Саvitation-erosion wear resistance composite electrolytic coatings in neutral medium

Abstract

The work presented technology of wear-resistant composite electrolytic coatings on nickel base. Composite coatings containing a filler consisting of silicon carbide powders of different factions nanopowders of up to 50 nm, 5 (M5) mk, 20/28 mk, 40/50 mk and amorphous B particle size of about 1 micron to form during the subsequent heat treatment of solid solutions. Accordingly, in the accepted designation: Ni-SiC nano ; Ni-SiC 5 ; Ni-SiC 28 ; Ni-SiC 50 . To form the CEP was established setting that lets you adjust the resistance of the near-electrode layer of electrolyte, which in turn, makes it possible to form CEP in a wide range of process parameters electrolysis both horizontally and vertically on the cathode. The novelty of the design of the installation is protected by a patent of Ukraine № 55154 from 10.12.2010. Investigation of cavitation-erosion wear resistance in hard water and in 3% solution of NaCl showed that CEP formed can be divided into 2 groups: group I - CEP SiC nano of Ni-and Ni-SiC 5 and group II - CEP of Ni-SiC 28 , Ni -SiC 50 . Therefore, to enhance cavitation-erosion wear resistance of parts of sodium chloride, particularly in sea water (3% solution of NaCl), the most effective CEP of SiC nano and Ni-SiC 5 (group I). Thermal annealing at 400 o C for 1 ... 2 hours increases the cavitation wear CEP Ni- SiC nano 20% in hard water and 30% in a solution of NaCl, due to the increase of microhardness and tension leveling coating and increase corrosion resistance by reducing the electrochemical heterogeneity. Vacuum annealing CTR with particles of silicon carbide and boron in 1080-1090 o C can obtain wool - dense and smooth coatings Kavita -ment of durability enhancement schuyetsya an average of more than 2-fold by the formation of a solid frame with eutectic Ni-Ni 3 B and borides Ni 3 B.