scholarly journals Comparison of the methods of solid state reaction and sol-gel in the preparation of HgBa2Ca2Cu2.8Zn0.2O8+δ superconducting compound

2019 ◽  
Vol 1234 ◽  
pp. 012027
Author(s):  
Haider MJ. Haider ◽  
Kareem A. Jasim
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Sol Gel ◽  
Superconducting Compound

Electrical assessment of brownmillerite-type calcium ferrite materials obtained by proteic sol-gel route and by solid-state reaction using mollusk shells

2021 ◽  
pp. 122172
Author(s):  
Chrystian G.M. Lima ◽  
Allan J.M. Araújo ◽  
Rinaldo M. Silva ◽  
Rafael A. Raimundo ◽  
João P.F. Grilo ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Sol Gel ◽  
Calcium Ferrite ◽  
Mollusk Shells

Preparation and Microwave-Absorption Property of SiO2-SiC-Based Composites

2010 ◽  
Vol 434-435 ◽  
pp. 231-234
Author(s):  
Li Guan ◽  
Bing Bing Fan ◽  
Ming Liang Li ◽  
He Jing Wen ◽  
Kai Li ◽  
...  
Keyword(s):  
Solid State ◽  
Microwave Absorption ◽  
Solid State Reaction ◽  
Sol Gel ◽  
Composite Particles ◽  
Network Analyzer ◽  
Epoxide Resin ◽  
Maximum Reflectivity ◽  
Sol Gel Process ◽  
Sic Composites

SiO2-SiC composite particles were prepared using a sol-gel process. BaTiO3 powders were synthesize through solid-state reaction. They were mixed as microwave absorbents with Fe3O4 powders to obtain the complex absorption. Epoxide resin (EP) was used as matrix and solidified with the mixtures. The techniques of DSC-TG, XRD were used to characterize the composite particles and the obtained compacts. A vector network analyzer was used to measure the reflectivity of the SiO2-SiC-based composites. The effects of the aborbents’ contents on the reflection of the microwave absorption materials were disscussed. It was found that SiO2-SiC composites could be prepared using sol-gel process and BaTiO3 powders could be synthesize through solid-state reaction. The results indicated that SiO2-SiC composite is contribute to absorb microwave, where SiO2-SiC: BaTiO3: Fe3O4 = 6:2:2 (vol %), the frequency region in which the maximum reflectivity is more than -10 dB is 5.4-7.6 GHz.

Synthesis of Pure Dicalcium Silicate Powder by the Pechini Method and Characterization of Hydrated Cement

2014 ◽  
Vol 787 ◽  
pp. 387-394 ◽  
Author(s):  
Yan Ni Tan ◽  
Yong Liu ◽  
Zhang Qing ◽  
Gurpreet Birdi ◽  
Liam M. Grover
Keyword(s):  
Solid State ◽  
Mass Loss ◽  
Solid State Reaction ◽  
Pechini Method ◽  
Sol Gel ◽  
Dicalcium Silicate ◽  
Hydrated Cement ◽  
Gel Method ◽  
Sol Gel Method

Calcium silicate (CS) is a main component of Portland cement and is responsible for the strength development. Recent research has shown that dicalcium silicate cement (CSC) is bioactive and is a potential candidate for bone replacement. Traditionally, dicalcium silicate powder is synthesized by a solid state reaction or a sol-gel method. The solid-state reaction, however, usually needs a higher temperature and a longer calcination time. Furthermore, the dicalcium silicate powder made by the sol-gel method is not pure, and contains a significant quantity of CaO which is harmful to the strength and biological properties of the CSC. The Pechini technique is an alternative, low temperature polymeric precursor route for synthesis of high purity powders. In this study, purer CS powder was synthesized via the Pechini method by calcination at 800°C for 3h. DSC-TGA, XRD, SEM were used for characterization of CS powder and the hydrated cement. The DSC-TGA curves showed that the main exothermic peak was at 479°C and the total mass loss was 79.2%. The XRD patterns of CSC after hydration for 7, 14, and 35 days illustrated that dicalcium silicate hydrate (Ca1.5SiO3.5·xH2O, C-S-H) was formed in the hardened CS paste. The XRD peaks on the diffraction pattern of the C-S-H of the day 35 sample were of greater intensity than those at day 7 and day 14. This demonstrates that the hydration speed was slow and complete hydration could take more than one month. Flake-like crystals were observed on scanning electron micrographs following hardening. The degradation study result showed that there was no mass loss of CSC after the samples were soaked into phosphate buffered saline (PBS) for 40 days. The silicon assay revealed that orthosilicic acid could be released from CSC after the samples were soaked in simulated body fluid (SBF). Silicon is known to be critical to skeletal mineralization. The existence of silicon may stimulate the proliferation of bone and activate cells to produce bone. Investigation of cell attachment confirmed that the MC-3T3 cells attached well to the surfaces of CSC after seeding.

