scholarly journals Preparation and Characterization of Mg–Al–B Alloy (Mg0.5Al0.5B2) Via High-Temperature Sintering

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3608
Author(s):  
Lin Yang ◽  
Jie He ◽  
Yusong Ma ◽  
Liang Zhang ◽  
Shizhou Ma ◽  
...  
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Sintering Temperature ◽  
Pure Aluminum ◽  
High Energy ◽  
Holding Time ◽  
Molar Ratio ◽  
Simple Substance ◽  
Improved Characteristics

Boron and its alloys have long been explored as potential fuel and increasingly replace pure aluminum powder in high-energy formulations. The ignition and burning properties of boron can be improved by making boron alloys. In this study, an Mg–Al–B alloy was synthesized from magnesium, aluminum and boron powders in a 1:1:4 molar ratio by preheating to 600 °C for 30 min, followed by high-temperature sintering in a tube furnace. The effects of sintering temperature (700–1000 °C) and holding time (0.5–10 h) on the phase composition of mixed powders were studied. After the samples were cooled to room temperature, they were ground into powder. The phase composition, micromorphology and the bonding forms of elements of the synthesized samples were studied using XRD, SEM and XPS. The results show that each element exists in the form of simple substance in the alloy. The influence of the sintering temperature on the synthesis reaction of Mg0.5Al0.5B2 is very important, but holding time has little effect on it. With the increase of sintering temperature, the content of the Mg0.5Al0.5B2 phase gradually increases, and the phase content of residual metal gradually decreases. The phase and morphology analyses show that the optimum sintering temperature is 1000 °C with a minimum holding time of 0.5 h. It is expected to be used in gunpowder, propellant, explosives and pyrotechnics with improved characteristics.

Effect of Mineral Composition and Sintering Temperature on the Synthetic Cordierite

2014 ◽  
Vol 633 ◽  
pp. 61-64
Author(s):  
Lei Li ◽  
Rui Long Wen ◽  
Xiao Guang Zhang ◽  
Cheng Biao Wang ◽  
Ming Hao Fang ◽  
...  
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Flexural Strength ◽  
Mineral Composition ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Temperature Reaction ◽  
Final Phase ◽  
High Temperature Reaction ◽  
Industrial Alumina

Cordierite samples were prepared using quartz sand tailings, industrial alumina and magnesite tailings as raw materials by high-temperature reaction. The influence of mineral composition and sintering temperature on the final phase composition and physical properties of cordierite were studied. The results shown that a large number of cordierite generated at 1300 °C. When the ratio of Al2O3/SiO2 equals to 1.08, the flexural strength of samples increased to 27.66 MPa.

Experimental Analysis and Material Characterization of Ultra High Temperature Composites

2021 ◽  
Author(s):  
Anindya Ghoshal ◽  
Michael J. Walock ◽  
Andy Nieto ◽  
Muthuvel Murugan ◽  
Clara Hofmeister-Mock ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Material Characterization ◽  
High Energy ◽  
Test Material ◽  
Layer System ◽  
Vannevar Bush ◽  
Sic Composites ◽  
Ultra High Temperature

Abstract Ultra high temperature ceramic (UHTC) materials have attracted attention for hypersonic applications. Currently there is significant interest in possible gas turbine engine applications of UHTC composites as well. However, many of these materials, such as hafnium carbide, zirconium carbide, and zirconium diboride, have significant oxidation resistance and toughness limitations. In addition, these materials are very difficult to manufacture because of their high melting points. In many cases, SiC powder is incorporated into UHTCs to aid in processing and to enhance fracture toughness. This can also improve the materials’ oxidation resistance at moderately high temperatures due to a crack-healing borosilicate phase. ZrB2-SiC composites show very good oxidation resistance up to 1700 °C, due to the formation of SiO2 and ZrO2 scales in numerous prior studies. While this may limit its application to hypersonic applications (due to reduced thermal conductivity and oxidation resistance at higher temperatures), these UHTC-SiC composites may find applications in turbomachinery, as either stand-alone parts or as a component in a multi-layer system. The US Army Research Laboratory (ARL), the Naval Postgraduate School (NPS), and the University of California – San Diego (UCSD) are developing tough UHTC composites with high durability and oxidation resistance. For this paper, UHTC-SiC composites and high-entropy fluorite oxides were developed using planetary and high-energy ball milling and consolidated using spark plasma sintering. These materials were evaluated for their oxidation-resistance, ablation-resistance, and thermal cycling behavior under a DoD/OSD-funded Laboratory University Collaborative Initiative (LUCI) Fellowship and DoD Vannevar Bush Fellowship Program. In the present paper experimental results and post-test material characterization of SPS sintered ZrB2, ZrB2+SiC, ZrB2+SiC+HfC, HfC+SiC, and HfC+ZrB2 pellets subjected to ablation test are presented.

