Effect of Heat Treatment on Corrosion Behavior of Amorphous Fe-Cr-P-C and Fe-Ni-Cr-P-B Alloys in 1N HCl Available to Purchase

Deterioration of corrosion resistance by crystallization of amorphous Fe-10Cr-13P-7C and Fe-36Ni-14Cr-12P-6B alloys has been studied to correlate the corrosion behavior with the increase in the heterogeneity of alloys by utilizing electrochemical method, X-ray and electron diffraction, differential thermal analysis, scanning and transmission electron microscopy, and platinum decoration techniques. Isothermal heat treatments of the alloys result in two stage crystallization of the amorphous phase (MS I and MS II). As soon as the MS I is formed in the amorphous matrix, the anodic current density suddenly increases. The current density in the active and passive regions continuously increases during the crystallization processes toward the current density of the alloy ingots. The current density in the transpassive region increases especially during the growth of MS II phases. Chemical heterogeneity based on the formation of precipitation, segregation, and other compositional fluctuations seems responsible for the deterioration of the corrosion resistance.