Superconducting Compound Hg0.8Sb0.2Ba2Ca2Cu3O8+δ Compared with Hg0.8Sb0.2Ba2Ca1Cu2O6+δ to Evaluate Transition Temperature

2020 ◽  
Vol 18 (11) ◽  
pp. 14-18
Author(s):  
Abbas K. Saadon ◽  
Kareem A. Jasim ◽  
Auday H. Shaban
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Solid State ◽  
Solid State Reaction ◽  
Hot Spot ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Superconducting Compound

The high temperature superconductor’s compounds are one of the hot spot field of science, due to their applications in industries. Hg0.8Sb0.2Ba2Ca2Cu3O8+δ and Hg0.8Sb0.2Ba2Ca1Cu2O6+δ, were manufactured using a doable-step of solid state reaction method. The samples were sintered at 800 ° C. The transition temperatures Tc are found from electrically resistively by using four probe techniques. The resistivity become zero when the transition temperature Tc(offset) have 131 and 119 K, and the onset temperature Tc(onset) have 139 K for Hg0.8Sb0.2Ba2Ca2Cu3O8+δ and 132 K for Hg0.8Sb0.2Ba2Ca1Cu2O6+δ. Analysis of X-ray diffraction showed a tetragonal structure with lattice parameters changes for all samples.

Luminescence of SrY2O4:Eu3+ associated with defects

2010 ◽  
Vol 25 (11) ◽  
pp. 2120-2124 ◽  
Author(s):  
Jia Zhang ◽  
Yuhua Wang
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Vacuum Ultraviolet ◽  
Sol Gel ◽  
Blue Emission ◽  
Solid State Reaction Method ◽  
Excitation Spectra ◽  
Blue Emission Band ◽  
Gel Method ◽  
Sol Gel Method

SrY2O4:Eu3+ phosphors were synthesized by both the solid-state reaction method and the sol-gel method, and their photoluminescence in vacuum ultraviolet (VUV) and the ultraviolet (UV) region were evaluated. The excitation spectra of SrY2O4:Eu3+ phosphors prepared by solid-state reaction show another excitation band centered at 324 nm except for the charge-transfer bands (CTB) of Eu3+ when monitored at 610 nm, and a blue emission band around 406 nm is observed when excited at 324 nm, which could be associated with defects. Both the excitation and emission bands mentioned above disappear when the samples were prepared by the sol-gel method. SrY1.98O4:0.02Eu3+ phosphors synthesized by the sol-gel method exhibit a higher emission intensity under 147 nm excitation compared with solid-state reaction technology. The main reason could be that the samples prepared by the solution-based route have more regular and uniform morphologies.

COMPARATIVE STUDY OF Bi-2223/Ag SUPERCONDUCTORS DERIVED FROM PARTICLES SIZE OF STARTING MATERIALS

2007 ◽  
Vol 21 (18n19) ◽  
pp. 3246-3249 ◽  
Author(s):  
D. SÝKOROVÁ ◽  
O. SMRČKOVÁ ◽  
K. RUBEŠOVÁ ◽  
P. VAŠEK
Keyword(s):  
Solid State ◽  
Comparative Study ◽  
Temperature Dependence ◽  
Solid State Reaction ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Sol Gel Process ◽  
Current Densities ◽  
Size Of Particles ◽  
Micrometer Size

Series of the samples with nominal compositions Bi 3.2 Pb 0.8 Sr 4 Ca 5 Cu 7 O x and Bi 3.2 Pb 0.8 Sr 4 Ca 5 Cu 7 O x / Ag (10 wt%) were prepared by the standard solid state reaction at the same calcination and sintering temperature and time. Three starting mixtures were used, carbonates, oxides and silver i) with nanoparticles, ii) with micrometer size of particles and iii) powder obtained by modified sol-gel process. The main phase in all samples was Bi -2223 and silver formed the separate phase. The sol-gel process was found to be effective way in term of porosity, bulk density and connectivity of the grains. The effect of the microstructure on the transport properties were described by the temperature dependence of resistivity and critical current densities.

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