Effect of Briquetting Pressure on the Performance of In Situ Formed Sialon in Al2O3-C Refractory Bricks

2014 ◽  
Vol 881-883 ◽  
pp. 1049-1052 ◽  
Author(s):  
Nai Peng ◽  
Cheng Ji Deng ◽  
Hong Xi Zhu

In this paper, the effects of briquetting pressure on the performance of in-situ formed Sialon in Al2O3-C refractory bricks are investigated. The phase compositions and microstructure of the Al2O3-C refractory were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM).The results show the briquetting pressure hardly has effect on the phase of the sintered specimens, two new phases of Sialon with a Z value of 2 and SiC formed. The micrographs of Sialon crystals have the shape of both column and tabular column, but with a cone tip in the specimens sintered at 200MPa and 300MPa and smooth tip in specimens sintered at 400MPa and 500MPa.

2014 ◽  
Vol 881-883 ◽  
pp. 914-917
Author(s):  
Xiao Jun Zhang ◽  
Nai Peng ◽  
Cheng Ji Deng ◽  
Hong Xi Zhu ◽  
Wen Jie Yuan

In this paper, the phase compositions and microstructure of MgO-C samples containing Si powder in N2sintered at 1350-1500°C were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). The α-Si3N4, β-Si3N4, MgSiN2and SiC phases have formed together with MgO and C phases in the sintered samples. The morphologies of β-Si3N4crystals were almost in the shape of rod-like through the α-β phase transformation of Si3N4by Mg-Si-O-N and silicon liquid. The morphologies of α-Si3N4crystals were in the shape of equiaxed. The morphology of MgSiN2crystals was in the shape of polyhedron with the size of 5 μm.


2013 ◽  
Vol 634-638 ◽  
pp. 2354-2357
Author(s):  
Nai Peng ◽  
Cheng Ji Deng ◽  
Wen Jie Yuan ◽  
Hong Xi Zhu

The microstructure and phase analysis of in situ nitrides formation in MgAl2O4-C refractory were investigated with different temperature. The phase compositions and microstructure of the MgAl2O4-C refractory were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that sintering temperature has a significant influence on the microstructure and phase analysis of MgAl2O4 refractory. As the sintering temperatures are 1450°C and 1500°C, nitride that formed in samples is β-Sialon and the crystal morphology is columnar with short size. With the temperature rise to 1550°C and 1600°C, nitride formed in sample is AlON with the crystal morphology is tabular polymorph with large size.


Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 497
Author(s):  
Lixin Zhao ◽  
Po Li

Sandstone pore-plugging is a serious problem that bothers acid in situ leaching (ISL) uranium deposit, but currently, the mechanism of pore-plugging has not attracted much attention. In this study, using X-ray fluorescence, scanning electron microscope, optical microscope, and X-ray diffraction, we present both macro- and micro-evidence of pore-plugging occurred during acid in situ mining of sandstone uranium deposit at Yili Basin, NW (northwest) China. Our study reveals that in comparison with normal sandstones, the plugged sandstones are yellow in color and have relatively high contents of Fe and chamosite. The plugging in studied samples is mainly caused by precipitation of Fe(OH)3 at a pH of 2.0–4.0 for quantitative effect and by precipitation of gypsum (CaSO4·2H2O) as well. Alteration/dissolution of chamosite and to a lesser extent, Fe-bearing microcline and muscovite, may have contributed iron for Fe(OH)3 precipitation. It is suggested that adjustment of injection pH < 2.0 throughout the leaching passage would be an effective way to avoid/minimize this type of sandstone pore-plugging.


2013 ◽  
Vol 538 ◽  
pp. 150-153
Author(s):  
Tian Hong Guo ◽  
Juan Li ◽  
Yong Cai Zhang ◽  
Zhan Jun Yang

An in situ thermal oxidation strategy was proposed for synthesizing different SnO2 nanostructures, using our homemade SnS2 nanoplates as a precursor. The characterization results from X-ray diffraction, energy dispersive X-ray spectroscopy, and field emission scanning electron microscope revealed that the heating temperature played an important role in the microstructure and composition of the resultant products. By heating the SnS2 nanoplates in air at 400, 600 and 800 °C for 5 h, nanoplates, a mixture of nanoplates and nanoparticles, and nanoparticles of SnO2 were synthesized, respectively. The residual S was about 2.2 mol % in the product synthesized at 400 °C, while no residual S was detected in the products synthesized at 600 and 800 °C.


