The disclosure relates to the use of H.sub.2SO.sub.4 as an electrolyte in processes for polishing metals, specifically metal parts, for example in jewellery. According to some embodiments the polishing is carried out based on ion transport with electrically conductive free solids in a gaseous environment. According to some embodiments the solids comprise spherical particles with porosity and affinity for retaining the electrolyte so that they have appreciable electric conductivity.

A low-hazardous electropolishing process has been developed to remove oxide layer(s) from the surface of nitinol needles. Low concentrations of citric acid and sulfamic acid are mixed with medium concentrations of sulfuric acid to use as an electrolyte solution. The process can be easily fitted into current suture needle manufacturing processes as well as into processes require electropolishing of nitinol-containing medical devices.

A low-hazardous electropolishing process has been developed to remove oxide layer(s) from the surface of nitinol needles. Low concentrations of citric acid and sulfamic acid are mixed with medium concentrations of sulfuric acid to use as an electrolyte solution. The process can be easily fitted into current suture needle manufacturing processes as well as into processes require electropolishing of nitinol-containing medical devices.

Methods for electropolishing and coating aluminum on a surface of an air and/or moisture sensitive substrate, including: in a vessel, submerging the substrate in a first molten salt bath and applying an anodizing current to the substrate at a first temperature to electropolish the surface of the substrate; wherein the first molten salt bath includes one of a first organic salt bath and first inorganic salt bath; wherein, when used, the first organic salt bath includes one of (a) aluminum halide and ionic liquid, (b) a combination of an aluminum halide and halogenatedmethylphenylsulfone (C.sub.6(H.sub.5y,X.sub.y)SO.sub.2CX.sub.3, where y is a number from 0-5), (c) a combination of an aluminum halide, an ionic liquid, and halogenatedmethylphenylsulfone (C.sub.6(H.sub.5y,X.sub.y)SO.sub.2CX.sub.3), and (d) AlF.sub.3-organofluoride-hydrofluoric acid adduct; wherein, when used, the first inorganic salt bath includes aluminum halide and alkali metal halide; and wherein the anodizing current is 10-30 mA/cm.sup.2.

The disclosure relates to the use of H.sub.2SO.sub.4 as an electrolyte in processes for polishing metals, specifically metal parts, for example in jewellery. According to some embodiments the polishing is carried out based on ion transport with electrically conductive free solids in a gaseous environment. According to some embodiments the solids comprise spherical particles with porosity and affinity for retaining the electrolyte so that they have appreciable electric conductivity.

The purpose of the present invention is to further level the amount of polishing during electrolytic polishing of the inside of a hollow pipe. A holding frame for vertically holding a hollow pipe is pivotally supported on a rack so as to be vertically invertible about the vertical center of the hollow pipe. An electrode is inserted through the hollow pipe and a liquid buffer is disposed on each end of the hollow pipe. A valve mechanism is capable of switching a liquid supply/discharge circuit so as to supply an electrolyte via the liquid buffer positioned at the bottom and discharge the electrolyte via the liquid buffer positioned at the top whether it is before or after the inversion of the holding frame (inversion of the hollow pipe). During an electrolyte supply period before and after the inversion, an electrolytic treatment is as a matter of course carried out for a predetermined length of time. Although said switching by the valve mechanism may be manually performed, a control means may also be used.

Disclosed is a method of manufacturing an emitter in which the tip of the emitter can be formed into a desired shape even when various materials are used for the emitter. The method includes performing an electrolytic polishing process of polishing a front end of a conductive emitter material so that a diameter of the front end is gradually reduced toward a tip; performing a first etching process by irradiating a processing portion of the emitter material processed by the electrolytic polishing process with a charged particle beam; performing a sputtering process by irradiating the pointed portion formed by the first etching process with a focused ion beam; and performing a secondary etching process of further sharpening the tip by an electric field induced gas etching processing while observing a crystal structure of the tip of the pointed portion processed by the sputtering process using a field ion microscope.

Disclosed is a method of manufacturing an emitter in which the tip of the emitter can be formed into a desired shape even when various materials are used for the emitter. The method includes performing an electrolytic polishing process of polishing a front end of a conductive emitter material so that a diameter of the front end is gradually reduced toward a tip; performing a first etching process by irradiating a processing portion of the emitter material processed by the electrolytic polishing process with a charged particle beam; performing a sputtering process by irradiating the pointed portion formed by the first etching process with a focused ion beam; and performing a secondary etching process of further sharpening the tip by an electric field induced gas etching processing while observing a crystal structure of the tip of the pointed portion processed by the sputtering process using a field ion microscope.

A method for electropolishing a manufactured metallic article, the method comprising: contacting the metallic article with an electropolishing electrolyte; and electropolishing the metallic article in the electropolishing electrolyte through the application of an applied current regime comprising: at least one electropolishing regime, each electropolishing regime comprising a current density of at least 2 A/cm.sup.2 and a voltage comprising a shaped waveform having a frequency from 2 Hz to 300 kHz, a minimum voltage of at least 0 V and a maximum voltage of between 0.5 to 500 V.

A method for electropolishing a manufactured metallic article, the method comprising: contacting the metallic article with an electropolishing electrolyte; and electropolishing the metallic article in the electropolishing electrolyte through the application of an applied current regime comprising: at least one electropolishing regime, each electropolishing regime comprising a current density of at least 2 A/cm.sup.2 and a voltage comprising a shaped waveform having a frequency from 2 Hz to 300 kHz, a minimum voltage of at least 0 V and a maximum voltage of between 0.5 to 500 V.