The Effect of Mineralizers on Synthesis of Perovskite-Phase Lanthanum Aluminate Powders

2011 ◽  
Vol 48-49 ◽  
pp. 1241-1244
Author(s):  
Xiu Hui Wang ◽  
Guo Quan Zhao ◽  
Yan Min Zhao ◽  
Hong Gao ◽  
Jin Long Yang
Keyword(s):  
Grain Growth ◽  
Raw Materials ◽  
Perovskite Phase ◽  
Good Control ◽  
Sem Analysis ◽  
Solid Reaction ◽  
Xrd Pattern ◽  
Lanthanum Aluminate

The solid-reaction was applied to synthesize perovskite-phase Lanthanum Aluminate powders by using AlOOH and La2(C2O4)3 as raw materials, mineralizer AlCl3 and AlF3 as the additives, graund and mixed, then calcined at 800°C and 1200°C for 3 h. The XRD pattern shows that mono-phase LaAlO3 powders can be obtained at 1200°C, and the SEM analysis indicates that the AlCl3 and AlF3 can promote the grain growth and have a good control of morphology.

Effect of Pressing Force on the Physical Properties of CaMgTiO3 Ceramic Prepared by HEBM

2014 ◽  
Vol 895 ◽  
pp. 311-314 ◽  
Author(s):  
Nurhashimah Hassim ◽  
Wan Nurulhuda Wan Shamsuri ◽  
Nur Liyana Amiar Rodin ◽  
Rosli Hussin ◽  
Karim Deraman ◽  
...  
Keyword(s):  
Physical Properties ◽  
Ball Milling ◽  
Grain Growth ◽  
Raw Materials ◽  
High Energy ◽  
Sem Analysis ◽  
High Energy Ball Milling ◽  
Particle Sizes ◽  
Milling Method ◽  
Energy Ball

CaMgTiO3 ceramics were synthesized by using the high energy ball-milling method (HEBM) at different pressing forces. The raw materials were ball milled for 20 hours and sintered at 1000°C. Ceramics surfaces morphologies and particle sizes were measured using SEM analysis. Archimedes’ method was adapted to obtain their densities and porosities. It was found that pressing forces influenced both morphologies and particle sizes. As pressing forces increased, the particle sizes decreased as shown in SEM observation. However, the particle sizes increased at 200 kN due to agglomerated grain growth. The densities were almost constant with increasing of pressing forces while porosities were reduced.

Preparation and Characterization of LaAlO3 via Sol-Gel Process

2012 ◽  
Vol 624 ◽  
pp. 26-29 ◽  
Author(s):  
Xiao Yan Zhang ◽  
Teng Zhang ◽  
Xi Wei Qi ◽  
Jian Quan Qi ◽  
Gui Fang Sun ◽  
...  
Keyword(s):  
Citric Acid ◽  
Ph Value ◽  
Raw Materials ◽  
Sol Gel ◽  
Chelating Agent ◽  
Sem Analysis ◽  
Lanthanum Aluminate ◽  
Water As Solvent ◽  
Sol Gel Process ◽  
Scherrer Formula

Lanthanum aluminate powders were synthesized by sol-gel process with metal nitrates as raw materials, 2-methoxyethanol/water as solvent and citric acid as chelating agent. The influence of this techniques (the amount of citric acid, pH value, calcination temperature and the ratio of 2-methoxyethanol/water) on the lanthanum aluminate powders were studied. The XRD shows pure LaAlO3 powders could be obtained after calcining at 600-900 °C. The SEM analysis indicates that the LaAlO3 particles are uniform and nanosized with a range of about 40-70 nm, which is slightly larger than the estimated particle size using Scherrer formula.

scholarly journals Mineralogical and Microstructure Analysis for Characterization and Provenance of Ceramic Artifacts from Late Helladic Kastrouli Settlement, Delphi (Central Greece)

