Xunzhong Shang

Lead-free In2O3-doped (Bi0.5Na0.5)0.93Ba0.07TiO3 ceramics synthesized by direct reaction sintering

Lead-free (Bi0.5Na0.5)0.93Ba0.07TiO3–xwt%In2O3 ceramics synthesized by direct reaction sintering have been studied. X-ray diffraction reveals that all (Bi0.5Na0.5)0.93Ba0.07TiO3–xwt%In2O3 ceramics are of a perovskite structure with coexistence of rhombohedral and tetragonal phases. It is found that the direct reaction sintering promotes growing of ceramic grains while doping of In2O3 contributes to inhibit and homogenize the grain growth, as shown by scanning electron microscopy. The ceramics show excellent piezoelectric and dielectric properties with thickness electromechanical coupling factor kt=0.503, piezoelectric constant d33=205pC∕N, dielectric constant e33T∕e0=1046, and loss tangent tanδ=0.036.

The Effects of Ta Substitution and K/Na Ratio Variation on the Microstructure and Properties of (K,Na)NbO3-Based Lead Free Piezoelectric Ceramics

Abstract[(Na0.5+yK0.5−y)0.94Li0.06][(Nb0.94Sb0.06)1−xTax]O3 + 0.08 mol% MnO2 lead-free piezoelectric ceramics were fabricated successfully by a conventional solid-state reaction method. The effects of Ta5+ substitution and K/Na ratio variation on the microstructure and properties of the ceramics have been systematically investigated. With the increasing of Ta5+ substitution content, the orthorhombic–tetragonal transition temperature To–t presents obvious “V” type variation while the Curie temperature Tc decreases monotonically. The ceramics properties were further enhanced by adjusting the Na/K ratio of the A-site. Under systematical optimization of the A-site and B-site elements, good overall electrical properties of d33 = 276 pC/N, kp = 44.5%, ε33T/ε0 = 1,175, tanδ = 0.027, Tc = 309 °C, Pr = 21.0 μC/cm2, and Ec = 1.14 kV/mm were obtained for ceramics with Ta5+ content x of 0.05 and Na/K ratio of 57/43 (y = 0.07).

Preparation of a modified (Pb,Ca)TiO3 piezoelectric ceramics with binary complex elements substitution in B-site

Abstract Preparation of a modified (Pb,Ca)TiO3 with (Zn1/2W1.2) (Ni1/2Nb1/2) substitution in B-site had been studied. Adding suitable amounts of MnCO3 in this modified PbTiO3 piezoelectric ceramics, the material performances could be improved further. Optimized fabricating procession had also been investigated. Study showed that the modified (Pb,Ca)TiO3 piezoelectric ceramics had large anisotropy high mechanical quality factor and curie temperature lower dielectric constant and loss. The microstructure of the ceramics and a kind of micro-domain had been observed by XRD and TEM.

Study of low—temperature sintering modified PbTiO3 piezoelectric ceramic

Abstract A new low-temperature sintering modified PbTiO3 piezoelectric ceramic material was prepared by adding Bi(Cd1/2Ti1/2)O3, MnO2, SiO2. The modified PT material has excellent properties such as low-sintering temperature, high piezoelectric activities, large piezoelectric anisotropy, high mechanical quality factor, low dielectric constant and dielectric loss. The main parameters are Kt=0.49, Kp=0.027, Kt/Kp=18.2, d33=65 × 10−12C-N−1, Qm=514, ρv = 7.4 × 103kg−m−3, Tc=312°C, ε T 33/ε0 = 177, tanδ=0.63%. It shows great application prospects in the fields of multilayer piezoelectric filter and multilayer piezoelectric step-down transformer.

Studies on a new type of PbTiO3 piezoelectric ceramic materials

Abstract A new type of modified PbTiO3 piezoelectric ceramic materials added with Pb(Mn1/3Sb2/3)O3, CaCO3, Bi2O3, NiO has been investigated. The typical composition of these materials is Pb0.80Ca0.20[(Mn1/3Sb2/3)0.05Ti0.95]O3 added with 0.5wt%NiO and lwt%Bi2O3. Under optimized fabrication processing, its main performance parameters are described as follows: Kt=0.61, Kp≌0, d33=70×10-12C * N-1; ϵ33 T/ϵ0=161, tg δ =0.01; Qm=43, Nt=2004Hz * m.

Annealing and characterisation of CuInS2 thin films prepared on sapphire substrates by pulsed laser deposition

Abstract Quasi-epitaxial CuInS2 thin films were deposited on c-sapphire substrates at optimised temperature by the pulsed laser deposition method using a self-made ceramic target. Crystalline and stoichiometric CuInS2 film with a band gap energy of 1·43 eV is obtained by a post-annealing/sulphurisation process at a temperature of 500°C, which shows a highly (112) preferential orientation with a smallest full width at half maximum value of 0·19°. The as-deposited films show the coexistence of CuInS2 chalcopyrite and CuAu orderings measured by Raman spectroscopy, and a polymorphic transformation of metastable CuAu ordering into the equilibrium chalcopyrite structure takes place at the annealing temperature of 500°C with the presence of a surface segregated CuxS phase. The morphologies and compositions of the films before and after annealing are characterised by scanning electron microscopy and energy dispersive X-ray analysis.