Ludmil Drenchev, Jerzy Józef Sobczak
AbstractDevelopment of instruments for micro- and macrostructure design in functionally graded materials is a challenge for the modern industry. In this path, mathematical modeling and numerical simulation are extremely helpful techniques for design and investigations of functionally graded materials. The aim of this paper is to show the possibility for production of gasars with graded porous structure. This is done by means of comprehensive mathematical model of fered by the authors in a previous work. The way to control the structure by means of processing parameters is discussed on the basis numerical experiments related to copper/hydrogen system.
Keywords: gasars, highly porous materials, designing, functionally graded materials, mathematical modeling, numerical simulation, copper-hydrogen system, oriented structure,
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Zbigniew Adamczyk, Katarzyna Jaszczółt, Barbara Jachimska, Małgorzata Nattich
AbstractHydroxyapatite [1-3] of structural formula Ca10(PO)6(OH)2 (HAp) and calcium triphosphate Ca3(PO)2 (TCP) powder sand suspensions have been characterized physicochemically. Physicochemical characteristics involved the analysis of phase composition using the X ray diffraction, the powder morphology using SEM method, determination of specific surface area by the BET method, the grain distribution of HAp water suspensions using laser diffractometer and the zeta potential as a function of suspension pH (isoelectric point) by the measurement of the electrophoretic mobility.
Keywords: calcium triphosphate, polyelectrolytes, slurries, hydroxyapatite,
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Marta Biel-Gołaska, Izabela Kalemba
AbstractDental tools are sometimes damaged as a results of exploitation or during sterilization and desinfection. The aim of durability improving of dental borers and tweezers and increasing of the biocompatibility was modification of the surface of tools by TiN and TiAlN coatings. The coatings were made by PAPVD technology (Plasma Assisted Physical Vapour Deposition). The dental borers and tweezers were observed after the operation time of 3, 6, 9, 12 and 24 months. The results of investigation are presented in this article.
Keywords: dental tools, TiN and TiAlN coatings, PAPVD method, metallographic observations, biocompatibility, wear resistance,
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Tomasz Reguła, Marian Bronicki, Marzena Lech-Grega, Edward Czekaj
AbstractThe aim of this publication is to assess the effect of different types of the standard heat treatment on changes in mechanical properties at room temperature of magnesium alloy from AZ91 family referred to the same properties in as-fabricated state. The investigated alloy was gravity cast into sand and metal moulds. The mechanically prepared specimens were subjected to a heat treatment during which they were transformed from the as-fabricated state to conditions: T4, T5 and T6. Testing of mechanical properties included determination of Rm, Rp02 and A5 during static tensile test and Brinell hardness measurements (HB). The results of the investigations indicate that the mechanical properties of cast AZ91 alloy can be successfully shaped through the application of proper heat treatment.
Keywords: AZ91 magnesium alloy, casting, heat treatment, mechanical properties,
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Irena Izdebska-Szanda
AbstractThe article presents the results of high-temperature investigations of the modified samples of hydrated sodium silicate and of the sand mixtures with an addition of this compound. To improve the knocking out properties of these sands when poured with molten metal, the effect of morphoactive additives used as modifiers of the hydrated sodium silicate on the high-temperature technological (cohesive-adhesive) properties of moulding sands prepared with an addition of this binder was determined. As a result of the investigations, an optimum addition of the morphoactive agent was selected.
Keywords: hydrated sodium silicate, modification, temperature and phase transformations, residual strength,
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