Corrosion behaviour of crystalline and amorphous forms of the glass forming alloy Fe43Cr16Mo16C15B10

► A Fe-based GFA is made, comprising two M23C6 phases, Mo2FeB2, M3Mo3C and some (-Fe. ► The largely amorphous form of the alloy has superior corrosion resistance to the crystalline form. ► The crystalline form corrodes by preferential dissolution of Mo-rich precipitates. ► The improved corrosion behaviour is due to the homogeneity of the largely amorphous alloy. ► Conversion of the crystalline form to a largely amorphous form by laser melting. ► The use of laser melting to amorphise the alloy is limited by induced cracking. ► HVOF can deposit coatings that largely retain the amorphous structure. ► HVOF microstructural details effect corrosion performance of the amorphous form.