Arena Tekstil ◽  
2013 ◽  
Vol 28 (1) ◽  
Author(s):  
Maya Komalasari ◽  
Bambang Sunendar

Partikel nano TiO2 berbasis air dengan pH basa telah berhasil disintesis dengan menggunakan metode sol-gel dan diimobilisasi pada kain kapas dengan menggunakan kitosan sebagai zat pengikat silang. Sintesis dilakukan  dengan prekursor TiCl4 pada konsentrasi 0,3 M, 0,5 M dan 1 M, dan menggunakan templat kanji dengan proses kalsinasi pada suhu 500˚C selama 2 jam. Partikel nano TiO2 diaplikasikan ke kain kapas dengan metoda pad-dry-cure dan menggunakan kitosan sebagai crosslinking agent. Berdasarkan hasil Scanning Electron Microscope (SEM),diketahui bahwa morfologi partikel TiO2 berbentuk spherical dengan ukuran nano (kurang dari 100 nm). Karakterisasi X-Ray Diffraction (XRD) menunjukkan adanya tiga tipe struktur kristal utama, yaitu (100), (101) dan (102) dengan fasa kristal yang terbentuk adalah anatase dan rutile. Pada karakterisasi menggunakan SEM terhadap serbuk dari TiO2 yang telah diaplikasikan ke permukaan kain kapas, terlihat adanya imobilisasi partikel nano TiO2 melalui ikatan hidrogen silang dengan kitosan pada kain kapas. Hasil analisa tersebut kemudian dikonfirmasi dengan FTIR (Fourier Transform Infra Red) yang hasilnya memperlihatkan puncak serapan pada bilangan gelombang 3495 cm-1, 2546 cm-1, dan 511 cm-1,  yang masing-masing diasumsikan sebagai adanya vibrasi gugus fungsi O-H, N-H dan Ti-O-Ti. Hasil SEM menunjukkan pula bahwa kristal nano yang terbentuk diantaranya adalah fasa rutile , yang berdasarkan literatur terbukti dapatberfungsi sebagai anti UV.


2012 ◽  
Vol 525-526 ◽  
pp. 277-280
Author(s):  
Guo Jin ◽  
Xiu Fang Cui ◽  
Er Bao Liu ◽  
Qing Fen Li

The effect of the neodymium content on mechanical properties of the electro-brush plated nanoAl2O3/Ni composite coating was investigated in this paper. The microstructure and phase structure were studied with scanning electron microscope (SEM) and X-ray diffraction (XRD). The hardness and abrasion properties of several coatings with different neodymium content were studied by nanoindentation test and friction / wear experiment. Results show that the coatings are much finer and more compact when the neodymium was added, and the hardness and abrasion property of the coatings with neodymium were improved obviously. Besides, the small cracks conduced by the upgrowth stress in the coatings were ameliorated when the rare earth neodymium was added. The improvement mechanism was further discussed.


2012 ◽  
Vol 620 ◽  
pp. 384-388
Author(s):  
Sharifah Aishah Syed Salim ◽  
Julie Juliewatty Mohamed ◽  
Zainal Arifin Ahmad ◽  
Zainal Arifin Ahmad

Numerous methods have been used to produce high purity TiC. There is no previous study has been reported on the formation using single elemental powders of Titanium (Ti) and Carbon (C) with addition Nickel (Ni) by tungsten inert gas (TIG) weld method. In this work, TiC was synthesized via TIG method by arc melting elemental powder mixture of Ti and C at ~5 second (s) and 80 ampere (A). The effect Ni contents on TiC formation was investigated. The mixed raw material was ball milled for 24 hours followed by synthesis via TIG method. The arced samples were characterized by X-ray diffraction (XRD) and Scanning electron microscope (SEM). It was revealed, that small amount of Ni additive to the metal powder allows the production of dense and tough TiC.


2020 ◽  
Vol 70 (1) ◽  
Author(s):  
Xiujie Gong ◽  
Hongtao Zou ◽  
Chunrong Qian ◽  
Yang Yu ◽  
Yubo Hao ◽  
...  

Abstract Purpose The highly efficient degradation bacteria were selected from the humus from the very cold straw in China for many years to construct the in situ degradation bacteria, and the degradation efficiency of corn straw was determined by process optimization. Methods According to the main components of corn straw, through morphological, physiological, and biochemical screening, three highly efficient complementary degradation strains were selected to construct the compound flora, and the degradation efficiency was analyzed by Fourier transform infrared spectrometer, field emission scanning electron microscope, and X-ray diffractometer. Result The corn straw selected in this paper is mainly composed of cellulose (31.99%), hemicellulose (25.33%), and lignin (14.67%). Through the determination of enzyme activity, strain Streptomyces sp. G1T has high decomposition ability to cellulose and hemicellulose but weak utilization ability to lignin; strain Streptomyces sp. G2T has the strongest decomposition ability to cellulose and hemicellulose among the three strains. The decomposition ability of strain Streptomyces sp. G3T to lignin was the strongest among the three strains. Therefore, by compounding the three strains, the decomposition ability has been greatly improved. The optimal process conditions obtained by single factor and response surface method are as follows: pH is 7, temperature is 30 °C, inoculation amount is 5%, rotational speed is 210 rpm, and the weight loss rate of straw is 60.55% after decomposing for 7 days. A large amount of degradation of corn straw can be seen by Fourier transform infrared spectrometer, field emission scanning electron microscope, and X-ray diffractometer. Conclusion Streptomyces sp. G1T, Streptomyces sp. G2T, and Streptomyces sp. G3T screened from straw humus in very cold areas were used to construct in situ degradation bacteria, which had good straw degradation activity and had the potential to be used for straw treatment in cold areas after harvest. This characteristic makes the complex bacteria become a strong competitive candidate for industrial production, and it is also an effective biotechnology in line with the current recycling of resources.


