粉体化学镀Ag工艺

概述了在无机质或有机质粉体芯材上的化学镀 Ag工艺。在粉体上依次进行化学镀镍 -化学镀铜 -化学镀银 ,以镀镍层代替部分镀银层 ,可以获得均匀致密和导电性优良的化学镀 Ag粉体 ,降低了镀银粉体的制造成本。

Selective synthesis and shape-dependent photoluminescence properties of (Y_(0.95)Eu_(0.05))_2O_3 submicron spheres and microplates

Red-emission （Y0.95Eu0.05）2O3 submicron spheres and microplates were selectively obtained via hydrothermal precursor synthesis （150 °C, 12 h） followed by calcination at 1000 °C. Characterizations of the products were carried out by combined means of XRD, FT-IR, FE-SEM and PL analysis. The precursors could be modulated from basic-carbonate submicron spheres to normal carbonate microplates by increasing the molar ratio of urea to Y＋Eu from 10 to 40-100. The resultant oxides largely retain their respective precursor morphologies at 1000 °C, but morphology confined crystal growth was observed for the microplates, yielding more enhanced exposure of the （400） facets. Both the （Y0.95Eu0.05）2O3 spheres and microplates exhibit nearly identical positions of the PL bands and similar asymmetry factors of luminescence [I（5D0→7F2）/I（5D0→7F1）, ～11] under 250 nm excitation, but the microplates show a significantly strong red emission at ～613 nm （ ～1.33 times that of the spheres） owing to their larger particle size and denser packing of primary phosphor crystallites.

Deformation and densification behavior of discrete media filled thin-walled tubes during forward extrusion

Discrete media filled thin-walled hollow profiles are frequently used as integer structures for special purpose, e.g., in certain materials processing or architectural components. To understand the deformation of such composite structures which is a complicate mechanics process, involving coupled elastic-plastic deformation of dense metal, compaction of particle and interaction between the filler and the wall, the forward extrusion of Al 6061 tubes filled with various particles was studied. The analysis regarding internal volume variation of round tubes during forward extrusion indicates that with the diameter reduction the volume of tubes decreases commonly. The cavity shrinkage brings about triaxial pressure on the filler, resulted in compaction and densification of it. Loose powders filling leads to higher extrusion load. Due to dissimilar migration behaviors of the particles, the load?stroke curves of the tubes filled with fine powders and coarse balls are quite different. Small Lankford value of the tube wall material leads to higher hydrostatic pressure of the filler and then more powders are compacted.

Characteristics of Inconel Powders for Powder-Bed Additive Manufacturing

In this study, the flow characteristics and behaviors of virgin and recycled Inconel powder for powder-bed additive manufacturing （AM） were studied using different powder characterization techniques. The results revealed that the particle size distribution （PSD） for the selective laser melting （SLM） process is typically in the range from 15 μm to 63 μm. The flow rate of virgin Inconel powder is around 28 s·（50 g）^-1. In addition, the packing density was found to be 60%. The rheological test results indicate that the virgin powder has reasonably good flowability compared with the recycled powder. The inter-relation between the powder characteristics is discussed herein. A propeller was successfully printed using the powder. The results suggest that Inconel powder is suitable for AM and can be a good reference for researchers who attempt to pro- duce AM powders.

Extracting indium and preparing ferric oxide for soft magnetic ferrite materials from zinc calcine reduction lixivium

A hydrometallurgical process for indium extraction and ferric oxide powder preparation for soft magnetic ferrite material was developed. Using reduction lixivium from high-acid reductive leaching of zinc oxide calcine as raw solution, copper and indium were firstly recovered by iron powder cementation and neutralization. The recovery ratios of Cu and In are 99% and 95%, respectively. Some harmful impurities that have negative influences on magnetic properties of soft magnetic ferrite material are deeply removed with sulfidization purification and neutral flocculation method. Under the optimum conditions, the content of impurities like Cu, Pb, As, Al in pure Zn-Fe sulfate solution are less than 0.004 g/L, but those of Cd, Si, Ca and Mg are relatively high. Finally, thermal precipitation of iron is carried out at 210 ℃ for 1.5 h. The precipitation ratio of Fe is 93.33%. Compared with the quality standard of ferric oxide for soft magnetic ferrite materials, the contents of Al and Mg in obtained ferric oxide powder meet the requirement of YHT1 level of ferric oxide, and those of Si, Ca meet the requirement of YHT3 level of ferric oxide. XRD and SEM characterizations confirm that the obtained sample is well-dispersed spindle spherule with regular a-Fe2O3 crystal structure. The length-to-diameter ratio ofa-Fe2O3 powder is （3-4）：1 with an average particle size of 0.5 μm.

Fabrication of Mg(OH)_2 Powders by Decomposition of Mg_3N_2 Powders

Mg（OH）2 powders were formed by the decomposition of Mg3N2 powders synthesized by a simple reaction of Mg with N Ha. X-ray diffraction（XRD）, Fourier transform infrared spectroscopy （FTIR）, and scanning electron microscopy（SEM） were used to study the structure, composition and morphology of the products. Mg （OH）2 nanowires with an average diameter about 300 nm-500 nm were found in these Mg（OH）2 powders.

