Increase of durability of working bodies of tillage machines by applying metal-ceramic coatings

Currently, the most promising to increase the durability of the working bodies of tillage machines are metal-ceramic materials that are applied to the cutting surfaces in the form of coatings. A promising way to create metal-ceramic coatings is carbovibar hardening (CVH). When using CVH, a multicomponent paste containing a metal matrix, ceramic components and an activator of the arc burning process (cryolite) is applied onto the hardened surface, which, after drying, is melted by a vibrating carbon electrode to form a metal-ceramic coating. The aim of the work is to substantiate the feasibility of using a matrix powder on an iron basis in the composition of multicomponent pastes for CVH in order to improve the structure and physicomechanical properties of metal-ceramic coatings and increase the durability of the working bodies of tillage machines. When conducting research, iron-based powders and nickel-based powders were used as the matrix material of multicomponent pastes for the CVH, and boron and silicon carbides were used as ceramic components of the pastes. The greatest microhardness (1354 HV) are metal-ceramic coatings obtained on pastes containing matrix powder and boron carbide. The microstructure of the obtained coatings is dense and practically non-porous, and their wear is 3,6 times less than the wear of 30 GR steel adopted as the reference standard. The use of the matrix powder in the paste leads to a significant reduction in the microhardness of metal-ceramic coatings (1033 HV using boron carbide and 942 HV - silicon carbide), they contain a significant number of pores of various sizes. The obtained data confirm the feasibility of using iron-based powder as a matrix material of multicomponent pastes for CVH. According to the results of the research, the paste should contain 60 % of powder, 30 % of boron carbide and 10 % of cryolite. Its use will significantly increase the durability of the working bodies of tillage machines, reinforced with metal-ceramic coatings obtained at CVH.

working body, cermet coating, durability, carbide-arc hardening, multi-component paste, soil tillage machines, matrix powder