Functionally graded materials: A review of fabrication and properties

Current state of fabrication technologies and materials for bone tissue engineering.

Antimicrobial activity of metal-substituted cobalt ferrite nanoparticles synthesized by sol–gel technique

Ceramic nanocomposites are attracting growing interest, thanks to new processing methods enabling these materials to go from the research laboratory scale to the commercial level. Today, many different types of nanocomposite structures are proposed in the literature; however, to fully exploit their exceptional properties, a deep understanding of the materials’ behavior across length scales is necessary. In fact, knowing how the nanoscale structure influences the bulk properties enables the design of increasingly performing composite materials. A further key point is the ability of tailoring the desired nanostructured features in the sintered composites, a challenging issue requiring a careful control of all stages of manufacturing, from powder synthesis to sintering. This review is divided into four parts. In the first, classification and general issues of nanostructured ceramics are reported. The second provides basic structure–property relations, highlighting the grain-size dependence of the materials properties. The third describes the role of nanocrystalline second-phases on the mechanical properties of ordinary grain sized ceramics. Finally, the fourth part revises the mainly used synthesis routes to produce nanocomposite ceramic powders, underlining when possible the critical role of the synthesis method on the control of microstructure and properties of the sintered ceramics.

/pdf/structural-ceramic-nanocomposites-a-review-of-properties-and-2gegh02o35.pdf

Structural Ceramic Nanocomposites: A Review of Properties and Powders' Synthesis Methods.

As baby boomers age, diabetes mellitus, cancer, osteoarthritis, cardiovascular diseases, and orthopedic disorders are more widespread and the demand for better biomedical devices and functional biomaterials is increasing rapidly. Owing to the good biocompatibility, chemical stability, catalytic efficiency, plasticity, mechanical properties, as well as strength-to-weight ratio, titanium dioxide (TiO2) based nanostructured materials are playing important roles in tissue reconstruction and diagnosis of these diseases. Here, recent advance in the research of nanostructured TiO2 based biomaterials pertaining to bone tissue engineering, intravascular stents, drug delivery systems, and biosensors is described.

Functionalized TiO2 Based Nanomaterials for Biomedical Applications

The synthesis and characterization of silver nanoparticles (AgNPs) using natural pigments from plants as reducing agents is presented in this study. The natural pigments were extracted from Alfalfa leaves. The reduction reaction was investigated by UV–Vis and FTIR analyses. The synthesized AgNPs were characterized by UV–Vis, XRD, TEM, and DLS. UV–Vis analysis revealed that AgNPs were produced with a persistent plasmonic absorption peak at about 418 nm accompanied by consumption of pigments. The reduction is suggested to occur, mainly, by chlorophyll a and carotenes. Characterization revealed pure synthesized AgNPs with an average particle size of 25 nm. In an interesting novel experiment, the progress of reduction reaction was traced at the interface between reacting phases under UV illumination making use of fluorescence of both chlorophylls and formed Ag nano-clusters (AgNCs). The enrollment of chlorophylls in reduction was suggested depending on FTIR and fluorescence analyses. The synthesized AgNPs possessed a superior antimicrobial activity towards Staphylococcus aureus ATCC 29213; 24.0 mm ZOI, followed by Escherichia coli ATCC 25922; 17.0 mm ZOI. In addition, AgNPs were a strong antifungal agent against Candida albicans ATCC 10231; 26.0 mm ZOI.

Synthesis of silver nanoparticles using natural pigments extracted from Alfalfa leaves and its use for antimicrobial activity

Thermo-mechanical properties of mullite/zirconia reinforced alumina ceramic composites

The aim of this research is to investigate the characteristics and mechanical properties of Nb 2 O 5 doped zirconia-toughened-alumina composites. Samples of partially stabilized-zirconia toughened alumina (ZTA) with the addition of 5 vol.% ZrO 2 doped with Nb 2 O 5 in amounts of 0.2, 0.4 and 0.6 vol.% were prepared by sol–gel technique. The powders of each composition were uniaxially pressed into discs and rectangular bars, and then pressureless sintered at 1500° up to 1650 °C for 1 h. The phase constitution and microstructures of the as sintered ceramic composites were characterized by using an X-ray diffractometer and a scanning electron microscope respectively. The mechanical properties of the ceramic composites were evaluated through Vickers hardness, flexural strength and fracture toughness tests. It was found that increasing the Nb 2 O 5 concentration had a strong effect on the densification behavior, microstructure and mechanical properties of the ZTA composites.

Mohamed Awaad

Papers

Synthesis of silver nanoparticles using natural pigments extracted from Alfalfa leaves and its use for antimicrobial activity

Thermo-mechanical properties of mullite/zirconia reinforced alumina ceramic composites

Toughening and strengthening of Nb2O5 doped zirconia/alumina (ZTA) composites

Effect of La2Zr2O7 coat on the hot corrosion of multi-layer thermal barrier coatings

Physical and mechanical properties of Ta2O5 doped zirconia-toughened alumina (ZTA) composites