Crystallization characteristics of Ni-W-P composite coatings reinforced by CeO_2 and SiO_2 nano-particles

Ni-W-P composite coatings reinforced by Ce O2 and Si O2 nano-particles on the surface of common carbon steels, were prepared by double pulse electrodeposition. The crystallization course was characterized by phase structures, crystallinity, grain sizes and microstructures. The results indicate that as-deposited composite coating is amorphous. Whereas it turns into the crystalline structure with 98.25% crystallinity, and Ni3 P, Ni2 P and Ni5P2 alloy phases precipitate from structures at 400 °C. Thereafter, Ni2 P and Ni5P2 metastable alloy phases turn into Ni3 P stable alloy phase at 500 °C. The crystallization course of the composite coating has finished when being heat-treated at 700 °C. The average sizes of Ni grains increase with the rise of heat treatment temperature from400 °C to 700 °C. Ce O2 and Si O2 nano-particles deposited into Ni-W-P alloys can delay the crystallization course and habit the growth of alloy phases.     

纳米颗粒强化氨水鼓泡吸收性能的机理与影响因素

基于Danckwerts的界面更新模型和Langevin方程,分析了纳米颗粒对氨水鼓泡吸收性能影响的非均相膜传递和液相内传递过程,初步解释了纳米颗粒强化氨水鼓泡吸收性能的机理.认为纳米颗粒对氨水鼓泡吸收的强化过程包括液相强化和界面强化两个同时进行的子过程,而对于界面传递,由于纳米颗粒引起的Marangoni对流,使其强...     

载荷对n-SiC/Ni镀层腐蚀磨损协同作用的影响

对不同载荷下n-SiC/Ni镀层在5%H2SO4溶液中磨损试验进行了研究,通过电化学试验和失重法计算出腐蚀磨损质量损失中各分量的损失,结果表明,随着载荷的增加腐蚀磨损协同作用成为镀层失重的主要原因,并且协同作用中以腐蚀促进磨损为主。腐蚀磨损的极化曲线和表面微观形貌证实了载荷为100N和300N时,镀层在磨损过程中没有出现钝化膜;载荷为200N,镀层表面生成钝化膜,并且钝化膜在摩擦力作用下很快破裂,从而加速腐蚀,接着又形成新的钝化膜。     

Alloys Preparation of Ag Particles/Islands on Si Wafer by RF Magnetron Sputtering

In order to investigate the morphology change of Ag nano-particles/island film with the sputtering time and annealing temperature,Ag nano-particles/island films were sputtered on the silicon wafers by radio-frequency(RF)magnetron sputtering.Ag nano-particles/islands films were sputtered on Si wafer with different time.After sputtering,the samples with Ag nano-particles/islands films were annealed at 100,200 and 400 o C for 1 h,respectively.Raman spectrum was employed to examine the phase stability of Ag particles/island film after annealed at 400 o C for 1h.The result showed that the Raman spectrum peak of Ag particles/island film with annealed at 400 o C was similar to that of pure Ag.Scanning electron microscope(SEM)was used to test the microstructures and morphology of the films with different condition.To further study the morphology change,atomic force microscope(AFM)was used to test surface morphology of the Ag particles/islands films.The SEM and AFM results showed that the morphology of Ag nano-particles/island films were different with the increasing sputtering time.Ag particles went through a dramatic change on the Si wafer surface,when sputtering time changed from 3 to 60 s,Ag particles diffused and agglomerated with the annealing temperature increasing.     

纳米镍粉在钛合金-不锈钢扩散焊接中的应用

采用恒温恒压扩散焊、相变超塑性扩散焊、冲击加压扩散焊对直接对焊和加纳米镍粉中间层的钛合金-不锈钢焊接接头进行了研究。测试了接头强度,并进行了断口形貌观察和组织分析,结果表明：3种试验方法中,恒温恒压扩散焊所得接头强度较小,而冲击加压扩散焊所得接头强度较高;直接扩散焊时,接头上两种基体材料之间的互扩散程度很大程度上影响了钛合金-不锈钢接头的强度;采用纳米镍粉作中间层能形成强度较高的接头,达到了213MPa、但纳米镍粉的致密度不够高,接头的强度在很大程度上受到了限制。     

