Qizhong Li

Corrosion Behavior of SnO2-based Electrode Ceramics in Soda-lime Glass Liquid

Dense SnO2-based electrode ceramics have extensive application prospect in glass electric-melting industry due to the excellent electrically-conductive and chemical property in high temperatures and oxidation environment. In this paper, dense SnO2-based electrode ceramics doped with MnO2 and Sb2O3 were prepared by pressureless sintering method and the corrosion rate in soda-lime glass liquid as well as the microstructure evolution was mainly investigated. The results suggested that SnO2-based ceramics had good corrosion resistance, and the minimum value was only 2.54×10−4 mm/h when MnO2 content is 1.0% and Sb2O3 content is 0.1%. Composition Elements of Glass liquid were detected in the grain boundary and some intergranular pores. It was found that SnO2 grains remained unchanged, whereas MnO2 was easily dissolved into molten glass liquid. SnO2-based electrode ceramics with dense structure and few amounts of additives had excellent corrosion resistance to the molten glass.

Preparation and Electrical-Conductive Property of SnO2-Based Ceramics

In this study, SnO2-based ceramics, with CuO as sintering aid and Sb2O3 as activator of the electrical conductivity, was obtained by pressure-less sintering at 1100°C ~ 1470°C. Addition of antimony leads to a higher densification temperature. Densification behavior and microstructure development are strongly dependant on CuO and Sb2O3. CuO gives rise to a liquid phase; Sb2O3 retards the formation of liquid phase and hinders the growth of grain. The electrical resistivities of SnO2-based ceramics vary in a wide range from 10-2 to 107 Ω•cm, depending on starting compositions and processing conditions. The electrical resistivities of samples with different amounts of CuO and Sb2O3 show different trends with the increasing of sintering temperature. The addition of antimony rapidly promotes electrical conductivity of SnO2-based ceramics containing CuO as the solid solution reaction of Sb2O3-SnO2. As the additions of CuO and Sb2O3 are the same, the electrical resistivity arrives the minimal value of 4.72×10-2 Ω•cm for 99%SnO2+0.5%CuO +0.5%Sb2O3 at 1470°C. More content of Sb2O3 than CuO causes the degression of density and the rising of electrical resistivity of ceramics.

Morphology and mechanical behavior of diamond films fabricated by IH-MPCVD

Morphology of diamond films has been controlled via intermediate frequency induction heated microwave plasma chemical vapor deposition (IH-MPCVD), which was transformed with various substrate temperatures (Tsub = 923–1123 K) and CH4/H2 ratios (ηc = 0.5–2 vol%). The coupling effects of Tsub and ηc on the structure of diamond films have been studied. At ηc = 0.5 vol%, the sp3/sp2 ratio of diamond films reached 98% at 1073 K, surface roughness (Rms) increased from 50 to 85 nm with increasing Tsub, the maximum hardness (Ha) reached 84 GPa at 973 K, and the maximum Youngs modulus (E) reached 642 GPa at 1023 K. The residual stress (σ) was calculated as a function of Tsub and ηc. The quality factor (Q), combining microstructure and mechanical behavior, has been creatively defined to evaluate the quality of diamond films.

Structural study of epitaxial NdBa2Cu3O7−x films by laser chemical vapor deposition

Epitaxial NdBa2Cu3O7−x films were prepared on (100) LaAlO3 single crystal substrates by laser chemical vapor deposition (laser CVD). The effect of deposition temperature on preferred orientation, crystallinity, microstructure, deposition rate of films was investigated. The preferred orientation of the NdBCO films changed from a, c-axis to c-axis, then back to a, c-axis, as the deposition temperature was increased from 993 to 1093 K. The highly c-axis-oriented epitaxial NdBa2Cu3O7−x film with critical transition temperature of 87 K was obtained at Tdep = 1033 K, with the in-plane epitaxial orientation relationship of NdBCO [100]∥LAO [010] and NdBCO [010]∥LAO [001]. The growth orientation varied from a-axis to c-axis as the film thickness increased in the case of the a, c-co-oriented NdBCO film. The contribution of thickness-dependent strain relaxation to preferred orientation of the NdBCO films was also discussed.

