Comparison of Different Alumina Powders for Aqueous Tape Casting Process

2015 ◽  
Vol 820 ◽  
pp. 172-177
Author(s):  
Fernanda P. Santos ◽  
Ediana Gambin ◽  
Cristina Moniz A. Lopes ◽  
Rosa Maria Rocha

Tape casting process was used to produce Al2O3 substrates in an aqueous system with acrylic latex emulsion as binder. The present work studied the slurry formulations in aqueous medium of Al2O3 powders with different particle size distribution and made correlation to the green and sintered tapes. Two commercial alumina powders, one sub-micrometric and other micrometric were used. Compositions of Al2O3 slurries with 80 and 83 wt% of solids were prepared by dispersing the powders in water with a dispersant with subsequently additions of 7 and 10 wt% of binder. Sub-micrometric Al2O3 resulted in a high densification tapes regardless solid concentration and binder amount in the slurry, though green density was affected. For micrometric alumina, increasing the solid concentration resulted in a little higher final density.

1984 ◽  
Vol 40 ◽  
Author(s):  
J. B. Blum ◽  
W. R. Cannon

AbstractFor the past two years we have been investigating the tape casting of BaTiO3 Specifically we have been interested in developing a useful tape casting formulation and procedure and in studying the effects of powder particle size distribution and dispersion processes on the forming of BaTiO3 tapes.The formulation we have developed is non-aqueous. An MEKethanol mixture is the solvent and an acrylic binder is used. Two dispersants are being used, a phosphate ester and Menhaden fish oil. Ultrasonic dispersion was found to be effective in breaking up weak powder agglomerates. We have found it important to add the dispersant before adding other organic components to obtain the best dispersion and strongest tapes. The drying method is also important to tape strength. The strongest tapes resulted when the tape was removed from the glass plate soon after casting. We have also demonstrated that for forming purposes a wide particle size distribution is preferred.


Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1080
Author(s):  
Aghiles Hammas ◽  
Gisèle Lecomte-Nana ◽  
Imane Daou ◽  
Nicolas Tessier-Doyen ◽  
Claire Peyratout ◽  
...  

In recent decades, talc and kaolinite have been widely used as raw materials for the ceramic industry. In this study, the final characteristics of kaolinitic clay mixed with 6 mass% of magnesite obtained in our previous work were compared with those obtained with mixtures of kaolin (kaolin BIP) and talc (as the source of magnesium oxide). However, different amounts of talc in the kaolin powder were studied, namely 10, 30, and 50 mass% of added talc (with respect to kaolin + talc). The tape casting process was used during this work in order to manufacture the green tapes in an aqueous system with 0.2 mass% of dispersant. Subsequently, the green tapes were heated to 1000 and 1100 °C with a dwelling time of 12 min. The green and sintering tapes were characterized using the following techniques: DTA/TG, X-ray diffraction, porosity, and flexural strength analyses. The results obtained from our previous work indicate that the specimen with 6 mass% of MgCO3 sintered at 1200 °C for 3 h exhibited the best performances, with high flexural strength and weak porosity value—117 MPa and 27%—respectively. As results from this study, the optimal mechanical and thermal properties of sintering tapes were obtained for the specimen with 10 mass% of added talc sintered at 1100 °C. Indeed, this specimen exhibited 50 MPa and 43% of stress to rupture and apparent porosity, respectively.


2001 ◽  
Vol 123 (2) ◽  
pp. 271-280 ◽  
Author(s):  
B. K. Gandhi ◽  
S. N. Singh ◽  
V. Seshadri

The performance of two centrifugal slurry pumps has been reported for three solid materials having different particle size distribution (PSD) in terms of head, capacity, and power characteristics. The results have shown that the values of head and efficiency ratios are not only dependent on solid concentration but are also affected by PSD of the solids and properties of the slurry. The addition of fine particles in the slurry of coarser material leads to reduction in the additional losses that occur in the pumps due to the presence of solids. It is also observed that with the increase in the pump size, the additional losses due to presence of solids reduce.


2004 ◽  
Vol 19 (3) ◽  
pp. 90-93
Author(s):  
Cui Xue-min ◽  
Ouyang Shi-xi ◽  
Huang Yong ◽  
Yu Zhi-yong ◽  
Zhao Shi-ke ◽  
...  

2015 ◽  
Vol 766-767 ◽  
pp. 956-961
Author(s):  
K.S. Chethan ◽  
S. Kiran Aithal ◽  
A. Madhusudan ◽  
Rao Shailesh

Functionally Graded Materials (FGM) is a newly evolved concept to get desired properties in the material wherein the intermediate layer is transient since the particle size distribution gradually changes. Centrifugal casting [1] can produce only hollow shapes and Centrifuge casting can produce solid shape FGM very effectively. The study of particle distribution in a fluid using centrifuge casting process is carried out considering sand as particle and its distribution is studied under water, for different viscosity values and for viscosity varying with respect to temperature. Based on centrifugal force and density difference, an attempt has been made to mathematically model the centrifuge casting force to estimate the particle distribution over the length of the specimen and also to assess the influence of process parameters such as rotational speed (G-force) and density of the particles.


2007 ◽  
Vol 280-283 ◽  
pp. 753-756
Author(s):  
Xue Min Cui ◽  
Yong Huang ◽  
Ji Zhou ◽  
Chang An Wang ◽  
Shi Xi Ouyang

As a good binder for aqueous Al2O3 suspensions tape-casting process, a commercial styrene-acrylic latex binder had been investigated. This paper studied on the rheological behaviors of the suspensions and drying process of aqueous slurries with latex binder system, and the research results indicated the rheological behaviors was affected by pH value, solid loading and dispersant (PAA-NH4) additives; and the drying speed of slurries was most decided by drying temperature and slurry coating thickness.


Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 439
Author(s):  
Guihua Yang ◽  
Guangrui Ma ◽  
Ming He ◽  
Xingxiang Ji ◽  
Weidong Li ◽  
...  

Cellulose nanofibrils (CNFs) were exposed to the same levels of potassium chloride (KCl) and sodium chloride (NaCl) before being subjected to spray drying. The effect of NaCl and KCl on the size of atomized droplets and the hydrogen bond retardation between CNFs was investigated by characterizing product morphology, particle size distribution, dispersion stability in aqueous system, and surface chemistry. The results showed that the CNF suspensions treated with KCl could be atomized into smaller droplets during spray drying, and then CNF powder with smaller sizes could be obtained. As the agglomeration was less, and the CNF with KCl addition had good dispersion stability after redispersion compared with CNF treated by NaCl. Therefore, KCl treatment was an effective method to reduce the agglomeration of CNF during spray drying.


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