ВЛИЯНИЕ ДОБАВКИ В ЭЛЕКТРОЛИТ НАНОРАЗМЕРНЫХ ЧАСТИЦ SiO2 НА СОСТАВ И СВОЙСТВА ОКСИДНЫХ СЛОЕВ, ФОРМИРУЕМЫХ ПЛАЗМЕННО-ЭЛЕКТРОЛИТИЧЕСКИМ ОКСИДИРОВАНИЕМ МАГНИЯ

Abstract

Magnesium and its alloys, due to the combination of lightness and strength characteristics, are of interest in all production industries particular about the weight of products - shipbuilding, aviation, rocketry. However, the surface properties of magnesium alloys fail to meet many requirements, and at the moment, there is no the effective method for their improvement. The electrochemical method of plasma electrolytic oxidation (PEO) is promising in this case but the technology of obtaining the oxide layers using this method needs to be improved. One of the ways of modifying the PEO layers is the addition of nanoparticles to the electrolyte. The paper describes the synthesizing of the oxide layers on the pure magnesium by the PEO method using the electrolyte without nanoparticles and with the addition of SiO 2 nanoparticles to the electrolyte. The authors studied the obtained oxide layers using the methods of scanning electron microscopy, X-ray spectral microanalysis, X-ray phase analysis, instrumental indentation, and the electrochemical tests. The structure, element and phase composition, adhesion strength to the substrate and the corrosion resistance of the oxide layers on magnesium were studied. The study demonstrated the positive effect of the SiO 2 nanoparticles additions to the electrolyte on the functional properties of the oxide layer - the adhesion strength to the substrate and corrosion resistance. The mechanism of the positive effect of nanoparticles on these characteristics was suggested. The study detected the phase of magnesium silicate Mg 2 SiO 4 , as well as magnesium phosphate Mg 3 (PO 4 ) 2 in the oxide layer which indicates the participation of both the electrolyte components - phosphorus, and the added nanosized particles of silicon dioxide in the formation of the layer.