Electropolishing process

Abstract

The present invention relates to a method for the electropolishing of surfaces of metals and metal alloys. Said method is characterized in particular in that it can be applied to a wide range of metals. Thus, it is suitable for the electropolishing of metal surfaces comprising iron, tungsten, magnesium, aluminum or an alloy of these metals. The electrolyte used in the method comprises methanesulfonic acid and at least one alcoholic compound selected from aliphatic diols of general formula C_nH_2n(OH)₂ with n=2-6 and alicyclic alcohols of general formula C_mH_2m-1OH with m=5-8.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a method for the electrochemical polishing of surfaces of metals and metal alloys.BACKGROUND OF THE INVENTION[0002]The purpose of the process of electrochemical polishing or electropolishing is to produce metal surfaces of high purity, and to smooth and deburr the metal surfaces. Smoothing in the micro-range can also produce gloss of the surfaces so treated. Furthermore, electropolishing can also remove any stresses from the outer layers of the material.[0003]There are a great many different electropolishing processes that can be used for the processing of various metals or metal alloys. As a rule these processes are based on the use of electrolytes that comprise a concentrated inorganic acid such as phosphoric acid or sulfuric acid or a mixture of concentrated inorganic acids, often with additives for further enhancing the action of the electrolytes so as to obtain smoother and shinier metal surfaces. Some examples of suc...

AI Technical Summary

Benefits of technology

[0017]Preferably, the electrolyte used in the method according to the present invention contains no water or only small amounts of water. Thus, the water content of the electrolyte should not exceed a proportion of 10% water. Furthermore, the electrolyte does not require any addition of salts to increase its conductivity.

[0018]In a special embodiment of the present invention the method is carried out at a temperature between 40° C. and 100° C. It is especially preferred for the method to be carried out at a temperature between 60° C. and 100° C. Since the electrolyte of the present method does not contain any highly volatile constituents, higher temperatures can be used, for

Problems solved by technology

However, a feature that is common to all of these existing electrolytes, which are widely used industrially, is that they can only be used successfully for certain metals and/or alloys and thus have a very restricted application profile.

Often the individual electrolytes must be kept strictly separate and in particular must not be mixed, as any mixing may damage them and make them unusable.

Sometimes this can even result in certain constituents of the electrolytes reacting together and, for example, releasing substances that are hazardous or injurious to health.

This in turn causes considerable expenditure and