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AlN Powder (aln + powder)
Selected AbstractsNear-Net Shape ,-Si4Al2O2N6 Parts by Hydrolysis Induced Aqueous Gelcasting ProcessINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 1 2009Ibram Ganesh In this paper, a new net-shaping process, an hydrolysis-induced aqueous gelcasting (GC) (GCHAS) has been reported for consolidation of ,-Si4Al2O2N6 ceramics from aqueous slurries containing 48,50 vol%,-Si3N4, ,-Al2O3, AlN, and Y2O3 powders mixture. Dense ceramics of same composition were also consolidated by aqueous GC and hydrolysis assisted solidification routes. Among three techniques used, the GCHAS process was found to be superior for fabricating defect-free thin wall ,-Si4Al2O2N6 crucibles and tubes. Before use, the as purchased AlN powder was passivated against hydrolysis. The sintered ,-Si4Al2O2N6 ceramics exhibited comparable properties with those reported for similar materials in the literature. [source] Blue-emitting AlN:Eu2+ Powder Phosphor Prepared by Spark Plasma SinteringJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2010Hyoung-SeoK Do Blue-emitting AlN:Eu2+ powder phosphor was synthesized by spark plasma sintering (SPS) using AlN, Si3N4, and Eu2O3 as the starting materials, and its luminescence properties were investigated. A single-phase Eu- and Si-co-doped AlN powder was successfully fabricated by SPS in the range of 1650°,1800°C for 5 min. The AlN:Eu2+ obtained exhibited a strong blue emission at 480 nm under the excitation of ,exc=340 nm and an electron beam. The highest photoluminescence intensity was observed in the phosphor sintered at 1700°C, which was comparable to that of the phosphor prepared by gas pressure sintering at 1750°C for 4 h. [source] Novel Way to Synthesize Nanocrystalline Aluminum Nitride from Coarse Aluminum PowderJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2003Yu Qiu A new process has been developed for the synthesis of nanocrystalline AlN powder by the nitridation of coarse aluminum powder in flowing NH3 gas, using NH4Cl and KCl as additives. The resulting powders have been characterized using XRD, TEM, and XRF techniques. XRD-pure AlN nanoparticles with a diameter of 10,20 nm can be obtained by nitridation at 1273 K for 5 h. NH3 is proved to eliminate the effect of water impurity. The effects of the additives on the conversion of aluminum are also discussed. [source] Ion-Exchange Loading of Yttrium Acetate as a Sintering Aid on Aluminum Nitride Powder via Aqueous ProcessingJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2000Yasuhiro Shimizu A novel fabrication process of AlN ceramics via aqueous colloidal processing and pressureless sintering has been presented. The chemical stability of AlN powder in water was improved by the surface chemical modification with sebacic acid, while maintaining a hydrophilic surface. The treatment of the sebacic acid-modified powder with yttrium acetate tetrahydrate resulted in strong immobilization of Y3+ ions, as a sintering aid, at a highly dispersive level on the AlN powder surface through ion exchange with the free carboxyl groups of the sebacic acid molecules attached to the AlN surface. By selecting slip compositions for a well-deflocculated condition and firing conditions to burn out organic components in the slip cast compacts, a thermal conductivity of about 250 W/(m·K) could be attained by the pressureless sintering at 1900°C for 5 h. [source] | ||||||||||