The exceptional properties of graphene and its structural uniqueness can improve the performance of nanocomposites if it can attain the uniform dispersion. Tip sonication assisted graphene solvent dispersion has been emerged as an efficient approach but it can cause significant degradation of graphene structure. This study aimed to evaluate the parametric influence of tip sonication on the characteristics of sp carbon structure in graphene nanoplatelets by varying the sonication time and respective energy at three different amplitudes (60%, 80% and 100%). The study is essential to identify appropriate parameters so as to achieve high-quality and defect-free graphene with a highly desirable aspect ratio after solvent dispersion for composite reinforcement. Quantitative approach via Raman spectroscopy is used to find the defect ratio and lateral size of graphene evolved under the effect of tip sonication parameters. Results imply that the defect ratio is steady and increases continually with GNPs, along with the transformation to the nano-crystalline stage I up to 60 min sonication at all amplitudes. Exfoliation was clearly observed at all amplitudes together with sheet re-stacking due to considerable size reduction of sheets with large quantity. Finally, considerable GNPs fragmentation occurred during sonication with increased amplitude and time as confirmed by the reduction of sp domain (La) and flake size. This also validates the formation of edge-type defect in graphene. Convincingly, lower amplitude and time (up to 60 min) produce better results for a low defect content and larger particle size as quantified by Raman analysis.

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Biomaterials play a significant role in revolutionizing human life in terms of implants and medical devices. These materials essentially need to be highly biocompatible and inert to the human physiological conditions. This paper provides an in-depth, critical and analytical review on the previous research work and studies conducted in the field of metals and alloys used as implant materials including stainless steel, titanium and its alloys, cobalt chromium and others. Since the manufacturing of medical implants relies on selected grades of biomaterials, metals play a significant role in biomaterials market. This paper focuses on highlighting some basic principles of manufacturing implant materials underlying composition, structure and properties of these materials. Finally, attention is also given to the role of these implant materials on the betterment of human life in terms of their failures by critically analysing these materials.

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The exceptional potential of the graphene has not been yet fully translated into the Al matrix to achieve high-performance Al nanocomposite. This is due to some critical issues faced by graphene during its processing such as the dispersion uniformity, structure damage, compatibility/wettability, and low graphene embedding content in Al matrix. In the present work, a new integrative method was adopted and named as "solvent dispersion and ball milling" (SDBM) to address the issues above efficiently in a single approach. This strategy involves effective graphene nanoplatelets (GNPs) solvent dispersion via surfactant decoration and solution ball milling employed to polyvinyl alcohol (PVA) coated Al with various GNPs content (0.5, 1 and 1.5 wt. %). Flaky Al powder morphology attained by optimizing ball milling parameters and used for further processing with GNPs. Detailed powders characterizations were conducted to investigate morphology, graphene dispersion, group functionalities by FTIR (Fourier transform infrared spectroscopy) spectroscopy and crystallinity by powder XRD (X-ray diffraction)analysis. Compaction behaviour and spring back effect of the GNPs/Al powders was also investigated at different compaction pressure (300 to 600 Mpa) and varying GNPs fractions. In response, green and sintered relative density (%) along with effect on the hardness of the nanocomposites samples were examined. Conclusively, in comparison with the unreinforced Al, GNP/Al nanocomposite with 1.5 wt. % GNPs exhibited the highest hardness gives 62% maximum increase than pure Al validates the effectiveness of the approach produces high fraction uniformly dispersed GNPs in Al matrix.

Austenitic 316L stainless steel has been the most widely acceptable biomaterial for producing implants. The downside of this material includes the leaching of nickel ions from the matrix that limits its’ usage in implant manufacturing. In this research, production of stainless steel alloy modified with boron and titanium is investigated. The sintering of the alloy systems is carried out in nitrogen atmosphere for a dwell time of 8 h. The X-Ray diffraction (XRD) analysis reveals that dwell time and alloy composition leads to the formation of strong nitrides and borides. The X-Ray Photoelectron Spectroscopy (XPS) results show the presence of nitrogen on to the surface of sintered specimens. The nitride layer on the surface of the specimens is helpful in the retention of nickel ions in the stainless steel matrix, as indicated in the weight loss measurements. The cytotoxicity assessment indicates that the developed alloys are biocompatible and can be used as implant materials.

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In the past, 316L stainless steel (SS) has been the material of choice for implant manufacturing. However, the leaching of nickel ions from the SS matrix limits its usefulness as an implant material. In this study, an efficient approach for controlling the leaching of ions and improving its properties is presented. The composition of SS was modified with the addition of boron and niobium, which was followed by sintering in nitrogen atmosphere for 8 h. The X-ray diffraction (XRD) results showed the formation of strong nitrides, indicating the diffusion of nitrogen into the SS matrix. The X-ray photoelectron spectroscopy (XPS) analysis revealed that a nitride layer was deposited on the sample surface, thereby helping to control the leaching of metal ions. The corrosion resistance of the alloy systems in artificial saliva solution indicated minimal weight loss, indicating improved corrosion resistance. The cytotoxicity assessment of the alloy system showed that the developed modified stainless steel alloys are compatible with living cells and can be used as implant materials.