| Abstract: | Corrosion and stress corrosion cracking behaviour of a series of amorphous iron alloys FeNiMoxB (x = 0, 2, 4, 8.5) has been investigated in several neutral and acidic media. In particular in aqueous solutions of ferric chloride, potassium tetrathionate and sulphuric acid containing chlorides stress corrosion cracking (SCC) has been studied by means of constant strain tests and corrosion rates have been evaluated by means of weight loss measurements. In several cases polarization curves have been recorded in order to clarify the electrochemical behaviour of the amorphous alloys. SEM observations of the fracture surfaces have been performed. It has been observed that the glassy alloys under investigation are susceptible to SCC at free corrosion potential in all the environments. SCC has been observed on specimens cathodically and anodically polarized in sulphuric acid containing chlorides. Hydrogen embrittlement can reasonably be considered responsible of the SCC phenomenon, except in sulphuric acid solution on specimens anodically polarized and in iron chloride solution. A deleterious effect of molybdenum has been noted on the corrosion rates of unstressed specimens and on the time to failures of stressed samples. |
