Dense alumina-mullite composite ceramics from alumina and spodumene-albite feldspar binary mixtures: Processing and properties

Hernández, María F.; López, Paula V.; Violini, María Agustina; Suárez, Gustavo; Conconi, María Susana; Rendtorff, Nicolás M.

doi:10.2298/sos1904445h

Cited by 9 publications

(4 citation statements)

References 51 publications

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“…The increase in firing shrinkage refers to a more efficient firing process due to a homogenous grain distribution and an increase of the contact area between the grains. Moreover, the high rate of contraction affects other properties such as the thermal expansion and thermal shock resistance of the mullitezirconia composite sample [17]. The decrease of porosity with the increase of the ZrO 2 content is shown in Fig.…”

Section: Resultsmentioning

confidence: 98%

Thermal decomposition and reaction sintering for synthesis of mullite-zirconia composite using kaolin, γ-alumina and zirconia

Aswad

Alfatlawi

Saud³

2021

Cerâmica

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The refractory materials used in the wall of the furnaces for glass melting can be prepared from mullite-zirconia composite material. The composite of mullite/zirconia was synthesized from Iraqi kaolin, γ-alumina, and zirconia using thermal decomposition with reaction sintering at 1600 °C. Several batches were prepared with various ratios of kaolin, γ-alumina, and zirconia, and the composite compositions were selected from the Al 2 O 3-SiO 2-ZrO 2 phase diagram. The mullite-zirconia composite was prepared with different steps beginning with milling the starting materials, semi-dry uniaxial pressing, and then reactive sintering at various temperatures (1200, 1400, and 1600 °C). The predicted phases ZrO 2 and Al 6 Si 2 O 13 were identified by X-ray diffraction patterns according to the phase diagram for all the batches. The lower amount of the zirconia added to mullite reduced porosity and improved the bulk density of the mullite/zirconia composite. The thermal expansion coefficient slightly increased with the addition of zirconia. It also enhanced the thermal shock resistance of the composite. Finally, the mechanical properties were improved by increasing the amount of zirconia particles in a matrix of mullite due to the phase transformation of zirconia from tetragonal to monoclinic phase.

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Section: Resultsmentioning

confidence: 98%

Thermal decomposition and reaction sintering for synthesis of mullite-zirconia composite using kaolin, γ-alumina and zirconia

Aswad

Alfatlawi

Saud³

2021

Cerâmica

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“…The two endothermic processes are also observed in the DTA curves, accompanied by a small exothermic peak at 980 °C. This corresponds to the spinel aluminosilicate formation [12,31,32]. This is difficult to observe in the Gd10 mixture.…”

Section: Bauxite -Gd 2 O 3 Mixtures Characterizationsmentioning

confidence: 94%

High macroscopic neutron capture cross section ceramics based on bauxite and Gd2O3

et al. 2020

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The effect of the addition of Gadolinium oxide (Gd2O3) up to 10 wt.% in bauxite was studied and its thermal behavior compared with pure bauxite. The incorporation of Gd2O3 is of technological interest for the design of smart traceable ceramic proppants used for unconventional gas and oil well stimulation. These high macroscopic neutron capture cross section proppants are used to obtain relevant information, such as the location and height of the created hydraulic fractures, through a neutron based detection technology. The study comprised a set of thermal and sintering behavior analyses up to 1500 ?C of mixtures up to 10 wt.% addition of Gd2O3. The developed texture and microstructure was also assessed. A simple mechanical characterization was performed as well. Fully-dense pore-free microstructures were developed, with alumina and mullite as the main crystalline phases. Gadolinium secondary and ternary alumino-silicate phases were also observed after thermal treatment. These present a needle morphology that might result in reinforcement mechanisms. No important glassy phase was detected; although sintering was enhanced, the Gd2O3 oxide main role was found to be as a sintering aid rather than a strict flux agent. The mechanical behavior remained fragile with the rare oxide addition. In fact, the mechanical resistance increased up to 20 wt.% for the 10 wt.% added sample. The oxide addition together with the bauxite dehydroxilation mass loss resulted in materials with up to 1.5 x 105 (c.u.) macroscopic neutron capture cross section materials. The obtained results permit to define design strategies of high macroscopic neutron capture ceramic materials for wellbore and developed fractures description.

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“…Characterization methods: identification of crystalline phases in the sintered ceramics was performed by X-ray diffraction (XRD) using a diffractometer (PW 3020/10, Philips . The crystalline phase contents (wt%) of the materials were determined using the Rietveld method of refinement using the program FullProf v.2019 [19,20].…”

Section: Methodsmentioning

confidence: 99%

Dolomite-zirconia reaction sintered bonded coarse magnesia ceramics: effect of the bonding proportion

et al. 2021

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Refractory ceramic materials were manufactured, mainly composed of magnesia grains (coarse and medium fraction) and CaZrO 3 /MgO as a binding phase produced from the reaction sintering between CaMg(CO 3 ) 2 (dolomite) and m-ZrO 2 (monoclinic zirconia), which constituted the finer fraction. Different relationships between the proportion and the size of the different aggregates were studied. The microstructure of the materials was characterized in terms of density, crystalline phases, grain phase distribution, and morphology. A combination of X-ray diffraction analysis and scanning electron microscopy with microanalysis was used. The mechanical behavior was determined in terms of the room temperature dynamic Young's modulus and the 3-point bending modulus of rupture (MOR) at room temperature. All the materials remained with porosities above 30%. The microstructure developed was similar between the sintered materials, characterized with MgO coarse grains bonded by CaZrO 3 /c-ZrO 2 phases, and dispersed irregularly shaped pores. The MOR was directly related to the finer fraction content in the composition, where a higher quantity of finer fraction resulted in a higher MOR.

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Dense alumina-mullite composite ceramics from alumina and spodumene-albite feldspar binary mixtures: Processing and properties

Cited by 9 publications

References 51 publications

Thermal decomposition and reaction sintering for synthesis of mullite-zirconia composite using kaolin, γ-alumina and zirconia

Thermal decomposition and reaction sintering for synthesis of mullite-zirconia composite using kaolin, γ-alumina and zirconia

High macroscopic neutron capture cross section ceramics based on bauxite and Gd2O3

Dolomite-zirconia reaction sintered bonded coarse magnesia ceramics: effect of the bonding proportion

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