Porous Ceramic Structures Obtained from Calcium Carbonate as Pore Generating Agent

2014 ◽  
Vol 775-776 ◽  
pp. 755-760 ◽  
Author(s):  
Lisandro Simão ◽  
Oscar Rubem Klegues Montedo ◽  
Rafael Caldato ◽  
Murilo Daniel de Mello Innocentini ◽  
Marcos Marques da Silva Paula ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Heating Rate ◽  
Ball Mill ◽  
Sintering Temperature ◽  
Porous Ceramic ◽  
Hydraulic Press ◽  
Experimental Results ◽  
Crystalline Phases ◽  
Heat Treated

The aim of this work is to present experimental results related to the use of calcium carbonate as pore generating agent. Four compositions containing 20 wt.% of limestone were used and characterized chemically and thermally. Each composition was homogenized in a porcelain ball mill, dried in a laboratory drier, humidified at 7 wt.%, and pressed in an uniaxial hydraulic press. Compacted samples were dried and heat treated with a suitable heating rate for the degasification of calcium carbonate and sintered at 800, 900, and 1050 °C. Sintered samples were characterized to determine the porosity, crystalline phases formed and microstructural features. The results showed that the porosity has increased with the sintering temperature of the compositions increasing due porosity generated by the calcium carbonate degasification and the material expansion.

Obtainment of Porous Ceramic Structures: A Comparison among Different Compositions and Methods of Conformation

2018 ◽  
Vol 912 ◽  
pp. 224-229
Author(s):  
Lisandro Simão ◽  
Débora Cristina Niero Fabris ◽  
Morgana de Medeiros Machado ◽  
Rafael Caldato ◽  
Murilo Daniel de Mello Innocentini ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Calcium Carbonate ◽  
Porous Ceramic ◽  
Slip Casting ◽  
Sintering Behavior ◽  
X Ray ◽  
Heat Treated ◽  
Porosity And Permeability ◽  
Comparative Results

This paper presents comparative results concerning to the obtaining of porous ceramic structures obtained by pressing, slip casting and polymeric sponge method. Three compositions were prepared, using calcium carbonate as pore-generating agent and characterized by X-ray fluorescence, thermogravimetric analysis and determination of sintering behavior. Each formulation was wet mixed and dried. Then, each formulation was formed by each one of the investigated methods. The obtained samples were dried and heat treated with the appropriate heating rate for calcium carbonate degasification and sintered at 900, 1100 and 1180 °C. The sintered samples were characterized by determination of porosity, crystalline phases formed, compressive strength and permeability. Results showed that porosity and permeability depends strongly on the composition and used conformation method.

scholarly journals SYNTHESIS OF Cu1.6Bi4.6S8 COMPOUND FOR THERMOELECTRIC APPLICATION

2019 ◽  
Vol 25 (2) ◽  
pp. 86
Author(s):  
Binh Ngoc Duong ◽  
Long Duc Bui
Keyword(s):  
Heat Treatment ◽  
Heating Rate ◽  
Ball Mill ◽  
Milled Powder ◽  
Xrd Analysis ◽  
High Energy ◽  
Starting Mixture ◽  
Heat Treated ◽  
Annealed Powder ◽  
Thermoelectric Application

<p class="AMSmaintext">In this work, Cu<sub>1.6</sub>Bi<sub>4.6</sub>S<sub>8</sub> thermoelectric compound was synthesized using high energy milling and heat treatment. The starting mixture include Cu, Bi and S elemental powders at the stoichiometry ratio of the formula Cu<sub>1.6</sub>Bi<sub>4.6</sub>S<sub>8</sub> were ball milled in a planetary ball mill and heat treated in an electric furnace. The results shown that after 10 hours of milling, a compound identified as Cu<sub>3.21</sub>Bi<sub>4.79</sub>S<sub>9</sub> was formed. The 16h milled powder was heat-treated at 350, 400 and 450ºC for 1 hours at a heating rate of 8 ºC/minute, XRD of the annealed powder reveals that the Cu<sub>3.21</sub>Bi<sub>4.79</sub>S<sub>9</sub> obtained fully transformed into Cu<sub>1.6</sub>Bi<sub>4.6</sub>S<sub>8</sub> after being heat treated at 400ºC. Meanwhile, Bi<sub>2</sub>S<sub>3</sub> was found in the powder being annealed at 350ºC. The 5h milled powder was also annealed at 400ºC for 1 hours at a heating rate of 2 and 8 ºC/minute, XRD analysis show that Cu<sub>1.6</sub>Bi<sub>4.6</sub>S<sub>8</sub> was also formed in the heat-treated powder with the heating rate of 2 ºC/min.</p>

scholarly journals Optimization of Sintering Process of Alumina Ceramics Using Response Surface Methodology

2021 ◽  
Vol 13 (12) ◽  
pp. 6739
Author(s):  
Darko Landek ◽  
Lidija Ćurković ◽  
Ivana Gabelica ◽  
Mihone Kerolli Mustafa ◽  
Irena Žmak
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Heating Rate ◽  
Sintering Temperature ◽  
Nonlinear Models ◽  
Slip Casting ◽  
Holding Time ◽  
Alumina Ceramics ◽  
Aqueous Suspensions ◽  
Temperature Heating

