Synthesis and characterization of (Zn,Co)TiO3 by modified low temperature preparing route

Low-temperature synthesis and characterization of (Zn,Ni)TiO3 ceramics by a modified sol–gel route

“…4(a)-(d)) as the amount of nickel increased. The results were in accordance with those calculated by the Scherrer equation from XRD patterns [14,20], where the grain sizes of (Zn 1−x Ni x )TiO 3 powders (x = 0, 0.85, 0.9, and 1.0) were calculated as about 192, 121, 106, and 75 nm respectively. It appears that the surface flatness, morphology and microstructure of ZnTiO 3 were notably influenced by nickel doping.…”

“…It might be ascribed to the formation of more stably hexagonal ilmenite phase with the increasing x, for the cubic spinel phase would strongly deteriorate the tan δ and induce a high value. In addition, the higher ε r and tan δ values of ZnTiO 3 than that of our previous study [14] could be interpreted as that the samples sintered at a higher temperature of 920 • C, rather than 800 • C in [14]. As we knew, the density, impurities and dopants of the ceramics strongly influence the tan δ value at microwave frequency.…”

“…1 shows the TG-DTA curves of (Zn 1−x Ni x )TiO 3 (x = 0.9 and 1.0) precursor powders derived from the gel dried at 130-150 • C. A weight-loss occurred continuously from ∼200 to ∼600 • C due to the water and excess organic substance losses. The DTA curves exhibit an obviously endothermic peak at about 250-270 • C, which was due to the evolution of citrate [(Zn,Ni)Ti(C 6 H 6 O 7 ) 3 ] decomposed to aconitate [(Zn,Ni)Ti(C 6 H 4 O 6 ) 3 ] as represented by the following reaction [7,14]:…”

“…However, purely hexagonal ZnTiO 3 is not so easy to be obtained because ZnTiO 3 decomposes into ␣-Zn 2 TiO 4 and rutile at temperature 945 • C [9]. In recent years, doping divalent cations such as Mg 2+ , Co 2+ , Ni 2+ , Sr 2+ , etc., in ZnTiO 3 has been investigated so as to enhance the stability of the hexagonal phase and to improve the microwave dielectric properties in the ZnTiO 3 -based system ceramics [4,[14][15][16][17][18]. Nevertheless, the syntheses of (Zn 1−x M x )TiO 3 (where M is one of divalent cations) are generally through high temperature sintering solid-state reactions.…”

“…Nevertheless, the syntheses of (Zn 1−x M x )TiO 3 (where M is one of divalent cations) are generally through high temperature sintering solid-state reactions. Chemical solution methods, which can either overcome the drawbacks of high sintering temperature, large particle size and limited degree of chemical homogeneity in solid-state reaction method [6,7] or extend the range of solubility x in hexagonal phase [4,[14][15][16], were less involved to prepare (Zn,M)TiO 3 .…”