Structural analysis and corrosion studies on an ISO 5832-9 biomedical alloy with TiO2 sol–gel layers

Abstract

The aim of this study was to demonstrate the relationship between the structural and corrosion properties of an ISO 5832-9 biomedical alloy modified with titanium dioxide (TiO 2 ) layers. These layers were obtained via the sol-gel method by acid-catalyzed hydrolysis of titanium isopropoxide in isopropanol solution. To obtain TiO 2 layers with different structural properties, the coated samples were annealed at temperatures of 200, 300, 400, 450, 500, 600 and 800°C for 2 h. For all the prepared samples, accelerated corrosion measurements were performed in Tyrode's physiological solution using electrochemical methods. The most important corrosion parameters were determined: corrosion potential, polarization resistance, corrosion rate, breakdown and repassivation potentials. Corrosion damage was analyzed using scanning electron microscopy. Structural analysis was carried out for selected TiO 2 coatings annealed at 200, 400, 600 and 800°C. In addition, the morphology, chemical composition, crystallinity, thickness and density of the deposited TiO 2 layers were determined using suitable electron and X-ray measurement methods. It was shown that the structure and character of interactions between substrate and deposited TiO 2 layers depended on annealing temperature. All the obtained TiO 2 coatings exhibit anticorrosion properties, but these properties are related to the crystalline structure and character of substrate-layer interaction. From the point of view of corrosion, the best TiO 2 sol-gel coatings for stainless steel intended for biomedical applications seem to be those obtained at 400°C.

Effects of serum proteins on corrosion behavior of ISO 5832–9 alloy modified by titania coatings

“…7 The XPS high-resolution N1s spectra for M30NWalloy with TiO 2 coating annealed at 400°C (the curves are shifted by 300 counts relative to each other for better separation) substrate. Such differences in crystalline structure and character of substrate layer interaction imply differences in anticorrosion properties of titania coatings [7]. The results presented in this paper indicate that M30NW alloy both uncoated and modified with titania coatings has a very good corrosion resistance also during weekly exposition to corrosion medium with and without addition of serum proteins.…”

“…This improvement is dependent on the annealing temperature used. In our previous paper [7], we characterized the structure and character of interactions between substrate and deposited TiO 2 sol-gel layers in relation to different annealing temperatures. We have stated that the coating annealed at temperature of 400°C has an adhesive character and it has an amorphous structure with anatase crystallites.…”

“…Samples prepared in such a way were ready for TiO 2 coating. The precursor for TiO 2 coating was titanium (IV) isopropoxide (Ti[OCH(CH 3 ) 2 ] 4 , 97 %, Aldrich) [7]. Titania coating (as a single layer) was applied onto alloy surface by dip-coating technique using a dip-coater DCMono 75 (NIMA Technology).…”

“…The differences result from entirely different surface properties of TiO 2 coating depending on applied annealing temperature. In previous paper [7], we have reported that TiO 2 sol-gel coating heat-treated at 800°C is a porous, diffusive layer which contains new TiO 2 -based phases instead of pure TiO 2 crystal structures. Therefore, in addition to solution resistance R s , double layer capacitance CPE dl , and charge transfer resistance R ct , the electrical equivalent circuit contains elements associated with pores and coating properties.…”

Comparison of Corrosion Resistance in Physiological Saline Solution of Two Austenitic Stainless Steels – 316LV and REX734

“…These materials should meet the requirements of biocompatibility, good mechanical strength and corrosion resistance. It is known that the corrosion resistance is an effective prognostic of the biocompatibility and further application of these materials (Burnat et al, 2014;Sumita et al, 2004;Reclaru et al, 2003;Uggowitzer et al, 2003). From the very large group of biomaterials, an austenitic stainless steel 316LV (ISO 3581-A) is frequently used for various orthopaedic and surgical applications, due to good ductility and fatigue behaviour, decent corrosion resistance, good formability and low cost of production (Thomann and Uggowitzer, 2000, Giordani et al, 2004, Gotman, 1997.…”