In situ synthesis of titanium carbide coating on foam titanium by molten salt electrolysis

In this study, TiC coatings were formed on titanium foam by the carbon precipitation reaction (CO32- +4e- =C+3 O2-) during molten salt electrolysis, and the effects of the pre-oxidation process, electrolysis time and molten salt composition on the formation of TiC coatings were explored. The results show that the pre-formed oxide layer on the titanium foam surface can promote the formation of TiC coating. Prolonging the electrol-ysis time can increase the thickness of the TiC coating, but a long time will cause the excessive growth of TiC particles and the falling off the coating. Reducing the surface tension of molten salt can promote the diffusion of CO32-in the titanium foam, and TiC coating can also be formed inside foam titanium. When there is TiC coating on the surface of foam titanium, the hardness increased from 144.5 HV to 795.6 HV, and the wear amount is reduced by about 86%.

Automated summary

TiC coatings were formed on titanium foam by carbon precipitation reaction during molten salt electrolysis, and the effects of pre-oxidation process, electrolysis time, and molten salt composition on the formation of TiC coatings were explored. The results showed that the pre-formed oxide layer on the titanium foam surface promoted the formation of TiC coating. Prolonging electrolysis time increased coating thickness but also caused excessive growth of TiC particles and coating detachment. Reducing surface tension of molten salt promoted CO32- diffusion in the titanium foam, enabling formation of TiC coating inside the foam titanium. The presence of TiC coating on foam titanium surface increased the hardness and reduced wear amount.