2007 ◽  
Vol 43 (2) ◽  
pp. 141-150 ◽  
Author(s):  
G.P. Vassilev ◽  
K.I. Lilova ◽  
J.C. Gachon

Phase equilibria were studied in the system Ni-Sn-Bi. Special attention has been paid to the identification of the recently found ternary phase. For this purpose samples were synthesized using intimately mixed powders. After annealing and quenching, all alloys were analyzed by scanning electron microscope and by X-ray diffraction. The results give evidences about the existence of a ternary compound with approximate formula Ni6Sn2Bi to Ni7Sn2Bi. Overlapping of some neighboring diffraction peaks of this phase with NiBi and Ni3Sn_LT is the reason for the difficulties related to the X-ray diffraction identification of the ternary phase.


2020 ◽  
Vol 16 (2) ◽  
pp. 12
Author(s):  
Solihudin Solihudin ◽  
Haryono Haryono ◽  
Atiek Rostika Noviyanti ◽  
Muhammad Rizky Ridwansyah

<p>Komposit forsterit-karbon merupakan salah satu material modifikasi dari forsterit yang berpotensi memiliki sifat isolator panas baik. Karbon dalam komposit dapat mengisi cacat titik pada kristal forsterit. Arang sekam padi (residu gasifikasi) mengandung SiO2 amorf dan karbon yang tinggi. Penelitian ini bertujuan menentukan pengaruh suhu kalsinasi dalam medium gas inert (dengan pengaliran gas argon) terhadap karakteristik komposit forsterit-karbon dari arang sekam padi dan magnesium karbonat. Metode penelitian meliputi preparasi arang sekam padi hasil gasifikasi, dan sintesis forsterit-karbon. Proses sintesis komposit forsterit karbon dilakukan dengan cara mencampurkan arang sekam padi dengan kalium karbonat pada rasio mol magmesium terhadap silikon sebesar 2 : 1 kemudian dikalsinasi dengan suhu divariasikan (700, 800, 900, dan 1000 oC). Selanjutnya sampel hasil sintesis dikarakterisasi dengan Fourier-transform infrared (FTIR), X-ray diffraction (XRD), dan scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). Hasil karakterisasi dengan FTIR dan XRD diperoleh kesimpulan bahwa forsterit mulai terbentuk pada suhu kalisiasi 800 oC dan sempurna pada suhu 1000 oC, karenanya komposit yang terbentuk pada 1000 oC dimungkinkan sebagai forsterit-karbon, di mana unsur-unsur yang terkandung ditunjukkan oleh SEM-EDS.</p><p> </p><p><strong>The Effect of Calcination Temperature on the Characteristics of Forsterite-Carbon Composites Synthesized in Argon Gas Medium</strong>. Forsterite-carbon composite is one of the material modifications of forsterite, which potentially has a good heat insulation property. Carbon in composites can fill point defects in forsterite crystals. Rice husk charcoal, as gasification residues, contains high amorphous SiO2 and carbon. This study aims to determine the effect of temperature on the calcination of a mixture of rice husk charcoal and magnesium carbonate under an inert gas (argon gas) on the characteristics of the forsterite-carbon composite produced. The experimental research performed includes the preparation of gasified rice husk charcoal and the synthesis of the carbon-forsterite composite. The synthesis process of the carbon-forsterite composites was carried out by mixing rice husk charcoal with potassium carbonate at a mole ratio of magnesium to silicon of 2 : 1. The mixture was then calcined with varying temperatures (700, 800, 900, and 1000 °C). Furthermore, the synthesized sample was characterized by Fourier-transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). The FTIR and XRD analysis show that the forsterites began to form at a calcination temperature of 800 °C and perfectly formed at a temperature of 1000 °C; therefore, the composite formed at 1000 °C is possible as forsterite-carbon, in which the contained elements were indicated by SEM-EDS.</p>


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