Calcination and associated structural modifications in boehmite and their influence on high temperature densification of alumina

Nampi, Padmaja Parameswaran; Ghosh, Sourja; Warrier, K. G. K.

doi:10.1016/j.ceramint.2011.04.129

Cited by 19 publications

(13 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The procedure was repeated, and the sample was fired at 1200 °C for corundum [α-Al 2 O 3 ]. 42 The bayerite [Al(OH) 3 ] sample was synthesized using the procedure of Jiao et al 43 In the procedure, NaAlO 2 (Alfa Aesar, 99.9%) was dissolved in a mixture of hot distilled water and ethanol (Fisher Scientific). A mixture of diethyl adipate (Alfa Aesar, 99%) and ethanol was added to the NaAlO 2 solution and stirred for 1 h. The resulting white solid was filtered, then washed with hot distilled water, and dried overnight.…”

Section: ■ Experimental Methodsmentioning

confidence: 99%

The Effect of Crystallinity and Crystal Structure on the Immersion Freezing of Alumina

et al. 2019

View full text Add to dashboard Cite

Determining the factors that constitute an efficient ice nucleus is an ongoing area of research in the atmospheric community. In particular, surface characteristics such as functional groups and surface defects impact the ice nucleation efficiency. Crystal structure has been proposed to be a possible factor that can dictate ice nucleation activity through the templating of water molecules on the surface of the aerosol particle. If the crystal structure of the surface matches that of the crystal structure of ice, it has been shown to increase ice nucleation activity. In this study, alumina was chosen as a model system because crystal structure and crystallinity can be tuned, and the effect on immersion freezing was explored. The nine alumina samples include polymorphs of AlOOH, Al(OH) 3 , and Al 2 O 3 , which have a range of crystal structures and crystallinities. The samples were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and Brunauer−Emmett−Teller (BET) analysis. From the immersion freezing experiments, corundum [α-Al 2 O 3 ] was shown to have the highest ice nucleation activity likely because of its high lattice match and high degree of crystallinity. Crystal structure alone did not show a strong correlation with ice nucleation activity, but a combination of a hexagonal crystal structure and a highly crystalline surface was seen to nucleate ice at warmer temperatures than the other alumina samples. This study provides experimental results in the study of ice nucleation of a range of alumina samples, which have possible implications for alumina-based mineral dust particles. Our findings suggest that crystallinity and crystal structure are important to consider when evaluating the ice nucleation efficiency of aerosol particles in laboratory and modeling studies.

show abstract

Section: ■ Experimental Methodsmentioning

confidence: 99%

The Effect of Crystallinity and Crystal Structure on the Immersion Freezing of Alumina

et al. 2019

View full text Add to dashboard Cite

show abstract

“…If the pre-anodic substrate(seen in Figure 1) is placed in a electrolyte tank, due to the impact of electric spark or plasma discharge, according to the Equation (4), the amorphous alumina can be transformed to alumina ceramic coating at room temperature [26] by the strong exothermic (center temperature of 7000 K) effect of in situ oxygen plasma ionization. With the crystal phase transformation of amorphous alumina, the amorphous alumina colloid shifts slightly to the aluminum alloy substrate under the effect of dehydration shrinkage force as well as oxygen bubble collapse force [27]. The through-hole of the anodic coating can be sealed, and a thick compact alumina ceramic coating can be obtained, meeting the requirements of high power LED on the insulation as well as thermal conductivity of substrate coating.…”

Section: Of 15mentioning

confidence: 99%

Fabrication of a Thick Crystalline Al2O3 Coating with Insulation and High Thermal Conductivity via Anodic Oxidation and Subsequent Mic Arc Discharge Treatment

Song

Jiang

2020

Coatings

View full text Add to dashboard Cite

Amorphous Al2O3 coating with a thickness of 143 μm was firstly prepared by anodic oxidation, then the amorphous Al2O3 was transformed into crystalline Al2O3 through applying micro arc discharge. The crystal structure of the Al2O3 coatings was analyzed with an X-ray diffractometer. Results indicated that the coating consisted of amorphous and crystalline Al2O3. The microstructure of the coating was characterized by scanning electron microscopy, which showed that the coating had a compact structure. The thermal conductivity of the coating was 23.7 W/m·K, which is significantly higher than that of amorphous Al2O3 coating. The total and specific breakdown voltages of the coating were 3.85 kV and 26.92 kV/mm, which is suitable to apply for high power LED heat sink substrate.

show abstract

“…TGA/DTA analysis results show that the crystallisation of different phases takes place when aluminum electrode generated EC sludge is heated at higher temperature. 26,27…”

Section: Thermogravimetric Analysismentioning

confidence: 99%

Synthesis of different crystallographic Al₂O₃ nanomaterials from solid waste for application in dye degradation

et al. 2014

View full text Add to dashboard Cite

show abstract

Calcination and associated structural modifications in boehmite and their influence on high temperature densification of alumina

Cited by 19 publications

References 29 publications

The Effect of Crystallinity and Crystal Structure on the Immersion Freezing of Alumina

The Effect of Crystallinity and Crystal Structure on the Immersion Freezing of Alumina

Fabrication of a Thick Crystalline Al2O3 Coating with Insulation and High Thermal Conductivity via Anodic Oxidation and Subsequent Mic Arc Discharge Treatment

Synthesis of different crystallographic Al₂O₃ nanomaterials from solid waste for application in dye degradation

Contact Info

Product

Resources

About

Calcination and associated structural modifications in boehmite and their influence on high temperature densification of alumina

Cited by 19 publications

References 29 publications

The Effect of Crystallinity and Crystal Structure on the Immersion Freezing of Alumina

The Effect of Crystallinity and Crystal Structure on the Immersion Freezing of Alumina

Fabrication of a Thick Crystalline Al2O3 Coating with Insulation and High Thermal Conductivity via Anodic Oxidation and Subsequent Mic Arc Discharge Treatment

Synthesis of different crystallographic Al2O3 nanomaterials from solid waste for application in dye degradation

Contact Info

Product

Resources

About

Synthesis of different crystallographic Al₂O₃ nanomaterials from solid waste for application in dye degradation