α-Tricalcium phosphate: Synthesis, properties and biomedical applications

The chemically treated Labeo rohita scale is used for synthesizing hydroxyapatite (HAp) biomaterials. Thermogravimetric and differential thermal analyses of fish scale materials reveal the different phase changes with temperature and find out the suitable calcination temperatures. The composition and structures of wet ball-milled calcined HAp powders are characterized by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray analysis (EDX). The EDX as well as chemical analysis of fish scale-derived apatite materials confirms that the Ca/P ratio is 1.71. The compressive stress, hardness and porosity have been evaluated on sintered HAp biomaterials. The cell attachment on HAp surfaces, cytotoxicity evaluation and MTT assay, which are carried out in RAW macrophage-like cell line media demonstrate good biocompatibility. The histological analysis also supports the bioaffinity of processed HAp biomaterials in Wistar rat model for investigating the contact reaction and stability at the artificial or natural prosthesis interface.

Physico-chemical characterization and biological response of Labeo rohita-derived hydroxyapatite scaffold

Microwave sintering (MWS) of commercially available 15-nm-size nanocrystalline TiN powder was studied. Densification kinetics and grain growth mechanisms of nano-TiN were evaluated using non-isothermal heating up to 1500 °C with variable heating rates. A true nanocrystalline ceramic with ~80-nm-size grains and 94.5 % theoretical density was obtained via MWS consolidation at 1400 °C. At higher temperatures, however, an uncontrolled grain growth and a formation of bimodal microstructure were noticed. A temperature dependence of grain growth suggested grain boundary sliding as a primary mechanism of densification below 1100–1200 °C. An activation energy of nano-TiN densification under MWS varied from 26 ± 3 kJ/mol at the initial stage of sintering (900–1200 °C) to 162 ± 22 kJ/mol at higher temperatures. In addition, a relationship coupling microstructural characteristics (grain size, grain boundary) with mechanical properties of titanium nitride ceramics obtained via both microwave and pressureless sintering techniques was discussed.

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Densification Kinetics and Structural Evolution During Microwave and Pressureless Sintering of 15 nm Titanium Nitride Powder.

Abstract—This paper covers the topic of the interaction process between a detonation wave and a cloud of inert particles. A computer code based on numerical method on Flux Corrected Transport algorithm was developed to solve the Euler equations for inviscid flow. The chemical reaction is modeled with one-step Arrhenius chemistry, and the particle phase is modeled in Lagrangian frame of reference. Simulation results illustrate that detonation wave could be suppressed by a cloud of inert particle, if the cloud parameters meet some critical conditions.

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CFD Simulation of Particles Effects on Characteristics of Detonation

Microstructure and mechanical properties of Mo-ZrC-Cu composites synthesized by reactive melt infiltration of Zr-Cu melt into porous Mo2C preforms at 1300 °C

A technique for direct determination of free carbon nanoforms present as impurities in boron carbide powders has been developed. This technique substantially enhances the existing instrumental methods and can be used for developing ISO standards for qualification of carbon nanomaterials.

Selective Oxidation for Quantitative Determination of Free Carbon Nanoforms in Boron Carbide Powders

Titanium nitride and silicon nitride nanopowders are subjected to microwave treatment to stimulate reduction and nitration reactions. It is established that oxygen content of the nanopowders after microwave treatment is 30–60% lower than that of the starting powders. It is also studied how the efficiency of thermochemical treatment and the particle-size distribution depend on the amount of the phase that absorbs microwave energy.

Thermochemical microwave treatment of refractory nanopowders

Acceptance testing of the elemental and phase composition of two commercial examples of boron carbide has been conducted. Complex oxidation reactions for carbon components in situ and boron at 973–1473 K are studied. Thermal, dynamic, and energy activation characteristics of these processes are provided.

Studying the Oxidation of Commercial Boron Carbide Powders by Chemical Analysis Methods

Wetting of molybdenum with molten Cu-O alloys

A chemical model for the formation of nanosized turbostratic boron nitride powder from urea is proposed. The mechanism is based on the interaction of metaborate acid O=B—OH with urea (NH2)2CO. When OH groups are replaced by NH2 groups, H2O and CO2 are released. Metaboryl amide O=B—NH2 formed in the replacement process is studied. It is found that dehydration of the compound releasing >B—N< radicals promotes the subsequent formation of turbostratic boron nitride.

V. V. Garbuz

Papers

Selective Oxidation for Quantitative Determination of Free Carbon Nanoforms in Boron Carbide Powders

Thermochemical microwave treatment of refractory nanopowders

Studying the Oxidation of Commercial Boron Carbide Powders by Chemical Analysis Methods

Wetting of molybdenum with molten Cu-O alloys

Model of Reactions for the Synthesis of Turbostratic Boron Nitride Nanoparticles from Urea