scholarly journals Effect of reduced Al2O3 mole ratio on fabrication of cordierite ceramic by solid-state sintering method

2019 ◽  
Vol 51 (2) ◽  
pp. 189-197
Author(s):  
Ye Li ◽  
Hengze Zhao

Cordierite ceramic was fabricated by reducing Al2O3 mole ratio from 2.0 to 1.4 with kaolin, silicon dioxide and magnesium oxide as the raw materials. The effect of reduced Al2O3 mole ratio on the sintering behaviors, phase transition, main properties, and microstructure were characterized in detail. The results show that cordierite phase becomes the main crystallization phase at 1300?C, and mullite phase can be consumed to produce cordierite phase by reducing Al2O3 mole ratio. But additional quartz phase still exists until 1400?C. Moreover, the open porosity, pore connectivity and pore size increase as Al2O3 mole ratio reduces from 2.0 to 1.4 while the linear shrinkage percent and bulk density decrease with the reduced Al2O3. It is considered that the sintering activity of the raw materials at low temperature decreases due to the increase of chemically pure magnesium oxide and silica with the decrease of Al2O3 mole ratio, while the crystallization process, pore growth and cordierite phase rather than the liquid phase control the densification process at high temperature.

2021 ◽  
Vol 11 (8) ◽  
pp. 3545
Author(s):  
Fernanda Andreola ◽  
Isabella Lancellotti ◽  
Paolo Pozzi ◽  
Luisa Barbieri

This research reports results of eco-compatible building material obtained without natural raw materials. A mixture of sludge from a ceramic wastewater treatment plant and glass cullet from the urban collection was used to obtain high sintered products suitable to be used as covering floor/wall tiles in buildings. The fired samples were tested by water absorption, linear shrinkage, apparent density, and mechanical and chemical properties. Satisfactory results were achieved from densification properties and SEM/XRD analyses showed a compact polycrystalline microstructure with albite and wollastonite embedded in the glassy phase, similar to other commercial glass-ceramics. Besides, the products were obtained with a reduction of 200 °C with respect to the firing temperatures of commercial ones. Additionally, the realized materials were undergone to leaching test following Italian regulation to evaluate the mobility of hazardous ions present into the sludge. The data obtained verified that after thermal treatment the heavy metals were immobilized into the ceramic matrix without further environmental impact for the product use. The results of the research confirm that this valorization of matter using only residues produces glass ceramics high sintered suitable to be used as tile with technological properties similar or higher than commercial ones.


Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 422
Author(s):  
Kuai Zhang ◽  
Yungang Li ◽  
Hongyan Yan ◽  
Chuang Wang ◽  
Hui Li ◽  
...  

An Fe/FeAl2O4 composite was prepared with Fe-Fe2O3-Al2O3 powder by a hot press sintering method. The mass ratio was 6:1:2, sintering pressure was 30 MPa, and holding time was 120 min. The raw materials for the powder particles were respectively 1 µm (Fe), 0.5 µm (Fe2O3), and 1 µm (Al2O3) in diameter. The effect of sintering temperature on the microstructure and mechanical properties of Fe/FeAl2O4 composite was studied. The results showed that Fe/FeAl2O4 composite was formed by in situ reaction at 1300 °C–1500 °C. With the increased sintering temperature, the microstructure and mechanical properties of the Fe/FeAl2O4 composite showed a change law that initially became better and then became worse. The best microstructure and optimal mechanical properties were obtained at 1400 °C. At this temperature, the grain size of Fe and FeAl2O4 phases in Fe/FeAl2O4 composite was uniform, the relative density was 96.7%, and the Vickers hardness and bending strength were 1.88 GPa and 280.0 MPa, respectively. The wettability between Fe and FeAl2O4 was enhanced with increased sintering temperature. And then the densification process was accelerated. Finally, the microstructure and mechanical properties of the Fe/FeAl2O4 composite were improved.


