Low-temperature synthesis and characterization of complex perovskite (Ca0.61, Nd0.26)TiO3–(Nd0.55, Li0.35)TiO3 nanopowders and ceramics by sol–gel method

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].…”

“…Among the methods of wet chemical techniques, the sol-gel is undoubtedly one of a useful process for producing powders with a good control over stoichiometry and homogeneity, yielding nano-sized particles. For example, Wu et al [14] recently reported that nano-sized B 2 O 3 -doped ZnTiO 3 particles were successfully synthesized through the sol-gel technique at 800 • C and Zhang et al [15] reported that a sol-gel process was adopted to synthesize nanopowders with composition of (1 − x)(Ca 0.61 ,Nd 0.26 )TiO 3 − x(Nd 0.55 ,Li 0.35 )TiO 3 . Dense ceramics synthesized by the nanoparticles could be achieved at low-temperature of 1150 • C due to the effect of small size nanoparticles.…”

A new temperature stable microwave dielectric ceramics: ZnTiNb2O8 sintered at low temperatures

“…And many researchers have developed several approaches to reduce the sintering temperature of the ceramics: (i) the usage of small particle sized starting materials synthesized by wet chemical methods such as the sol-gel and coprecipitation methods and (ii) the addition of low-melting glasses, oxide or mixed-oxide additives, such as ZnO-B 2 O 3 -SiO 2 (ZBS), Li 2 [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. For the first approach, chemical synthesis complicates the manufacturing and increases the production cost.…”

Low-temperature sintering and microwave dielectric properties of Li3MO4 (M=Ta, Sb) ceramics

“…Transition from surface mount discrete components to integrated components in a substrate requires LTCC materials which can be co-fired with metal electrodes. In order to use the most common electrode silver, ceramic must have low sintering temperature below 960 • C and chemical compatibility with Ag [1][2][3][4][5][6][7][8][9].…”