Photoelectron spectroscopic studies of the formation of hydroxyapatite films on 316L stainless steel pretreated with etidronic acid

Abstract

The valence band and core‐level X‐ray photoelectron spectroscopy was used to probe hydroxyapatite films formed on the surface of stainless steel. These films formed on steel may find application in medical implants. The key to the successful adhesion of the hydroxyapatite films is shown to be the initial formation of a thin, oxide‐free etidronate film on the metal. It was not found possible to prepare the hydroxyapatite films directly on the metal surfaces. Since hydroxyapatite is a key component of bone and teeth, it is likely that the coated metals will have desirable biocompatible properties. The hydroxyapatite film was exposed to air, water, and 1M sodium chloride solution as representative components of the environment of the film in the human body, and these exposures led to no detectable decomposition of the film. The thin hydroxyapatite and etidronate film on the metal show differential charging effects that caused a doubling of the peaks in some core level spectra. The valence band spectra proved especially valuable in the identification of the surface chemistry of the films, and these spectra were interpreted by comparing the experimental spectra with spectra calculated using band structure calculations which showed good agreement with experiment. The calculated spectrum of etidronic acid was found to be significantly different to that of etidronate. Copyright © 2012 John Wiley & Sons, Ltd.

Influence of phytic acid on the corrosion behavior of iron under acidic and neutral conditions

“…The O1s region shows one feature at 529.5 eV due to alpha-Fe 2 O 3 [28] or other Fe-O bonds and another feature at 531.5eV due to phosphate [29][30]. The curve fitting of Fe2p core level spectrum generates two pairs of spin orbit doublet peaks with the fixed area ratio 2 : 1 between each Fe2p 3/2 and Fe2p 1/2 component [32].…”

“…attributed to oxygen atoms from -Fe 2 O 3 [28] or other Fe-O bonds, a small peak centered at 532.9 eV (marked with violet color) is associated with chemisorbed H 2 O, and another small peak (marked with cyan color) at 531.5 eV is due to the phosphate [29][30]. On the basis of fitted XPS spectra, the peak positions and the corresponding atomic ratios were collected and listed in Table 4.…”

The Formation of Phytic Acid–Silane Films on Cold-Rolled Steel and Corrosion Resistance

“…As shown in Figure 6c, two pairs of peaks were fitted in the Fe2p region. The first pair of peaks of Fe 2p3 and Fe 2p1 are located at 710.52 eV and 723.76 eV, respectively, which were characteristic peaks of iron oxides, and the other pair of peaks of Fe 2p3 and Fe 2p1 are located at 712.7 eV and 726.1 eV, respectively, which were the peaks of a type of ferric phosphate salt [50,51]. Meanwhile, fitting the P 2p region yielded two different chemical states (Figure 6d), with the peak at 133.0 eV being the P-O-C bond in phytate, while the peak at 134.2 eV corresponded to the P-O-Fe bond [52,53].…”

Static Robust Design Optimization Using the Stochastic Frontier Method: A Case Study of Pulsed EPD Process on TiO2 Films

“…One way to mitigate this problem is to create a conversion layer (CL) before the coating using conventional techniques for chemical etching of the surface [4]. Stainless steel (SS-316L) is employed as a substrate for titanium dioxide (TiO 2 ) films because of its electrical and mechanical properties as well as its low corrosion rate [8][9][10]. However, the adhesion between the TiO 2 and bare SS-316L is poor due to their chemical incompatibility [11,12].…”