2014 ◽  
Vol 616 ◽  
pp. 157-165 ◽  
Author(s):  
Chang Lian Chen ◽  
Hong Quan Wang ◽  
Jia You Ji ◽  
Ma Ya Luo ◽  
Bo Wu ◽  
...  

In this paper, using ZrO2 and Ca (NO3)•4H2O as raw materials, we prepared a series of calica stabilized zirconia (CSZ) ceramics by pressureless sintering method. The results show that the relative densities of all sintered samples are above 90%, and the sintered samples are composed of cubic, tetragonal and monoclinic ZrO2, and the main phase is cubic ZrO2 and tetragonal ZrO2. The content of cubic phase increases with the increase of sintering temperature and adding CaO content. The grain size of the sintered samples is relatively uniform and some pores exist. Increasing the additive amount of CaO, the conductivity first rises and then decreases, and the conductivity value of the sample containing 5wt% CaO is the maximum. When the sintering temperature is up to 1600 oC, the conductivity of the sample containing 5wt% CaO is up to 0.016S•cm-1 at 800 oC. Furthermore, the conductivity of sintered samples is increasing with the increase of test temperature according to the Arrhenius equation.


2010 ◽  
Vol 105-106 ◽  
pp. 778-781
Author(s):  
Yin Feng Xia ◽  
Zhao Hui Huang ◽  
Jia Zheng Yuan ◽  
Lin Jun Wang ◽  
Jie Hua Xie

Crystalline glaze is a kind of art glaze with excellent decorative performance, the existing crystalline glaze mainly willemite crystalline glaze, systems on a single track. In this paper, the use of crystalline glaze raw materials for glass, ZnO and coke gemstones, CuO as coloring agents, using ortho- gonal to determine the formula, this paper researched that added TiO2 to the willemite crystalline glaze crystal phase composition as well as the amount of TiO2 and processing conditions on the preparation of crystalline glaze crystal flower morphology impact. The results show that under the conditions of 1250°C melting 1130°C crystallization process crystal spontaneous growth in crystalline glaze can be able to cover the entire glazed, shape of crystals was feathered, cross growth, the number of crystal increased with crystallization temperature, glaze was smooth and shiny sense. XRD and optical microscopy analysis showed that the precipitation of crystals was the long column of rutile, crystal distributed equality, under a polarizing microscope in purple, green and black, with strong aesthetic values.


Cerâmica ◽  
2013 ◽  
Vol 59 (351) ◽  
pp. 473-480 ◽  
Author(s):  
K. C. P. Faria ◽  
J. N. F. Holanda

The sugarcane industry generates huge amounts of sugarcane bagasse ashes (SCBA). This work investigates the incorporation of a SCBA waste as an alternative raw material into a clay body, replacing natural clay material by up to 20 wt.%. Clay ceramic pieces were produced by uniaxial pressing and fired at temperatures varying from 700 to 1100 ºC. The technological properties of the clay ceramic pieces (linear shrinkage, apparent density, water absorption, and tensile strength) as function of the firing temperature and waste addition are investigated. The phase evolution during firing was followed by X-ray diffraction. The results showed that the SCBA waste could be incorporated into red ceramics (bricks and roofing tiles) in partial replacement for natural clay material. These results confirm the feasibility of valorisation of SCBA waste to produce red ceramic. This use of SCBA can also contribute greatly to reducing the environmental problems of the sugarcane industry, and also save the sources of natural raw materials used in the ceramic industry.


