Известия Томского политехнического университета: Инжиниринг георесурсов (Sep 2017)
Features of silver surface electrochemical decorating
Abstract
The relevance of the discussed issue is caused by the need to improve of methods of decorative processing of silver and its alloys. New phases are formed on anode surface (job) in the vast majority of the anode electrochemical processes, carried out to modify the properties of metal surfaces. Use of short current impulses (millisecond range duration) of a rectangular shape for anode processes allows affecting flexibly the course of phenomena at the interface «metal-electrolyte». The main aim of the study is to form the decorative invoices and films on sterling silver surface in thiosulfate electrolyte by pulse currents; to study the processes occurring at the interface «metal-electrolyte» at anode electrochemical decorating of sterling silver. The methods used in the study: modeling the pulse electrochemical treatment; photography of microgeometrical parameters with microscopes MIS-11 and MII-4; registration of amplitude-time parameters of impulses by oscillograph GRS-6052A; X-ray diffraction determination of film crystallites (grains) size by diffractometer DRON UM-1; photocolorimetry with software packages ColorPicker Eyedropper, ColorHexa - Color Information and Conversion. The results. The authors have studied the features of anode electrochemical decorating in thiosulfate electrolyte by unipolar and bipolar pulse currents. It was ascertained that electrochemical invoicing as well as electrochemical polishing take place at parallel passivation and activation of a surface. The authors revealed the dependence of processing result on the structure and a microstructure of silver-copper alloy and studied the composition and structure of the generated anode film. The methods of formation of small, average and big size decorative invoices of a surface and decorative color oxide films possessing high decorative properties on the sterling silver surface were offered.
