AgNi15 composite particles prepared by ultrasonic arc spray atomization method

Ultrasonic arc spray atomization (UASA) method was used to prepare high-melting-point, immiscible AgNi15 (mass fraction, %) composite particles. Sieving was used to determine the size distribution of the AgNi15 particles. The morphology, rapidly solidified structure and metastable solution expansion of the AgNi15 particles were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS), respectively. The results show that the AgNi15 composite particles are spherical and well-dispersed, and the mass fractions of the particles with diameters <74μm and <55 μm are 99.5% and 98%, respectively. The rapidly solidified structure of the AgNi15 particles consists of spherical nickel-richβ(Ni)-phase particles dispersed throughout a silver-richα(Ag)-phase matrix andα(Ag)-phase nanoparticles dispersed throughout largerβ(Ni)-phase particles. The silver and nickel in the AgNi15 particles form a reciprocally extended metastable solution, and the solid solubility of nickel in the silver matrix at room temperature is in the range of 0.16%?0.36% (mole fraction).

Tribological properties of nanostructured Al_2O_3-40%TiO_2 multiphase ceramic particles reinforced Ni-based alloy composite coatings

The Ni-based alloy composite coatings reinforced by nanostructured Al2O3-40%TiO2 multiphase ceramic particles were prepared on the surface of 7005 aluminum alloy by plasma spray technology. The microstructure and tribological properties of the composite coatings were researched. The results show that the composite coatings mainly consist of γ-Ni, α-Al2O3, γ-Al2O3 and rutile-TiO2 etc, and exhibit lower friction coefficients and wear losses than the Ni-based alloy coatings at different loads and speeds. The composite coating bears low contact stress at 3 N and its wear mechanism is micro-cutting wear. As loads increase to 6-12 N, the contact stress is higher than the elastic limit stress of worn surface, and the wear mechanisms change into multi-plastic deformation wear, micro-brittle fracture wear and abrasive wear. With the increase of speeds, the contact temperature of worn surface increases. The composite coating experiences multi-plastic deformation wear, fatigue wear and adhesive wear.

PREPARATION OF 6066 Al/SiC_p(+Gr) COMPOSITES BY MULTI-LAYER SPRAY DEPOSITION

ＰＲＥＰＡＲＡＴＩＯＮＯＦ６０６６Ａｌ／ＳｉＣ_ｐ（＋Ｇｒ）ＣＯＭＰＯＳＩＴＥＳＢＹＭＵＬＴＩ－ＬＡＹＥＲＳＰＲＡＹＤＥＰＯＳＩＴＩＯＮ￥ＣｈｅｎＺｈｅｎｈｕａ；ＺｈａｎｇＨａｏ；ＣｈｅｎＧａｎｇ；ＬｉｕＱｉｕｌｉｎ；ＳｕｎＺｈａｎｇｍｉｎｇ；Ｙａｎ?..

High Speed Steel and WC Particle-Reinforced Composites Produce by Spray Forming

The process of spray forming utilized to fabricate WC particle-reinforced high speed steel composites has been studied. In addition, microstructures and mechanical properties of M2 high speed steel and its composites made by spray forming have been analyzed. The results show that the primary carbides of high speed steel are of two types: MC and MbC. With the increase in flight distance, the morphology of the primary carbides varies from fine fish-bone-like to islandlike and both bending strength and hardness increase. With the increase in volume fraction of WC reinforcement particles,hardness of the composites increases considerably, but bending strength, however, appears to be a decreasing tendency.

Role of binders in reactive composites: A case study with spherical B/Pb_(3)O_(4) particles

The strategic selection of appropriate preparation methods and binder strategies is crucial for enhancing the particle and combustion performance of pyrotechnic delay compositions(PDCs).This study,utilizing droplet microfluidics technology(DMT)and micron-scale raw materials,prepared spherical B/Pb_(3)O_(4) composite particles with varying concentrations of fluorine rubber(F_(2604)).The morphology,specific surface area,bulk density,flowability,friction sensitivity,thermal decomposition,and combustion performance of these microspheres were characterized.The results indicate that as the binder content increases,the particle size of the microspheres first decreases and then increases,the specific surface area decreases,and the bulk density increases,correlating with tighter binding of the reactant powders by the binder.Furthermore,tighter powder-to-powder binding results in a progressive decrease in the thermal decomposition peak temperature of the samples(from 404.2℃ to 346.4℃).Additionally,increased binder content reduces the friction sensitivity and combustion rate of the samples,which is attributed to the energy absorption properties of the binder.Compared to the control group,the microsphere samples exhibit significantly enhanced bulk density,flowability,friction safety,and combustion delay precision,potentially improving the reliability of PDCs in ignition sequences.

