Amino Functionalization of Zirconium Diboride for High Dispersion Stability and Solid Loading

2020 ◽  
Vol 20 (11) ◽  
pp. 6747-6752
Author(s):  
Jae Rok Shin ◽  
Bong-Gu Kim ◽  
Sung-Churl Choi ◽  
Yeon-Gil Jung ◽  
Gye Seok An
Keyword(s):  
Zirconium Diboride ◽  
Solid Loading ◽  
High Dispersion ◽  
Distribution Analysis ◽  
Thermal And Mechanical Properties ◽  
Surface Functional Groups ◽  
Low Viscosity ◽  
High Dispersity ◽  
Amine Groups ◽  
Ultrahigh Temperature

Zirconium diboride (ZrB2) is an ultrahigh-temperature ceramic (UHTC) with excellent thermal and mechanical properties. To fabricate a complexly structured UHTC sintered body with high density a high-solid-loading slurry with low viscosity is required to fill the mold well. Extensive studies have been carried out to improve the dispersion properties, including those on solvents and surfactants. In this study, a surface treatment using polyethylenimine (PEI) was investigated. This reagent was used to provide ZrB2 particles with desirable properties, such as electrostatic repulsive force and steric hindrance, by the functionalization of amine groups. Additionally, surface treatments with different concentrations of PEI were performed. The appropriate content for a high dispersity was determined. The surface functional groups of the PEI-treated ZrB2 were observed by Fourier-transform infrared spectroscopy. The surface charge and enhancement in dispersion were evaluated by zeta potential and particle size distribution analysis, respectively. The rheological properties of the ZrB2 slurries with various solid loadings were analyzed by viscosity measurements. In conclusion, ZrB2 slurries with solid loadings up to 50 vol% could be prepared through the PEI treatments.

Comparative Study of Metakaolin and Zeolite Tuff Influence on Properties of High-Strength Concrete

2022 ◽  
Author(s):  
Leonid I. Dvorkin ◽  
Vadim Zhitkovsky ◽  
Nataliya Lushnikova ◽  
Mohammed Sonebi
Keyword(s):  
High Strength ◽  
Economic Feasibility ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
High Dispersion ◽  
High Dispersity ◽  
Energy Consuming ◽  
Effective Use ◽  
Pozzolanic Properties ◽  
Zeolite Tuff

Composite admixtures which include active pozzolanic components and high-range water reducers, allows to obtain high-strength, particularly dense and durable concrete to achieve a reduction in resources and energy consumption of manufacturing.Zeolite, containing a significant amount of active silica, can serve as one of the alternative substances to resources and energy consuming mineral admixtures like metakaolin and silica fume. The deposits of zeolites are developed in Transcarpathia (Ukraine), USA, Japan, New Zealand, Iceland and other countries. It is known that zeolite tuffs exhibit pozzolanic properties and are capable to substitution reactions with calcium hydroxide.However, the high dispersion of zeolite rocks leads to a significant increase in the water consumption of concrete. Simultaneous introduction of zeolite tuffs with superplasticizers, which significantly reduce the water content, creates the preconditions for their effective use in high-strength concrete.Along with dehydrated (calcined) zeolite, natural (non-calcined) zeolite expresses itself as an effective mineral admixture of concrete. When using non-calcined zeolite, the effect of increasing in compressive strength at the age of 3 and 7 days is close to the effect obtained when using dehydrated zeolite: 8-10% and 10- 12%, respectively, and 28 days the strength growth is 13-22%. The use of non-calcined zeolite has a significant economic feasibility, so it certainly deserves attention. There were compared the effect of zeolite to metakaolinThe results of the research indicate that the use of composite admixtures, consisted of calcined (non-calcined) zeolite tuff of high dispersity and superplasticizer of naphthalene formaldehyde type, allows to obtain concretes classes C50…C65.

Preparation of high solid loading and low viscosity ceramic slurries for photopolymerization-based 3D printing

2019 ◽  
Vol 45 (9) ◽  
pp. 11549-11557 ◽  
Author(s):  
Zhangwei Chen ◽  
Junjie Li ◽  
Chengbo Liu ◽  
Yu Liu ◽  
Junyi Zhu ◽  
...  
Keyword(s):  
3D Printing ◽  
Solid Loading ◽  
High Solid ◽  
High Solid Loading ◽  
Low Viscosity

FABRICATION OF ALUMINA/ZIRCONIA (YSZ) NANOCOMPOSITES BY GELCASTING PROCESS

2008 ◽  
Vol 22 (18n19) ◽  
pp. 3237-3246 ◽  
Author(s):  
SOMAYE SAADAT ◽  
SAEED MALEKSAEEDI ◽  
MOHAMMAD HOSSEIN PAYDAR ◽  
HAFEZ AHMADI
Keyword(s):  
In Situ Polymerization ◽  
Viscosity Measurement ◽  
Solid Loading ◽  
Alumina Matrix ◽  
Nanosized Powders ◽  
High Solid Loading ◽  
Dense Microstructure ◽  
Low Viscosity ◽  
Gelcasting Process

Gelcasting process as a promising method for fabrication of reliable ceramics has been utilized to develop alumina-zirconia nanocomposites from nanosized powders. Sedimentation and viscosity measurement were performed to find the accurate dispersing condition for production of alumina-zirconia nanocomposite slurry with high solid loading and low viscosity. The gelcasting was accomplished by in situ polymerization of an acrylamide base monomer. The effects of solid loading, viscosity and deairing were also studied. Finally, crack and flaw free samples with relative densities of 99%, were achieved from the optimal slurry with 35vol. % solid loading, by performing sintering at 1600°C for 2 hours. SEM micrographs showed dense microstructure with fine and homogenous dispersion of zirconia phase in the alumina matrix.

