Innovative Bioactive Ag-SiO2/TiO2 Coating on a NiTi Shape Memory Alloy: Structure and Mechanism of Its Formation

Abstract

In recent years, more and more emphasis has been placed on the development and functionalization of metallic substrates for medical applications to improve their properties and increase their applicability. Today, there are many different types of approaches and materials that are used for this purpose. Our idea was based on a combination of a chemically synthesized Ag-SiO2 nanocomposite and the electrophoretic deposition approach on a NiTi shape memory substrate. As a result, silver-silica coating was developed on a previously passivated alloy, which was then subjected to sintering at 700 °C for 2 h. The micrometer-sized coat-forming material was composed of large agglomerates consisting of silica and a thin film of submicron- and nano- spherical-shaped particles built of silver, carbon, and oxygen. Structurally, the coatings consisted of a combination of nanometer-sized silver-carbonate that was embedded in thin amorphous silica and siloxy network. The temperature impact had forced morphological and structural changes such as the consolidation of the coat-forming material, and the partial coalescence of the silver and silica particles. As a result, a new continuous complex ceramic coating was formed and was analyzed in more detail using the XPS, XRD, and Raman methods. According to the structural and chemical analyses, the deposited Ag-SiO2 nanocomposite material’s reorganization was due to its reaction with a passivated TiO2 layer, which formed an atypical glass-like composite that consisted of SiO2-TiO2 with silver particles that stabilized the network. Finally, the functionalization of the NiTi surface did not block the shape memory effect.

Solar hydrogen production from ethanol-water vapours over metal/TiO2 photocatalysts supported on β-SiC alveolar foams

“…Thus, the Ti 2p region shows, in addition to the doublet corresponding to Ti 4+ in TiO 2 , another component at higher binding energies that has been ascribed to Ti-O-Si linkages [16], indicating a chemical interaction between the TiO 2 layer and the SiO 2 washcoat at their interface. In line with this, three contributions are observed in the Si 2p region, which include, in addition to those corresponding to SiC and SiO 2 , a signal with intermediate binding energy that has been interpreted both as SiO x C y silicon oxycarbide from the oxygen-rich natural washcoat of the SiC foam [12], and as Si-O-Ti linkages in SiO 2 /TiO 2 composites [26]. This last feature can be seen more clearly in the high-resolution O 1 s spectrum, in which a component ascribed to interfacial Si-O-Ti cross-linking bonds appears with a binding energy intermediate to those of the SiO 2 and TiO 2 photopeaks [27].…”

Advanced Surface Modification for 3D-Printed Titanium Alloy Implant Interface Functionalization

“…Furthermore, owing to the electrolytic process being carried out in solution, EPD is capable of covering the substrate materials with a complex shape. EPD is widely used in preparing inorganic coatings on the surface of orthopedic implants, such as hydroxyapatite (HA), graphite oxide (GO), and Ag + in coatings ( Boccaccini et al, 2010 ; Shalom et al, 2018 ; Dulski et al, 2020 ; Srimaneepong et al, 2020 ). Moreover, the depositing environment of EPD is milder than the technologies requiring high temperature environment, such as plasma spraying and chemical vapor deposition.…”

Determination of the Effect of TiN Coating on Self-Fitting Properties of Dental Implants Made of NiTi Alloy

“…TiN differs from the others in terms of better mechanical properties and biocompatibility; a passive TiO 2 film is formed during its formation. , In a review study, del Castillo et al, investigating TiN coating specific to dental implants, reported that TiN coatings reduce early bacterial colonization and biofilm formation and improve fibroblast cell attachment and adhesion . In addition, Ag–SiO 2 chemically produced by electrophoretic deposition (EPD) method is used in nanocomposite coatings. − Corrosion tests in Ringer’s solution are used to determine the effectiveness of the coatings. , …”