钎焊工艺对Au-Sn/Ni焊点组织及力学性能的影响*

通过回流焊技术制备Au-Sn/Ni焊点,通过扫描电子显微镜和能谱检测分析钎焊接头的微观组织及其相组成,利用疲劳试验机对焊点的剪切强度进行检测,研究不同钎焊工艺对Au-Sn/Ni焊点组织和力学性能的影响。结果表明,在310 ℃钎焊1 min的Au-Sn/Ni焊点经过水冷或空冷后,焊料内部均形成镶嵌有离散分布的(Ni,Au)₃Sn₂相的(Au₅Sn+AuSn)共晶组织,焊料/Ni界面处形成(Ni,Au)₃Sn₂金属间化合物(intermetallic compound,IMC)层;钎焊后炉冷的焊点,由于冷却速度过慢,导致焊料中Ni质量分数增大,(Ni,Au)₃Sn₂相异常长大消耗共晶组织中的(Au,Ni)Sn相,焊料共晶组织消失。随着钎焊时间的延长,基板中的Ni原子不断往焊料扩散,界面处的IMC层厚度均有不同程度的增加。随钎焊时间延长焊点的剪切强度逐渐下降,而剪切断裂模式为脆性断裂,发生在焊料与金属间化合物层的界面处。Au-Sn/Ni焊点在310 ℃下钎焊1 min,并采用水冷方式时得到的力学性能最佳。     

ICP-AES法测定标准阴极铜中的砷、铋、铁、镍、锡和锌

采用ICP－AES法测定标准阴极铜中的砷，铋，铁，镍，锡和锌等6种元素的含量。用（1＋1）硝酸溶解样品，ICP－AES仪器测定。本方法简单，快速，测定结果准确。     

羧甲基纤维素钠及其金属配合物的合成与表征

以羧甲基纤维素钠（CMC）为配体,与二价金属镍进行配位反应,生成CMC—Ni（Ⅱ）配合物,对该金属配合物可能的结构通过元素分析、红外光谱进行了确认。试验结果表明,生成的有机金属化合物是以金属镍离子为中心的八面体几何结构,其分子式可能为NiM·4H2O,而发生配位的有机官能团主要是羧基和羟基基团。     

电沉积铜／镍纳米多层膜及巨磁阻效应

以（110）高择优的Cu片为基体,在硫酸盐溶液中采用常规脉冲法制备了不同调制波长的Cu／Ni纳米多层膜。利用扫描电镜（SEM）分别对多层膜的断面及表面进行表征。结果表明,Cu／Ni纳米多层膜子层厚度均匀连续,且表面与调制波长有紧密联系。利用传统的四探针法对多层膜巨磁阻（GMR）进行测试。结果表明,在一定调制波长范围内GMR值随调制波长增大而减小。分别对铜和镍子层厚度及周期数进行优化,制备出GMR值高达34．4％的Cu／Ni多层膜。     

镍基合金耐蚀井管可加工性评述

以BG2250-125为例,阐述了镍基合金油井管的材料特点及物理性能,深入研究其可加工性,并以有限元仿真的结论为依据,探讨镍基合金油井管的加工参数。     

1Cr18Ni9Ti不锈钢在高温运行条件下的组织变化及其对性能的影响

对在炼油厂催化裂化高温烟机入口管线上使用的1Cr18Ni9Ti不锈钢的组织进行了试验分析，同时研究了其组织的变化对不锈钢力学性能和物理性能的影响。结果表明：不锈钢高温使用性能的变化是管线裂纹失效的主要原因，这对今后1Cr18Ni9Ti不锈钢的生产和使用将会起到一定的借鉴作用。     

Podocyte electrophysiology,in vivo and in vitro

Podocytes are the most differentiated cell types in the glomerulus, which have been assumed to participate in the regulation of the ultrafiltration coefficient K(f). In podocytes in vivo and in vitro vasoactive agonists, such as angiotensin II and acetylcholine, increase the free cytosolic Ca(2+) concentration via a release of Ca(2+) from intracellular stores and an influx of Ca(2+) from the extracellular space. An increase of the cytosolic Ca(2+) in podocytes activates Cl(-) channels in podocytes in vivo and in vitro, resulting in a depolarization of podocytes. In vitro studies have shown that in addition to Ca(2+)-activated Cl(-) channels, cAMP-activated Cl(-) channels and Ca(2+)-activated K(+) channels are present in cultured podocytes. The characterization of the signaling pathways that regulate ion channels in podocytes may be important in the understanding of the regulation of the ultrafiltration coefficient K(f). This review summarizes the currently known electrophysiological properties of podocytes.     

化学镀Ni—B合金与有机钼对金属基体的双重保护

采用表面镀层和润滑油中加入某些添加剂，使两者产生协同效应，是减少相对运动的零件表面间摩擦磨损的一项有效措施，本文研究了Ｎｉ－Ｂ合金镀层与油溶性有机钼的联系及摩擦磨损机理，摩擦磨损实验结果表明，Ｎｉ－Ｂ合金镀层与油溶性有机钼（ＭｏＤＴＰ）有良好的协同效应，可大幅度提高运动副的减摩性和耐磨性，如Ｎｉ－Ｐ合金镀层经４０℃热处理，油中加ＭｏＤＴＰ比４５钢基础油润滑下，耐磨性提高１２．８倍，摩擦系数降低５４     

电铸制备SiC颗粒增强镍基复合材料的工艺与性能

采用电铸技术(氨基磺酸镍电铸液)成功制备了SiC颗粒增强镍基复合材料;用Leica Qwin图形分析软件和显微硬度计分析了电铸工艺参数对SiC颗粒增强镍基复合材料中SiC颗粒含量以及SiC含量对该复合材料显微硬度的影响;用场发射扫描电镜分析了复合材料的截面形貌和SiC分布.结果表明:在SiC加入量50 g·L-1、电流密度3 A·dm-2和磁力搅拌强度1.5次/min条件下,复合材料中SiC颗粒体积分数达到最高值27%,其显微硬度值也最高,为710 HV.     