Review of Determination of Minimum Ignition Energy of Combustible Gases or Dusts

MIE is an important parameter to be used to rank the ignition risk of the combustible materials.Commonly used electric circuits for generating spark have been reviewed and their features are analyzed in detail.Attention to avoiding test errors is stressed.Ranking of ignition risk is suggested based on MIE data.

Utilization of Sweet Potato Starch for Producing Biocomposite Semiconductor Materials

Starch is one of the most promising natural polymers source However, the properties of starch-based materials are not satisfactory. because it is an adsorbent, universally available and low cost. This weakness can be overcome by adding other materials to form biocomposite. Biocomposite is a composite material of a natural polymer （organic phase） and reinforcement/filler （inorganic phase）. The use of filler material that has the properties of semiconductor will produce composite that have semiconducting properties as well. In this research, biocomposite was cast using ZnO as filler in the matrix of sweet potato starch plasticised by glycerol. From the results of XRD （X-ray diffraction） and SEM （scanning electron microscope） analysis showed that ZnO has been dispersed in the matrix and the results of FT-IR was found that sweet potato starch, glycerol, and ZnO are united to form biocomposite. From the test results of mechanical, physical and electrical properties were found that the addition of ZnO concentration of 1%, 3% and 6% lead to improvement of tensile strength from 24.68 kgf/cm2 to 34.43 kgffcm2, decrease in elongation from 26.96% to 8.5%, decrease in water vapour transmission rate from 8.6270 gr·m^2·h^-1 to 4.581 gr·m^2·h^-1, increase in UV absorbance, and conductivity of 5.864 × 10^-7 S/cm. Addition of glycerol concentration of 15%, 25% and 35% wt causes an increase in elongation from 8.75% to 33.04%, and decrease in tensile strength from 54.57% to 14.64%.

Structure, Energy Band Gap and Electrical Conductivity of Tapioca/Metal Oxide Composite

A natural polymer composite is the main choice to replace composites from petroleum derivatives. A composite is formed in two or more phases （i.e., organic and inorganic phases）. A composite that has specified energy band gap, electrical conductivity, and tensile strength can be used as semiconductor material. The objective of this research was to study the effect of production methods, concentration and type of metal oxide filler （TiO2, A1203, Fe203, and ZnO） on structure, energy band gap, and electrical conductivity of composites. Composites were prepared using a melt intercalation process with tapioca as a matrix and addition of 1%, 3%, 5o and 7% filler concentrations, and sonication processing time in interval of 40, 50, and 60 min. Structure and morphology of the composite were analyzed using FT-IR, XRD, SEM, and TEM. UV-vis was used to measure the energy band gap while electrical conductivity was measured using a potentiostat through determination of resistivity. In addition, tensile strength and elongation were measured by ASTM 822-02. The energy band gap of the tapioca/metal oxide composite was between 4.9-1.62 eV. Electrical conductivity showed a percolation thresholds for concentrations of 3%-5% TiO2, A1203, and Fe203 and 7% ZnO. The tapioca/ZnO composite with 5% ZnO and 50 min of processing time showed a maximum tensile strength of 74.84 kgf/cm2, 6% elongation, 1.27 - 10^-7ohm^-1cm^-1 electrical conductivity and energy band gap of 3.27 eV. The characteristics described show that the tapioca/metal oxide composite can be used as a semiconductor material.

山西卓锋钛业3D打印用球形海绵钛粉研制成功

山西卓锋钛业有限公司把握商机,瞄准钛产业高端市场,经历两年多的研发试验,成功研制出3D打印球形海绵钛粉,填补了我国钛工业高端钛粉产业和技术的空白,打破了西方发达国家对这一项目的垄断。3D打印的适用材料钛合金球形粉末,一直是制约3D打印技术发展的关键环节,为美、德、英等西方发达国家所垄断,其进口价格高达每吨400~600万元。为此。

Enhanced Li^＋ storage properties of few-layered MoS2-C composite microspheres embedded with Si nanopowder

A few-layered MoS2-C composite material is studied as a supporting material for silicon nanopowder. Microspheres of the few-layered MoS2-C composite embedded with 30 wt.% Si nanopowder are prepared by one-pot spray pyrolysis. The Si nanopowder particles with high capacity are completely surrounded by the few-layered MoS2-C composite matrix. The discharge capacities of the MoS2-C composite microspheres with and without 30 wt.% Si nanopowder after 100 cycles are 1,020 and 718 mAh·g^-1 at a current density of 1,000 mA·g^-1 respectively. The spherical morphology of the MoS2-C composite microspheres embedded with Si nanopowder is preserved even after 100 cycles because of their high structural stability during cycling. The MoS2-C composite layer prevents the formation of unstable solid-electrolyte interface （SEI） layers on the Si nanopowder. Furthermore, as the MoS2-C composite matrix exhibits high capacity and excellent cycling performance, these characteristics are also reflected in the MoS2-C composite microspheres embedded with 30 wt.% Si nanopowder.