Magneto-Impedance Effect of Composite Wires Prepared by Chemical Plating under DC Current

CuBe composite wires of 100 μm in diameter coated with a layer of NiCoP were prepared by a chemical plating method under DC current(CPUDC). The influences of DC current on coating morphology,deposition rate, composition, giant magneto-impedance(GMI) effect and magnetic properties were investigated.It was shown that the circumferential domain structure of coating layer was induced by the DC current going through the wires. A maximum GMI ratio of 870% was obtained in the composite wire prepared under 150 m A and tested at 180 k Hz. It is 30 times higher than that of the composite wire plated in the same condition by conventional chemical plating method, indicating that CPUDC is an easy and effective approach to obtain composite wires and its applications will be further extended on magnetic sensors.

Preparation and Properties of Conductive Polyester Fabric Based on Ni-P Chemical Plating with Pd-Chitosan Activation

In this study, an effective deposition of Ni-P alloy on polyester （PET） was proposed by a chemical plating method with PdCl2 solution and a chelating agent chitosan （CTS）. As a critical step in chemical plating of making electromagnetic shielding fabric, the optimized processing of textile chemical plating is the fabrics padded with 3 % acetic acid （HAc） solution containing 10 g/L CTS and 5.5 mL/L formaldehyde （HCHO） as cross-linking agent for 20 min at room temperature. The highest weight gain and the lowest surface resistance of the treated fabric were achieved by the optimum pretreatment method. The CTS-Pd PET fabrics were characterized by scanning electron microscopy （SEM）, scanning probe microscope （SPM）, and the glancing incident angle X-ray diffraction （XRD） pattern. The results showed that CTS acting as a chelating had effectively fixed Pd （H） ions. A uniform and continuous structure of Ni-P plating layer was obtained using the CTS pretreatment.

Joint Strength with Soldering of Al_2O_3 Ceramics After Ni-P Chemical Plating

Ni-P alloy was chemically plated on Al2O3 ceramics to produce uniform alloy coatings at tem- peratures below 70℃. Cu metal was electroplated onto the Ni-P coating to facilitate the soldering and shorten the chemical plating time. Then, the electroplated ceramic specimens were soldered with 60 wt.% Sn-40 wt.% Pb solder in active colophony. The highest shear strength was acquired after the heat treatment at 170℃ for 15 min. The joint fractures mostly propagated along the interface between the ceramics and the Ni-P coating, with some fracture in both the ceramics and the Ni-P coating near the interface and some along the interface between the Cu and Ni-P coatings. The results show that ceramic surface roughness and the chemical plating parameters influence the coating quality, and that suitable heat treatment before the soldering also improves the adhesion between the ceramics and Ni-P coatings, thus strengthening the joints.

Preparation and microwave absorption properties of flexible composites containing Ag decorated polystyrene powders

Polystyrene(PS)microspheres have the advantages of good stability,corrosion resistance and low density,which have a broad application prospect.In this paper,PS composite microspheres with 20%silver plating content were prepared by chemical plating method and incorporated into polydimethylsiloxane(PDMS)flexible matrix to prepare Ag@PS/PDMS flexible wave-absorbing materials.The electromagnetic parameters were adjusted to optimize the dielectric and wave-absorbing properties by varying the additional amount of Ag@PS composite microspheres in Ag@PS/PDMS composites.The X-ray diffraction(XRD)results proved the successful preparation of Ag@PS composite microspheres.The SEM and EDS images indicated that the Ag particles were attached to the external surface of PS.The presence of Ag particles in the Ag@PS composite microspheres enhances their electrical conductivity and enables the formation of a conductive network.This,in turn,improves the composites’dielectric constant.The optimal wave-absorbing capability of the composites was achieved when the Ag@PS composite microspheres were added at a weight percentage of 50%.When the sample attains a thickness of 1.8 mm,a reflection loss of at least-39.8 dB is attained at 10.4 GHz,along with a bandwidth of 1.6 GHz(9.1–10.7 GHz)for the effective absorption bandwidth(EAB).The pressure-sensitive properties of the pliable composites were investigated as well.The optimal pressure-sensitive performance of Ag@PS/PDMS composites was achieved with a 60 wt.%addition of Ag@PS composite microspheres.The resistance undergoes significant changes when subjected to pressure with a sensitivity of 9.7.The results indicate that the flexible composites’wave-absorption and pressuresensitivity properties can be modulated by adjusting the amount of Ag@PS composite microspheres added.

Ni_(1-x)Pt_(x) (x=00.08) Films as the Photocathode of Dye-Sensitized Solar Cells with High Effi ciency

Films of Ni_(1-x)Pt_(x)(x=0,0.02,0.04,0.06,and 0.08)have been prepared on fluorine-doped tin oxide-coated(FTO)glass substrates by a chemical plating method and used as the photocathode for dye-sensitized solar cells(DSCs).The Ni_(0.94)Pt_(0.06 )film consisted of nanoparticles with a size of 46 nm and a Pt loading of 5.13μg/cm^(2).The Ni_(0.94)Pt_(0.06) photocathode exhibited high catalytic performance toward triiodide reduction,high light refl ectance,and low charge-transfer resistance.The DSC assembled with the Ni_(0.94)Pt_(0.06) photocathode gave a short-circuit photocurrent density(Jsc)of 16.79 mA/cm^(2),an open-circuit photovoltage(Voc)of 736 mV,and a fi ll factor(FF)of 66.4%,corresponding to an overall conversion effi ciency of 8.21%under standard AM 1.5 irradiation(100 mW/cm^(2)),which is higher than that for the DSC with a pure Pt photocathode obtained by conventional thermal decomposition.Furthermore,the DSC based on the Ni0.94Pt0.06 photocathode showed good stability.The results indicate that Ni0.94Pt0.06 fi lms are promising low-cost and high-performance photocathodes for use in DSCs.

Effect of Diamond Additions on Wettability and Distribution of SnAgCu Composite Solder

Diamond/SnAgCu composite solder bumps were prepared on Cu pad by mechanically incorporating diamond particles into Sn3.0Ag0.5Cu （SAC） solder powders, mixing with flux and reflowing at 260℃ for 60 s. The spreading areas of composite solder were calculated and the distributions of copper-coated diamonds were characterized. When diamond additions were below 3 wt%, the spreading area decreased with diamond additions, and the diamonds distributed mainly at the interface between solder and Cu pad; however, when additions were beyond 4 wt%, the discharge of diamond particle occurred, and the spreading area increased due to the reduction of surface energy.