Fabrication of oxide-based near infrared-shielding coatings for a smart window to prevent infrared-induced photoaging in human skin

Oxide-based near infrared (IR)-shielding coatings consisting of quarter‐wave stacks of oxygen-deficient tantalum oxide (Ta₂O_5?x) and silicon oxide (SiO₂) multilayers and tin-doped indium oxide (In₂O₃) (ITO) films with the thicknesses of 200–600 nm can block the passage of IR-A (wavelength: 760–1400 nm) and IR-B (wavelength: 1400–3000 nm) radiation, respectively. In this study, the optical properties and microstructure of these oxide-based IR-shielding coatings were investigated. Transmission electron microscopy images indicated that amorphous Ta₂O_5?x/amorphous SiO₂ multilayers were uniform and dense. ITO films were found to be highly crystalline and show carrier concentrations of up to 7.1 × 10²⁰ cm^?3, resulting in the strong IR-B optical absorption due to the plasma excitation of the free carriers. Oxide-based IR-shielding coatings with an ITO thickness of 420 nm were found to have near-IR shielding rates of >90% and an average visible light transmittance of >70%. The effects of IR on human keratinocytes were studied to evaluate the IR-induced photoaging in human skin. It was found that the downregulation of cellular proliferation and the enhancement of senescence-associated β-galactosidase activity induced by IR irradiation were significantly inhibited by oxide-based IR-shielding coatings. Thus, this study provides a facile method for the development of coatings for smart windows with high IR-shielding ability and high visible light transmittance.     

Reduced texaphyrin: A ratiometric optical sensor for heavy metals in aqueous solution

We report here a water-soluble metal cation sensor system based on the as-prepared or reduced form of an expanded porphyrin, texaphyrin. Upon metal complexation, a change in the redox state of the ligand occurs that is accompanied by a color change from red to green. Although long employed for synthesis in organic media, we have now found that this complexation-driven redox behavior may be used to achieve the naked eye detectable colorimetric sensing of several number of less-common metal ions in aqueous media. Exposure to In(III), Hg(II), Cd(II), Mn(II), Bi(III), Co(II), and Pb(II) cations leads to a colorimetric response within 10 min. This process is selective for Hg(II) under conditions of competitive analysis. Furthermore, among the subset of response-producing cations, In(III) proved unique in giving rise to a ratiometric change in the ligand-based fluorescence features, including an overall increase in intensity. The cation selectivity observed in aqueous media stands in contrast to what is seen in organic solvents, where a wide range of texaphyrin metal complexes may be prepared. The formation of metal cation complexes under the present aqueous conditions was confirmed by reversed phase high-performance liquid chromatography, ultra-violet-visible absorption and fluorescence spectroscopies, and high-resolution mass spectrometry.     

电感耦合等离子体质谱法测定锡铅焊料中11种杂质元素

锡铅焊料中的杂质元素对焊点的抗氧化性、润湿性、扩展面积有重要影响,因此对其进行测定意义重大。采用硝酸、氢氟酸溶解样品,选择H₂动态反应池模式测定Fe,标准模式测定Al、P、Cu、Zn、As、Cd、Ag、Sb、Au、Bi,同时以Sc校正Al、P、Fe、Cu,以Cs校正Zn、As、Ag、Cd,以Tl校正Sb、Au、Bi,实现了电感耦合等离子体质谱法(ICP-MS)对锡铅焊料中这11种杂质元素含量的测定。在优化的实验条件下,11种杂质元素校准曲线的相关系数均大于0.999,方法的检出限在0.002~0.80μg/g范围内,测定下限在0.007~2.73μg/g范围内。用建立的实验方法测定锡铅焊料样品中Al、P、Fe、Cu、Zn、As、Cd、Ag、Sb、Au、Bi,平行测定11次结果的相对标准偏差(RSD)为0.85%~3.5%,加标回收率为90%~110%。将实验方法应用于锡铅焊料标准物质YT9302中Al、Fe、Cu、Zn、As、Sb、Bi共7种杂质元素的测定,结果与认定值一致。     

Low cycle fatigue behavior of a eutectic 80Au/20Sn solder alloy

The eutectic 80Au/20Sn solder alloy is widely used in high power electronics and optoelectronics packaging. In this study, low cycle fatigue behavior of a eutectic 80Au/20Sn solder alloy is reported. The 80Au/20Sn solder shows a quasi-static fracture characteristic at high strain rates, and then gradually transforms from a transgranular fracture (dominated by fatigue damage) to intergranular fracture (dominated by creep damage) at low strain rates with increasing temperature. Coffin-Manson and Morrow models are proposed to evaluate the low cycle fatigue behavior of the 80Au/20Sn solder. Besides, the 80Au/20Sn solder has enhanced fatigue resistance compared to the 63Sn/37Pb solder.     

