Bioceramics coating on Ti–6Al–4V alloy by microwave processing
TL;DR: In this paper, a novel method of hydroxyapatite (HA) coating on Ti-6Al-4V alloy by microwave (MW) processing has been developed to form an adherent coating within ∼25 min.
Abstract: A novel method of hydroxyapatite (HA) coating on Ti–6Al–4V alloy by microwave (MW) processing has been developed to form an adherent coating within ∼25 min. The X-ray diffraction pattern of the coated sample shows the presence of HA and titanium oxides. Scanning electron micrograph indicates that the thickness of the coating is to be ∼150 μm with a good interface with the alloy. The compositional analysis using energy dispersive X-ray spectroscopy also confirms the formation of a composite coating of apatite and titanium oxides. The MW active nature of the non-stoichiometric titanium oxides seems to influence the bonding of HA with the titanium oxide grown on the alloy surface. The presence of the Widmanstatten structure of the substrate as observed by optical microscopy indicates that the process temperature of the coating may be above β transus temperature of the alloy. The alloy substrate also shows an increase in the hardness and Young's modulus which may be due to diffusion of oxygen and/or ...
Citations
More filters
TL;DR: In this paper, a composite coating of titania and hydroxyapatite on CPTi was obtained by a simple one-step process, where the coating induced apatite precipitation in bioactivity test.
Abstract: Microwave (MW) processing has been studied as an alternative method of hydroxyapatite (HA) based composite coatings on commercially pure titanium (CPTi) to enhance the bioactivity for orthopaedic and dental implant applications. The coating was formed by processing CPTi metal packed in HA and at 800 W microwave power for 22 min. The composition of the coating was found to be TiO 2 (rutile) as major phase along with HA as minor phase. The MW absorption of non-stoichiometric TiO 2 layer, which was grown during the initial hybrid heating, resulted in sintering of apatite particles interfacing them. The non-stoichiometric nature of TiO 2 was evident from the observed mid-gap bands in ultraviolet–visible diffusive reflectance (UV–VIS-DR) spectrum. The lamellar α structure of the substrate suggests that the processing temperature was above β transus of CPTi (1155 K). The oxygen stabilized α phase whose thickness increased with microwave processing time, was likely to be the reason for the increase in Young's Modulus and hardness of the substrate. The coating induced apatite precipitation in bioactivity test. The osteoblast cell adhesion test demonstrated cell spreading which is considered favourable for cell proliferation and differentiation. Thus, in situ composite coating of titania and HA on CPTi was obtained by a simple one-step process.
32 citations
TL;DR: The in vitro studies show that the Ca-TiP coating with synergistic features of nano-fibrous biomimetic topography and surface chemistry could elicit intensively osteogenic behavior and responses including enhanced cell adhesion, spreading and proliferation.
8 citations
TL;DR: In this paper, a new laser-microwave hybridization method, which comprises laser micropatterning, microwave heating and in situ synthesis has been developed to produce titania/hydroxyapatite/tricalcium phosphate (TiO 2 /HA/TCP) composite coating on titanium alloy (Ti6Al4V) substrate.
Abstract: Microwave heating is an efficient alternative approach for synthetic chemistry with many distinctive advantages of high heating rate, selective and homogeneous heating. In this study, a new laser-microwave hybridization method, which comprises laser micropatterning, microwave heating and in situ synthesis has been developed to produce titania/hydroxyapatite/tricalcium phosphate (TiO 2 /HA/TCP) composite coating on titanium alloy (Ti6Al4V) substrate. The composite coating with a fine porous network microarchitecture was selectively produced on the Ti6Al4V surface by laser ablation and alkaline treatment. Using TiO 2 sol-gel and mixed powders of calcium carbonate (CaCO 3 ) and dicalcium phosphate dihydrate (CaHPO 4 ·2H 2 O), the composite coating synthesized at a temperature of 800 °C in a short time of 20 min exhibited homogeneous microstructure, strong hydrophilicity and good adhesion strength of 34 MPa. The in vitro apatite-forming capability of the coating was examined by immersing the coated Ti6Al4V specimen into a simulated body fluid (SBF) for up to 7 days. Biodissolution was observed in the early stage of incubation, followed by apatite precipitation. The quantity and size of the apatite globules increased over time. After 7 days of immersion, the coating surface was nearly covered by a layer of bone-like apatite, showing a significant improvement of its osteoconductive property over the uncoated sample. The laser-microwave hybridization provides an efficient route to synthesize HA/TCP based coatings for bioactivity enhancement, and serves as an effective sterilization tool for implant materials.
