Papers by Keyword: Mica

Abstract: Present-day materials science requires development of compositions and technologies for production of composites with enhanced physical and technical properties. One of requirements towards such materials is an elevated heat strength. Materials, earlier used in electrothermy (ceramics, porcelain, asbestos and items made of them), have operating temperature of 400-500°С, high cost, low mechanical strength and a number of other drawbacks. Therefore, development of heat-resistant, mechanically strong and inexpensive insulation materials is an immediate problem. Mica’s characteristics to the maximum extent meet the requirements to a filler for the composite materials. Its use would enhance electric and physical properties of composites, contribute to development of waste-free technology, thus favoring the environment. Objectives of the paper: development of technology for production of heat-resistant materials on the base of heat-proof mica and special glass with elevated softening point; study of the interaction between composite components and high-temperature medium; giving recommendations on technology for fabricating heat-resistant composites with enhanced physical and technical properties. Objects of study: specimens of heat-proof mica (phlogopite), wastes of abrasive production, modifiers, glasses with high softening point. Methods of investigation: methods of thermodynamic and quantum-chemical studies were used with involvement of a complex of state-of-art physical and chemical methods. Results of study: development of theoretical grounds for forming the heat-resistant composite materials on the base of experimental studies and scientific generalizations. The technology for production of new heat-resistant materials on the base of rational use of mineral raw material and production wastes is proposed.

Abstract: After successful application of the sitting drop vapour diffusion route to deposit calcium phosphate layers on mica muscovite sheets, in this work we have extended the method to mineralize polymer surfaces (OSTE+) and bidimensional materials (graphene), aimed to prepare implants or scaffolds for nonload bearing applications in the medical sector. Thin octacalcium phosphate/apatite layers have been deposited on mica muscovite sheets. Thin apatite/octacalcium phosphate layers deposited on OSTE+ polymer lames. When graphene nanoflakes where used as support, this technique yielded apatite/graphene nanocomposites.

Abstract: A series of regenerated cellulose (RC) nanocomposites which were incorporated with the layered silicate mica were successfully prepared via ionic liquid. The effect of the mica loadings was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The mechanical properties which were investigated via tensile testing indicated that upon the introduction of the mica displayed a significant enhancement on the mechanical stability of the RC. The results showed the potential of mica to reinforce the RC polymers matrix.

Abstract: Metal Matrix Composites are being widely used in numerous applications like aerospace, Automobiles, Consumer goods etc. However, machining of these composites are being faced a lot of drawbacks in terms of increases in thrust force, machined surface roughness and tool wear etc. due to reinforcements of high hardness. In this paper, thrust forces in drilling of Al6061/mica composites with 1 and 3 weight% are recorded from Dynamometer for analysis. Cutting tool material of Tungsten carbide coated with TiAlN with 8 mm diameter was used. Al 6061/Mica_p composites were scrutinized on cast surface with the help of optical microscope. Also, Thrust force was analysed for different Cutting Speed and feed. It can be concluded that, as weight% of mica increases Thrust forces were decreased.

Abstract: SiO₂, Al₂O₃, MgO, MgF₂, SrCO₃, CaCO₃, CaF₂ and P₂O₅ were used to prepare machinable glass-ceramic with 4 mol% of fluorapatite for restorative dental applications. XRD showed that the glass heat treated at 792°C (the first crystallization temperature+20°C) for 6 hours consisted of calcium-mica, fluorapatite, strontium apatite, anorthite, forsterite, fluorite and stishovite crystalline phases. The microstructures of the resultant glass-ceramic, observed by SEM, were found to exhibit plate-like mica crystals and many tabular particles embedded in the mica phases. The particles, determined by EDS, were rich in calcium. The three-point bending strength (158 MPa) closely matched that of nature tooth. Average Vickers hardness of the received glass-ceramic (2.6 GPa) was lower than that of natural tooth.

Abstract: In this paper, In this paper, polypropylene / mica composites were prepared by blending, using polypropylene (PP) as matrix, mica as filler. In order to study the anti-aging properties of polypropylene / mica composite materials, the above polypropylene / mica composite materials were placed outside to study the influence of natural aging time on the anti-aging properties and to explore the natural aging mechanism of polypropylene / mica composites. Natural aging research results show that:with the extension of the natural aging time the surface of materials will appear cracks and sheddings. The trends of tensile strength reduce at first, then increase and then decrease; the notched impact toughness values show fluctuating in the early aging, then an increase following and then decreasing.The increase of mica content are good for maintaining the mechanical properties of PP / mica composite, PP-g-MAH helps to maintain the tensile strength, while toughening POE-g-MAH will weaken the anti-aging properties of polypropylene / mica composite materials.

Abstract: The study results of mica bearing rocks from the Mamskoye and Kuletskoye deposits and the processes, involved in grinding and activating muscovite mica from the rocks using a ball and a planetary mills, a disintegrator and a pneumoimpulsive installation depending on different time intervals and other grinding factors, are presented in this paper. The resultant materials were examined by the methods of X-ray phase analysis, derivatography, microscopy and others, which resulted in drawing the conclusions concerning the applicability of different mechanical treatment methods applied in obtaining ground mica for various uses.

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Abstract: The glass system of SiO₂-Al₂O₃-MgO-MgF₂-SrCO₃-CaCO₃-CaF₂-P₂O₅ was used to prepare machinable glass-ceramics for restorative dental applications. The aim of this study was to apply various heat treatments to produce mica-based glass-ceramics. Differential Thermal Analysis (DTA) was used to determine the optimal heat treatment conditions for nucleation and growth of the crystalline phases in the quenched glass. It was found that the optimum nucleation temperatures for the first and the second crystallization temperatures (T_p1 and T_p2) were 642°C and 635°C, respectively, and the optimum nucleation times were between 2 and 4 hours. X-Ray Diffraction (XRD) showed the phases developed were anorthite, calcium-mica, fluorapatite, strontium apatite, forsterite, fluorite and stishovite phases. The microstructures of glass-ceramics were observed by Scanning electron microscope (SEM), found to exhibit plate-like mica crystals with high interlocking and randomly oriented with a higher soaking temperature and prolongation of the soaking time for crystallization.

Abstract: Synthetic mica organically treated with alkylamines was added to poly (3-hydroxybutyrate-co-3hydroxyhexanoate) (PHBH), one of the bacterial co-polyesters. Mica dispersing in PHBH acted as a crosslinking point of PHBH chains and increased the melt viscosity of PHBH significantly. The melt spinnability of PHBH was greatly improved by the addition of mica and the crystallization of PHBH in the spinline was highly promoted. WAXD spectra showed that the as-spun fibers of PHBH/MICA contain both highly oriented α-and β-forms of PHBH crystal. Further the SAXS revealed that the mica dispersing in the PHBH fiber oriented with its surface parallel to the fiber axis. The crystalline orientation of PHBH, orientation of mica, and the formation of β-form all improve the mechanical property of PHBH fibers.