Авіаційно-космічна техніка та технологія (Aug 2021)
Influence of industrial cleaning fluids on anode-oxidative protective-decorative coating obtained in solutions of chrome anhydride
Abstract
The subject of research in this article is the anode-oxide coating of aluminum parts of the hull type of aircraft engine units and aircraft units under the influence of cleaning fluids of different nature and chemical compositions. The purpose of this work is to experimentally test, the effect of different cleaning fluids, under different operating conditions and on different equipment for the stability of the anode-oxide protective coating. Many experiments have been performed on three types of washing machines: jet and immersion washing machine, which works on all types of water-soluble detergents, washing machine cleaning in vacuum or low-pressure environment, uses modified alcohols or hydrocarbon solvents as a washing liquid, and specialized stand for cleaning parts with aviation kerosene, aviation fuel TS-1 or jet A-1. Flushing modes were, covered throughout the range of operation of this equipment. The operating conditions of engines and units and the need to use an anode-oxide coating of parts are determined. The main types of liquids for washing parts are considered. For each of the experiments a special technology of these studies was determined, as technological parameters, parameters that can change and affect the stability of the coating, were set the following temperature, detergent concentration, operating time, operating pressure in the detergent supply system. The change of each of these parameters was, carried out with the fixation of other technological parameters to determine the direct indicators of the impact of each of the parameters and to establish the growth of their impact on the anode-oxide coating. The conditions under which the coating is destroyed and the percentage of its damage from the total surface of the part are determined, and the quality of cleaning the part by particle size distribution and visual method was, also determined. It is determined that the greatest negative effects on the anodic oxide coating in the solution of chromic anhydride are acidic and alkaline water-soluble pore cleaning liquids, so they have the best quality of cleaning from contaminants, for which a range of indicators is determined at which the coating does not deteriorate.
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