Author(s):  
E. Gotlib ◽  
Phuong Ha ◽  
A. Hasanova ◽  
E. Galimov

The extraction of natural wollastonite in the world is limited, so it is relevant to synthesize it on the basis of available calcium and silicon-containing raw materials, and it is promising to use rice husks as a source of silicon dioxide, as a waste of rice processing. Due to the needle shape of the particles, natural wollastonite increases the wear resistance of epoxy coatings, which arouses interest to study the influence of the phase composition and properties of synthetic wollastonite on this property. The calcium silicate synthesized by authors contains β-wollastonite, which is the target component. Its maximum content is achieved at a synthesis temperature not higher than 950 °C, approximately at the level of natural Mivall 10–97. Larnite is found as an impurity in the composition of synthetic wollastonite, it is an island silicate with a chain structure and therefore cannot provide such a modifying effect as fillers with anisodiametric particle shape. The nature of the particle size distribution curves of both natural and synthetic volastonite has two maxima, regardless of the filler synthesis temperature, with the exception of calcium silicate obtained at 900 °C, the particle distribution is narrower than in synthesized fillers, and they are smaller. The wear resistance of epoxy compositions, when filled with both natural and synthetic wollastonite, increases. The greatest increase in this indicator is achieved when using synthetic wollastonite, obtained at a ratio of calcium oxide and silicon dioxide 1: 1 and temperatures of 900-1000 °C. Thus, epoxy materials filled with both natural and synthetic wollastonium obtained at optimal ratios of the initial components and synthesis temperatures can be effectively and economically used as wear-resistant coatings.


2020 ◽  
Vol 17 (2) ◽  
pp. 113-119
Author(s):  
H.E. Mgbemere ◽  
E.O. Obidiegwu ◽  
A.U. Ubong

In this research, kaolin, ball clay, sawdust and rice husk were used to produce insulation bricks through the solid state synthesis method. Two temperatures, 1100oC and 1200oC were used to sinter the green samples. X-ray fluorescence, scanning electron microscopy, compressive strength tests etc. were used to analyse the properties of the produced bricks. Chemical composition analysis on the starting raw materials showed that SiO2 and Al2O3 were the major constituents while Fe2O3, Na2O, K2O and TiO2 were the minor constituents. As the amounts of kaolin used in preparing the samples decrease, the bulk density, modulus of rupture and cold crushing strength of the bricks decreases while the water absorption capacity, linear shrinkage increases. The thermal analysis showed that on heating the samples, the reactions were mainly exothermic with between 8 to 10 mW/mg of heat released. The morphology of the samples showed that the pores began to collapse when the amount of kaolin present is below 70 wt. %. Sintering the samples at 1100oC and 1200oC led to slightly different values in the results and is therefore very significant. Keywords: Insulation bricks, Kaolin, sawdust, rice husk, temperature effects


2018 ◽  
Vol 6 (29) ◽  
pp. 7905-7912 ◽  
Author(s):  
Fei Yan ◽  
Haibo Yang ◽  
Lin Ying ◽  
Tong Wang

A (SrTiO3 + Li2CO3)/(0.94Bi0.54Na0.46TiO3 − 0.06BaTiO3) (STL/BNBT) lead-free ceramic with a multilayer structure was shaped via the tape-casting and subsequent lamination technique, and sintered using the conventional solid state sintering method.


2018 ◽  
Vol 281 ◽  
pp. 224-229 ◽  
Author(s):  
Fang Wang ◽  
Ming Han Xu ◽  
Ai Xia Chen ◽  
Long Tao Liu ◽  
Zhi Hui Li ◽  
...  

YAG materials have a number of unique properties, the application is very extensive, the burn is due to the temperature is too high or the residence time at high temperatures is caused. The undercurrent is the sintering temperature is too low or the holding time is not enough, resulting in product performance is too low or too small shrinkage. In this paper, the effect of sintering temperature on properties of YAG porous ceramics was investigated. The results showed that the firing temperature of the ingredients will be different and cause the same sintering process and sintering additives content of different samples burned. The increase in the content of SiO2 in the furnish with the sintering aid tends to occur. the effect of temperature on the mechanical properties of the samples after sintering was significant, so the raw materials include 60wt%YAG, 10wt% CaO, 10wt% SiO2 and 20wt% soluble starch, the molding process in 20MPa pressure 10min, the sintering at 1500°C for 2h, the sample porosity is 42.2%, the compressive strength is 5.8MPa, the outside shape is keep intact and the better pore microstructure is shown.


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