Effects of In Situ Formation of Magnesium Aluminate Spinel on Performance of Modified Sizing Nozzle

2013 ◽  
Vol 750-752 ◽  
pp. 1130-1136
Author(s):  
Guang Liang Yuan ◽  
Qun Hu Xue ◽  
Xiang Li ◽  
Yuan Yang
Keyword(s):  
Corrosion Resistance ◽  
Sol Gel ◽  
Magnesium Aluminate ◽  
Magnesium Aluminate Spinel ◽  
Sintering Process ◽  
Stabilized Zirconia ◽  
Composite Powders ◽  
The Stability ◽  
Better Than

The modified sizing nozzle with excellent performances was successfully prepared by using of Mg,Y-PSZ as aggregates, Mg,Y,Ca-PSZ as fines, adding a certain amount of Al2O3-ZrO2 composite powders prepared by sol-gel. Effects of magnesium aluminate spinel in-situ synthesized in modified sizing nozzle on its performances were studied in this experiment. The results show that, the content of cubic zirconia in the sizing nozzle was decreased with the increasing of Al2O3-ZrO2 composite powders; the samples of modified sizing nozzle have no diameter-expanded after 30 hours service. The use effects are obviously better than that of Al2O3-ZrO2 composite powders free. The main reason is that a new bond phase magnesium aluminate spinel was in-situ generated through the reaction between Al2O3 in Al2O3-ZrO2 composite powders and the stabilizer MgO from partially stabilized zirconia in the sintering process at high temperature. The spinels embedded in the substrate of zirconia grow further and fill between zirconia particles. This prevents the stabilizer of CaO further desolventizing and also stop losing the eutectics formed by the reaction with compositions of molten steel. Therefore, the stability of zirconia and the corrosion resistance of the sizing nozzle were improved.

Performance Studies on In Situ Spinel Solid Solution Bonded Periclase Refractories

2014 ◽  
Vol 633 ◽  
pp. 245-248
Author(s):  
Xin Lin ◽  
Yong Li ◽  
Yan Jing Li ◽  
Jun Jie Zhang ◽  
Chang He Gao ◽  
...  
Keyword(s):  
Solid Solution ◽  
Phase Composition ◽  
Performance Studies ◽  
Magnesium Aluminate ◽  
Spinel Solid Solution ◽  
Magnesium Aluminate Spinel ◽  
Crushing Strength ◽  
Cold Crushing Strength ◽  
Shock Resistance

Specimens were prepared using iron-rich magnesia (3~1 mm、≤1 mm) and high purity magnesia (≤0.088 mm) as the main starting materials, adding tabular alumina at different size (3~2、2~1、≤1 mm) and content:3%、6%、9%、12%、15% to discover the influence of tabular alumina on sample performance. Phase composition and microstructure were also analyzed. The results show that specimen with content of 6% of corundum possessed the best comprehensive performance:apparent porosity 17%, bulk density 2.95 g·cm-3, cold crushing strength 74 MPa, refractoriness under load 1700 °C, heat shock resistance of up to 18 times. The formations of magnesium aluminate spinel and hercynite solid solution were enhanced by Fe ion at high temperatures in the iron-rich magnesia-corundum system at the presence of iron oxides, which are able to largely dissolved in periclase.

Environmental Effects in Gel Derived Silicates

1984 ◽  
Vol 32 ◽  
Author(s):  
L.L. Hench
Keyword(s):  
Corrosion Resistance ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Thermal Exposure ◽  
Scientific Basis ◽  
Environmental Stability ◽  
Processing Variables ◽  
End Use ◽  
The Stability ◽  
Gel Processing

Various methods have been developed for producing crystals, powders, coatings and monoliths from gels [1]. The scientific basis for understanding compositional effects, gelation, aging, drying and densification is also advancing rapidly [2]. However, there is as yet relatively little information on the durability, weathering, or corrosion resistance of glasses, glass-ceramics, ceramics, or composites made via the gel route. Data is also sparse on the effects of vacuum, thermal exposure, or mechanical stress on the stability of gel-derived solids. Relationships between sol-gel processing variables and environmental stability are especially lacking at the present time. Since many end-use applications of gel derived materials involve exposure to severe environments, it is essential that the durability of these materials be established during their development.

Templated epitaxial coatings on magnesium aluminate spinel using the sol-gel method

2009 ◽  
Vol 44 (5) ◽  
pp. 1180-1186 ◽  
Author(s):  
David Browne ◽  
Hongwei Li ◽  
Edoardo Giorgi ◽  
Sreya Dutta ◽  
Jeffrey Biser ◽  
...  
Keyword(s):  
Sol Gel ◽  
Magnesium Aluminate ◽  
Magnesium Aluminate Spinel ◽  
Gel Method ◽  
Sol Gel Method

Magnesium-Aluminate Spinel Fibers Obtained by the Sol-Gel Method

2019 ◽  
Vol 76 (7-8) ◽  
pp. 302-306
Author(s):  
Yu. A. Balinova ◽  
G. Yu. Lyulyukina ◽  
S. G. Kolyshev
Keyword(s):  
Sol Gel ◽  
Magnesium Aluminate ◽  
Magnesium Aluminate Spinel ◽  
Gel Method ◽  
Sol Gel Method

Durability of Cement Mortar with Surface Treated by Superabsorbent Resin Synthesized In Situ

2012 ◽  
Vol 204-208 ◽  
pp. 4002-4006
Author(s):  
Dan Zhang ◽  
Xue Feng Song ◽  
Ting Shu He
Keyword(s):  
Corrosion Resistance ◽  
Cement Mortar ◽  
Concrete Durability ◽  
Water Penetration ◽  
Freeze Resistance ◽  
Micro Cracks ◽  
Novel Method ◽  
Superabsorbent Resin ◽  
Better Than

The deterioration of concrete durability seriously affects utilization and lifespan of concrete constructions. This paper presented a novel method to improve concrete durability by synthesizing Super-absorbent Resins (SAR) in micro-cracks or capillary-pores of concrete, i.e., the synthesized SAR swell after absorbing water, fill micro-cracks or capillary-pores and prevent water penetration into concrete. The main performance of impermeability, freeze resistance and sulfate resistance related to concrete durability were studied. The results show that the impermeability, freeze resistance and sulfate corrosion resistance of cement mortar handled by SAR are obviously better than cement mortar unhandled by SAR.

