Dynamic thermal study to rationalise the role of titania in reaction sintering of magnesia-alumina system

Sinhamahapatra, Somnath; Dana, Kausik; Ghosh, Arup; Reddy, Vakiti Pradeep; Tripathi, Himansu Sekhar

doi:10.1016/j.ceramint.2014.09.030

Cited by 26 publications

(7 citation statements)

References 23 publications

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“…As the formed Mg 2 TiO 4 from the phase‐evolving mixture would take in more MgO and Al 2 O 3 into solid solution, that would leave lesser reactants remaining for the MgAl 2 O 4 formation reaction, and hence the overall expansion was reduced. Sinhamahapatra et al 11 . also reported that in the presence of 3% TiO 2 , MgAl 2 O 4 formation expansion was significantly reduced, and the effect is expected to be amplified in our case as the sample's TiO 2 content was 26.4%.…”

Section: Resultssupporting

confidence: 49%

Use of dilatometer to screen refractory raw materials

Mandal

Mahapatra

2021

Int J Ceramic Engine & Sci

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Sudden shortage of a particular raw material due to freight disruptions, competitive market, and COVID restrictions have frequently forced the refractory industry to rapidly develop alternative formulations using available low‐cost materials. These alternative ingredients might cursorily appear to have similar total impurity content, but the presence of certain impurity combinations depending on the refractory type can produce more fluid liquid phase at high temperature, thereby drastically reducing hot strength. Undetected by the commonly used X‐ray fluorescence (XRF) analysis, the low‐cost material might differ in mineral‐phase content, whose phase transformations during firing might create excessive expansion producing warpage of the refractory along with a high porosity reducing strength and corrosion resistance. Finally, those cheap raw materials might have similar sieve analysis to that of the standard ingredient but might have much lower tapped density, which would introduce detrimental porosity into the resulting refractory. Hence, time‐consuming trials are often performed. Dilatometer studies on pressed or cast samples in a single test can identify reaction temperatures of spinel or mullite formation, which expand during firing, along with the amount of expansion and exact times at which firing needs to be done. It can also compare relative shrinkage due to liquid‐phase formation among impure raw materials like recycled grogs or low‐grade ores. Finally, dilatometric step scan is shown as a fast technique to prepare in‐house, low‐cost reactive spinel powder, which can also work for mullite.

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Section: Resultssupporting

confidence: 49%

Use of dilatometer to screen refractory raw materials

Mandal

Mahapatra

2021

Int J Ceramic Engine & Sci

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“…The effect of additives (compounds of alkali/alkali‐earth/transition metals) on the reaction sintering of MgAl 2 O 4 has been already well explored by many researchers 22–35 . TiO 2 was reported to improve the densification process but had no significant effect on spinellization 25,26 .…”

Section: Introductionmentioning

confidence: 99%

“…[19][20][21] The effect of additives (compounds of alkali/alkaliearth/transition metals) on the reaction sintering of MgAl 2 O 4 has been already well explored by many researchers. [22][23][24][25][26][27][28][29][30][31][32][33][34][35] TiO 2 was reported to improve the densification process but had no significant effect on spinellization. 25,26 Additives like LiF or LiF/CaCO 3 were found to lower the spinel formation temperature and also aid in increasing the amount of spinel content.…”

Section: Introductionmentioning

confidence: 99%

Influence of in situ dysprosium aluminate garnet formation on sintering of reaction sintered magnesium aluminate spinel

Baruah,

Sarkar

2024

Int J Applied Ceramic Tech

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In the present study, commercially available different sources of magnesia and alumina were used to produce reaction sintered magnesium aluminate spinel (MgAl2O4). Initially, spinel with stoichiometric composition was prepared from three different sources of Al2O3 and two sources of MgO and then the effect of dysprosia (Dy2O3) in a concentration range of 1–4 wt.% on the sintered properties of spinels was studied in the temperature range of 1550–1650°C. The densities of the doped compositions were higher compared with the undoped ones, and the maximum density was found for the 1 wt.% Dy2O3‐doped samples. Phase analysis and microstructural studies revealed that formation of dysprosium aluminum garnet (Dy3Al5O12) phase along the intergranular positions, which served as grain‐growth inhibitors and improved densification. Further, 1 wt.% Dy2O3‐doped compositions also revealed better flexural strength and retained strength post thermal shock values than undoped spinel.

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“…It has been reported that TiO 2 is a good mineralizer for promoting the crystallization of the MA and A 3 S 2 . In addition, TiO 2 was frequently employed to enhance the sintering of Al 2 O 3 ceramics through the formation of Al 2 O 3 ‐TiO 2 solid solution .…”

Section: Introductionmentioning

confidence: 99%

“…It has been reported that TiO 2 is a good mineralizer for promoting the crystallization of the MA and A 3 S 2 . [17][18][19][20] In addition, TiO 2 was frequently employed to enhance the sintering of Al 2 O 3 ceramics through the formation of Al 2 O 3 -TiO 2 solid solution. [21][22][23][24] Therefore, TiO 2 was added in this work to guarantee the formation of MA and A 3 S 2 in Al 2 O 3 ceramics.…”

Section: Introductionmentioning

confidence: 99%

Effect of talc and titania on the microstructure and mechanical properties of alumina ceramics

Wei

et al. 2017

Int J Applied Ceramic Tech

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Alumina (Al2O3) ceramics were prepared with nucleating agent of titania (TiO2) and fluxing agent of talc by the normal pressure sintering method. The effects of TiO2 and talc on phase composition, microstructure, and mechanical properties of Al2O3 ceramics, as well the strengthening and toughening mechanism were investigated. It was found that the introduction of TiO2 could be favorable for mullite formation and the improved densification of ceramics, resulting in improved mechanical properties of ceramics as well. Ceramics possess the best comprehensive mechanical performance with fracture toughness of 3.69 MPa·m1/2 and flexural strength of 255.9 MPa when 4 wt.% TiO2 and 15 wt.% talc were added. Mineral bridges and nanocrystallites were found in the glass‐ceramics, which caused the deflection of cracks so that it strengthened the grain boundary and improved the mechanical properties of ceramics.

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Dynamic thermal study to rationalise the role of titania in reaction sintering of magnesia-alumina system

Cited by 26 publications

References 23 publications

Use of dilatometer to screen refractory raw materials

Use of dilatometer to screen refractory raw materials

Influence of in situ dysprosium aluminate garnet formation on sintering of reaction sintered magnesium aluminate spinel

Effect of talc and titania on the microstructure and mechanical properties of alumina ceramics

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