Microwave sintering of mullite-Al2O3 from kaolin precursor

Navarro, Lilian Cecilia Reinoso; Menezes, Romualdo Rodrigues; Kiminami, R. H. G. A.

doi:10.1590/1516-1439.281114

Cited by 9 publications

(4 citation statements)

References 26 publications

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“…At the same time, the aspect ratio of mullite whiskers in ceramics becomes larger (Figure 10B). When AlOOH content is increased to 70 wt.%, it can be seen that the sintered ceramic shows more and larger pores, due to the complete consumption of the silica‐rich liquid phase 49 . Comparing the SEM images of mullite whiskers in Figure 10B,D, it can be clearly seen that the aspect ratio of the mullite whiskers in Figure 10D is obviously smaller.…”

Section: Resultsmentioning

confidence: 92%

“…However, when the sintering temperature is 1300°C, the fracture surface of mullite ceramic shows many pores. As we know, the liquid or glass phase in the ceramics efficiently decrease the pores, the fast consumption of the liquid silica, for example, through the reaction with γ ‐Al 2 O 3 to form mullite, and the loss of the liquid phase exposes the pores to some extent, and the pore could be filled or closed through the mullitization process with different holding time during HPS 49 . It can be seen from the mapping images in Figure 6 that mullite ceramics with a higher Al–Si ratio can be formed when sufficient AlOOH exists and reacts with the silicon‐rich liquid.…”

Section: Resultsmentioning

confidence: 99%

“…When AlOOH content is increased to 70 wt.%, it can be seen that the sintered ceramic shows more and larger pores, due to the complete consumption of the silica-rich liquid phase. 49 Comparing the SEM images of mullite whiskers in Figure 10B,D, it can Figure 11 shows the effect of the AlOOH content on bulk density and apparent porosity of ceramics. When the AlOOH content is 40 wt.%, the bulk density and apparent porosity of the ceramics are lower (Figure 10A), which is due to the high content of silica in the pyrophyllite, and the added AlOOH cannot completely consume the liquid silica from pyrophyllite.…”

Section: Effect Of Alooh Content On the Structure And Properties Of M...mentioning

confidence: 99%

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High‐toughness mullite ceramics fabricated by hot‐press sintering of pyrophyllite and AlOOH at low temperatures

Wang

Chen

Han

et al. 2023

Int J Applied Ceramic Tech

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High-toughness mullite ceramics were fabricated through hot-press sintering (HPS) of pyrophyllite and AlOOH, which were wet-milled and well mixed using a planetary ball mill. The impacts of sintering temperatures and contents of AlOOH on mullite phase formation, densification, microstructure and mechanical properties in ceramic materials were investigated through XRD, SEM and mechanical properties determination. The results indicated that high-toughness mullite ceramics could be successfully prepared by HPS at temperatures higher than 1200 • C for 120 min. Increasing the sintering temperature from 1000 to 1300 • C significantly enhanced the flexural strength and fracture toughness of samples. The highest flexural strength of 297.97±25.32 MPa and fracture toughness of 4.64±0.11 MPa⋅m 1/2 were obtained for samples sintered at 1300 • C. Further increase of temperature to 1400 • C resulted in slight decrease of flexural strength and fracture toughness. Compared with the mullite ceramics prepared only using pyrophyllite as raw material, incorporation of AlOOH into raw material significantly increased the mechanical properties of final mullite ceramics. And stoichiometric AlOOH and pyrophyllite as starting material gave the best performance in fracture toughness. The high-toughness of mullite ceramics were ascribed to the high mullite phase content, fine mullite whiskers and in situ formed, intertwined three-dimensional network structure obtained through HPS at a low temperature of 1300 • C.

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Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Section: Effect Of Alooh Content On the Structure And Properties Of M...mentioning

confidence: 99%

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High‐toughness mullite ceramics fabricated by hot‐press sintering of pyrophyllite and AlOOH at low temperatures

Wang

Chen

Han

et al. 2023

Int J Applied Ceramic Tech

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“…At this stage there is the greatest intensity discrepancy of LS values displayed in Table 6, when comparing the HR of 2°C/min with 15°C/min and 30°C/min. The end of this stage can be identi ed by the change in the curve slope, initiating the spinel and/or primary mullite formation [41][42][43][44].…”

Section: Resultsmentioning

confidence: 99%

Heating rate effect during sintering on the technological properties of Brazilian red ceramics

Guimarães¹,

Delaqua²,

Azevedo³

et al. 2022

Int J Adv Manuf Technol

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Unbalanced energy consumption in the production of ceramic artifacts is responsible for considerable undesirable impacts, such as increased emissions of polluting gases, excessive consumption of fuel materials, land degradation and unpredictable nancial costs. By contrast, the practice of optimizing the ceramic sintering, which in associated with ring of high temperature, can result in increased productivity and reduced production costs preserving an environmentally friendly production system. Moreover, it allows further improvements in the quality of the nal product. This work compares the effect of different sintering cycles, with heating rates of 2, 15 and 30°C/min, on the technological properties of a Brazilian industrial clay ceramic body. Initially the clay ceramic specimens was characterized in terms of mineralogical, chemical and physical properties. Specimens were prepared by extrusion and red at temperatures of 800, 900 and 1000°C. The evaluated properties by standard tests were water absorption, post-ring linear shrinkage and exural strength. It was found that owing to sintering carried out at higher heating rates, red ceramic products with superior technological properties were obtained. This is an unprecedented conclusion for common clay ceramics produced in Brazil. Based on the promising obtained results it is evidenced, in a clear and detailed way, the bene ts of rapid sintering cycle application for conventional brick production.

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Microwave Sintering of Mullite-Nd2O3 Composites: Investigation of Microstructure and Mechanical Properties

Ghasali

Kariminejad

Ghahremani

et al. 2022

JOM

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Microwave sintering of mullite-Al2O3 from kaolin precursor

Cited by 9 publications

References 26 publications

High‐toughness mullite ceramics fabricated by hot‐press sintering of pyrophyllite and AlOOH at low temperatures

High‐toughness mullite ceramics fabricated by hot‐press sintering of pyrophyllite and AlOOH at low temperatures

Heating rate effect during sintering on the technological properties of Brazilian red ceramics

Microwave Sintering of Mullite-Nd2O3 Composites: Investigation of Microstructure and Mechanical Properties

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