| 摘要 |
The invention relates to a process for obtaining a composite chemical coating deposited onto metal and nonmetal surfaces of the device pieces, and may be used in the machine building and instrument engineering. The process for obtaining a composite chemical coating includes preparation of the suspension, containing the following components, g/L: nickel sulphate 20...30, lactic acid 35...45, sodium hypophosphite 10...30, maleic anhydride 1...2 and dispersed particles 5...10, deposition of the suspension coating at mixing at the temperature of 70...90oC, and subsequent annealing thereof in inert atmosphere. In the capacity of dispersed particles are used inhibited transition metal borides. Mixing of the suspension is carried out at quasi-liquefaction of the gummed ferromagnetic spherical particles of barium hexaferrite with a diameter of 3...5 mm, magnetized to saturation. Obtaining of the inhibited transition metal borides is carried out by introduction at mixing into the spent electrolytes of galvanic nickel-plating, cobalt plating and/or iron plating baths, heated up to 70...90oC, of the sodium borohydride solution, at the same time the molar ratio of the sodium borohydride: transition metal ions solutions constitutes (0,8...1,2):1, with subsequent treatment of surface of the obtained particles in solutions of lead chloride and sodium chromate. The result of the invention consists in improving the properties of the composite chemical coatings due to the utilization of highly dispersed inhibited particles providing for the increase in the stability of the obtained suspensions as well as due to the rigidity and thermo-stability of the metal borides.
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