用于金属密封联接的自动热压封接设备研制

针对手工作业难以保证铟封工艺的质量和一致性,研制了一台自动热压封接设备,用于实现某型号精密金属器件的密封。分析了金属铟封的热压工艺过程和工艺参数;介绍了自动热压封接设备的基本结构和控制系统;详细说明了设备温度、压力等工艺参数的控制方法,并对研制设备的压力、温度的控制性能进行了测试实验。使用研制的设备进行了热压铟封实验,并对连接的可靠性和密封性能进行了测试。结果表明,热压铟封后的金属器件符合产品要求。该设备能够保证精密金属器件的封接质量和一致性,提高了铟封工艺的自动化程度,提高了生产效率。     

Thermal reliabilities of Sn-0.5Ag-0.7Cu-0.1Al2O3/Cu solder joint

The effects of trace addition of Al₂O₃ nanoparticles (NPs) on thermal reliabilities of Sn-0.5Ag-0.7Cu/Cu solder joints were investigated. Experimental results showed that trace addition of Al₂O₃ NPs could increase the isotheraml aging (IA) and thermal cyclic (TC) lifetimes of Sn-0.5Ag-0.7Cu/Cu joint from 662 to 787 h, and from 1597 to 1824 cycles, respectively. Also, trace addition of Al₂O₃ NPs could slow down the shear force reduction of solder joint during thermal services, which was attributed to the pinning effect of Al₂O₃ NPs on hindering the growth of grains and interfacial intermetallic compounds (IMCs). Theoretically, the growth coefficients of interfacial IMCs in IA process were calculated to be decreased from 1.61×10^-10 to 0.79×10^-10 cm²/h in IA process, and from 0.92×10^-10 to 0.53×10^-10 cm²/h in TC process. This indicated that trace addition of Al₂O₃ NPs can improve both IA and TC reliabilities of Sn-0.5Ag- 0.7Cu/Cu joint, and a little more obvious in IA reliability.     

A Modular Solder System with Hierarchical Morphology and Backward Compatibility

A modular solder system with hierarchical morphology and micro/nanofeatures in which solder nanoparticles are distributed on the surface of template micropowders is reported. A core–shell structure of subsidiary nanostructures, which improved the intended properties of the modular solder is also presented. In addition, polymer additives can be used not only as an adhesive (like epoxy resin) but also to impart other functions. By combining all of these, it is determined that the modular solder system is able to increase reflowability on a heat‐sensitive plastic substrate, oxidation resistance, and electrical conductivity. In this respect, the system could be readily modified by changing the structure and composition of each constituent and adopting backward compatibility with which the knowledge and information attained from a previously designed solder can offer feedback toward further improving the properties of a newly designed one. In practice, In–Sn–Bi nanoparticles engineered on the surface of Sn–Zn micropowders result in pronounced reflowing on a flexible Au‐coated polyethylene terephthalate (PET) substrate even at the low temperature of 110 °C. Depending on their respective concentrations, the incorporation of CuO@CeO₂ nanostructures and poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) polymers increases oxidation resistance and electrical conductivity of the modular solder.     

Shear analysis of rice husk ash (RHA) reinforced tin-0.7-copper composite solders on electroless nickel/immersion silver (ENIAg) surfaces

In this study, the mechanical performance of the rice husk ash-reinforced tin-0.7 copper composite solder was investigated. 0.01 wt.%, 0.05 wt.% and 0.1 wt.% of rice husk ash (RHA) were added to the solder matrix to prepare the composite solders. In order, to replace the costly electroless nickel immersion gold surface finish on the copper substrate, the effect of electroless nickel immersion silver (ENIAg) as the surface finish was studied. The differential scanning calorimetry (DSC) analysis showed that the composite solder exhibited lower melting temperature relative to the plain solder owing to the inclusion of rice husk ash. Shear strength analysis was carried out to investigate the influence of rice husk ash and electroless nickel immersion silver surface finish on the shear strength of the developed composite solders. The results proved that the rice husk ash failed to enhance the shear strength of tin-0.7 copper lead-free solder with the plain solder exhibiting the highest shear strength.     

Ultrasonic-assisted wetting and soldering of AlN ceramic by using a nonactive solder (Sn9Zn) in air

AlN ceramic was successfully wetted and then joined with nonactive Sn9Zn eutectic solder assisted by ultrasonication in air. The effect of ultrasonic time on the formation of joint was studied. Results indicated that the defect-free joint can be obtained at an ultrasonic time of 5 s. Two regions, namely, AlN/Sn (s,_s) and AlN/Zn (s,_s), were found in the bonding interface. Zn and O accumulated in the AlN/Sn (s,_s) interface. An amorphous and nanocrystalline layer of ZnO formed in the hard-wet AlN surface. And Zn (s,_s) directly bonded with AlN. The low temperature and fast bonding of the AlN was attributed to the high pressure and temperature caused by cavitation effect. The shear strength of the joint increased from 10.6 MPa to 30.7 MPa when the ultrasonic treatment time increased from 5 s to 150 s. With the prolongation of ultrasonic time, more AlN ceramic particles entered the solder and acted as the reinforcing phase.