Formation mechanism of ZrB2-Al2O3 nanocomposite powder by mechanically induced self-sustaining reaction

ZrB2-Al2O3 nanocomposite powder was produced by aluminothermic reduction in Al/ZrO2/B2O 3 system. In this research, high energy ball milling was used to produce the necessary conditions to induce a mechanically induced self-sustaining reaction. The ignition time of the composite formation was found to be about 13 min. The synthesis mechanism in this system was investigated by examining the corresponding sub-reactions as well as changing the stoichiometry of reactants. Thermal behavior of the system was also studied. © 2013 Springer Science+Business Media New York.Peer Reviewe

Mechanochemical synthesis of ZrB2-SiC-ZrC nanocomposite powder by metallothermic reduction of zircon

Aluminium and magnesium were used in the M/ZrSiO4/B 2O3/C (M = Al, Mg) system to induce a mechanically induced self-sustaining reaction (MSR). Aluminium was not able to reduce the system to the desired products, and the system became amorphous after 10 h milling. However, nanocomposite powder of ZrB2-SiC-ZrC was in situ synthesized by the magnesiothermic reduction with an ignition time of approximately 6 min. The mechanism for the formation of the product in this system was determined by studying the relevant sub-reactionsGobierno de España No. MAT2011-2298

Formation mechanism of ZrB2-Al2O3 nanocomposite powder by mechanically induced self-sustaining reaction

ZrB2-Al2O3 nanocomposite powder was produced by aluminothermic reduction in Al/ZrO2/B2O 3 system. In this research, high energy ball milling was used to produce the necessary conditions to induce a mechanically induced self-sustaining reaction. The ignition time of the composite formation was found to be about 13 min. The synthesis mechanism in this system was investigated by examining the corresponding sub-reactions as well as changing the stoichiometry of reactants. Thermal behavior of the system was also studied.Gobierno de España No. MAT2011-2298

Mechanosynthesis of nanocrystalline ZrB2-based powders by mechanically induced self-sustaining reaction method

Preparation of nanocrystalline ZrB2-based powder by aluminothermic and magnesiothermic reductions in M/ZrO2/B 2O3 (M = Al or Mg) systems was investigated. In this research, high energy ball milling was employed to persuade necessary conditions for the occurrence of a mechanically induced self-sustaining reaction (MSR). The course of MSR reactions were recorded by a noticeable pressure rise in the system during milling. Ignition times for ZrB2 formation by aluminothermic and magnesiothermic reductions were found to be 13 and 6 min, respectively. Zirconium diboride formation mechanism in both systems was explained through the analysis of the relevant sub-reactions. © 2013 Institute of Materials, Minerals and Mining Published by Maney on behalf of the Institute.Gobierno de España No. MAT2011- 2298

In-situ synthesis of a ZrB2–based composite powder using a mechanochemical reaction for the zircon/magnesium/boron oxide/graphite system

A ZrSiO4/B2O3/Mg/C system was used to synthesize a ZrB2-based composite through a high-energy ball milling process. As a result of the milling process, a mechanically induced self-sustaining reaction (MSR) was achieved in this system. A composite powder of ZrB2–SiC–ZrC was prepared in situ by a magnesiothermic reduction with an ignition time of approximately 6 min. The mechanism for the formation of the product was investigated by studying the relevant subreactions, the stoichiometric amount of B2O3, and thermal analysis.Gobierno de España No. MAT2011-2298

An investigation on the formation mechanism of nano ZrB2 powder by a magnesiothermic reaction

Nanocrystalline zirconium diboride (ZrB2) powder was produced by mechanochemistry from the magnesiothermic reduction in the Mg/ZrO 2/B2O3 system. The use of high-energy milling conditions was essential to induce a mechanically induced self-sustaining reaction (MSR) and significantly reduce the milling time required for complete conversion. Under these conditions, it was found that the ignition time for ZrB2 formation was only about a few minutes. In this study, the mechanism for the formation of ZrB2 in this system was determined by studying the relevant sub-reactions, the effect of stoichiometry, and the thermal behavior of the system.Gobierno de España No. MAT2011-2298

Formation mechanism of ZrB 2 -Al 2 O 3 nanocomposite powder by mechanically induced self-sustaining reaction

Abstract ZrB 2 -Al 2 O 3 nanocomposite powder was produced by aluminothermic reduction in Al/ZrO 2 /B 2 O 3 system. In this research, high energy ball milling was used to produce the necessary conditions to induce a mechanically induced self-sustaining reaction. The ignition time of the composite formation was found to be about 13 min. The synthesis mechanism in this system was investigated by examining the corresponding sub-reactions as well as changing the stoichiometry of reactants. Thermal behavior of the system was also studied

The Role of Spiritual Well-being in Predicting Pregnancy-Specific Stress

Background & objectives: Stress during pregnancy can be associated with serious and long-term adverse outcomes for mothers, fetuses, newborns, children, and even adolescents. One of the coping mechanisms with stress during pregnancy is paying attention to women's spiritual beliefs and values. The aim of the current study was to determine the role of spiritual well-being in the prediction of pregnancy-specific stress in women referred to health centers in Hafshjan. Methods: The current study was a descriptive- correlational study. The study population consisted of all pregnant women referred to health centers in Hafshejan, 2015. Two hundred pregnant women were selected using convenience sampling method. Spiritual well-being (Paloutzian and Ellison) and pregnancy-specific stress questionnaires (Sallary) were used for data collection. Data analyses were performed by Pearson correlation and multivariate linear regression tests using SPSS version 20. Results: The mean age of the study sample was 27.68±4.75. The results showed a significant negative correlation between spirituality and pregnancy stress (r= -0.29, p<0.001). Multiple regression analysis indicated that spiritual well-being is capable to predict the stress during pregnancy (β = -0.444, R2=0.139, p<0.001). Conclusion: Taking into consideration the predictive role of spiritual well-being in pregnancy stress, women's health care professionals should pay particular attention to implement effective strategies for promoting of spiritual well-being level during pregnancy