bending strength of 40.37MPa.By the way, in sintering reducing atmosphere, TiC can be generated in composite cathode, this Increased mechanical properties of the composite cathode, and still have a very ideal resistivity.
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