Synthesis of Alumina Sub-Microstructure Particles Using In-House Methods (original) (raw)

Preparation of nanosized alumina using a low cost precursor

International Journal of Nanotechnology, 2010

Alpha alumina powders have been prepared by the pyrolysis of sucrose, aluminium nitrate and ammonium nitrate. After spray pyrolysis at 400°C the mixture yields fluffy light brown precursor mass. After grinding followed by heat-treatment at 900°C and 1000°C it produced the alpha-alumina having particle sizes of 42 nm and 55 nm with surface area 12 m 2 /gm and 16 m 2 /gm respectively .The yield per unit time from precursor with ammonium nitrate is 3-4 times that of simple thermal spray pyrolysis without ammonium nitrate. The particle size and crystallite size have been decreased with increase of sucrose commensurated with ammonium nitrate in the reaction mixture. The crystallite sizes are comparable with particle sizes due to poor agglomeration due to excess addition of sucrose and ammonium nitrate.

The Effect of Novel Synthetic Methods and Parameters Control on Morphology of Nano-alumina Particles

Nanoscale research letters, 2016

Alumina is an inorganic material, which is widely used in ceramics, catalysts, catalyst supports, ion exchange and other fields. The micromorphology of alumina determines its application in high tech and value-added industry and its development prospects. This paper gives an overview of the liquid phase synthetic method of alumina preparation, combined with the mechanism of its action. The present work focuses on the effects of various factors such as concentration, temperature, pH, additives, reaction system and methods of calcination on the morphology of alumina during its preparation.

Synthesis of Nanostructured Alumina from Byproduct Aluminum Filings: Production and Characterization

Inorganics

Aluminum oxide production from aluminum filings, which are a byproduct of several industrial machining processes and cannot be recycled to attain bulk aluminum (Al), is vital due to its wide use in scientific research and industry. The goal of this paper is to produce ultrafine and down-to-the-nanoscale alumina powder (Al2O3), starting from a waste Al filings. The microstructure and composition of the starting Al used were investigated using scanning electron microscopy (SEM), which was equipped with an attached energy dispersive spectrometer (EDS) unit. The results of this investigation confirmed that the starting Al was mainly Al–Mg alloy. Al2O3 was produced using two routes: The first involved the burning of aluminum hydroxide Al(OH)3 that was precipitated from aluminum chloride solution (AlCl3) resulting from dissolving the Al filings in 2M HCl. The second route involved direct precipitation as a reaction product of aluminum chloride with sodium carbonate solution. The Al2O3 pro...

Nano Alumina: A Review of the Powder Synthesis Method

Interceram - International Ceramic Review, 2016

Nanocrystalline ceramic materials are those with size smaller than 100 nm which have great importance in the field of nanotechnology. Nano-sized The main author, Pallavi Suhasinee Behera received an M.Sc. degree in Physics from National Institute of Technology, Rourkela and M.Tech. degree in Nanoscience and Technology from Pondicherry University. She is currently working toward her Ph.D. in Ceramic Engineering from National Institute of Technology, Rourkela. The main research interests of the author are ceramic materials, ceramic processing and nanotechnology.

Effect of Dispersants on Microstructures of Nano Alpha Alumina Developed from Aluminium Dross Waste

This paper compares the effect of dispersants which are Sodium Laureth Sulfate (SLS) and distilled water (DW) on the crystallization, particle size distribution and morphological behavior of nano alpha Alumina (α-Al2O3) synthesized from Aluminium (Al) dross waste. The synthesizing of nano α-Al2O3 via wet milling method was performed using a planetary mill for 4 hours at a speed of 550 rpm. The nano α-Al2O3 powders with dispersants were characterized with x- ray diffraction (XRD), particle size analyzer (PSA) and transmission electron microscopy (TEM). XRD analysis shows the broadening and shifting of peaks after the sample was calcined at 1300 ̊C, indicating high crystallinity. The crystallite size of α-Al2O3 milled with SLS is also smaller than the α-Al2O3 milled with DW. These results are consistent with the PSA analysis in which the graphs displayed a symmetrical trend. Then, the PSA analysis is validated with TEM observation up to 100000x magnification, particularly for α-Al2O3 milled with SLS.

Synthesis of α-alumina powder with internal nanostructures from Al13-cluster

Materials Letters, 2008

Nanostructured α-alumina powder was synthesized by precipitation and calcination of Al 13-clusters that were formed by the hydrolysis of Al 3+ ions with hydroxide. The Al 13-clusters were precipitated with oxalic acid by two-stage and one-stage precipitation techniques. The precipitates were calcined in air at 1100°C. The resulting α-alumina particles were characterized using particle size analyzer, X-ray diffraction (XRD) and transmission electron microscope (TEM). The pH and precipitation technique were found to influence the microstructural features of the α-alumina powder produced. Alumina with more extensive nanostructures inside the grain can be produced through the two-stage precipitation technique.

Process for Producing Nano-Alpha-Alumina Powder

2011

This paper is trying to explore the effect of stirring time on the synthesis of nano-α-Alumina particles. In this study, alumina nanoparticles were synthesized through alkoxide route using sol-gel method, where aqueous solutions of aluminum isopropoxide and 0.5 M aluminum nitrate nanohydrate were used for preparing alumina sol. Sodium dodecylbenzen sulfonate (SDBS) was used as the surfactant stabilizing agent. The prepared solution was stirred at different times (24, 36, 48, and 60 hours) at 60◦ C.

Synthesis of Alumina Powders by Mechanical Activation

Materials Science Forum, 2006

Alumina is utilized in many areas of modern industry because of its unique mechanical, electrical and optical properties. Various methods are been employed for produce alumina for different end uses. The preparation of fine and sintering-reactive alumina powders is probably one of the most important steps for production alumina ceramics with controlled microstructure. In this work, it was studied the production of alumina powders by “Pechini” method associated to highenergy milling. For this, it was prepared the resin by Pechini method, using aluminum nitrate nonahydrate. This resin was calcined at 500oC. Then, the calcined powders were submitted a high energy milling for different times. The powders mechanically activated were characterized by x ray diffraction, FT-IR and scanning electronic microscopic. After milling, the powders were calcined at 900oC. The results showed that the alumina phase transitions and powders characteristics were modified when the step of activation mecha...

Control of structural type and particle size in alumina synthesized by the spray pyrolysis method

Solid State Ionics, 1997

Fine particles of aluminum oxide (amorphous, a, 3' and 0) have been synthesized by spray pyrolysis as a function of both in situ and annealing temperatures and nature of precursors used in the preparation method. A scanning electron micrograph study shows as-received materials constituted by filled spherical particles, the ulterior annealing leading to the formation of small crystallites on the precursor spheres.

Making Alumina Microcomponents From Al Powder

Materials Science Forum, 2007

Alumina microcomponents have distinguishing advantages over Si counterparts. However, the shrinkage of alumina, as high as 20%, makes it difficult to produce precision components that require a high tolerance. A new fabrication process is presented to greatly reduce the shrinkage. The process consists of forming an Al powdered component through sintering and transforming the Al powdered component into an alumina part. In this way, the shrinkage occurring in sintering the Al powder component will be compensated by the expansion occurred when Al transforms into alumina. The process involves producing micro-moulds, preparing metallic paste, filling the micro-moulds with the metallic paste, demoulding, sintering the green Al patterns and finally oxidising the sintered Al-based components to achieve alumina components. The process was proven successful. Characterization of the sintered alumina microcomponents has been undertaken, including SEM image analysis, density and scale measurements.