- P-ISSN 1225-0163
- E-ISSN 2288-8985
Corrosion resistances in various acids and high temperature oxidation properties have been investigated for the Ni-base superalloy KM 1557. Corrosion tests were performed in <TEX>$H_2SO_4$</TEX>, HCl, <TEX>$HNO_3$</TEX>, <TEX>$H_3PO_4$</TEX> and <TEX>$CH_3COOH$</TEX>. Oxidation tests were carried out in air for 20 and 110hrs at <TEX>$900^{\circ}C$</TEX>, <TEX>$950^{\circ}C$</TEX> and <TEX>$1050^{\circ}C$</TEX>. Hot corrosion tests were done in salt bath of 75% <TEX>$Na_2SO_4-25%$</TEX> NaCl at <TEX>$900^{\circ}C$</TEX> for 20hrs. After the tests, the samples were observed by optical microscopy and analysed by EPMA and X-ray mapping in order to investigate the distribution of composition. It was shown that corrosion resistances in various acids and hot salt bath were proven to be excellent. It was suggested that the amounts of oxides were determined mainly by the depth of internal and intergranular <TEX>$Al_2O_3$</TEX> oxide layers.