INVESTIGATION ON MECHANICAL PROPERTIES OF ZN-AL/SIC PARTICULATE COMPOSITES

In order to improve the properties of ZA 27 and ZA4-3 zinc alloys and broaden their application ranges,SiC particlj1Ale composites, prepared by means of rheological casting technology, are investigated individually on their rT..t'llanical properties. The results of ne-cural strength, impact strensttl, compressive strength, hardness values and wear rate of the composites show that the addition of SiCp, leads to the increase of the compressive strength and hardness values at both room and higher temperature, and wear resistance of the materials, accompanying with the slight decrease of the fie-cural strength and sharp reduction of the impacttoughness. The factors affecting the mechanical properties of the composites are discussed in the paper.

WC Particle High Speed Steel Composites Manufactured by Ultrasonic Spray Forming

The process of manufacturing high speed steel matrix composites reinforced by WC particles was studied. The changes in microstructures and mechanical properties of composites with WC particles were also investigated. The results show that increasing the deposition height can significantly enhance the bending strength and hardness of the alloy, and that the fishbone like carbide ledeburite structure gradually diminishes as the WC particles content increases. It was discovered that the hardness of the composites increases due to the increase of pointlike carbide ledeburite, accompanying the breaking of the fishbone like and the net like carbides. However, the bending strength deteriorates due to excessive WC particles increasing the brittle interfacial phase.

Electrochemical characterization and microstructure of cold sprayed AA5083/Al_(2)O_(3) composite coatings

This work focused on the role of Al_(2)O_(3) particles in the corrosion behavior of cold sprayed AA5083 aluminum alloy matrix composite(Al-MMC)coatings.The electrochemical characterization of the coatings was investigated in a 3.5 wt.%NaCl solution as a function of time.The results show that fragmentation of Al_(2)O_(3) particles is not clearly observed in the case of AA5083/20 vol.%Al_(2)O_(3) coating,while the broken Al_(2)O_(3) particles can be seen clearly in AA5083/40 vol.%Al_(2)O_(3) and AA5083/60 vol.%Al_(2)O_(3) coatings.The addition of 20 vol.%Al_(2)O_(3) particles yield the coating with the lowest porosity,and different volume fractions of Al_(2)O_(3)in the feedstock have important effects on the electrochemical behavior of composite coatings.The Al-MMC coating reinforced with 20 vol.%Al_(2)O_(3) particles exhibits the highest Ecorrand the lowest icorrcompared with the other conditions.The order of current density is as follows:AA5083/20vol.%Al_(2)O_(3)<AA5083<AA5083/40 vol.%Al_(2)O_(3)<AA5083/60 vol.%Al_(2)O_(3).

Spray pyrolysis synthesis of nickel-rich layered cathodes LiNi_(1-2x)Co_xMn_xO_2(x = 0.075, 0.05, 0.025) for lithium-ion batteries

In this study we report a series of nickel-rich layered cathodes LiNi1-2xCoxMnxO2（x = 0.075, 0.05,0.025） prepared from chlorides solution via ultrasonic spray pyrolysis. SEM images illustrate that the samples are submicron-sized particles and the particle sizes increase with the increase of Ni content.LiNi0.85Co0.075Mn0.075O2 delivers a discharge capacity of 174.9 mAh g-1 with holding 93% reversible capacity at 1 C after 80 cycles, and can maintain a discharge capacity of 175.3 mAh g-1 at 5 C rate. With increasing Ni content, the initial specific capacity increases while the cycling and rate performance degrades in some extent. These satisfying results demonstrate that spray pyrolysis is a powerful and efficient synthesis technology for producing Ni-rich layered cathode（Ni content 〉 80%）.

