Active Soldering of ZnS–SiO2 Sputtering Targets to Copper Backing Plates Using an Sn56Bi4Ti(Ce,Ga) Filler

ZnS–SiO₂ targets have been directly soldered to copper backing plates at 180°C in air using an Sn56Bi4Ti(Ce, Ga) filler. The affinity of cerium to oxygen protects titanium from oxidation, allowing titanium to react with ZnS–SiO₂ sputtering target. The shear strengths are 1.7, 8.7, and 1.3 MPa for ZnS–SiO₂/ZnS–SiO₂, copper/copper and ZnS–SiO₂/copper joints, respectively. EPMA elemental mapping shows that aging test at 120° for 100 hours enhanced the segregation of titanium at the ZnS–SiO₂/solder interfaces. The shear strength of ZnS–SiO₂/copper joint after aging test is 1.3 MPa that shows no trace of degradation compared to the initial quality of the samples.     

Preparation of (Ti, Sn)O2 Nano-Composite Photocatalyst by Supercritical Fluid Dry Combination Technology

A series of TiO2-SnO2 nano-sized composite photo-catalysts containing Sn (9.3%-30.1%) were prepared from TiCI4 and SnCl4·5H2O by using sol-gel, supercritical fluid dry and solid-phase reaction (SCFD) combination technology. Characterizations with X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FTIR) showed that, in addition to anatase type TiO2, a new active phase (Ti, Sn)O2 (with particle size of 2.0-4.3 nm) formed, and there were no SnO2 crystals observed in the range of the doping concentration studied. Photo-catalytic reaction of phenol was used as a model reaction to evaluate the catalytic activities of the obtained catalysts. Compared with pure TiO2 or Ti-Sn catalyst prepared with general sol-gel method, Ti-Sn nano-composite photo-catalyst thus obtained showed significant improvement in catalytic activity. The photo-catalytic degradation rate of phenol could reach as high as 93.5% after 7 h. The preparation conditions of the new phase (T     

细晶铈、镁复合稳定PSZ陶瓷的制备及性能研究

以工业ZrO2为主要原料,CeO2,MgO及α－Al2O3作为复合稳定剂及颗粒添加剂,采用机械球磨混合法制备粉料,进而在较低的固溶烧结温度（≤1550℃）下,经1100℃适当时间热处理,制备出具有较好力学性能的细晶PSZ陶瓷材料,其室浊度约655MPa,断裂韧性在15MPa.m^1/2左或,所制备细晶PSZ材料的临界热震温差△Tc在750℃左右,其中微裂纹增韧机制的存在对材料的抗热震性有积极作用,在（180℃,1MPa）水热条件下,采用CeO2作为复合稳定剂的PSZ陶瓷材料具有较好的抗水化性能。     

Optical properties of Cu(In,Ga)Se2 and Cu2ZnSn(S,Se)4

The optical properties of CuInSe₂, CuGaSe₂, Cu₂ZnSnS₄, and Cu₂ZnSnSe₄ are investigated using three different first-principles methods, namely the generalized gradient approximation by Perdew, Burke, and Ernzerhof (PBE), the hybrid Hartree-Fock-like functional by Heyd, Scuseria, and Ernzerhof (HSE), and a Green's function approach (GW). The density-of-states, the complex dielectric function ε(ω) = ε₁(ω) + iε₂(ω), and the optical absorption coefficient α(ω) are determined, providing fundamental understanding of these materials. We find that even though the PBE method generates fairly accurate effective crystal potentials, the HSE and GW methods improve considerably the band-gap energies E_g and also the localization of the semicore states, thereby describing the optical properties much better. Furthermore, we also present optimized convergence parameters for the self-consistent HSE calculation in order to reduce the computational time of this orbital-dependent method.     

细晶(Y/Ce,Mg)-PSZ/MgAl2O4陶瓷制备工艺及性能的研究

在化学共沉淀法制备细晶PSZ陶瓷的基础上，用工业ZrO2作原料，以MgO、Y2O3、CeO2及α-Al2O3作为复合稳定剂及添加剂，采用机械球磨混合法，并在制备过程中部分用去离子水代替乙醇作为球磨介质，探讨了水磨混合法制备粉料的可行性．实验结果表明：在较低的固溶烧结温度（1550℃）下，经1100℃适当时间热处理，亦可制备出具有较好力学性能的细晶PSZ陶瓷材料，其室温强度约700MPa，断裂韧性在15MPa·m1／2左右；在（180℃，1MPa）水热条件下，采用CeO2作复合稳定剂的PSZ陶瓷材料要比Y2O3复合稳定的PSZ材料更具良好的抗水化性．     

MgO/SrO/La2O3多元添加对(Zr0.8Sn0.2)TiO4微波陶瓷结构性能影响

基于液相促进固相反应烧结机制, 设计MgO/SrO/La₂O₃多元复合添加(Zr_0.8Sn_0.2)TiO₄(ZST)体系, 探究复合添加剂对ZST陶瓷的物相组成、微观结构、烧结特性以及高频介电性能等参数的影响。实验结果表明: 陶瓷的主晶相均为ZST相; 适量添加MgO/SrO/La₂O₃可以有效地降低ZST陶瓷的烧结温度, 获得较优的微波介电性能; 但MgO添加量的增多对材料的综合性能有小幅度的影响; SrO的添加量过大会造成晶粒的不完全生长、瓷体不致密和气孔的增多, 从而导致材料的密度、介电常数和Q×f值的下降; 此外, 添加剂对陶瓷的频率温度系数(τ_f)影响不大。在复合添加0.2wt%MgO、0.6wt%SrO、1.0wt%La₂O₃时, 1300℃保温5 h的ZST陶瓷综合性能优异: ρ=5.14 g/cm³, ε_r=40.11, Q×f=51000 GHz (f=5.61 GHz), τ_f=-2.85×10^-6℃^-1。     

Influence of sodium compounds at the Cu(In,Ga)Se2/(PVD)In2S3 interface on solar cell properties

The present contribution deals with indium sulfide buffer layers grown by thermal co-evaporation of elemental indium and sulfur. It has been found necessary to deposit these buffer layers at low substrate temperatures in order to reach V_oc values similar to those with (CBD)CdS. However, such deposition conditions lead to the formation of a highly recombinative Cu(In,Ga)Se₂/indium sulfide interface. This behaviour may be associated to the presence of sodium carbonates/oxides at the interface even though the Cu(In,Ga)Se₂ surface was cleaned in NH₃ (1 M, room temperature) prior to the indium sulfide deposition. An explanation is that, despite the chemical etch, sodium carbonates/oxides remain in the air exposed Cu(In,Ga)Se₂ grain boundaries and can migrate towards the surface when the Cu(In,Ga)Se₂ is heated under vacuum. These polluted interface areas act as recombination zones and thus inferior devices. A possibility to improve the device performance (i.e. improve the interface quality) is to sulfurize the remaining sodium carbonates/oxides. The resulting Na₂S can then leave the interface by formation of a solid solution with the indium sulfide. By adapting the buffer layer deposition process, 13.3% efficiency devices with co-evaporated indium sulfide are realized, performance which is close to that reached with (CBD)CdS.