Probing the stability of Pt nanoparticles encapsulated in sol–gel Al 2 O 3 using in situ and ex situ characterization techniques

2014 ◽  
Vol 485 ◽  
pp. 108-117 ◽  
Author(s):  
R.U. Ribeiro ◽  
D.M. Meira ◽  
C.B. Rodella ◽  
D.C. Oliveira ◽  
J.M.C. Bueno ◽  
...  
Keyword(s):  
Sol Gel ◽  
Pt Nanoparticles ◽  
Ex Situ ◽  
Characterization Techniques ◽  
The Stability

Influence of Accelerator Residues on Age Resistance of Vulcanizates

1960 ◽  
Vol 33 (2) ◽  
pp. 490-501
Author(s):  
Z. T. Ossefort
Keyword(s):  
Zinc Oxide ◽  
Natural Rubber ◽  
Network Structure ◽  
Dual Process ◽  
Curing Process ◽  
Active Inhibitor ◽  
The Stability ◽  
Prime Function ◽  
Better Than

Abstract It has been shown that the age resistance of elastomeric vulcanizates is influenced to a very marked degree by residues formed in situ in the vulcanizate during the curing process. By a dual process of removal of these residues and incorporation of selected ingredients subsequent to vulcanization, it has been shown that age resistance (as measured by accelerated oven-aging tests at 212° F) in rubbers cured by sulfur and/or sulfur bearing accelerators, is a prime function of these residues and nearly independent of the stability of the network structure. An extremely active inhibitor is formed in situ during vulcanization of SBR and natural rubber using thiuram accelerators. This inhibitor can be used to “reinhibit” acetone-extracted accelerator-cured rubber. When added to sulfur/accelerator, peroxide, or radiation-cured vulcanizates, it improves their age resistance, but only in the case of the sulfur/accelerator cured rubber is this improvement better than with conventional inhibitors. This leads to the conclusion that the efficiency with which an inhibitor protects a vulcanizate varies widely, and conversely it appears that certain types of network structures are more readily protected or that certain inhibitors can function more efficiently in the protection of certain structures than others. In the case of natural rubber cured with TMTD (zinc oxide present), the bulk of the accelerator residue is ZnDMDC, and this residue has been shown to function as a very efficient antioxidant when incorporated into acetone-extracted, accelerator-cured vulcanizate. It is no more effective than conventional inhibitors, however, when incorporated into an acetone-extracted, sulfur/accelerator-cured vulcanizate. Finally, it has been shown that acetone extraction of the various vulcanizates may lead to improvement or worsening of their age resistance, depending upon the nature of the residues resulting from the curing process.

Synthesis and Characterization of Magnesium Aluminate Spinel Porous Ceramics by Novel Molten Salt Method

2016 ◽  
Vol 697 ◽  
pp. 399-403 ◽  
Author(s):  
Xian Gong Deng ◽  
Jun Kai Wang ◽  
Hai Jun Zhang ◽  
Jiang Hao Liu ◽  
Shao Wei Zhang
Keyword(s):  
Molten Salt ◽  
Porous Ceramics ◽  
Magnesium Aluminate ◽  
Molten Salt Method ◽  
Magnesium Aluminate Spinel ◽  
X Ray Diffraction ◽  
Liquid Environment ◽  
X Ray

Magnesium aluminate spinel (MgAl2O4) porous ceramics were in-situ synthesized by heating the mixture of Al2O3 and MgCO3 with MgCl2 salt at 1400~1600 °C for 3 h, and then characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The morphology of as-prepared MgAl2O4 porous ceramics was dependent on the addition of MgCl2, and it indicated that the MgCl2 molten salt not only acted as a template for pore formation of the porous ceramics, but also provided a liquid environment for the synthesis of MgAl2O4.

The Electrical Conductivity Stability of Polyaniline Doped with Three Different Acids

2013 ◽  
Vol 774-776 ◽  
pp. 803-806
Author(s):  
Ren Chun Fu ◽  
Jun Du ◽  
Hui Huang ◽  
Zhong Cheng Guo
Keyword(s):  
Electrical Conductivity ◽  
Sulfuric Acid ◽  
Hydrochloric Acid ◽  
Temperature Dependence ◽  
Methanesulfonic Acid ◽  
Variable Range Hopping ◽  
As Doping ◽  
The Stability ◽  
Better Than

The doping acid will obviously effect on the properties of polyaniline. In order to investigate the industrial acids influence the electrical conductivity stability of polyaniline, the hydrochloric acid (HCl), sulfuric acid (SA) and methanesulfonic acid (MSA) in industrial degree were chosen as doping acids to synthesize polyaniline. The stability of electrical conductivity was measured by in situ temperature. The mechanism of temperature dependence of electrical conductivity was discussed. The results revealed that the stability of polyaniline doped by hydrochloric acid (HCl) was better than that of polyaniline doped by other acids. The variable-range hopping (VRH) model could explain the temperature dependence of electrical conductivity of polyaniline.

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