Geosciences ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 36
Author(s):  
Vayia Xanthopoulou ◽  
Ioannis Iliopoulos ◽  
Ioannis Liritzis
Keyword(s):  
Raw Materials ◽  
Analytical Techniques ◽  
Sem Analysis ◽  
Petrographic Analysis ◽  
Ceramic Assemblage ◽  
Thin Sections ◽  
Central Greece ◽  
High Calcium ◽  
Local Geology

The present study deals with the characterization of a ceramic assemblage from the Late Mycenaean (Late Helladic III) settlement of Kastrouli, at Desfina near Delphi, Central Greece using various analytical techniques. Kastrouli is located in a strategic position supervising the Mesokampos plateau and the entire peninsula and is related to other nearby coeval settlements. In total 40 ceramic sherds and 8 clay raw materials were analyzed through mineralogical, petrographic and microstructural techniques. Experimental briquettes (DS) made from clayey raw materials collected in the vicinity of Kastrouli, were fired under temperatures (900 and 1050 °C) in oxidizing conditions for comparison with the ancient ceramics. The petrographic analysis performed on thin sections prepared from the sherds has permitted the identification of six main fabric groups and a couple of loners. The aplastic inclusions recognized in all fabric groups but one confirmed the local provenance since they are related to the local geology. Fresh fractures of representative sherds were further examined under a scanning electron microscope (SEM/EDS) helping us to classify them into calcareous (CaO > 6%) and non-calcareous (CaO < 6%) samples (low and high calcium was noted in earlier pXRF data). Here, the ceramic sherds with broad calcium separation are explored on a one-to-one comparison on the basis of detailed mineralogical microstructure. Moreover, their microstructure was studied, aiming to estimate their vitrification stage. The mineralogy of all studied samples was determined by means of X-ray powder diffraction (XRPD), permitting us to test the validity of the firing temperatures revealed by the SEM analysis. The results obtained through the various analytical techniques employed are jointly assessed in order to reveal potters’ technological choices.

scholarly journals Study on microcrystalline cellulose/chitosan blend foam gel material

2020 ◽  
Vol 27 (1) ◽  
pp. 424-432
Author(s):  
Hongkai Zhao ◽  
Kehan Zhang ◽  
Shoupeng Rui ◽  
Peipei Zhao
Keyword(s):  
Microcrystalline Cellulose ◽  
Raw Materials ◽  
Pore Space ◽  
Sodium Dodecyl ◽  
Cost Effective ◽  
High Water ◽  
Aldehyde Group ◽  
Sem Analysis ◽  
Present Contribution ◽  
Bet Analysis

AbstractIn the present contribution, an environmental-friendly and cost-effective adsorbent was reported for soil treatment and desertification control. A novel foam gel material was synthesized here by the physical foaming in the absence of catalyst. By adopting modified microcrystalline cellulose and chitosan as raw materials and sodium dodecyl sulfonate (SDS) as foaming agent, a microcrystalline cellulose/chitosan blend foam gel was synthesized. It is expected to replace polymers derived from petroleum for agricultural applications. In addition, a systematical study was conducted on the adsorbability, water holding capacity and re-expansion performance of foam gel in deionized water and brine under different SDS concentrations (2%–5%) as well as adsorption time. To be specific, the adsorption capacity of foam gel was up to 105g/g in distilled water and 54g/g in brine, indicating a high water absorption performance. As revealed from the results of Fourier transform infrared spectroscopy (FTIR) analysis, both the amino group of chitosan and the aldehyde group modified by cellulose were involved. According to the results of Scanning electron microscope (SEM) analysis, the foam gel was found to exhibit an interconnected pore network with uniform pore space. As suggested by Bet analysis, the macroporous structure was formed in the sample, and the pore size ranged from 0 to 170nm. The mentioned findings demonstrated that the foam gel material of this study refers to a potential environmental absorbent to improve soil and desert environments. It can act as a powerful alternative to conventional petroleum derived polymers.

scholarly journals Fabrication of (SiC-AlN)/ZrB2 Composite with Nano-Micron Hybrid Microstructure via PCS-Derived Ceramics Route