Morphological Evolution of Vertically Standing Molybdenum Disulfide Nanosheets by Chemical Vapor Deposition

In this study, we demonstrated the chemical vapor deposition (CVD) of vertically standing molybdenum disulfide (MoS2) nanosheets, with an unconventional combination of molybdenum hexacarbonyl (Mo(CO)6) and 1,2-ethanedithiol (C2H6S2) as the novel kind of Mo and S precursors respectively. The effect of the distance between the precursor’s outlet and substrates (denoted as d) on the growth characteristics of MoS2, including surface morphology and nanosheet structure, was investigated. Meanwhile, the relationship between the structure characteristics of MoS2 nanosheets and their catalytic performance for hydrogen evolution reaction (HER) was elucidated. The formation of vertically standing nanosheets was analyzed and verified by means of an extrusion growth model. The crystallinity, average length, and average depth between peak and valley (Rz) of MoS2 nanosheets differed depending on the spatial location of the substrate. Good crystalized MoS2 nanosheets grown at d = 5.5 cm with the largest average length of 440 nm, and the highest Rz of 162 nm contributed to a better HER performance, with a respective Tafel slope and exchange current density of 138.9 mV/decade, and 22.6 μA/cm2 for raw data (127.8 mV/decade and 19.3 μA/cm2 for iR-corrected data).

Catalytic Decomposition of Nitric Oxide by LaCoO3 Nano-particles Prepared by Rotary CVD

Catalytic direct decomposition of NO by perovskite-type catalysts has attracted much attention for the various possible components and the unique structure. LaCoO3 nanoparticles were precipitated on α-Al2O3 micro powders by rotary chemical vapor deposition (rotary CVD) and its catalytic performance for the decomposition of NO was investigated. LaCoO3 nano-particles with 100 nm in average diameter and 1.5% in mass were uniformly dispersed on α-Al2O3 powder. The conversion of NO increased with increasing temperature from 400 to 950 °C, and reached 28.7% at 950 °C. The gas velocity of transformed NO on LaCoO3 nano-particles catalyst per mass unit was 7.7 mL/(g min), showing a good catalytic activity over the calculated results of pure catalysts. After five times of aging performance experiments, the NO conversion kept the same value, showing a good aging performance and thermal stability.

Thickness dependence of structure and superconductivity of the SmBa2Cu3O7 film by laser CVD

SmBa2Cu3O7 (SmBCO) superconductive films with thicknesses in the range from 0.47 to 2.72 μm were prepared on single-crystalline LAO (100) substrates by laser chemical vapor deposition (laser CVD). The effect of thickness on the orientation, microstructure, and superconductivity of SmBCO films was investigated. The preferred orientation of the SmBCO film changed from c-axis to a- and c-axis co-orientation with an increase in thickness from 0.47 to 2.72 μm. The SmBCO film with 1.06 μm thickness exhibited excellent c-axis epitaxial orientation with a minimum full width at half maximum of 1.07° for φ-scan and an in-plane epitaxial orientation relationship of SmBCO[100]//LAO[010] and SmBCO[010]//LAO[001]. The highest critical transition temperature and critical current density were 89.5 K and 1.92 MA cm−2 (corresponding to the critical current of 204 A cm−1-W) with a deposition rate of 7.6 μm h−1.

The preparation and property of PEG/CNTs/SiO2 microspheres phase change materials

Abstract For the purpose of overcoming the property defects of polyethylene glycol (PEG) phase change materials, this study prepared a novel PEG/SiO2/carbon nanotubes (CNTs) microspheres phase change material by taking CNTs as an ingredient, which can enhance the material thermal conductivity. What is more, the composition and structure as well as miniature heat transfer process of the material were further studied.

Preparation of B4C–ZrB2–SiC ternary eutectic composites by arc melting and their properties

Abstract B4C–ZrB2–SiC composites were synthesised by arc melting in Ar atmosphere using B4C, ZrB2 and β-SiC powders as starting materials. The ternary eutectic composition of 40B4C–20ZrB2–40SiC (mol-%) was first identified and a lamellar eutectic texture was observed. SiC and ZrB2 grains about 1 μm in thickness were uniformly dispersed in B4C matrix of B4C–ZrB2–SiC eutectic composite. B4C (003) and ZrB2 (100) planes were perpendicular to the growth direction. The Vickers hardness of B4C–ZrB2–SiC ternary eutectic composite was 30–34 GPa. The fracture toughness of B4C–ZrB2–SiC composite increased with the decrease of B4C content and the rise of ZrB2 content.