Near net shape fabrication of porous cordierite by combination of foam gel‐casting and freeze‐drying

2021 ◽  
Author(s):  
Hao Li ◽  
Junwen Li ◽  
Cuiwei Li ◽  
Mengli Fu ◽  
Chang‐An Wang
Keyword(s):  
Freeze Drying ◽  
Gel Casting ◽  
Near Net Shape ◽  
Porous Cordierite

scholarly journals Effect of glutinous rice flour and dried egg white in fabrication of porous cordierite by gel casting method

Cerâmica ◽  
2018 ◽  
Vol 64 (370) ◽  
pp. 242-247 ◽  
Author(s):  
A. Kamil Fakhruddin ◽  
Hasmaliza Mohamad
Keyword(s):  
Compression Test ◽  
Raw Materials ◽  
Fine Powder ◽  
Rice Flour ◽  
Egg White ◽  
Casting Method ◽  
Porosity Level ◽  
Gel Casting ◽  
Glutinous Rice ◽  
Porous Cordierite

Abstract In this study, cordierite was produced using MgO, SiO2 and Al2O3 as raw materials through glass route method. The raw materials were mixed for 6 h and the mixture was melted at 1550 °C and then water quenched. The glass produced was milled for 5 h to obtain fine powder, which was used to prepare porous cordierite through gel casting method. The effect of addition of different natural binders, glutinous rice flour (GRF) and dried egg white (DEW), on porous cordierite was investigated. GRF and DEW were added to the slurry during mixing. The synthesized cordierite powder was analyzed by X-ray diffraction. Porous cordierite was characterized through Archimedes method, morphological analysis, and compression test. The porosity level varied from 60.6% to 78.7% depending on the amount of natural binder added. Compression test results showed that the compressive strength of porous cordierite increased with increasing amount of natural binder added.

Research the Performance of Alumina Insulation Material by Freeze-Drying

2012 ◽  
Vol 512-515 ◽  
pp. 527-530
Author(s):  
Dao Yuan Yang ◽  
Guang Hui Wei
Keyword(s):  
Freeze Drying ◽  
Bending Strength ◽  
High Strength ◽  
Raw Material ◽  
Insulation Material ◽  
Direct Foaming ◽  
Gel Casting ◽  
Alumina Particles ◽  
Additive Combination ◽  
Ice Sublimation

The traditional method of preparation alumina insulation material includes the addition of pore-forming agent, direct foaming, foam impregnation and gel-casting. In this experiment, α-alumina as raw material, silica fume as an additive, Combination freeze-drying method, add pore-forming agent and direct foaming successfully prepared low-density, high strength, low thermal conductivity of alumina insulation material. Change the particle size of pore-forming agent can be get different properties of the sample. The SEM photograph was clearly observed that the hole wall dense uniform, α-alumina particles sufficient contact, no significant ice sublimation hole left. There are also the reasons of the sample with higher value of bending strength and compressive strength. This can make a control of porosity, as well as pore size, pore shape and pores space topology of alumina insulation material.

scholarly journals Preparation and Optimization Green Gel Casting Technique for Manufacturing Near-Net-Shape Ceramics Using Genetic Algorithm

2021 ◽  
Vol 877 (1) ◽  
pp. 012035
Author(s):  
Mohammed A. Ahmed Al-dujaili ◽  
Imad Ali Al-hydary ◽  
Montaha Abdalhussien
Keyword(s):  
Genetic Algorithm ◽  
Aqueous Solution ◽  
Surface Roughness ◽  
Yttria Stabilized Zirconia ◽  
Solid Loading ◽  
Stabilized Zirconia ◽  
Casting Technique ◽  
Gel Casting ◽  
Near Net Shape ◽  
Cross Linker

