Hydrogen Effects on an Amorphous Fe-Si-B Alloy

HYDROGEN interaction with amorphous alloys has Ribbons (,25-mm thick) of amorphous Fe80B11Si9 were been studied extensively due to both scientific and technoused for this research. The ribbons were produced by planarlogical interest. In the framework of a more comprehensive flow casting and were kindly supplied by AlliedSignal Inc. investigation of hydrogen interaction with amorphous and (Parsippany, NJ). It is well known that various surface phequasicrystalline Zr69.5Cu12Ni11Al7.5 alloys, hydrogen effects nomena may affect the interaction of hydrogen with materion amorphous Fe80B11Si9 were studied as well, for comparials. For amorphous alloys, crystalline phases were detected son. As Fe80B11Si9 does not contain hydride-forming elenear the surface of the ribbon that had not been in contact ments, the effect of chemical composition on hydrogen with the rotating wheel during melt spinning. Furthermore, interaction with amorphous alloys may be estimated by comsurface-oxide layers were reported to hinder the desorption paring results for this alloy to results for an amorphous of hydrogen from an amorphous Zr69.5Cu12Ni11Al7.5 alloy.[7] Zr69.5Cu12Ni11Al7.5 alloy. The Fe80B11Si9 alloy belongs to the Hence, Auger electron spectroscopy/X-ray photoelectron group of amorphous alloys composed of late transition metspectroscopy (AES/XPS) experiments were carried out in als (LTM) and metalloids (M). The ratio LTM:M (atomic this research before hydrogen charging, in order to compare concentrations) in this group is usually 80:20. Bennett et the chemical composition of both sides of the ribbon. The al.[3] suggested that this ratio results from the filling of all results indicated that both were slightly oxidized. By large Bernal holes with the smaller and softer metalloid means of optical microscopy, entrapped gas blisters were atoms to stabilize the random configuration. identifiedon the dull side. As others have observed as well, The aim of this article is to present results on hydrogen this side had been in contact with the rotating wheel. Optical absorption in and desorption from an amorphous Fe80B11Si9 microscopy inspections, X-ray diffraction (XRD), and elecalloy. In addition, hydrogen effects on the microstructure, trical resistivity measurements, performed following a preas well as the characteristics and mechanism of hydrogen liminary series of cathodic chargings, did not reveal any embrittlement (HE) in this alloy, are discussed in detail. difference between the effects of hydrogen on the nearFinally, the effects of metalloids on hydrogen diffusion are surface material from both sides. Nevertheless, all results briefly discussed, applying a new model to simulate the presented herein refer to the bright side of the ribbon. diffusion behavior of hydrogen in dilute amorphous Fe-H, Electrochemical hydrogen charging of the amorphous ribFe-Si-H, and Fe-B-H alloys, as described in detail elsebons was performed in a solution of 0.1 N H2SO4 with 5 where. In a recent complementary article, the authors mg/L NaAsO2 as a surface poison. This solution is often applied laser-induced shock-wave measurements to deterused as a catholyte for ferrous samples in electrochemical mine the dominant mechanism of HE in an amorphous permeation experiments, due to the ease of the cathodic Fe80B11Si9 alloy and to estimate the effects of the high presreaction for hydrogen evolution.[9] All chargings were carsures involved in cathodic charging. Therefore, these results ried out galvanostaticallyat room temperature, applying curare not presented within the present article. rent densities of 2 to 150 A/m for 0.25 to 121 hours.