Influence of Calcining Temperature on the Microstructure of LaPO4 Powders

2009 ◽  
Vol 79-82 ◽  
pp. 2231-2234
Author(s):  
Zi Feng Liu ◽  
Xin Wang ◽  
Yan Sheng Yin ◽  
Qiang Liu

Nanometer LaPO4 powders were synthesized by liquid-liquid direct precipitation method. La(NO3)3•6H2O and (NH4)3PO4•3H2O were used as raw materials. The calcining temperature was 900°C, 1000°C, 1100°C, respectively. DTA result shows that the LaPO4 precursor is LaPO4•4H2O. The calicined powders were characterized by X-ray powder diffraction (XRD) and Scanning Electron Microscope (SEM), and exhibited a pure LaPO4 phase with a monazite structure about 50-100 nm in diameter size. With the calcining temperature increasing, the crystallization of the LaPO4 became better and the grain shape changed from elongated grain shape to spherical grain shape.

2018 ◽  
Vol 163 ◽  
pp. 05008
Author(s):  
Anna Skawińska

This paper presents the results of the studies carried out in the model systems and concerning the tobermorite synthesis with an addition of metahalloysite. Quartz sand and quicklime were the main raw material constituents. The mixtures in the form of slurries underwent hydrothermal treatment with an addition of metahalloysite (5%, 10%, 15%, 20% and 30%) for 4 hours and 12 hours. The resultant composites were analysed for their phase composition using X-ray powder diffraction. The microstructure was examined using the Scanning Electron Microscope. Tobermorite was the principle reaction product. When 30% metahalloysite was added to the mixture containing CaO and SiO2, the formation of katoite was found.


Author(s):  
Kezhen Qi ◽  
Ruidan Wang ◽  
Jiaqi Fu ◽  
Ke Chen ◽  
Chunying Zuo

Hierarchical ZnO crystals with flower-like microstructures were successfully synthesized via a facile hydrothermal route without using any surfactants. The morphology of these microstructures can be easily controlled by adjusting the pH of the reaction solution. The products were characterized by X-ray powder diffraction (XRD) and scanning electron microscope (SEM). Furthermore, a possible growth mechanism of ZnO hierarchical microstructures was proposed.  


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Jing Wang ◽  
Yang Liu ◽  
Yang Jiao ◽  
Fengyu Qu ◽  
Qingzhi Pan ◽  
...  

The well-aligned Ag2O/ZnO microflowers heterostructure was synthesized by a straightforward two-step procedure. The diameters of the as-synthesized products were as much as 1.5 μm. The as-grown Ag2O/ZnO heterostructure was investigated by X-ray powder diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and photoluminescence (PL) spectroscopy analysis. A possible growth mechanism for flowerlike Ag2O/ZnO heterostructure was proposed based on the experimental results. Compared with pure ZnO microflowers, PL spectrum of the composite with only one strong peak at 383 nm showed good intrinsic emission.


2011 ◽  
Vol 117-119 ◽  
pp. 870-872
Author(s):  
Shi Cai Cui ◽  
Zhao Bo Meng

Calcium silicate for filling material used in dissolved acetylene cylinders was prepared by adding alum as additive. Samples were characterized by X-ray powder diffraction (XRD) and scanning electron microscope (SEM). The effects of alum on the bleeding, shrinkage, strength, porosity, morphology and phase composition were studied. The experimental results show that the adding of alum can improve the comprehensive performance of samples. The mechanism was discussed in detail.


Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1435
Author(s):  
Olev Vinn

Aragonite plays an important role in the biomineralization of serpulid polychaetes. Aragonitic structures are present in a wide range of serpulid species, but they mostly belong to one clade. Aragonitic structures are present in a wide range of marine environments, including the deep ocean. Aragonitic tube microstructures were studied using a scanning electron microscope. X-ray powder diffraction was used to identify the aragonite. Aragonite is used to build five different types of microstructures in serpulid tubes. The most common aragonitic irregularly oriented prismatic structure (AIOP) is also, evolutionarily, the most primitive. Some aragonitic microstructures, such as the spherulitic prismatic (SPHP) structure, have likely evolved from the AIOP structure. Aragonitic microstructures in serpulids are far less numerous than calcitic microstructures, and they lack the complexity of advanced calcitic microstructures. The reason why aragonitic microstructures have remained less evolvable than calcitic microstructures is currently unknown, considering their fit with the current aragonite sea conditions (Paleogene–recent).


