Kinetics of the formation of diffusion titanium coatings on the surfaces of hard alloys during isothermal mass transfer of titanium in the Pb-Bi-Li melt

E.E. Bobylyov ORCID logo , E.G. Sokolov ORCID logo show affiliations and emails
Received 22 May 2023; Accepted 29 August 2023;
Citation: E.E. Bobylyov, E.G. Sokolov. Kinetics of the formation of diffusion titanium coatings on the surfaces of hard alloys during isothermal mass transfer of titanium in the Pb-Bi-Li melt. Lett. Mater., 2023, 13(4) 335-340
BibTex   https://doi.org/10.22226/2410-3535-2023-4-335-340
Elements composition and coating mechanism formation on WC-8%Co and WC-15%TiC-6%Co hard alloysThis paper describes the technology for manufacturing diffusion titanium coatings on cemented carbides, WC-Co and TiC-WC-Co (VK8 and T15K6 hard alloys respectively). The purpose of the work is to elucidate the mechanism and kinetics of the formation of diffusion coatings on cemented carbides in isothermal mass transfer of titanium in the Pb-Bi-Li eutectic. It has been demonstrated that in isothermal Pb-Bi-Li exposure of cemented carbides with powdered titanium added at 950 to 1100°C temperatures, mass transfer of titanium to the cemented carbide surface occurs. Meanwhile, an 8 to 32 µm coating is formed, depending on the cemented carbide composition, process temperature, and time. The greatest thickness of the coating has been obtained at 1100°C and exposure to the processing medium for 120 minutes. The coatings are formed from the TiC titanium carbide, with α-Ti, the Ti2Co intermetallic compound, and the WC tungsten carbide present, too. For the T15K6 hard alloy, concentration of titanium reaches 93 % in surface layers and remains so at the depth of up to 15 µm. For the VK8 hard alloy, the surface concentration of titanium was 87.6 %, remaining the same at the depth of up to 20 µm.