2.1. Sample preparation
Co63Fe4B22.4Si5.6Nb5 amorphous wires with average diameter of 100 μm were prepared by arc melting type melt extraction method. They were cleaned and degreased in ethanol and distilled water before being exposed to AP 18 base/acid sequence to enhance the concentration of surface hydroxides (10 min. sonication in 1 M NaOH, 5 min. sonication conc. H2SO4). The –OH on the surface may react with the silane molecule as the process shown in Fig.?1. The cleaned wires were then immersed for 30 s in a 2% solution of 3-Aminopropyltriethoxysilane (APTS) in acetone, rinsed free of excess materials with acetone and allowed to dry at room temperature for at least 2 h before use.
Fig.?1. The procedure of the coating reaction of APTS with Co63Fe4B22.4Si5.6Nb5 amorphous wires.Figure optionsDownload full-size imageDownload as PowerPoint slide
2.2. Surface characterization of untreated and treated wires
XPS spectra were obtained using a Kratos AXIS ULTRADLD instrument with a monochromic Al Kα X-ray source (hν = 1486.6 eV). Spectral responses were subjected to standard curve fitting procedures in order to determine the chemical state of the elements. All peak binding energies presented were corrected for charging against the C 1s binding energy that was taken to be 284.8 eV. The binding energies associated with the surface species were identified using the NIST XPS database .