Formation of mullite thin film via a sol-gel process with polyvinylpyrrolidone additive

Chen, Yen‐Yu; Wei, Wen‐Cheng J.

doi:10.1016/s0955-2219(01)00277-1

Cited by 35 publications

(11 citation statements)

References 9 publications

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“…After mixing for 30 min, the pseudo‐boehmite colloids were added and stirred for 1 h. The formulation of the precursor mixture in molar ratio is SiO 2 :Al 2 O 3 :H 2 O:ethanol=1.0:1.5:28.0:2.7. Experimental details have been described previously 12 . Pure SiO 2 sol and pseudo‐boehmite sol were also prepared as the comparison cases, which were prepared either from acidic TEOS solution or the pseudo‐boehmite precursor, respectively.…”

Section: Methodsmentioning

confidence: 99%

Growth of Tabular α‐Al₂O₃ Grains on Porous Alumina Substrate

Wei

2008

Journal of the American Ceramic Society

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Gradient, porous alumina ceramics were prepared with the characteristics of microsized tabular α‐Al2O3 grains grown on a surface with a fine interlocking feature. The samples were formed by spin‐coating diphasic aluminosilicate sol on porous alumina substrates. The sol consisted of nano‐sized pseudo‐boehmite (AlOOH) and hydrolyzed tetraethyl orthosilicate [Si(OC2H5)4]. After drying and sintering at 1150°–1450°C, the crystallographic and chemical properties of the porous structures were investigated by analytical electron microscopy. The results show that the formation of tabular α‐Al2O3 grains is controlled by the dissolution of fine Al2O3 in the diphasic material at the interface. The nucleation and growth of tabular α‐Al2O3 grains proceeds heterogeneously at the Al2O3/glass interface by ripening nano‐sized Al2O3 particles.

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Section: Methodsmentioning

confidence: 99%

Growth of Tabular α‐Al₂O₃ Grains on Porous Alumina Substrate

Wei

2008

Journal of the American Ceramic Society

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“…10,11 In previous research, mullite coatings were synthesized from a colloidal sol-gel precursor using boehmite and TEOS, or from aluminum nitrates (AN) and TEOS. 12 The mullite phase was often not observed until firing at above 1200°C, and the coating still contained impurity phases. [13][14][15] Furthermore, abnormal grain growth occurred as a consequence of the high temperature sintering.…”

Section: Introductionmentioning

confidence: 99%

“…[13][14][15] Furthermore, abnormal grain growth occurred as a consequence of the high temperature sintering. 12 To ensure the high temperature mechanical properties, it is important to eliminate spinel phase and lower the mullite formation temperatures to relatively low temperatures (e.g., ,1200°C) to avoid excessive grain growth. [16][17][18] So far, achieving such a goal seems to be difficult.…”

Section: Introductionmentioning

confidence: 99%

Dense and crack-free mullite films obtained from a hybrid sol–gel/dip-coating approach

et al. 2017

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A novel hybrid processing has been developed to achieve dense and crack-free mullite films with large critical thicknesses. The amorphous solid nanoparticles obtained from the mullite sol-gel precursor were mixed with the same liquid precursor to form stable suspensions, which were subsequently used to form mullite coatings with the dip-coating method, followed by drying and firing. The hybrid precursor suspensions resulted in highly close-packed nanoparticles, which reduced shrinkage during sintering. Selecting the solvent with a low evaporation rate and high surface tension can effectively eliminate the surface instability caused by the lateral flow during solvent evaporation. The mullite film density was significantly improved at low sintering temperatures, because of the high packing density and viscous flow at above the glass transition temperature of the amorphous gel nanoparticles before crystallization. Dense and crack-free mullite films with 500-600 nm thickness can be obtained from the novel hybrid approach.

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“…Therefore, the high adhesion of PVP to the surface of different solid materials is a significant additional advantage of this polymer, which can provide the formation of uniform optical coatings containing different nanoparticles. [24][25][26][27] The aims of this paper are the following:…”

Section: Introductionmentioning

confidence: 99%