8 citations
TL;DR: In this paper, a glass-quartz and glassquartz-aluminium composite coatings were successfully produced on Ti-6Al-4V alloy by slurry method and the oxidation behavior of the specimens at 800°C for 100 h was studied.
Abstract: Glass–quartz and glass–quartz–aluminium composite coatings were successfully produced on Ti–6Al–4V alloy by slurry method. The oxidation behaviour of the specimens at 800°C for 100 h was studied. Both composite coatings exhibited good high temperature oxidation resistance. After oxidation for 100 h, quartz and diopside were main crystalline phases in the glass–quartz composite coating. Some open pores appeared on the surface of the glass–quartz composite coating, which might be related to the intensive crystallisation of diopside in the composite coating. While in the glass–quartz–aluminium composite coating, no open pores could be seen, and some new phases such as silicon and alumina were observed. The silicon and alumina phases might be originated from the reaction between glass and molten aluminium. Because of this, incorporation of aluminium particles into the composite coating slows the nucleation and growth rate of diopside.
8 citations
References
More filters
15 Mar 1998-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: Titanium alloys are expected to be much more widely used for implant materials in the medical and dental fields because of their superior biocompatibility, corrosion resistance and specific strength compared with other metallic implant materials.
Abstract: Titanium alloys are expected to be much more widely used for implant materials in the medical and dental fields because of their superior biocompatibility, corrosion resistance and specific strength compared with other metallic implant materials. Pure titanium and Ti–6Al–4V, in particular, Ti–6Al–4V ELI have been, however, mainly used for implant materials among various titanium alloys to date. V free alloys like Ti–6Al–7Nb and Ti–5Al–2.5Fe have been recently developed for biomedical use. More recently V and Al free alloys have been developed. Titanium alloys composed of non-toxic elements like Nb, Ta, Zr and so on with lower modulus have been started to be developed mainly in the USA. The β type alloys are now the main target for medical materials. The mechanical properties of the titanium alloys developed for implant materials to date are described in this paper.
1,708 citations
TL;DR: In this paper, the fundamentals of electromagnetic theory, dielectric response, and applications of microwave heating to materials processing, especially fiber composites, are reviewed in this article, and a knowledge of electromagnetic theories and dielectrics is essential to optimize the processing of materials through microwave heating.
Abstract: In microwave processing, energy is supplied by an electromagnetic field directly to the material. This results in rapid heating throughout the material thickness with reduced thermal gradients. Volumetric heating can also reduce processing times and save energy. The microwave field and the dielectric response of a material govern its ability to heat with microwave energy. A knowledge of electromagnetic theory and dielectric response is essential to optimize the processing of materials through microwave heating. The fundamentals of electromagnetic theory, dielectric response, and applications of microwave heating to materials processing, especially fiber composites, are reviewed in this article.
1,296 citations
TL;DR: TiO2/HA coatings resulted to be bioactive owing to the presence of hydroxyl groups detected on their surface that promote the calcium and phosphate precipitation and improve the interactions with osteoblastic cells.
288 citations
TL;DR: The benefits of, and the need for, a multilevel approach to evaluate and improve these plasma-sprayed ceramic-metal substrate interfaces are illustrated.
Abstract: The successful use of plasma-sprayed hydroxyapatite (HA) coatings on Ti-alloy implants for implant-to-bone fixation requires strong adherence of the ceramic coating to the underlying metal substrate. In this study, the metal-ceramic interface was evaluated using mechanical, chemical, and structural characterization methods. Evaluations of an HA-coated Ti-6A1-4V implant system using a modified short bar technique for interfacial fracture toughness determination revealed relatively low fracture toughness values. Additionally, conventional tensile bond strength testing indicated much lower values than previously reported. Using high resolution electron spectroscopic imaging, evidence of chemical bonding was revealed at the plasmasprayed HA/Ti-6AI-4V interface, though bonding was primarily due to mechanical interlock at the interface. This study illustrates the benefits of, and the need for, a multilevel approach to evaluate and improve these plasma-sprayed ceramicme tai subst rate interfaces.
242 citations
TL;DR: The calcination and natural sintering of calcium deficient hydroxyapatite powders Ca(10-x)(PO4)(6-x](HPO4)x(OH)(2-x) (with 0 < or = x = 1) and particle coalescence occurs without densification were studied.
210 citations