Sedimentation Resistance of Electrolyte-Suspension and Microhardness of Nanocomposite Galvanic Coatings Based on Chromium

Abstract

By adding nanosized materials to electrolytes, coatings with improved physical and mechanical properties can be obtained. Galvanic coatings are used to solve the problems of machine-building and repair production, both in the automotive industry and in construction, aviation, radio and electronic industries. The most interesting were potassium polytitanates. To obtain chromium-based nanocomposite electroplating coatings, the following group of nanosized particles was selected for research: Al2O3, AlN, SiC, TiC, WC, K2OnTiO2. The article considers methods of increasing sedimentation resistance of electrolytes for application of nanocomposite electroplating coatings based on chromium. To obtain chromium-based nanocomposite electroplating coatings, a self-regulating chromium electrolyte was selected. The method of plasma re-condensation is selected, allowing to obtain various nanodisperse materials with particle size from 10 to 100 nm. Studies have shown that electrolyte suspension obtained by ultrasonic generator treatment with frequency of 22 kHz for 10-12 min is most resistant. Coating application should be carried out under constant action of ultrasonic oscillations of ultrasonic bath with frequency of 18 kHz. The microhardness of the coatings obtained by this method, using nano-sized particles Al2O3, reaches 14.1 GPa, which is 1.03... 1.21 times the microhardness of the coatings obtained with other particles and 1.47 times the microhardness of the coatings without adding nano-sized particles.