Influence of particle size and aggregation state of alumina on the rheology of a ceramic paste with an organic binder of ethylene–vinyl acetate copolymer and stearic acid

Murakami, Setsuaki; Ri, Kinki; Itoh, Toshio; Izu, Noriya; Shin, Woosuck; Inukai, Koji; Takahashi, Yosuke; Ando, Yasunori

doi:10.1016/j.ceramint.2011.09.046

Cited by 17 publications

(7 citation statements)

References 13 publications

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“…In fact zeta-potential has already been linked to the rheology of catalyst shaping; ,, however, up to now no clear conclusions about an optimal zeta-potential for extrusion have been made. Many studies are devoted to the rheology of ceramics − and zeolites, ,,, unfortunately not focusing on the tensile strength and texture characteristics of final materials. There are very few studies , of impact of rheological behavior of molding masses on textural properties of extrudates.…”

Section: Introductionmentioning

confidence: 99%

Shaping of Sulfated Zirconia Catalysts by Extrusion: Understanding the Role of Binders

Devyatkov

Zinnurova

Aho

et al. 2016

Ind. Eng. Chem. Res.

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Sulfated zirconia hydroxide shaping by extrusion is studied based on elucidating the impact of zeta-potential and rheological characteristics on physical and chemical properties of technical catalysts. Zeta potential measurements of sulfated zirconium hydroxide prior and after poly(vinyl alcohol) (PVA) additions were made. Rheological curves of sulfated zirconium hydroxide suspensions with different amounts of PVA were recorded at different zeta-potential values. The addition of PVA nonlinearly decreased shear yield stress. Experimental data were quantified with the Krieger–Dougherty equation. The influence of a boehmite-type binder on the zeta-potential confirmed that the surface properties of the particles to a large extent are determined by the presence of binder. The pore structure of shaped catalysts was unaffected by rheological parameters when zeta-potential is close enough to zero. At the same time deviations of the zeta potential from the zero-value afforded more uniform pore size distribution.

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Section: Introductionmentioning

confidence: 99%

Shaping of Sulfated Zirconia Catalysts by Extrusion: Understanding the Role of Binders

Devyatkov

Zinnurova

Aho

et al. 2016

Ind. Eng. Chem. Res.

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“…65 Pastes are overconcentrated suspensions whose rheology depends on factors associated to solid concentration, particle size distribution and shape, the wetting properties of both the liquid additive and the solid, the configuration of the mixing apparatus, and to a less extent on the environmental conditions. 59,61,78 In this case, when relatively small shear rates are applied, the finer particles are very sensitive to the effects of Brownian motion or colloidal forces, while the coarser particles experience frictional or colliding contacts or hydrodynamic forces. 78 When water is used as the wetting liquid, it is important to ensure a good compromise between its concentration and that of the used organic additives to get suspensions with adequate viscosity profiles (flow curves) because otherwise the mixer apparatus may be ineffective.…”

Section: Wet Mixturesmentioning

confidence: 99%

Elements of the Manufacture and Properties of Technical Catalysts

García-Sánchez

Medrano

2023

Ind. Eng. Chem. Res.

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Despite the humongous volume of literature aiming to present the synthesis of innovative, more selective, stable, and active solid catalysts, the catalysts that come to be used at the industrial level, known as technical catalysts, are scarcely studied and poorly understood starting from the fact that most of the information on their manufacturing remains as an industrial secret. Therefore, many knowledge gaps and uncertainties in the techniques suitable to transform catalytic powders into technical catalysts lie ahead of those researchers who decide to engage in the development and study of applied catalysis. Therefore, this review seeks to provide guidance on the process for manufacturing technical catalysts from catalytic powders while also providing insight into the targeted properties of such materials. Specifically, this review examines the aspects related to the manufacture of technical catalysts spanning from the operations related to the mixture of their components to the thermal treatments to which the corresponding shaped bodies are submitted. Furthermore, we define and discuss the properties considered as key when evaluating the catalytic performance of the shaped materials.

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“…G ′ eq is a measure of the stiffness of a fluid and represents the resistance to flow at rest for that fluid. 22 Minimum values of yield stress and G ′ eq for successful direct writing have been reported as σ y > 50 Pa and G ′ eq > 10 4 Pa. 12,16,22 Factors that affect the rheology of ceramic pastes with a specified particle loading include suspension pH, 16,23,24 particle size and size distribution, 11,[25][26][27][28][29] particle geometry, 11,[29][30][31][32] and organic additives. [12][13][14]18,24,[33][34][35] The pH of the paste can dramatically affect particle surface charge and organic molecule conformation, and subsequently cause the viscosity of the paste to change by orders of magnitude.…”

Section: Introductionmentioning

confidence: 99%

“…Minimum values of yield stress and

G_{eq}^{'}

for successful direct writing have been reported as σ y > 50 Pa and

G_{eq}^{'}

> 10 4 Pa 12,16,22 . Factors that affect the rheology of ceramic pastes with a specified particle loading include suspension pH, 16,23,24 particle size and size distribution, 11,25‐29 particle geometry, 11,29‐32 and organic additives 12‐14,18,24,33‐35 …”

Section: Introductionmentioning

confidence: 99%

Dispersion and rheology for direct writing lead‐based piezoelectric ceramic pastes with anisotropic template particles

et al. 2020

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Controlling the rheology of direct writing pastes is essential for producing high quality printed ceramics. Ceramic pastes were formulated to explore the relation between surface chemistry and rheology of complex pastes of Pb(In1/2Nb1/2)O3‐Pb(Mg1/3Nb2/3)O3‐PbTiO3 (PIN‐PMN‐PT) powder, large BaTiO3 (BT) platelet particles, and a commercial poly(acrylic) acid‐based binder system. Zeta potential of the ceramic powder, the conformation of the poly(acrylic) acid, and the effect of these factors on rheology were evaluated as a function of suspension pH. Effective dispersion and amenable rheology for direct writing were achieved at mixing pH 5. Additions of 0.3 to 2.6 vol% BT tabular particles dramatically altered the rheology of the pastes due to the shear alignment of the BT particles. Powder‐organic interactions and the size and concentration of BT platelet particles can be tailored to direct write either space‐filling filaments to form dense ceramics or non‐flowing filaments to form spanning ceramic structures.

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Influence of particle size and aggregation state of alumina on the rheology of a ceramic paste with an organic binder of ethylene–vinyl acetate copolymer and stearic acid

Cited by 17 publications

References 13 publications

Shaping of Sulfated Zirconia Catalysts by Extrusion: Understanding the Role of Binders

Shaping of Sulfated Zirconia Catalysts by Extrusion: Understanding the Role of Binders

Elements of the Manufacture and Properties of Technical Catalysts

Dispersion and rheology for direct writing lead‐based piezoelectric ceramic pastes with anisotropic template particles

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