Peculiarities of Chromium Coating in Low-Concentrated Electrolytes when Repairing Details

Abstract

The physical-mechanical properties of chromium coatings from low-concentrated electrolytes with additions of organic substances were studied when comparing with similar ones from standard sulphate electrolyte. It has been established that the properties of chromium coatings from low concentrated electrolytes are superior to those of standard sulphate electrolyte. An additional advantage of low-concentrated electrolytes is less carry-over of chromium anhydrate through ventilation and wash water, which reduces the cost of cleaning them when they are discharged. However, under operating conditions, more frequent adjustment of the composition of such electrolytes is required. The electrolyte is distinguished by a good scattering over the surface of parts and covering power when restored to size on a thickness of 250-300 μm of hydraulic cylinders of agricultural and mining equipment, having a length of up to 4 m and a diameter of up to 0.5 m, an increased current output of up to 24-36 % and up to 3-4 times higher corrosion resistance, micro hardness of up to 1,300 kg / mm2, determined by the conditions of deposition relative to the standard sulfate electrolyte of chromium plating. Chromium coatings from a low-concentration electrolyte with organic additives passed the recommended tests for adhesion, tearing, wear and micro hardness according to GOST methods. Their use at the enterprises of technical service for repair of agricultural parts promises economic advantages in the field of practical application (higher deposition rate and less application time), as well as lower costs for environmental protection.