Journal of Advanced Materials in Engineering (Esteghlal)

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In this study, forsterite nanopowder was prepared by mechanical alloying and post-heat treatment method. Bioactive properties of forsterite nanopowder were studied by immersing the powder in the SBF. Nanostructure forsterite bulk dense form was prepared by the two step sintering method. It was found that pure forsterite nanopowder with 25-60nm particle size was produced. The results of soaking of forsterite nanopowder in the SBF showed that forsterite nanopowder is bioactive. Also, forsterite dense bulk with the optimal hardness of 940 Hv and fracture toughness of 3.61 MPa.m1/2 was produced. These findings suggest that forsterite nanostructure ceramics possess good biocompatibility, bioactivity and mechanical properties and could be suitable for orthopedic and dental implant materials.

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Despite excellent bioactivity of bioactive ceramics such as hydroxyapatite, their clinical applications have been limited due to their poor mechanical properties. Using composite coatings with improved mechanical properties could be a solution to this problem. Therefore, the strength of metal substrate and the bioactivity of the improved composite coating combined could yield suitable results. The aim of this work was fabrication and characterization of hydroxyapatite-forsterite-bioactive glass nanocomposite coating. The sol-gel technique was used to prepare hydroxyapatite-forsterite-bioactive glass nanocomposite in order to coat on 316L stainless steel (SS) by deep coating technique. The X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and energy dispersive X-ray analysis (EDX) techniques were used to investigate the microstructure and morphology of the prepared coating. The results obtained from XRD analysis showed that the suitable temperature for calcination is 600 °C. At this temperature, the homogenous and crack-free coating could attach to the 316L SS substrate. The crystallite size of composite coatings determined via AFM was lower than 100 nm. Overall, the results obtained from this work indicate that hydroxyapatite-forsterite-bioactive glass nanocomposite coating can be a good candidate for biomedical applications.

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Short life of current total hip replacement metallic implants is generally dependent on the aseptic loosening of the implant, which occurs due to mismatch of elastic modulus between bone and metallic implant materials. Decreasing in elasticmodulus of implant could be successful. Forsterite is biocompatible and bioactive ceramic which has suitable mechanical properties. In presented research the composite materials based on Co-Cr-Mo alloy with 10, 15 and 20wt% of forsteritenanopowder as reinforcement were fabricated and mechanical behavior of the composites were evaluated. Composites were fabricated by ball milling, cold pressing and sintering. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used for characterization and evaluation phase composition and microstructure of the composites. Density, microhardness, compressive strength and elastic modulus of fabricated composites were evaluated. Obtained results showed elastic modulus of composite materials based on Co-Cr-Mo alloy reinforced with 10, 15 and 20wt% of forsteritenanopowder decreased significantly. Results also showed that the compressive strength of Co-base alloy composites reinforced with 10, 15 and 20 wt% forsterite were lower than cast Co-Cr-Mo alloy. With increasing in the content of reinforcement, compressive strength of the composites were decreased. Microhardness of prepared composites were higher than cast Co-Cr-Mo alloy. With increasing in content of bioceramic reinforcement, microhardness of the composites were increased.

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The objective of this study was to synthesize glass ionomer–forsterite nanocomposite and study the effect of incorporating forsterite nanoparticles to the ceramic part of glass ionomer cement in order to improve mechanical properties and bioactivity. So, Forsterite nanoparticles were made by the sol-gel process using different weight percentages added to the ceramic part of commercial GIC (Fuji II GC). X-ray diffraction (XRD) was used in order to characterize and determine grain size of the produced forsterite nanopowder. In order to study the mechanical properties of the produced glass ionomer cement-forsterite nanocomposite, the compressive strength (CS), three-point flexural strength (FS) and diametral tensile strength (DTS) of specimens were measured. Statistical analysis was done by one Way ANOVA and differences were considered significant if P‹0.05. The morphology of fracture surface of specimens was studied using scanning electron microscopy (SEM) technique. Bioactivity of specimens was investigated by Fourier transitioned-infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The results of XRD analysis confirmed the nanocrystalline and pure forsterite synthesis. According to the mechanical properties measurements, the optimum weight percentages of forsterite nanoparticles for enhancement of CS, FS, and DTS were obtained equal to 3, 1 and 1 wt.%, respectively. Statistical analysis showed that the differences between all the groups were significant (P<0.05). SEM images and results of the ICP-OES and FTIR tests confirmed the bioactivity of the nanocomposite. Glass ionomer-forsterite nanocomposite containing 1 to 3 wt.%-forsterite nanoparticles can be a suitable candidate for dentistry and orthopedic applications due to the improvement of mechanical properties and bioactivity.