THE CORROSION BEHAVIOR OF AISI 304L AND 316L STAINLESS-STEELS PREPARED BY POWDER-METALLURGY IN THE PRESENCE OF ORGANIC-ACIDS

The corrosion rates of AISI 304L and 316L stainless steels prepared by powder metallurgy (P/M) have been studied by continuous current elect rochemical methods, in organic acid solutions (acetic, formic, lactic and oxalic) at different concentrations. For comparison purposes a sim ultaneous study was carried out on cast AISI 304L and AISI 316L steels of similar composition. For this investigation polarization resistanc e was the technique chosen and values for the Tafel slopes and the Ste rn-Geary constant B were obtained. The sintered AISI 304L, and AISI 31 6L steels had the highest corrosion rates. Subsequently, a kinetic stu dy of the corrosion process has been carried out. A crevice corrosion mechanism for the materials tested in organic acid has been suggested in accordance with the results obtained for the P/M materials. The cre vice attack is localized in the pore areas, close to the powder partic le contact zone. (C) 1997 Elsevier Science Ltd.