ABSTRACT
Herein, we studied light induced interactions between two well-known luminescent materials, SrAl2O4:Eu2+, Dy3+ and nano-scale TiO2 in poly(methyl methacrylate) (PMMA). These two materials were chosen due to their stable nature, efficient spectral properties and more specifically, overlapping excitation/emission bands. When these materials were used together in 1:1 ratio by weight (w/w), the composite exhibited 76% enhancement in the emission intensity with respect to the individual phosphor. Although the luminescence mechanism of both materials is clarified in the literature, spectral interactions of them have not been studied up to now. In our opinion, the TiO2 nano-particles (TiO2 NPs) act as light-harvesting agents for the phosphor particles creating a substantial enhancement on the light absorption efficiency of the phosphor. Additionally, the TiO2 nanoparticles suggest a promising way to boost the phosphorescent activity of the SrAl2O4:Eu2+, Dy3+ by a cost-effective way and further investigation of the mechanism may be subject of future studies.
ABSTRACT
The bioceramic calcium phosphate (CaP) is frequently used for improving bone fixation in titanium medical implants and thus increasing lifetime of the implant. It is known that the application of CaP coatings on metallic implant devices offers the possibility of combining the strength of the metals and the bioactivity of the ceramic materials. Many different techniques are available for producing CaP coatings. Electrochemical deposition method is widely used because of its ease of operation parameters, low temperature requirement, reproducibility and suitability for coating complex structures. This technique allows obtaining CaP coatings which promote bone in growth during the first healing period leading to permanent fixation. Electrochemical pulse technique is an alternative to calcium phosphate deposition techniques usually employed to cover orthopedic or dental titanium implant surfaces. Additionally, pulse electrodeposition technique can produce more uniform and denser CaP coatings on metallic implants. In this study, CaP based coatings were produced by electrochemical pulse technique on Ti6Al4V substrates. The resulting CaP deposits were investigated by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Corrosion properties of the CaP coatings were also investigated. The results showed that various duty cycle ranges have remarkably effect on morphology, crystallinity and corrosion properties of the produced CaP coatings.
Subject(s)
Calcium Phosphates/chemistry , Coated Materials, Biocompatible/chemistry , Implants, Experimental , Titanium/chemistry , Alloys , Corrosion , Surface PropertiesABSTRACT
Bioactive coatings are frequently used to improve the osseointegration of the metallic implants used in dentistry or orthopaedics. Among different types of bioactive coatings, hydroxyapatite (Ca10(PO4)6(OH)2) is one of the most extensively used due to its chemical similarities to the components of bones and teeth. In this article, production and characterization of hydroxyapatite films deposited on Ti6Al4V alloy prepared by magnetron sputtering were reported. Besides, SiC was deposited on substrate surface to study the interlayer effect. Obtained coatings were annealed at 600 °C for 30 and 120 min in a mixed atmosphere of N2 + H2O vapours with the heating rate of 12 °C min(-1). The effects of SiC interlayer and heat treatment parameters on the structural, mechanical and corrosion properties were investigated. After heat treatment process, the crystalline hydroxyapatite was obtained. Additionally, cell viability tests were performed. The results show that the presence of the SiC interlayer contributes a decrease in surface roughness and improves the mechanical properties and corrosion performance of the hydroxyapatite coatings. Biological properties were not affected by the presence of the SiC interlayer.