In this work, alumina (Al2O3) ceramics were prepared using an environmentally friendly slip casting method. To this end, highly concentrated (70 wt.%) aqueous suspensions of alumina (Al2O3) were prepared with different amounts of the ammonium salt of a polycarboxylic acid, Dolapix CE 64, as an electrosteric dispersant. The stability of highly concentrated Al2O3 aqueous suspensions was monitored by viscosity measurements. Green bodies (ceramics before sintering) were obtained by pouring the stable Al2O3 aqueous suspensions into dry porous plaster molds. The obtained Al2O3 ceramic green bodies were sintered in the electric furnace. Analysis of the effect of three sintering parameters (sintering temperature, heating rate and holding time) on the density of alumina ceramics was performed using the response surface methodology (RSM), based on experimental data obtained according to Box–Behnken experimental design, using the software Design-Expert. From the statistical analysis, linear and nonlinear models with added first-order interaction were developed for prediction and optimization of density-dependent variables: sintering temperature, heating rate and holding time.

scholarly journals Transparent TiO2/Cu/TiO2 Multilayer for Electrothermal Application

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1024
Author(s):  
Jingjing Peng ◽  
Changshan Hao ◽  
Hongyan Liu ◽  
Yue Yan
Keyword(s):  
Optical Properties ◽  
Heating Rate ◽  
Figure Of Merit ◽  
Annealing Temperature ◽  
Critical Thickness ◽  
Experimental Results ◽  
Tio2 Layer ◽  
Electrical And Optical Properties ◽  
Partial Crystallization

Highly transparent indium-free multilayers of TiO2/Cu/TiO2 were obtained by means of annealing. The effects of Cu thickness and annealing temperature on the electrical and optical properties were investigated. The critical thickness of Cu mid-layer with optimal electrical and optical properties was 10 nm, with the figure of merit reaching as high as 5 × 10−3 Ω−1. Partial crystallization of the TiO2 layer enhanced the electrical and optical properties upon annealing. Electrothermal experiments showed that temperatures of more than 100 °C can be reached at a heating rate of 2 °C/s without any damage to the multilayers. The experimental results indicate that reliable transparent TiO2/Cu/TiO2 multilayers can be used for electrothermal application.

Characterization of Nigerian Clay as Porous Ceramic Material

2013 ◽  
Vol 845 ◽  
pp. 256-260 ◽  
Author(s):  
M. Abubakar ◽  
A.B. Aliyu ◽  
Norhayati Ahmad
Keyword(s):  
Thermal Properties ◽  
Bulk Density ◽  
Sintering Temperature ◽  
Starch Content ◽  
Porous Ceramic ◽  
Porous Ceramics ◽  
Cassava Starch ◽  
Compaction Method ◽  
Percentage Porosity

Porous ceramics were produced by compaction method of Nigerian clay and cassava starch. The samples were prepared by adding an amount from 5 to 30%wt of cassava starch into the clay and sintered at temperature of 900-1300°C. The influence of cassava starch content on the bulk density and apparent porosity was studied. The result of XRD and DTA/TGA shows that the optimum sintering temperature was found to be 1300°C. The percentage porosity increased from 12.87 to 43.95% while bulk density decreased from 2.16 to 1.46g/cm3 with the increase of cassava starch from 5 to 30%wt. The effect of sintering temperature and cassava starch content improved the microstructure in terms of porosity and the thermal properties of porous clay for various applications which requires a specific porosity.

Production of Dispersion-Strengthened Cu-TiB2 Alloys by Ball-Milling and Spark-Plasma Sintering

2007 ◽  
Vol 534-536 ◽  
pp. 1489-1492 ◽  
Author(s):  
Dae Hwan Kwon ◽  
Jong Won Kum ◽  
Thuy Dang Nguyen ◽  
Dina V. Dudina ◽  
Pyuck Pa Choi ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Ball Milling ◽  
Spark Plasma Sintering ◽  
Ball Mill ◽  
Milling Time ◽  
Rotation Speed ◽  
Sintering Temperature ◽  
Milled Powder ◽  
Plasma Sintering ◽  
Spark Plasma

Dispersion-strengthened copper with TiB2 was produced by ball-milling and spark plasma sintering (SPS).Ball-milling was performed at a rotation speed of 300rpm for 30 and 60min in Ar atmosphere by using a planetary ball mill (AGO-2). Spark-plasma sintering was carried out at 650°C for 5min under vacuum after mechanical alloying. The hardness of the specimens sintered using powder ball milled for 60min at 300rpm increased from 16.0 to 61.8 HRB than that of specimen using powder mixed with a turbular mixer, while the electrical conductivity varied from 93.40% to 83.34%IACS. In the case of milled powder, hardness increased as milling time increased, while the electrical conductivity decreased. On the other hand, hardness decreased with increasing sintering temperature, but the electrical conductiviey increased slightly

