Effects of high concentrations of liquid phase and magnesia on the grain growth of alumina

Chan, Tien-Yin; Liu, Shi-Ji; Lin, Shun‐Tian

doi:10.1016/s0272-8842(97)00075-8

Cited by 13 publications

(3 citation statements)

References 18 publications

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“…The presence of MgO limits the anisotropic segregation of CaO at the grain boundaries and at the pore surfaces thereby improving the chemical homogeneity of commercial grade alumina powder. This is according to the literature [23] caused by the precipitation of MgAl 2 O 4 . However, magnesia when co-existing with a large quantity of liquid phase (consisting of SiO 2 and CaO), did not effectively reduce the degree of anisotropy in the interfacial energy of alumina [23].…”

Section: Resultssupporting

confidence: 67%

“…This is according to the literature [23] caused by the precipitation of MgAl 2 O 4 . However, magnesia when co-existing with a large quantity of liquid phase (consisting of SiO 2 and CaO), did not effectively reduce the degree of anisotropy in the interfacial energy of alumina [23]. In another study, when alumina contained magnesia and 15 vol.-% of the liquid phase, abnormal grain growth still occurred, leading to an abundance of elongated grains in the microstructure [24].…”

Section: Resultssupporting

confidence: 67%

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The influence of spinel and magnesia powder bed on mechanical properties of alumina sintered under air and nitrogen atmosphere

Michalková

Michálek

Blugan

et al. 2018

Advances in Applied Ceramics

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The aim of the present work was changing the surface properties of alumina ceramic via sintering of samples in spinel MgAl 2 O 4 and magnesia MgO powder bed. During sintering nitrogen and air atmosphere were used; and the reference material was sintered at the same conditions but in an alumina powder bed. All samples were sintered to a density higher than 99.2% of theoretical density of alumina. In order to examine samples SEM, EDX and XRD (Xray diffraction from 18 to 70 °2Theta) analysis were performed together with B3B flexural strength measurement. Results revealed that by sintering of alumina samples in a spinel powder bed pore-free surfaces were prepared, which had a favourable effect on B3B flexural strength. This was ascribed to the high solubility of Al 3+ in spinel at sintering temperatures, which increases the sintering driving force. A further positive effect on B3B flexural strength was observed when samples were sintered in nitrogen instead of air.

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Section: Resultssupporting

confidence: 67%

Section: Resultssupporting

confidence: 67%

The influence of spinel and magnesia powder bed on mechanical properties of alumina sintered under air and nitrogen atmosphere

Michalková

Michálek

Blugan

et al. 2018

Advances in Applied Ceramics

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“…16,17 The precipitation of MgAl 2 O 4 also has been reported to decelerate the fast-moving boundary by pinning and prevent the evolution of large elongated grains. 21 Both the grain size and the aspect ratio (Table III) are greater in D2 S alumina, compared to that of either C2 S or C1 I alumina (Feret's diameter of 2.04 m and an aspect ratio of 2.06). Although a larger amount of liquid phase is expected to be present in D2 S alumina, the amount of MgAl 2 O 4 present is similar in these materials, as observed from the XRD patterns that are presented in Fig.…”

Section: (3) Grain Growthmentioning

confidence: 91%

Impurity‐Dependent Morphology and Grain Growth in Liquid‐Phase‐Sintered Alumina

Goswami

Roy

Mitra

et al. 2001

Journal of the American Ceramic Society

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The alumina grains in liquid-phase-sintered (LPS) materials prepared from different commercial sources have a predominantly platelet morphology. Generally, the MgO:(CaO ؉ BaO ؉ Na 2 O ؉ K 2 O) ratio in the chemical composition controls the morphology in LPS alumina that is 91-94 wt% pure. Within a given range of SiO 2 content (i.e., 4.3-5.2 wt% in the chemical composition), a low MgO:(CaO ؉ BaO ؉ Na 2 O ؉ K 2 O) ratio (i.e., <1.0) in the LPS compositions favors the formation of elongated grains, whereas ratios of >1.0 result in equiaxed grains. SiO 2 contents outside the 4.3-5.2 wt% range favor the formation of elongated grains. A tendency to form platelike grains is observed for LPS alumina with a purity of 91-94 wt% when both the MgO:(CaO ؉ BaO ؉ Na 2 O ؉ K 2 O) ratio and the SiO 2 content are relatively low. The sintered density generally increases as the SiO 2 content in the chemical composition decreases.

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Influence of Fe and Ti addition on properties of Na+-β/β″-alumina solid electrolytes

Lee

Kim

et al. 2017

Met. Mater. Int.

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Effects of high concentrations of liquid phase and magnesia on the grain growth of alumina

Cited by 13 publications

References 18 publications

The influence of spinel and magnesia powder bed on mechanical properties of alumina sintered under air and nitrogen atmosphere

The influence of spinel and magnesia powder bed on mechanical properties of alumina sintered under air and nitrogen atmosphere

Impurity‐Dependent Morphology and Grain Growth in Liquid‐Phase‐Sintered Alumina

Influence of Fe and Ti addition on properties of Na+-β/β″-alumina solid electrolytes

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