2022 ◽  
Author(s):  
RongMin Cheng ◽  
Conghong Zhan ◽  
Juanjuan Gao

Using Ni foam as a template, Mn0.6Ni0.4CO3 nanosheet assembles were synthesized by hydrothermal method and calcination treatment. X-ray powder diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Inductively...


2013 ◽  
Vol 785-786 ◽  
pp. 745-748
Author(s):  
Deng Liang He ◽  
Shi Xin Fang

butyl titanate, water and anhydrous ethanol were used as raw materials; Cerium-doped TiO2 was prepared by sol method at room temperature. Then it was characterized by X ray diffraction, Raman spectra, Uv-vis absorption spectra and Scanning Electron Microscope. The results show that TiO2 crystal can be got by sol method at room temperature. Cerium-doped TiO2 has the better catalytic performance for methyl orange.


2015 ◽  
Vol 816 ◽  
pp. 676-681 ◽  
Author(s):  
Xiao Long Qu ◽  
Zheng Fu Zhang ◽  
Jin Cheng ◽  
Xiao Yan Wang

The spherical Ni0.5Co0.2Mn0.3(OH)2 powders were prepared by ammonia-hydroxide co-precipitation method. The influence of different synthesizing factors on the precursors characteristic were investigated. The product prepared with optimized condition has tap density of D≥1.7g·cm-3, and middle particle size D50≈3.6μm. The X-ray diffraction (XRD) results showed that the precursor can be indexed by a hexagonal β-Ni (OH)2 structure. The scanning electron microscope (SEM) results showed that the powders had quasi-spherical pattern and homogeneous particle size distribution.


Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 357
Author(s):  
János Kovács ◽  
Éva Farics ◽  
Péter Szabó ◽  
István Sajó

In sedimentary rocks, Fe-Al phosphate minerals occur in different rocks and depositional environments. Herein, we present microcrystals of wavellite, crandallite, and cacoxenite from pedogenic goethite pisoliths and nodules. Pisoliths and nodules are generally dominated by Fe oxides and oxihydroxides. Frequently, pisoliths and nodules demonstrate high phosphatization and a substantial contribution of allogenic detritus. The aim of our study is to present these remarkable crystals found in goethites. We describe the geochemistry and mineralogy of the pisoliths and try to interpret the possible paragenesis of the minerals. Loose ferruginous pisoliths and nodules are separated from the red paleosol and analyzed using field emission scanning electron microscope (FE-SEM) coupled with the energy dispersive X-ray detector (EDS), X-ray fluorescence spectroscopy (XRF), and X-ray powder diffraction (XRD) methods. The studied paleosols are weathered in a subtropical climate and the newly formed precipitation products, such as crandallite, wavellite, cacoxenite, and goethite, accumulate during the weathering of apatite.


2011 ◽  
Vol 399-401 ◽  
pp. 851-854 ◽  
Author(s):  
Jun Ding ◽  
Wen Jie Yuan ◽  
Jun Li ◽  
Hong Xi Zhu ◽  
Cheng Ji Deng

Magnesia-magnesium aluminate (MA) spinel composite refractory was prepared by using fused magnesia, industrial alumina and AlCl3•6H2O as the raw materials. The effects of calcining temperature and holding time on phase compositions of MgO-MgAl2O4system samples were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). With the increase of calcining temperature, the hydration mass increasing rate of the sample decreases significantly. The results show that MgO-MgAl2O4composite refractory has quite excellent hydration resistance because of periclase grains with exsolved spinel phase.


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