Abstract Gel casting technique is a promising technology that has ability to produce near-net shape ceramics via using toxic and non-ecofriendly agents. The current work aim to develop green gel casting technique using water as a solvent, agar as a gelling agent, and the microwave thermal treatment instead of cross linker. 8mo l% Yttria stabilized zirconia was selected as a case study to produce near-net shape ceramics. The experimental work involved the preparation of Yttria stabilized zirconia nanoparticles via chemical precipitation method. The effect study of agar ratio, Yttria stabilized zirconia solid loading percent on the physical, mechanical, surface properties of the prepared ceramics and selecting of suitable casting conditions. The study has been found that the microwave thermal treatment develops thermally activated cross linking in the agar aqueous solution leading to higher glass transition temperature for agar. The green combination (agar aqueous solution and microwave treatment) can be used as alternative to (monomer, solvent, cross linker) Companion. Also, using the ultrasonic treatment can effectively eliminate needs for dispersants, also the vacuum de-airing treatment. Yttria stabilized zirconia ceramic with high dimensional accuracy, low surface roughness (Ra=2. 81 nm) can be obtained using an agar ratio of (0.4%) and solid loading of (65%). The sample can be moulded with complex shape and the green gel, also the pre-sintered body is machineable. The sintered samples have a porosity of (31%) and compressive strength of (234MPa). Regression analysis and genetic algorithm are showed that the obtained microhardness, compressive strength, and surface roughness are predictable.

Fabrication and Characterization of Porous Biphasic Calcium Phosphate Scaffolds by Doping TiO2

2013 ◽  
Vol 747 ◽  
pp. 190-193 ◽  
Author(s):  
Naruporn Monmaturapoj ◽  
Witoon Thepsuwan
Keyword(s):  
Freeze Drying ◽  
Testing Machine ◽  
Minor Phase ◽  
X Ray ◽  
Gel Casting ◽  
Universal Testing ◽  
Xrd Patterns ◽  
A Minor ◽  
Highly Porous

This study aims to improve the strength of porous BCP samples by the addition of titanium dioxide (TiO2), the well known biocompatible and strong ceramic. BCP powder with HA/TCP ratio of 70/30 (BCP7030) obtained by mixing a pure HA and β-TCP powder. TiO2 powder with 2 (BCP_2Ti), 5 (BCP_5Ti) and 10 (BCP_10Ti) %wt were added into the BCP7030 powder, then ball milled in ethanol for 6 hrs. The porous samples were fabricated by the combination of the gel-casting and freeze drying techniques. All samples were sintered at 1100°C for 2 hrs. X-ray diffractometry (XRD) and scanning electron microscopy (SEM) were used to determine crystal structures and morphology of the sintered samples, respectively. Mechanical properties and porosity of samples were measured by using the universal testing machine and Archimedess principle, respectively. XRD results showed that the phases of the undoped sample can be indexed HA and β-TCP with the ratio of 70/30 as the major phases. In BCP_2Ti, CaTiO3 was observed as a minor phase among the crystallization of HA and β-TCP with the proportion of 30:70. Meanwhile, in BCP_5Ti and BCP_10Ti, XRD patterns revealed a completely transformation of HA to β-TCP with minor phases of CaTiO3 and TiO2. The microstructure of sintered samples present highly porous structure which consisted of two-dimensional pore channels along the long axis and the short axis, which replicates the ice and pore orientation in the direction of freezing. Relatively, the porosity of the samples was increased with the amount of TiO2. Surprisingly, an additions of the TiO2 was not rather improved the mechanical strength of porous BCP7030 in this study. This might be a result of a high percentage of porosity (84%).