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 334
Author(s):  
Aidong Xia ◽  
Jie Yin ◽  
Xiao Chen ◽  
Zhengren Huang ◽  
Xuejian Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Raw Materials ◽  
Secondary Phase ◽  
Pressing Temperature ◽  
Xrd Pattern ◽  
Mean Grain Size ◽  
The Mean

In this work, a (SiC-AlN)/ZrB2 composite with outstanding mechanical properties was prepared by using polymer-derived ceramics (PDCs) and hot-pressing technique. Flexural strength reached up to 460 ± 41 MPa, while AlN and ZrB2 contents were 10 wt%, and 15 wt%, respectively, under a hot-pressing temperature of 2000 °C. XRD pattern-evidenced SiC generated by pyrolysis of polycarbosilane (PCS) was mainly composed by 2H-SiC and 4H-SiC, both belonging to α-SiC. Micron-level ZrB2 secondary phase was observed inside the (SiC-AlN)/ZrB2 composite, while the mean grain size (MGS) of SiC-AlN matrix was approximately 97 nm. This unique nano-micron hybrid microstructure enhanced the mechanical properties. The present investigation provided a feasible tactic for strengthening ceramics from PDCs raw materials.

scholarly journals Synthesis of 3D-porous scaffold from cockle shells waste-based hydroxyapatite with addition silica from tin tailings

2021 ◽  
Vol 926 (1) ◽  
pp. 012044
Author(s):  
F Afriani ◽  
J Evi. ◽  
R A Rafsanjani ◽  
R Amelia ◽  
M Hudatwi ◽  
...  
Keyword(s):  
Diffraction Pattern ◽  
Goodness Of Fit ◽  
Porous Scaffold ◽  
Raw Materials ◽  
Synthesis Method ◽  
Decomposition Temperature ◽  
Porous Scaffolds ◽  
Xrd Pattern ◽  
Replication Method ◽  
Tailings Sand

Abstract This study aims to synthesize a porous scaffold based on hydroxyapatite and silica using the polymer sponge replication method. In bone tissue engineering technology, the development of porous scaffolds is a topic that is intensively studied because it is expected to be a solution to various problems of conventional bone therapy. In addition to proposing a porous scaffold synthesis method, we also utilize natural waste-based materials such as cockle shells and tin tailings as raw materials in this research. Investigation through x-ray diffraction (XRD) pattern with the goodness of fit coefficient, X 2 = 0.09 shows that the coprecipitation method is effective for the synthesis of hydroxyapatite. Analysis of XRD pattern of tin tailings sand with a value of X 2 = 0.008 showed that the diffraction pattern was related to silica with space group P 41 21 2. The polymer sponge replication method with polyurethane template succeeded in obtaining scaffolds with macropores above 300 μm. Based on the diffraction pattern of the three porous scaffolds prepared with different percentages of HA, it is known that all porous scaffolds have peaks related to HA and silica. It indicates that the decomposition temperature of polymer does not provide sufficient energy for the HA and silica to transform or react chemically.

Correlation between Powder Characteristic and Microstructure Development of Y-Doped BaCeO3

2014 ◽  
Vol 90 ◽  
pp. 78-83
Author(s):  
H.E. Araujo ◽  
D.P.F. Souza
Keyword(s):  
Diffusion Coefficient ◽  
Fracture Surface ◽  
Grain Growth ◽  
Sem Analysis ◽  
Microstructure Development ◽  
X Ray ◽  
Calcination Step ◽  
Citrate Process

Ceramics based on Y-doped BaCeO3 were prepared by citrate process. The X-ray fluorescence shows that barium stoichiometry deviation is established during calcination step. Through the SEM analysis of fracture surface of sintered samples it was possible to infer that powder highly deficient of barium shows higher diffusion coefficient during sintering than stoichiometric powder promoting grain growth and, consequently, trapping pores into the grains.

