INFLUENCE OF Li_2CO_3-SiO_2 ADDITIVE ON THE PROPERTIES AND PROCESSING OF DOUBLE-FUNCTION SrTiO_3-BASED LOW VOLTAGE VARISTOR CERAMICS

Semiconducting SrTiO 3 based voltage sensing and dielectric ceramics were prepared by single step sintering with Li 2CO 3 SiO 2 as liquid phase additives.The effects of the content of liquid phase,the ratio of Li/Si and the sintering temperatures on properties were discussed in terms of electrical properties and microstructures of materials.The results showed thatSrTiO 3 based varistor ceramics,with 0.6 mol% Li 2CO 3 SiO 2(Li/Si=3/2) and sintered at 1 380 ℃ in graphite and N 2 reducing atomosphere,had excellent current volatage sensing and dielectric characteristics.

INFLUENCE OF Li2CO3-SiO2 ADDITIVE ON THE PROPERTIES AND PROCESSING OF DOUBLE-FUNCTION SrTiO3-BASED LOW VOLTAGE VARISTOR CERAMICS

Semiconducting SrTiO 3 based voltage sensing and dielectric ceramics were prepared by single step sintering with Li 2CO 3 SiO 2 as liquid phase additives.The effects of the content of liquid phase,the ratio of Li/Si and the sintering temperatures on properties were discussed in terms of electrical properties and microstructures of materials.The results showed thatSrTiO 3 based varistor ceramics,with 0.6 mol% Li 2CO 3 SiO 2(Li/Si=3/2) and sintered at 1 380 ℃ in graphite and N 2 reducing atomosphere,had excellent current volatage sensing and dielectric characteristics.

Stability of [BMIM]HSO_4 for using as additive during zinc electrowinning from acidic sulfate solution

The stability of ionic liquid additive 1-butyl-3-methylimidazolium hydrogen sulfate （[BMIM]HSO4） during zinc electrowinning from acidic sulfate solution was investigated by cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy. Compared with the traditional industrial additives, gelatine and gum arabic, [BMIM]HSO4 has more excellent chemical and thermal stabilities. The inhibition effects of gelatine and gum arabic on the zinc electrocrystallization are observed to markedly weaken due to their part degradation after 12 h longtime successive electrolysis and high temperature （90 ℃） treatments. In contrast, the activity of [BMIM]HSO4 is practically unaffected after 24 h longtime successive electrolysis and high temperature treatments. These results are corroborated with the corresponding morphological analysis of the cathodic deposits.

A simple,efficient and green procedure for Michael addition catalyzed by [C_4dabco]OH ionic liquid

A dabco-based basic ionic liquid,1-butyl-4-aza-1-azaniabicyclo[2.2.2]octane hydroxide,has been developed as a catalyst for a convenient and rapid method for the Michael addition of active methylene compounds to a b-unsaturated carboxylic esters and nitriles.The method is very simple,and the yields are very high.The catalyst can be recycled several times without much loss of activity.

Reducing surficial and interfacial defects by thiocyanate ionic liquid additive and ammonium formate passivator for efficient and stable perovskite solar cells

Organic–inorganic metal halide perovskites have attained extensive attention owing to their outstanding photovoltaic performances,but the existence of numerous defects in crystalline perovskites is still a serious constraint for the further development of perovskite solar cells(PSCs).In particular,the rapid crystallization guided by anti-solvents leads to plenty of surficial and interfacial defects in perovskite films.Herein,we report the adoption of a pseudo-halide anion based ionic liquid additive,1-butyl-3-methylimidazolium thiocyanate(BMIMSCN)for growing ternary cation(CsFAMA,where FA=formamidinium and MA=methylammonium)perovskites with large-scale crystal grains and strong preferential orientation via the enhanced Ostwald ripening.Meanwhile,a novel halide-free passivator,benzylammonium formate(BAFa),was employed as a buffering layer on the perovskite films to suppress surface-dominated charge recombination.As a result,the cooperative effects of BMIMSCN additive and BAFa passivator lead to significant enhancements on fluorescence lifetime(from 79.41 to 201.01 ns),open-circuit voltage(from 1.13 to 1.19 V),photoelectric conversion efficiency(from 18.90%to 22.33%).Moreover,the BMIMSCN/BAFa-CsFAMA PSCs demonstrated greatly improved stability against moisture and heat.This work suggests a promising strategy to improve the quality of perovskite materials via reducing the surficial and interfacial defects by the synergistic effects of lattice doping and interface engineering.

Shape controlled synthesis and tribological properties of CeVO_4 nanoparticles as lubricating additive

Shape controlled structure of CeVO4 nanocrystals were successfully synthesized via a hydrothermal method from Na3VO4·12H2O and Ce（NO3）3·6H2O. The resulting products were characterized by X-ray powder diffraction （XRD）, electron microscopy （SEM） and other techniques. On the basis of the experimental results, CeVO4 nanoparticles exhibited the crystal tetragonal structure and the pH value of solu-tion had an important effect on the crystal structure and morphology of CeVO4 nanoparticles. Furthermore, the tribological properties of CeVO4 nanoparticles as additives in liquid paraffin were evaluated on a four-ball tester. The results indicated that the wear resistance was im-proved by the additive CeVO4 nanoparticles which exhibited very good antiwear and friction reduction performance in wear.