纳米-微米复合图形化衬底及其在半导体异质外延上的应用

报道了一种新型的纳米-微米复合的蓝宝石图形化衬底,采用dip-coating的方法在微米级SiO2半球阵列表面静电自组装一层SiO2纳米球,形成了适合纳米范围选择性生长的区域。研究发现,该复合结构的制备过程与后续外延的工艺兼容。经封装后,在复合图形衬底上制造的LED芯片,其所测试的光通量比未添加SiO2纳米颗粒的微米图形衬底制造的LED光通量提高57%左右,而光输出功率则提高了17.8%。研究表明,在传统的微米图形衬底上加入SiO2纳米颗粒阵列不仅能够提供纳米级区域外延生长的模板,有效减少外延层的线位错密度,而且能够进一步粗化衬底表面,增加有源层光线逸出的几率,从而有效地提高了光提取效率。     

Electrical properties of sub-100 nm Cu films deposited by electroless plating on amino-terminated silicon oxide activated with Au nano-particles

Self-assembled organic monolayers (SAMs) are good coupling agents and diffusion barriers at Cu/SiO₂ and Cu/low-k interfaces and are considered therefore as important elements of future all-wet ULSI metallization with sub-45 nm Cu deposited by electroless plating (ELD). We formed SAM of 3-aminopropyltrimethoxy silane (APTMS) onto SiO₂/Si substrate, activated the surface of APTMS with 5, 8, 15 and 25 nm Au nano-particles (AuNPs), deposited (30-100) nm films of Cu by ELD and measured electrical resistivity ρ of the films in the as-deposited state and after vacuum annealing at 220 C. The size of AuNPs was found to be a key factor in getting low resistance sub-100 nm Cu films by ELD. The resistivity ρ ≈ 4 ± 0.8 μΩ·cm - considerably smaller compared to the previously reported data - was achieved with the use of 5 nm AuNPs. XPS and AFM revealed nano-pores, which can contribute to ρ but do not compromise likely the diffusion barrier properties of the SAM.     

混合纳米粒子作为润滑脂添加剂最佳配比的实验研究

在MRH-3型高速环块摩擦磨损试验机上,研究混合纳米粒子Al2O3-Al-Cu和Al2O3-Al-MgO作为润滑脂添加剂的摩擦学性能,通过减摩、表面修复以及抗极压性能实验,确定混合纳米粒子的最佳配比。结果表明:在几种纳米粒子之间的协同作用下,含有混合粒子Al2O3-Al-Cu和Al2O3-Al-MgO的润滑脂具有良好的表面修复、抗极压等摩擦学特性,混合粒子比多数单粒子在减摩方面都具有更好的效果。     

超临界法制备(CeZrLaPr)O稀土汽车尾气催化剂的研究

以CeZrLaPr氢氧化物为前驱体,经乙醇洗涤置换成醇凝胶。CeZrLaPr氢氧化物在乙醇溶剂中,当温度和压力超过乙醇临界点(243℃,6.4 MPa)时,氢氧化物脱水、晶化和干燥3个过程一步完成,制得粒径5 nm、具有高储氧能力(OSC)的(CeZrLaPr)O稀土汽车尾气催化剂,并可实现规模化生产。     

微粒团聚的尺度效应及其分形表征

利用全自动激光粒度分析仪,研究了乙醇分散液中羟基磷灰石微粒团聚过程中粒径分布、微粒的平均团聚粒径和比表面积随微粒团聚时间的变化关系,以及微粒质量分数对平均团聚粒径和比表面积的影响,对微粒团聚平均粒径、比表面积及团聚速率与微粒质量分数及微粒团聚时间的关联性进行了分形表征。结果表明：随微粒团聚时间的延长,所测微纳米微粒的最大分布粒径值、最小分布粒径值逐渐增大,分布曲线有逐渐向正态分布发展的趋势;随团聚时间增加,或微粒质量分数的增大,微粒团聚平均粒径逐渐增大,而比表面积逐渐减小,并都在一定的时间内达到动态平衡;微粒团聚速率分形维数可以客观地描述微粒团聚基本规律,当微粒质量分数一定时,微粒团聚分形维数越大,其团聚速度越大,当微粒团聚分形维数一定时,微粒质量分数越大,团聚速率越大。