Effect of Y2O3 on the Sintering, Mechanical and Dielectric Properties of Mullite/h-BN Composites

2016 ◽  
Vol 848 ◽  
pp. 28-31
Author(s):  
Han Jin ◽  
Yong Feng Li ◽  
Zhong Qi Shi ◽  
Hong Yan Xia ◽  
Guan Jun Qiao
Keyword(s):  
Fracture Toughness ◽  
Dielectric Constant ◽  
Phase Composition ◽  
High Temperature ◽  
Dielectric Properties ◽  
Liquid Phase ◽  
Flexural Strength ◽  
Sintering Temperature ◽  
Pressureless Sintering ◽  
Different Temperatures

Mullite/10 wt. %h-BN composites with 5 wt. % Y2O3 additive were fabricated by pressureless sintering at different temperatures. The densification, phase composition, microstructure, mechanical and dielectric properties of the mullite/h-BN composites were investigated. With the addition of Y2O3, the sintering temperature of the mullite/h-BN composites declined, while the density, mechanical and dielectric properties all increased. The addition of Y2O3 promoted the formation of liquid phase at high temperature, which accelerated the densification. Besides, Y2O3 particles which were located at the grain boundaries inhibited the grain growth of mullite matrix. For the mullite/h-BN composites with Y2O3 additive, the appropriate sintering temperature was about 1600°C. The relative density, flexural strength, fracture toughness and dielectric constant of the Y2O3 doped mullite/h-BN composite sintered at 1600 °C reached 82%, 135 MPa, 2.3 MPa·m1/2 and 4.9, respectively.

Synthesis and Characterization of Pb(Zr0.52Ti0.48)O3 Properties via High Planetary Mill

2017 ◽  
Vol 888 ◽  
pp. 96-102
Author(s):  
Shafiza Afzan Sharif ◽  
Julie Juliewatty Mohamed ◽  
Hasmaliza Mohamed ◽  
Zainal Arifin Ahmad ◽  
Wan Azhar Wan Yusoff
Keyword(s):  
Sintering Temperature ◽  
Xrd Analysis ◽  
High Energy ◽  
Planetary Mill ◽  
Firing Process ◽  
Material System ◽  
Sintering Process ◽  
Grain Growth Behavior ◽  
Sintering Condition

In this work, the piezoelectric material system of Pb (Zr0.52Ti0.48)O3 ceramics were synthesized by conventional solid state via high energy planetary mill reaction. This process were chosen in order to skip the calcinations and implement a single firing process which very effective to reduce the possibility of PbO loss. The effect of sintering parameters on structural behavior of pure PZT ceramic was discussed in detail. Comprehensive studies have been carried out in order get optimum parameter for sintering process, thus improved the performance of the pure PZT ceramics. Grain size properties of Pb (Zr0.52Ti0.48)O3 ceramics increased with increasing the sintering temperature and duration. However longer sintering condition (1200 °C, 3 hours) causes excessive PbO loss which leads to presence new phases in XRD analysis, promote grain growth behavior with inhomogenous microstructure and tend to have more pores.

scholarly journals Chemical and Structural Analysis of Newly Prepared Co-W-Al Alloy by Aluminothermic Reaction

