Papers by Keyword: Mechanochemical Treatment

Abstract: The structural and phase changes in the carbon nanomaterial of the “Taunit” series were studied depending on the time of mechanochemical treatment (MCT) in a high-speed ball mill. The possibility of the formation of a carbon material with an amorphous and diamond-like component is shown.

Abstract: Studied the structure and phase changes in graphite MPG-7 depending on time of mechanochemical treatment (MCT) in high-speed ball mill at different rotation frequencies. The formation of the carbon material with amorphous and diamond-like component shows. Note the spontaneous combustion of the carbon powder after 8 hours of the MCT at 1500 rpm.

Abstract: The technology of composite micropowders’ obtaining that allows the production of a wide range of composite powders suitable for use in additive technologies is proposed. The technology includes modification of the metal powder surface with the mechanochemical treatment. The production modes for the AlSi12-Al₂O₃ composite powder are determined.

Abstract: The paper presents a comparative study of Ca_0.25Cu_0.75TiO₃ (CCTO) electrical properties produced by two methods - mechanochemical synthesis and high temperature treatment. Products differ significantly in terms of grain morphology and the degree of defects in structure. This is the reason why electrical properties are different.

Abstract: Titanium Silicalite-1 (TS-1) zeolite was successfully synthesized through a mechanochemical assisted processing. In this method, an amorphous silica-titania precursor was firstly prepared through a mechanochemical treatment. TS-1 was then synthesized by the hydrothermal treatment of the silica-titania precursor with tetrapropylammonium bromide (TPABr) as the template. The results of the XRD, UV-vis, and FT-IR spectrum indicated that the titanium atom was incorporated into the amorphous silica-titania precursor during the grinding, and was also retained in the final TS-1 framework after the hydrothermal treatment. SEM image showed that the TS-1 appeared in a shape of elongated prism. The catalytic performance of TS-1 was examined by phenol hydroxylation with hydrogen peroxide as the oxidant. The results indicated that TS-1 synthesized by this method exhibited a good activity.

Abstract: An investigation has been undertaken of the structural characteristics of the manganese oxides to understand these characteristics affected by mechanochemical treatment conditions. Chemically pure manganese (II, III) oxides and their mixtures were used as the initial components.

Abstract: Mechanical alloying and mechanochemical treatment are the major powder processing techniques on the nano scale. In these processes a high energy ball mill has been applied to synthesize compounds and nanocomposites such as aluminum metal matrix nanocomposite, hydroxyapatite and bionanocomposites based on hydroxyapatite. These processes involve deformation, cold welding, fracturing, and rewelding of powder particles. Due to the applied mechanical forces, chemical reactions and phase transformations could also take place. In the present research work, the effects of milling time, milling media, and sonication process on the microstructures and morphology of the obtained materials were evaluated by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The results indicate that increasing the milling time leads to an increased lattice strain and decreased crystallite sizes. Furthermore, the results show that the sonication process leads to the morphological improvement of nanocrystalline hydroxyapatite. The obtained data show that the nanocrystalline hydroxyapatite with low contamination and suitable morphology can be produced in Polyamide6 vials similar to stainless steel vials, therefore it seems that using polymeric and polymeric based nanocomposite vials with high strength and wear resistance could lead to a new way for the mass production of nanocrystalline hydroxyapatite with high performance, low contamination and low cost.

Abstract: Ni catalyst was removed from as received multi-walled Carbon Nanotubes (MWNTs) by acid treatment. Then, the nanotubes were treated with 4M HCl during a ball milling processing yielding mechanochemical treated MWNTs (mech-MWNTs). TEM micrographs indicate that the mech-MWNTs were still of a tubular form but with much shorter length. The equilibrium adsorption of metal ions, e.g Cu2+ and Ni2+, on the mech-MWNTs was investigated at room temperature. The adsorption isotherms gave excellent consistence with the Langmuir theory and the best fit values of K-1 and Κmax can be evaluated using non-linear least-squares. As results, the maximum of Cu2+ and Ni2+ ions uptake on to the mech-MWNTs are 0.93 ± 0.004 mg/g and 2.11 ± 0.01 mg/g respectively. There is no evidence indicating that the pore structure and layer surfaces at both ends of the mech-MWNTs are appropriate sites for metal ions adsorption.

Abstract: In this work, a simple, reproducible and low-cost synthesis method for the preparation of ß-tricalcium phosphate (ß-TCP) was developed. ß-TCP was prepared via wet mechanochemical treatment using calcium oxide and calcium hydrogen phosphate as raw materials. XRD and FTIR analysis indicated that the as-treated precursor was non-stoichiometric, poorly-crystallized carbonated hydroxyapatite (CHA) resulting from the mechanochemical reaction, and the crystalline ß-TCP powder was obtained by calcining the precursor at 800°C for 2 hours. SEM observation showed that the addition of surfactants could eliminate the agglomeration of the powder and well-dispersive ß-TCP powder with a particle diameter between 0.1 and 2.0 2m can be obtained.

Abstract: It is legally demanded that the wastes containing asbestos should be change to harmless substances completely due to the harmful effects of asbestos fiber on health. The purpose of present research was to construct a safe, reliable and facile technique by using mechano-chemical reaction, which is a non-combustion process and operated in a closed system. It was confirmed that the needle crystal of chrysotile asbestos was changed perfectly to amorphous state after grinding by using a planetary ball mill. Furthermore, these products could be remade to useful materials by addition of soil which consists of inorganic materials based on CaO and so one. After the obtained fine powders were mixed with water, pressed and held under the humid condition, the stable hydrates were found in these products after XRD analysis. These inorganic compounds were much useful as a new raw material for cement-like.