J. Marcheva et al., MOSSBAUER STUDY OF SURFACE-FILMS ON STEELS FORMED IN PHOSPHATE ENVIRONMENTS UNDER STRESS-CORROSION CRACKING CONDITIONS, Journal of radioanalytical and nuclear chemistry, 212(5), 1996, pp. 383-398
A study on the composition of the surface films and corrosion products
of mild and low-alloy (2% Cr) steels in 1M NaH2PO4 under stress-corro
sion cracking (SCC) conditions has been carried out using Mossbauer sp
ectroscopy. At potentials in the SCC region the films formed on both s
teels contain Fe-3 (PO4)(2).4H2O, Fe-3 (PO4)(2).8H(2)O and FePO4.xH(2)
O. The precipitates in the solution formed under these conditions cons
ist of FePO4.xH(2)O and iron(III) hydrogen phosphate [most probably Fe
(H2PO4)(3).2H(2)O]. An attempt has been made to relate the surface fil
m composition to SCC susceptibility.