Search

Wollastonite nanopowder (β-CaSiO3) is the most nanoceramic powder that is most frequently applied in biomedical applications due to its good bioactivity and biocompatibility. Although the preparation of wollastonite in a solid-state is distinguished as a simple and cheap method with large-scale production, it requires high temperatures (=1400 °C) and consumes quite a long time. The wet methods are considered the best when it comes to preparing the wollastonite nanopowders. However, it has some drawbacks such as its extravagant raw materials and its shorting in preparation which inhibits successful coverage for large-scale production. Herein facile, one-pot modified co-precipitation approach with an easy procedure, shorter reaction time, and in-expensive precursor sodium meta-silicate-pentahydrate and CaCO3 has been utilized for large-scale production of wollastonite nano-powders (76–150 nm). The precipitated product was calcined at different temperatures (800, 900, 1000, and 1100 °C). The phase composition and microstructure of the calcined powders were investigated. They were analyzed by XRD, FTIR, FESEM, and HRTEM. The in-vitro bioactivities of the calcined powders at 1000 &1100 °C were investigated by analyzing their abilities to form apatite on their surface after 21 days in SBF. The apatite mineralization of the powder surfaces was examined through FESEM, EDX, and Raman spectra. The results show that a single-phase wollastonite got formed at all calcined temperatures with a unique silkworm texture. SBF in-vitro test states the formation of HA on the powder surface. Therefore, these powders are expected to be valuable and promising for biomedical applications such as coating and bio cement.

MAX phases (M: early transitionA:13 and 14 group A-element; X:C and/or N) are ternary carbides/nitrides with a unique combination of metallic and ceramic properties. Bulk MAX phases can be prepared from different starting materials and pre-synthesized powders mostly at high temperature and long sintering time. Here, we prove an efficient one-step technological method to produce bulk MAX phase based materials using self-propagation high-temperature synthesis. We show that bulk materials (relative density of 95.5% and 97.2%) can be produced in the form of plates and rods with 67.5% wt. and 81.9% wt. of MAX phases. The compressive strength of 720 ± 2 and 641.5 ± 2 MPa Young's modulus of 221.5 ± 4 and 198.3 ± 2.8 GPa, and thermal conductivity of 22.9 and 22.3 W m−1 K−1 are achieved as a result of extrusion and compression self-propagation high-temperature synthesis. The sintered materials are good thermal conductors with high mechanical characteristics that can be used as promising materials for high-temperature application.

Mesoporous carbonated hydroxyapatite (HAp) with different size, shapes, and the specific surface area has received much interest in various biomedical applications. In this study, we reported a rapid microwave-assisted hydrothermal amalgamation of mesoporous carbonated HAp with tunable nanoscale characteristics using organic modifiers such as oxalic acid and sodium dodecyl sulfate (SDS) as a regulator. The synthesized HAp was analyzed to obtain its physiochemical properties using different characterization techniques to figure out its crystallization nature, particle size, phase purity, elemental composition, pore size, pore volume, and particle size distribution. The observed results clearly showed that the mesoporous carbonated HAp with tunable nanoscale characteristics can be achieved through a microwave enabled hydrothermal digester with the aid of organic modifiers. Moreover, it was found that the addition of oxalic acid during the synthesis can make strong interaction with calcium ions which resulted in the HAp along with calcium oxalate phase whereas the addition of SDS leads to pure HAp phase. Oxalic acid-mediated synthesis leads to form loosely agglomerated rod-like mesoporous nanoparticles having 10 nm width and 20–40 nm length with a specific surface area of 89 m 2 g −1 while SDS-mediated synthesis leads to form nanorods bearing 20–45 nm of width, and 55–100 nm of length with specific surface area of 48 m 2 g −1 . In addition, oxalic acid and SDS also help in tuning the pore size and pore volume by making interaction with HAp crystallites during the synthesis process. Thus, oxalic acid and SDS can plays an important role in modifying structural and physiochemical properties of HAp and it can be used to produce mesoporous HAp nanoparticles through microwave enabled hydrothermal digester for different biomedical applications.

We report the rapid microwave-assisted hydrothermal synthesis of mesoporous hydroxyapatite (HAp) nanocrystals with controlled size, morphology, and surface area using various organic modifiers as regulators. The products were analyzed for their crystalline nature, phase purity, morphology, particle size and pore size distribution. Results indicated that ascorbic acid, cetyltrimethyl ammonium bromide (CTAB) and polyvinylpyrrolidone (PVP) play an important role to obtain needle like, rod like and fiber like mesoporous HAp nanocrystals with different specific surface area by controlling growth habit of HAp along c -axis. In addition, the prepared samples were B-type carbonated HAp similar to bone minerals. Therefore, the present approach can be a promising way to obtain precursor for making tissue engineering scaffolds, drug/protein delivery carriers and bone fillers with tunable characteristics.

Mussel shell, a calcium-rich resource, is found plenty in nature. We have developed a novel and facile method to convert mussel shell bio-waste into hydroxyapatite (HAp) biomaterial using microwave irradiation with the aid of ethylenediaminetetraacetic acid (EDTA) as chelating agent. The obtained HAp had flower-like morphology which can be a potential candidate for developing biomaterial for orthopedic applications. Moreover, the developed method has the potential to recover the bio-waste and reduce environment pollution.

Ceramic composites based on different mixtures of the powdered slags from silicomanganese manufacturing and synthetic potassium titanates, were produced and investigated. Green bodies were fabricated by uni-axial compression at 35 and 196 MPa. The sinters were obtained by one-stage (1100 °C/1 h) or two-stage (800 °C/1 h and 1100 °C/1 h) thermal regimes. The best mechanical properties were achieved for conditions of 33 wt% of slag, compressed under 196 MPa and treated by the two-stage regime of sintering. Structural investigation of the processes taking place in the produced ceramic materials was carried out by scanning electron microscopy and X-ray diffraction. The resulting products were characterized by a gradient phase composition constituted by perovskite, leucite, potassium hexatitanate, pyrophanite-ilmenite solid solutions, hollanadite-like and pyroxene-like crystalline phases as well as glassy phase of varied chemical composition. The mechanism of the sintering processes was also characterized.