Abstract
The peculiarity of obtaining metal powders by direct current electrolysis is changes in the morphology of particles over the loose deposit layer thickness up to the formation of large spherulites. Deposit should be periodically removed from the cathode in order to obtain a powder with homogeneous composition. This paper justifies the choice of the parameter describing the change in loose deposit properties, and proposes a method for determining the periodicity of its removal from the cathode. Loose zinc deposits were obtained at 25 °C from zincate electrolyte containing 0.3 mol·l –1 of ZnO and 4 mol·l –1 of NaOH at a current setpoint exceeding 6 times the limiting diffusion current calculated using the smooth electrode. Electrode potential, deposit thickness and evolved hydrogen volume were measured directly in the process of electrolysis. Current redistribution between the metal reduction and hydrogen evolution leads to a change in the structure of loose deposit particles. It is shown that the differential current efficiency of zinc is the parameter describing the change in the loose zinc deposit density. Its value should not exceed 0.96 to ensure deposition of loose deposit with homogeneous properties. A further increase in current efficiency will lead to the formation of aggregates at the deposit growth front. It is proposed to determine the periodicity of loose deposit removal from the cathode using the empirical equation for the time dependency of differential current efficiency of zinc. The mathematical and statistical analysis of the data obtained in six replicates was carried out. The interval approach made it possible to significantly narrow the range of permissible differential current efficiency values and, as a consequence, to determine empirical equation coefficients with acceptable accuracy and calculate the growth time period of a deposit with homogeneous structure. The obtained approach can be used to estimate the time period of loose metal deposition accompanied by hydrogen evolution.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Izvestiya vuzov. Poroshkovaya metallurgiya i funktsional’nye pokrytiya
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
