ETCHANT FOR MICROSTRUCTURE ANALYSIS FOR FERRITIC STEELS, MANUFACTURING METHOD THEREOF AND METHOD OF ETCHING

摘要

The present invention provides etchant having picric acid, sodium thiosulfate, and hydrochloric acid. According to the present invention, provided is a manufacturing method of the etchant, which comprises the following steps of: manufacturing a picric acid solution having picric acid, hydrochloric acid, and a solvent; manufacturing a sodium thiosulfate solution having sodium thiosulfate and a solvent; and mixing the picric acid solution and the sodium thiosulfate solution. Moreover, provided is an etching method which comprises the following steps of: depositing ferritic steel into the etchant to obtain the etched ferritic steel; and cleaning the etched ferritic steel with nitric acid. Thus, a microstructure of the ferritic steel to which a plurality of alloy elements are added is clearly sorted to improve reliability of biopsy measurement data.