Secondary metals as raw materials for powder metallurgy

The possibility of using new technology based on the disintegrator milling method for utilizing metal chips of cast iron, high-alloy steels, nonferrous alloys (Al−Cu, Zn−Al, Cu−Zn), and used parts of hard metals based on tungsten carbide was investigated. The powders produced were used for corrosion- and wearresistant coatings having properties similar to those of traditional powders. Tallinn Technical University, Republic of Estonia. Published in Poroshkovaya Metallurgiya, Nos. 1–2(405), pp. 1–6, January–February, 1999.     

The action of micro bio species and some inhibitors on the corrosion of stainless steel

The influence of local factors on the susceptibility to crevice corrosion of stainless steel in seawater has been investigated with specimens of UNS S31600, 316 L in Adriatic Sea, at the location in Dubrovnik, Croatia. Besides the other factors, as salinity, redox potential, oxygen content, temperature, and pH, bio species present in the seawater can particularly influence the oxygen cathodic reduction reaction and stimulate crevice corrosion process. Specimens with crevice formers were exposed in natural and biological inert seawater. Crevice phenomena were detected by potential versus time measurement and by visual and microscopic observation. In another series of experiments the action of ecological corrosion inhibitors, non‐toxic carboxylic salts, zinc gluconate, and sodium benzoate, has shown the suppression of crevice formation in the seawater.