Preparation of porous cordierite ceramic by gel-casting method

2017 ◽  
Vol 116 (7) ◽  
pp. 362-367 ◽  
Author(s):  
Yuanyuan Sun ◽  
Jingde Zhang ◽  
Shuaishuai Lu ◽  
Huichao Liu
Keyword(s):  
Casting Method ◽  
Gel Casting ◽  
Cordierite Ceramic ◽  
Porous Cordierite

Porous hydroxyapatite scaffolds produced by the combination of the gel-casting and freeze drying techniques

2011 ◽  
Vol 19 (4) ◽  
pp. 441-447 ◽  
Author(s):  
Naruporn Monmaturapoj ◽  
Wiwaporn Soodsawang ◽  
Witoon Thepsuwan
Keyword(s):  
Freeze Drying ◽  
Porous Hydroxyapatite ◽  
Gel Casting ◽  
Drying Techniques

Ca-Histochemistry in slime mold plasmodia

1978 ◽  
Vol 36 (2) ◽  
pp. 130-131
Author(s):  
Ulrich Dierkes
Keyword(s):  
Physarum Polycephalum ◽  
Carbon Coating ◽  
Freeze Drying ◽  
Freeze Fracture ◽  
Freeze Substitution ◽  
Uranyl Acetate ◽  
Slime Mold ◽  
Staining Procedure ◽  
Protoplasmic Streaming ◽  
Intracellular Ca

Calcium is supposed to play an important role in the control of protoplasmic streaming in slime mold plasmodia. The motive force for protoplasmic streaming is generated by the interaction of actin and myosin. This contraction is supposed to be controlled by intracellular Ca-fluxes similar to the triggering system in skeleton muscle. The histochemical localisation of calcium however is problematic because of the possible diffusion artifacts especially in aquous media.To evaluate this problem calcium localisation was studied in small pieces of shock frozen (liquid propane at -189°C) plasmodial strands of Physarum polycephalum, which were further processed with 3 different methods: 1) freeze substitution in ethanol at -75°C, staining in 100% ethanol with 1% uranyl acetate, and embedding in styrene-methacrylate. For comparison the staining procedure was omitted in some preparations. 2)Freeze drying at about -95°C, followed by immersion with 100% ethanol containing 1% uranyl acetate, and embedding. 3) Freeze fracture, carbon coating and SEM investigation at temperatures below -100° C.

The Critical Point Drying Method Applied to Scanning Electron Microscopy of L-929 Cells

1970 ◽  
Vol 28 ◽  
pp. 278-279
Author(s):  
Charles TurnbiLL ◽  
Delbert E. Philpott
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Surface Tension ◽  
Critical Point ◽  
Freeze Drying ◽  
Attractive Alternative ◽  
Crystal Formation ◽  
Critical Point Drying ◽  
Time Required ◽  
Scanning Electron

The advent of the scanning electron microscope (SCEM) has renewed interest in preparing specimens by avoiding the forces of surface tension. The present method of freeze drying by Boyde and Barger (1969) and Small and Marszalek (1969) does prevent surface tension but ice crystal formation and time required for pumping out the specimen to dryness has discouraged us. We believe an attractive alternative to freeze drying is the critical point method originated by Anderson (1951; for electron microscopy. He avoided surface tension effects during drying by first exchanging the specimen water with alcohol, amy L acetate and then with carbon dioxide. He then selected a specific temperature (36.5°C) and pressure (72 Atm.) at which carbon dioxide would pass from the liquid to the gaseous phase without the effect of surface tension This combination of temperature and, pressure is known as the "critical point" of the Liquid.

Preservation of Plant Cell Surfaces For Scanning Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 472-473
Author(s):  
Linda M. Sicko ◽  
Thomas E. Jensen
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Critical Point ◽  
Filter Paper ◽  
Freeze Drying ◽  
Cell Surfaces ◽  
Air Drying ◽  
Popular Method ◽  
Critical Point Drying ◽  
Scanning Electron

The use of critical point drying is rapidly becoming a popular method of preparing biological samples for scanning electron microscopy. The procedure is rapid, and produces consistent results with a variety of samples. The preservation of surface details is much greater than that of air drying, and the procedure is less complicated than that of freeze drying. This paper will present results comparing conventional air-drying of plant specimens to critical point drying, both of fixed and unfixed material. The preservation of delicate structures which are easily damaged in processing and the use of filter paper as a vehicle for drying will be discussed.

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