Shaohong Wang

Thermal crystallization kinetic and electrical properties of partly crystallized amorphous indium oxide thin films sputtering deposited in the presence or the absence of water vapor

Partly crystallized amorphous indium oxide thin films were deposited under water vapor atmosphere by magnetron sputtering. XRD analysis revealed that appropriate water vapor could suppress the film’s crystallinity. In situ thermal crystallization process was monitored by high-temperature XRD. The crystallization data were analyzed using the Kolmogorov–Johnson–Mehl–Avrami equation. The kinetic exponent n is determined to be approx. 1/2 and 3/2 for film deposited in the absence and the presence of water vapor, respectively. The activation energy of crystallization for film deposited under 1xa0×xa010−5xa0Torr water vapor pressure was determined to be 30.7xa0kJxa0mol−1, which is higher than 18.9xa0kJxa0mol−1 for film deposited in the absence of water vapor. The increased activation energy caused by the chemically bonded hydrogen and embedded O–H bonds from the water vapor resulted in the suppression of crystallization. Introduction of appropriate water vapor during the deposition decreased the resistivity because of the increase of Hall mobility. The resistivity of the films after annealing increased due to the evaporation of water vapor resulted in crystal defects.

Lamination of Green Ceramic Tapes by Applying Pressures Directly at Ambient Temperature

The lamination of green ceramic tapes is the basis of the production of multilayer ceramic devices. In this paper, cordierite green ceramic tapes are laminated by applying pressures directly at ambient temperature. As a first attempt, the effect of pressure, layers, dwell time on lamination and the sintering temperature on laminates are investigated. It is shown that pressure makes the greatest effect on lamination and dwell time is not obvious. The effect of layers on lamination is mainly related to the pressure that is executed on tapes, and the sintering temperature is contributed to the dense of laminates. The pressure of lamination is not high, and the tapes do not need to be heated. Taking a pressure-assisted method, the deformation of laminates during sintering can be avoided, and a better lamination effect is acquired. The lamination and pressure-assisted methods are both of low cost and simple and feasible to work.

Heat capacities and standard molar enthalpy of formation of pyrimethanil maleic salt and pyrimethanil fumaric salt

Novel anilino-pyrimidine fungicides, pyrimethanil maleic salt, and pyrimethanil fumaric salt (C28H30N6O4) were synthesized by a chemical reaction of pyrimethanil with maleic acid/fumaric acid. The low-temperature heat capacities of the two compounds were measured with an adiabatic calorimeter from 80 to 350xa0K. The heat capacities of pyrimethanil fumaric salt are bigger than that of pyrimethanil maleic salt in the measurement temperature range. The thermodynamic function data relative to 298.15xa0K were calculated based on the heat capacity-fitted curves. The melting points, the molar enthalpies (ΔfusHm), and entropies (ΔfusSm) of fusion of pyrimethanil maleic salt and pyrimethanil fumaric salt were determined from their DSC curves. The values indicate that pyrimethanil fumaric salt was more thermostable than pyrimethanil maleic salt. The constant-volume energies of combustion (ΔcUmo) of pyrimethanil maleic salt and pyrimethanil fumaric salt were measured using an isoperibol oxygen bomb combustion calorimeter at Txa0=xa0(298.15xa0±xa00.001)xa0K. From the Hess thermochemical cycle, the standard molar enthalpies of formation of the two compounds were derived and determined to be ΔfHmo (pyrimethanil maleic salt)xa0=xa0−459.3xa0±xa04.9xa0kJxa0mol−1 and ΔfHmo (pyrimethanil fumaric salt)xa0=xa0−557.2xa0±xa04.8xa0kJxa0mol−1, respectively. The results suggest that pyrimethanil fumaric salt is more chemically stable than pyrimethanil maleic salt.

Molar heat capacities and standard molar enthalpy of formation of pyrimethanil butanedioic salt

A noval anilino-pyrimidine fungicide, pyrimethanil butanedioic salt (C28H32N6O4), was synthesized by a chemical reaction of pyrimethanil and butanedioic acid. The low-temperature heat capacities of the compound were measured with an adiabatic calorimeter from 80 to 380xa0K. The thermodynamic function data relative to 298.15xa0K were calculated based on the heat capacity fitted curve. The thermal stability of the compound was investigated by TG and DSC. The TG curve shows that pyrimethanil butanedioic salt starts to sublimate at 455.1xa0K and totally changes into vapor when the temperature reaches 542.5xa0K with the maximal speed of weight loss at 536.8xa0K. The melting point, the molar enthalpy (ΔfusHm), and entropy (ΔfusSm) of fusion were determined from its DSC curves. The constant-volume energy of combustion (ΔcUm) of pyrimethanil butanedioic salt was measured by an isoperibol oxygen-bomb combustion calorimeter at Txa0=xa0(298.15xa0±xa00.001) K. From the Hess thermochemical cycle, the standard molar enthalpy of formation was derived and determined to be ΔfHmo (pyrimethanil butanedioic salt)=−285.4xa0±xa05.5xa0kJxa0mol−1.

Co-Firing Characteristics of Cordierite Tapes with Ag/Pd for High Frequency Chip Inductors

As a new electronic material, low-temperature sintering, low-dielectric cordierite tapes exhibit great potential in the manufacturing of high frequency inductors. While the co-firing of cordierite dielectric material with conductive metal in lower sintering temperature is always a difficulty, and it directly affects the practical application of the inductors. In this paper, the prepared cordierite tapes with low-sintering temperature, low dielectric constant, and low losses were used as matrix material, and the co-firing characteristics of cordierite tapes with Ag/Pd was preliminary studied to investigate the feasibility in the manufacturing process. Deformation, pores, and delaminations are three main defects of the co-fired samples. With an Al2O3 powders and press blocks assisted process, good co-firing effect of cordierite tapes with Ag/Pd can be obtained at 900 °C. The co-firing interface of cordierite tape and Ag/Pd is very dense and no obvious element migration is detected. The paper is contributed to the manufacture of high frequency inductors.