Silicon Nitride/Boron Nitride Composite by Combustion Synthesis

2007 ◽  
Vol 561-565 ◽  
pp. 531-534
Author(s):  
Ke Zhang ◽  
Qiang Zhang ◽  
Peng Fei Wang ◽  
Ling Bai ◽  
Wei Ping Shen ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Boron Nitride ◽  
Combustion Synthesis ◽  
Bending Strength ◽  
Volume Fraction ◽  
Raw Materials ◽  
Solid Reaction ◽  
N2 Atmosphere ◽  
Scanning Electron

Machinable silicon nitride/ hexahedral boron nitride (Si3N4/h-BN) composites were in-situ synthesized in a nitrogen (N2) atmosphere by means of combustion synthesis gas-solid reaction with silicon (Si) powder and h-BN as raw materials. The effect of the volume fraction of h-BN on the machinable properties of Si3N4/BN composite was studied. The results show that Si powder was fully nitrified and no residual Si was found. Microstructures by a scanning electron microscopy (SEM) show Columnar crystals of β-Si3N4 are the main phase and acicular crystals of h-BN disperse β-Si3N4 intergranular. With the increasing of the volume content of h-BN, the machinability of the composite increases, but the bending strength of composite decreases firstly and then increases. The lowest bending strength is 84.96MPa at 25% volume fraction of h-BN.

Effects of Starting Materials on Molten Salt Synthesis of Bi4Ti3O12

2008 ◽  
Vol 55-57 ◽  
pp. 165-168
Author(s):  
Paisan Setasuwon ◽  
S. Kijamnajsak
Keyword(s):  
Molten Salt ◽  
Grain Growth ◽  
Grain Orientation ◽  
Crystal Size ◽  
Raw Materials ◽  
Piezoelectric Materials ◽  
Molten Salt Synthesis ◽  
Chloride Salt ◽  
Templated Grain Growth

Na0.5Bi0.5TiO3 is one of the potential candidates for non-lead piezoelectric materials to replace existing lead-based ones. Properties of BNT could be enhanced by reactive templated grain growth (RTGG) technique through induction of grain orientation with crystals of Bi4Ti3O12. Controlling the size of Bi4Ti3O12 crystals during the synthesis with molten salt is a major factor in optimizing RTGG. It was found that molten salt synthesis of Bi4Ti3O12 crystals with NaCl-KCl yielded larger particles, compared with Na2SO4-3K2SO4. Varying the proportion of chloride salt did not produce noticeable changes in crystal size. Bi4Ti3O12 crystals were significantly affected by raw materials treatment. Non-milling of starting powders could approximately double the crystal size

Preparation, Performances and Reaction Process of NiZrNb2O8 Microwave Dielectric Ceramics

2018 ◽  
Vol 281 ◽  
pp. 591-597
Author(s):  
Meng Juan Wu ◽  
Ying Chun Zhang ◽  
Jun Dan Chen ◽  
Yun Zhang
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Solid State Reaction ◽  
Raw Materials ◽  
Sem Analysis ◽  
Reaction Process ◽  
Microwave Dielectric Ceramics ◽  
Microwave Dielectric ◽  
Potential Applications ◽  
Dielectric Ceramics

Microwave dielectric ceramics have great potential applications in the fields of modern communication technology. However, the effects of processing of solid reaction on the crystal structure and properties of NiZrNb2O8 has not been reported. In this paper, the NiZrNb2O8 ceramic was prepared using different raw materials. The solid state reaction process, crystal structure, and dielectric properties of the NiZrNb2O8 ceramics were investigated. The X-ray diffractometer (XRD) results showed that the solid state reaction of NiZrNb2O8 could be divided into two steps using NiO, ZrO2 and Nb2O6 as raw materials. Scanning electron microscope (SEM) analysis results showed that the surface of NiZrNb2O8 prepared from NiNb2O6 and ZrO2 was more compact. The optimal density of the samples reached 99.28% of the theoretical value. And the dielectric constant (εr), quality factor (Q×f), temperature coefficient of resonant (τf) reached 23.6, 37237 GHz, -7.796 ppm/°C, respectively.

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