Gelcasting of BaO-Nd2O3-TiO2 Microwave Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 747-750
Author(s):  
C. Fang ◽  
Yan Xiang Wang ◽  
Z.G. Su ◽  
Zhao Xian Xiong
Keyword(s):  
Solid Loading ◽  
Green Body ◽  
Microwave Ceramics ◽  
Forming Process ◽  
High Solid Loading ◽  
Low Viscosity ◽  
Microwave Ceramic ◽  
Ceramic Components ◽  
Gelcasting Process

Gelcasting is a novel ceramic forming process for fabricating products of complex-shaped ceramics. In this contribution, the gelcasting process is applied to manufacture green body of microwave ceramic components for resonators, oscillators and antennas. Calcined powders, dispersant and organic monomers are mixed together by ball-milling to acquire high solid loading slurry with low viscosity. After addition of initiator and catalyst, the slurry is cast into a non-pours mold and then polymerized. The slurry is thus solidified in situ and the green bodies with the desired shapes are obtained. The dried body is rather strong and can be machined so as to get more precise or complex-shaped components. Then the green bodies are sintered at high temperature. The microwave properties (εr, Q, τf) and microstructures of the ceramics prepared by gelcasting are compared with those of die-pressed ones.

Effect of Surface Modification on Slip Casting of SiC Slurry

2013 ◽  
Vol 364 ◽  
pp. 799-803
Author(s):  
Cai Hua Zheng ◽  
Xiao Li Ji
Keyword(s):  
Surface Modification ◽  
Zeta Potential ◽  
Slip Casting ◽  
Solid Loading ◽  
Low Viscosity ◽  
Effect Of Surface

In this study,the Zeta potential of original and modified SiC micropowder was researched,and the effects of surface modification on SiC slurry solid loading,rheologyh and density of slip casting body were studied.The structure of body was looked through SEM. The results indicated that the dispersion of modified SiC micropowder was greatly improved,the slip casting SiC slurry which had 73vol% solid loading,low viscosity and good fluidity was prepared,after slip casting,the density of body was 2.698[g·cm-3],and the structure was uniform.

scholarly journals Milk ice cream composition and structure improvement

2019 ◽  
Vol 48 (2) ◽  
pp. 109-116
Author(s):  
Антонина Творогова ◽  
Antonina Tvorogova ◽  
Татьяна Шобанова ◽  
Tatyana Shobanova ◽  
Анна Ландиховская ◽  
...  
Keyword(s):  
Ice Cream ◽  
Food Product ◽  
Low Energy ◽  
Ice Crystals ◽  
High Mass ◽  
Survey Method ◽  
High Dispersion ◽  
Healthy Foods ◽  
Energy Value ◽  
High Dispersity

The work reveals the results of the study devoted to milk ice cream composition improvement in order to meet the requirements for healthy foods (with satisfactory nutritional value) to the fullest extent and to obtain creamy consistency as well as high dispersity of structural elements typical for products with high mass fractions of fat and dry substances. The significance of the research is determined by the worldwide trend in the production of healthy foods which is developed in our country by a number of legislative documents. The purpose of the research was to develop on the basis of the composition a milk ice cream product with low energy value and high organoleptic parameters including the state of its structure. Within the framework of the given research the author used such modern research methods as rheological, microstructural and thermostating ones as well as photographic survey method. The author justified analytically and experimentally the use of such food additive as polydextrose having low energy value. It increases the feeling that food product has high fat content and it does not have any negative effect on ice cream production process. The possibility of improving the product structure using synergistic compositions such as emulsifiers based on distilled monoglycerides and polyglycerol and fatty acids esters as well as stabilizers containing mainly locust bean gum which promotes the formation of small ice crystals was confirmed experimentally. The mentioned compositions of emulsifiers and stabilizers when used with polydextrose made it possible to achieve technologically significant results in milk ice cream production. They increased the effective viscosity of the mixtures, provided high form and thermal stability, and made it possible to get high dispersion of ice crystals. The accepted technological solutions had positive effect on the consistency and structure of milk ice cream with improved composition.

Gel Casting of Large-Sized, Complex-Shaped RBSC Component

2012 ◽  
Vol 512-515 ◽  
pp. 395-398 ◽  
Author(s):  
Hai Lin Liu ◽  
Yan Li Huo ◽  
Chun Peng Wang ◽  
Jie Tang ◽  
Yu Feng Chen
Keyword(s):  
Rheological Property ◽  
Process Parameters ◽  
Casting Process ◽  
Sintered Body ◽  
Solid Loading ◽  
Green Body ◽  
High Solid ◽  
High Solid Loading ◽  
Low Viscosity ◽  
Gel Casting

In this paper, gel casting process of RBSC was deeply studied. The rheological property of C/SiC slurry was analyzed, high solid loading (67%) slurry with low viscosity was produced. Also the properties of green body and sintered body were studied. Finally, through optimizations of process parameters, a large-sized (650mm), complex-shaped (with thin ribs about 2.5mm) was fabricated through gel casting process with no cracks and deformation. It was showed that gel casting process is suitable for producing large-sized, complex-shaped RBSC components.

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