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 658
Author(s):  
Štefan Michna ◽  
Anna Knaislová ◽  
Iryna Hren ◽  
Jan Novotný ◽  
Lenka Michnová ◽  
...  
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Structural Analysis ◽  
Surface Coating ◽  
Al Alloy ◽  
Metal Carbides ◽  
Aluminothermic Reaction ◽  
Carbide Particles ◽  
Very High

This article is devoted to the characterization of a new Co-W-Al alloy prepared by an aluminothermic reaction. This alloy is used for the subsequent preparation of a special composite nanopowder and for the surface coating of aluminum, magnesium, or iron alloys. Due to the very high temperature (2000 °C–3000 °C) required for the reaction, thermite was added to the mixture. Pulverized coal was also added in order to obtain the appropriate metal carbides (Co, W, Ti), which increase hardness, resistance to abrasion, and the corrosion of the coating and have good high temperature properties. The phase composition of the alloy prepared by the aluminothermic reaction showed mainly cobalt, tungsten, and aluminum, as well as small amounts of iron, titanium, and calcium. No carbon was identified using this method. The microstructure of this alloy is characterized by a cobalt matrix with smaller regular and irregular carbide particles doped by aluminum.

scholarly journals RhSn3 and the Modifications of RhSn4 – Structure and 119Sn Mössbauer spectroscopic characterization

2019 ◽  
Vol 74 (2) ◽  
pp. 203-209
Author(s):  
Thomas Fickenscher ◽  
Stefan Lösel ◽  
Harald Hillebrecht ◽  
Jutta Kösters ◽  
Theresa Block ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Spectroscopic Characterization ◽  
Molar Ratio ◽  
Final Annealing ◽  
X Ray ◽  
High Temperature Modification ◽  
Density Treatment ◽  
Tin Coordination

AbstractSingle crystals of the high-temperature modification of RhSn4 were obtained from a tin flux (1:20 molar ratio; final annealing at 920 K; dissolution of the tin matrix in 2N HCl). The structure was refined from single-crystal X-ray diffractometer data: I41/acd, a=629.73(5), c=2288.36(18) pm, wR2=0.0382, 447 F2 values and 14 variables. β-RhSn4 is isotypic with β-IrSn4. The rhodium atoms have slightly distorted square-antiprismatic tin coordination with Rh–Sn distances of 4×273.4 and 4×274.1 pm. The RhSn8 units are condensed via common edges to layers that are staggered with respect to each other and stacked in ABCD sequence. A 119Sn Mössbauer spectroscopic characterization of ß-RhSn4 and the stannides RhSn3 and α-RhSn4 shows the typical isomer shifts for transition metal stannides. Only for α-RhSn4 the three crystallographically independent tin sites could be resolved, a consequence of the different s-electron density. Treatment of α-RhSn4 under high-pressure (up to 10 GPa)/high-temperature (up to T=1370 K) conditions leads to decomposition into Rh1.5Sn, RhSn2 and β-Sn.

Preparation of Coated ZrSiO4-ZrB2 Using Sol-Gel Method and its Oxidation Resistance

2017 ◽  
Vol 727 ◽  
pp. 947-952 ◽  
Author(s):  
Meng Chen ◽  
Jun Guo Li ◽  
Hai Tao Yang ◽  
Qiang Shen ◽  
Lian Meng Zhang
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Holding Time ◽  
Crystal Phase ◽  
Catalytic Hydrolysis ◽  
Gel Method ◽  
Sol Gel Method ◽  
Testing Techniques

In this paper, coated ZrSiO4-ZrB2 powder was prepared by sol-gel method. The ZrSiO4 coating can improve the oxidation resistance of ZrB2 at high temperature. The effect of N (nZrSiO4/nZrB2), sintering temperature, holding time and catalytic hydrolysis condition of tetraethoxysilane (TEOS) on coated ZrSiO4-ZrB2 powder was discussed. The modern testing techniques such as XRD, SEM and TG-DSC were used to analyze the crystal phase compositions, microstructures and the oxidation resistance property. The results of experiments showed that the oxidation resistance of coated ZrSiO4-ZrB2 powder was excellent when N is 0.7, and TEOS is alkaline-catalyzed hydrolyzed.

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