Abstract
UDC 621.785.53
DOI https://doi.org/10.5281/zenodo.1053018
Changing the saturation capability of an aqueous electrolyte containing ammonium chloride and ammonia during nitriding VT22 titanium alloy is considered. Changes of the electrolyte composition are due to evaporation of water, ammonia, decomposition products of ammonium chloride and emission of ions from the boiling solution into the vapour-gas envelope by an electric field. It is found that the thickness of the layer of high hardness (460 HV), reaching 20 mm at processing in a fresh electrolyte, decreased by 40% when using a solution operated for 5 hours. The possibility to improve the durability of the electrolyte by returning gases and vapors from the shell to it is shown. Using an electrolyzer with the possibility of returning the exhaust vapors and gases at processing into the electrolyte allows saving its ability to saturating during 5 hours of operation to form a layer of about the same as that formed in a fresh electrolyte. The increase in conductivity of the solution and vapour-gas envelope as electrolyte is developing due to the preferential loss of dielectric components is found.
Keywords: plasma electrolysis, nitriding, titanium alloy, electrolyte depletion.