Abstract
In the determination of small amounts of oxygen in iron and steel, the formation of oxide film and the adhesion of oxide on the surface in sample preparation may make the significant errors in the analytical results. So the effects of various polishing methods, such as abrasions with emery paper and silicon carbide paper, buffing with alumina paste (1 μφ), roughing with lathe, filing, chemical polishing (phosphoric acid+hydrogen peroxide) and electropolishing (glacial acetic acid+perchloric acid), on the determination of oxygen in various kinds of iron and steel were investigated.
As a result of experiments, the specimens prepared by electropolishing gave the most correct and reproducible oxygen value, and it seemed that the electropolishing was most suitable for preparation of specimens containing small amounts of oxygen. In this case, the effects of selective dissolution of metal and oxides was not observed.
The specimens prepared by filing and abrasion with silicon carbide paper gave oxygen values a few ppm higher than the electropolished specimens, so that these methods may not be used for the low oxygen samples, but the samples containing more than 50 ppm may be used in routine analysis. In view of the fact that the abrasion with emery paper gave extraordinarily high oxygen values, it may not be used even in routine analysis.
