Sol–gel synthesis and characterization of Al2O3–CeO2 composite nanopowder

Synthesis, characterization, and microwave dielectric properties of Mg4Nb2O9 ceramics produced through the aqueous sol–gel process

“…The results indicated that the obvious weight losses began at 80 • C and all chemical reactions involving weight losses, such as decomposition of the organic polymeric network with evolution of CO 2 and H 2 O, were completed below 531.6 • C. The total weight loss was about 80%, which occurred in three steps: (i) initial weight loss (about 10%) below 250 • C, resulting from the evaporation of residual solvent and water, with wide and weak endothermic peaks from about 100 • C, (ii) a second significant weight loss (about 60% caused by the decomposition of the organic polymeric network with evolution of CO 2 and H 2 O, with endothermic peaks ranging from 250 • C to 400 • C, and (iii) a third weight loss (about 10-20%) in the TG curves, combined with an exothermal peak at the temperature region of 400-531.6 • C, which was attributed to the oxidation of metal-organic groups. The similar TG results of MN xerogel were also reported in other microwave dielectric ceramics with citrate sol-gel method [14][15][16][17]. No further significant weight loss and thermometric peaks were observed above 531.6 • C in the TG-DTA curves, indicating the minimum firing temperature to synthesize the magnesium niobate phases.…”

“…According to the sintering equation of initial stage [24], the use of MN nanopowders as the starting materials was effective in preparing high density MN ceramics through low-temperature sintering and short sintering time. Therefore, the sol-gel process showed significant advantages of sintering the ceramics at relatively low temperatures, which were demonstrated by other reports elsewhere [14][15][16][17].…”

“…Dense ceramics synthesized by the nanoparticles could be achieved at low-temperature of 1150 • C due to the effect of small size nanoparticles. Similarly, the sol-gel process was widely used in many other ceramic systems [16][17][18][19]. However, few researches about the microwave properties of the MN ceramic fabricated by the 0925-8388/$ -see front matter © 2010 Elsevier B.V. All rights reserved.…”

Investigating the Physical Properties of Sintered Alumina in the Presence of MgO Nanopowder

“…In vapor phase methods there are some disadvantages such as high cost equipment and low efficiency. Among these methods, sol-gel is a simple and economical route with high efficiency and specific properties at low temperature like high surface area in volume ratio, fine particle size distribution, and so on [10].…”

The Compaction, Sintering, and Mechanical Properties of Al2O3–CeO2 Composite Nanopowders

“…The precursor solution was stirred at 100°C for 3 h and was aged at 60°C until the batch set to a rigid gel. It was then dried at 80°C for 48 h. More details about the processing of nanopowder are mentioned elsewhere . The resultant synthesis product (gel) has been calcined at 900°C for 30 min to remove volatile components.…”