Corrosion Resistances of Iron-Based Amorphous Metals with Yttrium and Tungsten Additions in Hot Calcium Chloride Brine & Natural Seawater: Fe48Mo14Cr15Y2C15B6 and W-Containing Variants

Abstract

Yttrium-containing SAM1651 (Fe48.0Cr15.0Mo14.0B6.0C15.0Y2.0), has a critical cooling rate (CCR) of approximately 80 Kelvin per second, while SAM2X5 (Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4) with no yttrium has a higher critical cooling rate of approximately 600 Kelvin per second. SAM1651's low CCR enables it to be rendered as a completely amorphous material in practical materials processes. Chromium (Cr), molybdenum (Mo) and tungsten (W) provide corrosion resistance; boron (B) enables glass formation; and rare earths such as yttrium (Y) lower critical cooling rate (CCR). The passive film stability of these Fe- based amorphous metal formulations have been found to be superior to that of conventional stainless steels, and comparable to that of Ni-based alloys, based on electrochemical measurements of the passive film breakdown potential and general corrosion rates.