Silver oxalate films have been formed on silver electrodes by polarizing them slightly cathodically in dilute aqueous solutions containing Ag+ ions and dimethyl oxalate. The solutions were supersaturated with silver oxalate which was produced as a result of the hydrolysis of dimethyl oxalate and was sparingly soluble. The supersaturation was maintained during the film formation. The potential of the silver electrode with silver oxalate formed at a very low current density, showed a linear response to the oxalate ion concentration between 10-4 and 10-1 M.
A method and an apparatus to perform micro-etching and micro-inlay of patterns and numerals on the surfaces of artificial dental materials (ruby, nickel-chromium alloy, titanium alloy etc.) and artificial teeth by Penning discharge sputtering have been designed and evaluated. In this apparatus, selection of etching mode and inlay mode are made easily by a change of anode position. In etching mode, etching beam originates in a Penning discharge space and is guided through a duct in order to reach the surface covered with a pattern mask, and then forms an etched pattern on the surface. After etching is made, a new position of the anode is selected for inlay process and some of the metal atoms, sputtered from the cathode surface and passed through the duct, deposit on the previously etched portion. In the case of glass and ruby, etching rates are 70-90 nm/min and deposition rate of gold 60 nm/ min. Micro-etching of numerals (about 200 μm in size) on full casted crowns and heart-shaped micro-inlays on porcelain teeth and titanium alloy plate of denture are made respectively. This technique is very suitable for personal identification of corpse that met with traffic or fire accidents.