Wyniki wyszukiwania - BazTech

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Calorimetric studies of the enthalpies of formation of alloys from Ni75Al25-Ni75Cr25 and Ni75Al25-Ni85Cr15 sections at 873 K

Maciąg T., Rzyman K.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 2

275--279

EN

Purpose: The main purpose of the study was to determine value of formation enthalpy ΔfH of Ni3Al-based alloys with chromium additions at temperature 873 K. Experiment was carried in order to determine the course of phase boundaries γ’ / γ’+ γ / γ for Ni-Al-Cr system. Design/methodology/approach: Experiment was performed with use of high temperature solution calorimeter. This “in situ” method allows to determine formation enthalpy in a wide range of temperature thanks to intermediate multi socket container which was applied in the device. It is fundamental because keeping the structure of examined alloys during quenching is extremely difficult, often impossible in this type of alloys. Findings: Distinct breaks in the course of enthalpy of formation ΔfH as a function of chromium concentration were discovered, that are assigned to courses of γ’ / γ’+ γ / phase boundaries. Research limitations/implications: Experiment will be proceeded at higher temperatures and completed with resistometric measurements. All results will be used in CAPLHAD procedure in order to optimize course of phase boundaries. Originality/value: The results are valuable thermodynamic data and method proposed can become a new way of direct determination of phase boundaries in metallic systems.

2

Energetic Performances of Solid Composite Propellants

Lempert D., Nechiporenko G., Manelis G.

Central European Journal of Energetic Materials

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2011

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Vol. 8, nr 1

25-38

EN

Different kinds of solid composite propellant (SCP) are described. All ways to increase energetic potential of SCP are considered as well as pro et contra of each of these ways. Different kinds of oxidizer (perchlorates of ammonium, hydroxylammonium, and hydrazinium; ammonium salt of dinitramine; other saltlike and molecular oxidizers) are under consideration. The main principles creation of SCP formulation with optimal characteristics in the context of their concrete purpose are discussed, e.g. for rockets with considerably low ratio propellant volume/empty construction mass (V/M lower than 1 Litr/kg or so) the ballistic effectiveness may be increased with the replacement of aluminum by high-dense zirconium or zirconium hydride. Possibilities for creation of special SCP formulations for application at the far space, e.g. for Mars exploration are discussed as well.

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Formation enthalpy of AlNi3-based alloys with iron additions by calorimetric solution and direct reaction methods

Rzyman K., Gachon J-C.

Archives of Metallurgy and Materials

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2010

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Vol. 55, iss. 4

1021-1028

EN

The enthalpies of formation of AlNi3-based alloys with iron additions were determined both by solution and direct reaction calorimetry. The results were analyzed in order to determine phase boundaries in the pseudo-binary AlNi3-FeNi3 system.

PL

Entalpia tworzenia stopów na osnowie AlNi3 z udziałem żelaza została wyznaczona doświadczalnie kalorymetryczną metodą rozpuszczania oraz metodą bezpośredniej reakcji. Uzyskane wyniki przeanalizowano pod kątem wyznaczenia granic międzyfazowych w badanym pseudo-binarnym układzie AlNi3-FeNi3.