INFLUENCE OF STICKY RICE AND ANIONIC POLYACRYLAMIDE ON THE CRYSTALLIZATION OF CALCIUM CARBONATE IN CHINESE ORGANIC SANHETU

2015 ◽  
Vol 22 (06) ◽  
pp. 1550073 ◽  
Author(s):  
HUI LIU ◽  
CHANGSHENG PENG ◽  
MIN DAI ◽  
QINGBAO GU ◽  
SHAOXIAN SONG
Keyword(s):  
Reaction Time ◽  
Calcium Carbonate ◽  
Organic Material ◽  
Organic Materials ◽  
Experimental Results ◽  
Additive Concentration ◽  
Reactant Concentration ◽  
Natural Organic Material ◽  
Anionic Polyacrylamide

The crystallization of calcium carbonate ( CaCO 3) in soil controlled by natural organic material was considered a very important reason to enhance the property of ancient Chinese organic Sanhetu (COS), but how the organic material affected the crystallization of CaCO 3 in COS is still unclear. In this paper, a natural organic material (sticky rice, SR) and a synthetic organic material (anionic polyacrylamide, APAM) were selected as additives to investigate their effect on the crystallization of CaCO 3. The experimental results showed that the morphology and size of CaCO 3 crystals could be affected by the concentration of additives and reaction time, while only the size of CaCO 3 crystals could be affected by the concentration of reactant. Although the morphology and size of CaCO 3 crystals varied greatly with the variation of additive concentration, reactant concentration and reaction time, the polymorph of CaCO 3 crystals were always calcite, according to SEM/EDX, XRD and FTIR analyses. This study may help us to better understand the mechanism of the influence of organic materials on CaCO 3 crystallization and properties of COS.

Dlts-Studies on the “New Oxygen Donor” in Heat Treated and Hydrogenated CZ-Grown SI

1985 ◽  
Vol 59 ◽  
Author(s):  
Karlheinz Hölzlein ◽  
G. Pensl ◽  
M. Schulz ◽  
N. M. Johnson
Keyword(s):  
Low Temperature ◽  
Heat Treatments ◽  
Experimental Results ◽  
Interface Model ◽  
Trap States ◽  
High Concentration ◽  
Oxygen Donor ◽  
Heat Treated ◽  
Processing Steps

ABSTRACTCz-grown Si samples containing a high concentration of oxygen are investigated after various processing steps by DLTS. Heat treatments ranging from 500°C–1000°C are performed to study the formation and annihilation of the “New Oxygen Donor” (ND) traps. Hydrogenation at low temperature leads to a reduction of the ND trap states. The experimental results confirm the “SiOx Interface Model” which assumes two differing types of interfacerelated states.

scholarly journals The study of compositions based on parkent kaolin clay

2018 ◽  
pp. 29-33
Author(s):  
M. Kh. Rumi ◽  
Sh. K. Irmatova ◽  
M. A. Zufarov ◽  
Sh. A. Fayziev ◽  
E. P. Mansurova ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Liquid Glass ◽  
Calcium Sulfate ◽  
Kaolin Clay ◽  
Acid Activation ◽  
Kaolinite Clay ◽  
Aluminum Ions ◽  
Heat Treated ◽  
Rate Of Extraction ◽  
Subsequent Acid

The results of studies of the structure and composition of compositions based on red-burning kaolinite clay and calcium carbonate, heat-treated at 500oC, in the process of acid activation are presented. It is shown that when a 12 % solution of H2SO4is applied, leaching of iron and aluminum ions and the formation of calcium sulfate occur while maintaining the structure of kaolinite. The introduction of liquid glass into the composition of the material leads to the destruction of the structure of kaolinite, which contributes to an increase in the rate of extraction of aluminum ions during the subsequent acid activation. The components of the compositions with Ca2+and Fe3+in the presence of liquid glass are passivated by active amorphous silica formed during the reaction of liquid glass with CO2air.Ill. 2. Ref. 17. Tab. 1.

Effect of Thermal Treatment on Thermoelectric Properties of Extruded TiO2 Ceramics

2014 ◽  
Vol 604 ◽  
pp. 249-253 ◽  
Author(s):  
Agnese Pura ◽  
Janis Locs ◽  
Liga Berzina-Cimdina
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
Thermal Treatment ◽  
Seebeck Coefficient ◽  
Heating Rate ◽  
Thermoelectric Properties ◽  
Sintering Temperature ◽  
Extrusion Process ◽  
Vacuum Heat Treatment ◽  
Treatment Conditions

TiO2samples were obtained by extrusion process, sintered in air at 1000 °C, 1100 °C, 1200°C and 1300 °C and, afterwards, thermally treated under vacuum conditions at 1250 °C for 1 hour applying two different heating/cooling rates (2 °C/min and 5 °C/min). It was found that thermal treatment conditions substantially affected thermoelectric properties of the samples. Increasing sintering temperature, during the sample thermal treatment in air, the electrical conductivity of the specimens increased, while Seebeck coefficient decreased. With an increase in the heating rate during the vacuum heat treatment of the samples, the electrical conductivity of the samples decreased, while Seebeck coefficient increased.

Sign in / Sign up

Export Citation Format

Share Document