Lai Yanqing

Cu2SixSn1−xS3 Thin Films Prepared by Reactive Magnetron Sputtering For Low-Cost Thin Film Solar Cells

We report the preparation of Cu2SixSn1−xS3 thin films for thin film solar cell absorbers using the reactive magnetron co-sputtering technique. Energy dispersive spectrometer and x-ray diffraction analyses indicate that Cu2Si1−xSnxS3 thin films can be synthesized successfully by partly substituting Si atoms for Sn atoms in the Cu2SnS3 lattice, leading to a shrinkage of the lattice, and, accordingly, by 2θ shifting to larger values. The blue shift of the Raman peak further confirms the formation of Cu2SixSn1−xS3. Environmental scanning electron microscope analyses reveal a polycrystalline and homogeneous morphology with a grain size of about 200–300 nm. Optical measurements indicate an optical absorption coefficient of higher than 104 cm−1 and an optical bandgap of 1.17±0.01 eV.

Al2O3‐Na3AlF6 Man‐Made Ledge Composites for Aluminum Electrolysis Cells

Man-made Al2O3-Na3AlF6 composite ledge for aluminum reduction cell was developed because of the disadvantages of traditional self-forming ledge and the composite material was prepared by pressureless liquid-phase sintering under air atmosphere. The effect of Na3AlF6 mass fraction on the relative density, compressive strength, high-temperature stability and microstructure of Al2O3-Na3AlF6 composites was investigated. The results show that with the increasing of Na3AlF6 mass fraction from 0 to 15 wt%, the relative density increases from 62.05 % to 67.19 %, the compressive strength increases from 9.74 MPa to 17.81 MPa, and the high-temperature stability of composites under 1100 °C gradually becomes worse. However, compared to traditional self-forming ledge, Al2O3-Na3AlF6 composites have more excellent high-temperature stability. Such results indicate that Al2O3-Na3AlF6 composite is a promising man-made ledge for aluminum reduction cell.

2D finite element analysis of thermal balance for drained aluminum reduction cells

Based on the principle of energy conservation, the applicable technique for drained cell retrofitted from conventional one was analyzed with 2D finite element model. The model employed a 1D heat transfer scheme to compute iteratively the freeze profile until the thickness variable reached the terminating requirement. The calculated 2D heat dissipation from the cell surfaces was converted into the overall 3D heat loss. The potential drop of the system, freeze profile and heat balance were analyzed to evaluate their variation with technical parameters when designing the 150 kA conventional cell based drained cell. The simulation results show that the retrofitted drained cell is able to keep thermal balance under the conditions that the current is 190 kA, the anodic current density is 0.96 A/cm2, the anode-cathode distance is 2.5 cm, the alumina cover is 16 cm thick with a thermal conductivity of 0.20 W/(m·°C) and the electrolysis temperature is 946 °C.

Effect of CaO doping on mechanical properties and thermal shock resistance of 10NiO-NiFe2O4 composite ceramics

The CaO doped 10NiO-NiFe2O4 composite ceramics were prepared by the cold isostatic pressing-sintering process, and the effects of CaO content on the phase composition, mechanical property and thermal shock resistance of 10NiO-NiFe2O4 composite ceramics were studied. The results show that the samples mainly consist of NiO and NiFe2O4 when content of CaO is less than 4%(mass fraction), bending strength increases obviously by CaO doping. Bending strength of the samples doped with 2% CaO is above 185 MPa, but that of the samples without CaO is only 60 MPa. Fracture toughness is improved obviously by CaO doping, the samples doped with 2% CaO have the maximum fracture toughness of 2.12 MPa ·m1/2, which is about two times of that of the undoped ceramics. CaO doping is bad to thermal shock resistance of 10NiO-NiFe2O4 composite ceramics.

Effect of electrolysis superheat degree on anticorrosion performance of 5Cu/(10NiO-NiFe2O4) cermet inert anode

Abstracts5Cu/(10NiO-NiFe2O4) cermet inert anodes were prepared by cold-pressing and sintering process, and the effect of superheat degree of melting K3AlF6-Na3AlF6-AlF3 on their anticorrosion performance was studied under electrolysis conditions. The results show that, the fluctuation of cell becomes small with increasing of superheat degree, which is helpful to inhibit the formation of cathodic encrustation; the concentration of impurities from inert anode in bath goes up to certain degree, but it is far smaller than those in traditional high-temperature bath. Increasing the superheat degree of melting K3AlF6-Na3AlF6-AlF3 has unconspicuous effect on the contents of impurities in cathodic aluminum. The total mass fractions of Fe, Ni and Cu in aluminum are 15.38% and 15.09% respectively under superheat degree of 95 and 195 °C. From micro-topography of anode used view, increasing the superheat degree can aggravate corrosion of metal Cu in inert anode, and has negative influence on electrical conductivity of electrode to some extent.

Preparation of Chalcopyrite Cuinse2 Thin Films by Pulse-Plating Electrodeposition and Annealing Treatment

CuInSe2 (CIS) thin films have been prepared on molybdenum substrates by pulse-plating electrodeposition from an aqueous solution containing CuCl2, InCl3, SeO2 and Na-citrate. The most suitable pulse potential range for co-deposition is found to be-0.6~-0.75V vs the saturated calomel electrode (SCE). The electrodeposited films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDS). The influence of the square pulse potential on crystallinity, surface morphology and compositions has been studied. Chalcopyrite phase CuInSe2 films with smooth surfaces and stoichiometric composition have been obtained at a pulse potential of-0.65~-0.7V vs.SCE and annealing treatment.

Effect of LiAlO2 and KF on Physicochemical Properties for Industrial Aluminum Electrolyte

The aluminum electrolytes of 300 kA series cell in a Chinese aluminum plant were investigated. Compositions and physicochemical properties of these electrolyte samples were analyzed, and the effects of contents of additive LiAlO2 and KF on physicochemical properties were studied. The results show that with the increasing content of the LiAlO2 from 0 to 8.52 wt%, the liquidus temperature decreases gradually from 940.7 °C to 917.0 °C, whereas the alumina solubility obtained by oxygen content increases in the initial stage and then reduces. When increasing the content of LiAlO2 up to 3 wt%, the alumina solubility reaches the highest value of 6.44 wt%. The liquidus temperature decreases by 2.3–2.5 °C with per 1 wt% addition of KF, and meanwhile, the alumina solubility increases by 0.05–0.13 wt% correspondingly.

Liquidus Temperatures of the System Na 3 AlF 6 -K 3 AlF 6 -AlF 3

Liquidus temperatures for the primary crystallization of the molten salt system Na3AlF6-K3AlF6-AlF3 for aluminium electrolysis were determined by thermal analysis. The data were fitted to an empirical equation:

Effect of Sintering Atmosphere on Phase Composition and Mechanical Property of 5Cu/(10NiO-NiFe2O4) Cermet Anodes for Aluminum Electrolysis

T = 3478 - 1867 \times {[KR]^{0.12}} - 12.97 \times {[Al{F_3}]^{1.14}} + 3.538 \times [Al{F_3}] \times {[KR]^{0.98}} - 0.505 \times {[Al{F_3}]^{1.24}} \times {[KR]^{1.23}}