Protective Coatings Based on Titanium Diboride and Carbon Fillers

Research has been carried out on the development of compositions of protective coatings based on TiB2 and various carbon fillers, as well as the method of their application to cathode blocks of aluminum electrolyzers. The physical and chemical properties (surface morphology of particles, granulometric and phase composition) of initial powders of titanium diboride and the physicomechanical properties and microstructure of laboratory samples of protective coatings are determined. It is shown that compositions based on TiB2 and MKhNU carbon filler (low-shrinkage cold-filled mass) are most promising. High-temperature tests of laboratory samples of coatings of optimal composition with the addition of 50% MKhNU were carried out, which showed that the coating is wetted by aluminum melt and reduces the wear of cathode blocks. A 20-mm-thick coating was locally applied to the experimental electrolyzer bottom in the form of 900-mm-wide strips along the electrolyzer sides, taking into account the wear profile, and is currently undergoing industrial tests. Results of monitoring the titanium content in the metal for 196 days after the electrolyzer startup show the effectiveness of using the developed coating to protect cathode blocks from wear and increase the service life.