纳米材料制备技术及其研究进展

系统介绍了纳米材料体系中的纳米微粒、纳米薄膜和纳米复合材料的制备技术 ,对各种技术的特点进行了评述 。

颗粒增强金属基复合材料加工技术进展

颗粒增强金属基复合材料具有优良的物理力学性能,但材料的难加工特性限制了其应用。因此,对颗粒增强金属基复合材料加工技术的研究与发展是促进其进一步应用的关键之一。本文从加工方法、加工质量等方面综述了国内外颗粒增强金属基复合材料加工技术的进展情况,并指出了当前存在的问题及解决对策。

超细粒子及其复合技术在冷气溶胶灭火剂中的应用

概述了冷气溶胶灭火技术的现状,对超细微粒及复合粒子冷气溶胶灭火剂的制备、性能指标及灭火效能进行了研究测试,研究表明,NH4 H2 PO4 超细粒子及NaHCO3/SiO2 复合粒子应用于冷气溶胶灭火剂是可行的。

有机-无机复合粒子的制备技术研究进展

有机 无机复合粒子作为一种新型复合材料 ,结合了有机物和无机物的特点 ,已广泛应用于生物、医学、化工、电子、军事等领域。本文概述了有机 无机复合粒子的制备机理及制备技术的研究进展。

超细粒子复合技术进展

较全面、系统地综述了有关超细柱子(微米、纳米级)的复合技术,并按复合反应形式不同将其分类为物理复合法及化学复合法。同时对国内外近年来较新的复合技术(及设备)进行了介绍和说明,并对复合过程中一些需要注意的基本问题也作了简单的综述。另外,还阐述了粉末复合技术的发展方向。

悬浮聚合制备无机-高分子复合粒子的微观结构与形成机理

采用悬浮聚合工艺制备微米级铁红和苯乙烯 -丙烯酸丁酯共聚物复合粒子 ,通过跟踪观察体系在预分散过程的变化 ,分析相关表面张力、润湿角的测定结果 ,解释了复合粒子微观结构成因。实验测试结果显示在高速预分散过程 ,铁红以大部分伸入溶液水相的形式存在于油水界面 ;在SEM下观察到复合粒子的微观结构是铁红存在于复合粒子表面形成嵌入式结构。

碳化硅颗粒增强铝基复合材料研究现状与展望

分别从材料的制备工艺、性能与应用等方面,综述了碳化硅颗粒增强铝基复合材料的研究现状,分析了该材料在发展过程中存在的问题,并对其未来的发展进行了展望。

Ni-Al_2O_3纳米复合电镀工艺的初步研究

初步研究了复合电镀各工艺条件:电流密度、镀液pH值和温度以及搅拌方式对Al_2O_3纳米微粒在镍基复合镀层中含量的影响。研究表明:电流密度增大不利于提高镀层中纳米微粒的含量;pH值增大也明显使复合量降低;镀液温度升高,镀层中微粒的复合量随之略有改变;电镀时,加强搅拌或适当改变搅拌方式,可以使复合镀层中的纳米微粒含量提高。还利用扫描电镜及能谱对Ni-Al_2O_3镀层表面进行了观察与分析。

超细复合粒子制备技术研究

介绍了超细复合粒子的研究背景及其在各行业中的应用 ,其中详细综述了复合粒子的制备方法以及这些方法的基本原理和优缺点 。

Ni颗粒对SnBi焊点电迁移的抑制作用

为抑制芯片中微小焊点的电迁移,向共晶SnBi钎料中添加微米级Ni颗粒,并在φ0.5mm铜线接头上形成焊点。结果表明:当电流密度为104A/cm2、通电96h后,阳极附近没有出现富Bi层,即电迁移现象得到抑制。这是由于Ni颗粒与Sn形成了IMC,阻挡了Bi沿Sn基体扩散的快速通道,防止了两相分离,提高了焊点可靠性。

星点设计-效应面法优化复方巴戟天生骨颗粒提取工艺

目的:采用星点设计-效应面法优化复方巴戟天生骨颗粒的提取工艺。方法:按试验设计制备复方巴戟天生骨颗粒,以处方药材提取浓缩液中的淫羊藿苷含量、干膏率的综合评分OD为指标,分别对药材浸泡时间、料液比、提取时间、减压浓缩温度进行单因素考察,在此基础上选择对响应值有显著影响的料液比、提取时间、减压浓缩温度3个因素采取三因素五水平星点设计,考察其对该制剂提取效果的影响。结果:复方巴戟天生骨颗粒的最佳提取工艺为:料液比1∶11.33、提取时间39 min、减压浓缩温度66℃。成品的淫羊藿苷含量和干膏率与预测值的偏差分别为1.60%和1.55%。结论:星点设计-效应面法适用于复方巴戟天生骨颗粒工艺优化,该方法建立的数学模型预测性良好。