High Performance Corrosion‐Resistant Materials

Abstract

The outstanding corrosion that may be possible with amorphous metal alloys was recognized several years ago. Compositions of several iron‐based amorphous metals were published, including several with very good corrosion resistance. Examples include thermally sprayed coatings of Fe‐10Cr‐10‐Mo‐(C,B), bulk Fe‐Cr‐Mo‐C‐B, and Fe‐Cr‐Mo‐C‐B‐P. The corrosion resistance of an iron‐based amorphous alloy with yttrium (Y), Fe 48 Mo 14 Cr 15 Y 2 C 15 B 6 , was also been established. Yttrium was added to this alloy to lower the critical cooling rate. Several nickel‐based amorphous metals have been developed that exhibit exceptional corrosion performance in acids but have not been included in this study, which is restricted to Fe‐based materials. Very good thermal spray coatings of nickel‐based crystalline coatings were deposited with thermal spray but appear to have less corrosion resistance than nickel‐based amorphous metals. Two iron‐based amorphous metal alloys presented here as examples are SAM2X5 (Fe 49.7 Cr 17.7 Mn 1.9 Mo 7.4 W 1.6 B 15.2 C 3.8 Si 2.4 ) and SAM1651 (Fe 48 Mo 14 Cr 15 Y 2 C 15 B 6 ). These materials have been developed in the form of thin coatings, as well as thick layers forming composite surfaces, to provide exceptional corrosion resistance in environments including, but not limited to, 5 M CaCl 2 at 105–120°C and natural seawater at 30–90°C.