不同热处理对1Cr17Ni2钢材料性能及其应用的影响

研究两种不同热处理工艺对1Cr17Ni2钢材料性能的影响。通过相关的性能试验进行对比研究,试验包括抗拉试验、冲击韧度、应力腐蚀、常温拉伸疲劳、超声疲劳试验。研究结论为,对于1Cr17Ni2钢,使用相应于830MPa名义强度的热处理工艺,材料的综合性能优于名义强度为1080MPa的热处理工艺,这对在航空紧固件结构中合理选用1Cr17Ni2钢有实际指导意义。     

1Cr11Ni2W2MoV和16Ni3CrMoE两种钢的高温扭转疲劳性能研究

对1Cr11Ni2W2MoV和16Ni3CrMoE两种钢的高温扭转疲劳性能进行研究,采用三参数幂函数法拟合试验数据,并就温度、试样类型等因素对材料扭转疲劳强度的影响作简要分析.     

Time-of-flight atom probe measurements on Ni3Al and Co3W

In this study, a VG FIM100 was taken into operation, consisting of a field-ion microscope (FIM), a time-of-flight atom probe (TOFAP) and an imaging atom probe. A tungsten specimen was used to calibrate the conversion of flight times to m/n values. The resulting relative mass resolution of the TOFAP was calculated to be m/Deltam approximately 500 FWHM. In time-of-flight measurements of homemade boron-doped Ni-rich Ni(3)Al, a so-called ladder diagram was constructed from the evaporation data of a <001> pole. This ladder diagram revealed a very high degree of ordering in the alternating pure Ni and mixed Ni/Al planes: only 0.4% of the detected Al atoms were located on pure Ni planes. The number of null pulses to start a new plane was found to be much higher for Ni/Al planes (5 x 10(2)) than for Ni planes (1 x 10(2)). Moreover, the ladder diagram showed that boron was uniformly distributed through the matrix with nearly all boron found on pure Ni-planes. The suggestion that boron preferentially settles on these planes would be supported by reports of a strong Ni-B bond, since on Ni planes, B atoms can be accommodated on octahedral interstitial sites surrounded by only Ni atoms. Finally, we performed time-of-flight measurements on Co(3)W. The ion species observed in these measurements included a wide variety of WN(n)(2+) ions, with 0相似文献   

Ni/Al多层板的复合法制备及放热性能

在纯铝箔上化学镀镍得到微米级厚度的镍层,再将该镀镍铝箔堆垛热压后进行累积叠轧(1~7道次),得到Ni/Al多层板,研究了该多层板的组织结构及放热性能。结果表明:化学镀镍层为非晶态,在热压过程中发生晶化;随着叠轧道次的增加,镍层逐渐发生颈缩和断裂,其碎片镶嵌在铝中,增加了镍和铝的接触面积,从而提高了Ni/Al多层板的放热性能,其能量密度由1道次的520.27J·g^-1增大到7道次的1203.4J·g^-1,达到理论值的87.15%;不同道次叠轧Ni/Al多层板的起始反应温度均高于475℃,说明该多层板具有良好的室温稳定性。     

电感耦合等离子体发射光谱测定锂离子电池材料中钴、镍、锰的含量

本文报道了用电感耦合等离子体发射光谱（ICP～OES）仪测定锂离子电池材料中钴镍和锰量的试验。通过试验选择了测定酸度,测定波长。锂电池材料用盐酸溶解。锂电池材料用盐酸溶解,在5％的盐酸介质中,在波长Co257．8nm、Mn294．9nm、Ni352．4nm处测定其强度。回收率在96％～104％之间,相对标准偏差（RSD％）0．35％-0．40％之间。测定值与推荐值符合。本法简便、快速、准确。     

电沉积纳米晶材料摩擦学尺寸效应研究

采用脉冲电沉积法制备了不同晶粒尺寸的纳米晶镍材料,实现了纳米晶粒的有效可控。考察了晶粒尺寸对纳米晶镍材料摩擦磨损性能的影响。结果表明:粗晶镍呈现严重的粘着磨损,随着晶粒的细化,硬度和强度的增加显著提高了镀层的抗塑性变形和抗粘着磨损的能力。电沉积镍具有明显的摩擦学尺寸效应,随着晶粒尺寸的减小,镍的磨损机制由粘着磨损逐渐转变为微磨粒磨损和氧化磨损,其摩擦因数逐渐降低,耐磨性显著增强。     

超声电沉积镍/纳米碳化硅复合镀层组织结构研究

采用超声电沉积方法在20钢基体上制备了镍／纳米碳化硅的复合镀层。通过扫描电镜(SEM)观察了镀层的表面形貌和显微组织，用能谱仪(EDS)对镀层中特定区域进行了显微组织成分分析，使用X射线衍射仪检测了镀层的微观结构。结果表明：通过合适的超声电沉积工艺，得到的镀层中SiC纳米粒子含量较高，且分散均匀，没有出现团聚现象；同时镀层中的镍晶粒得到了细化，取向也由择尤取向趋于随机取向。     

Structural and mechanical properties of (Cr,Ni) N single and gradient layer coatings deposited on mild steel by magnetron sputtering

Ternary single and gradient layer (Cr, Ni) N thin films were deposited on the mild steel substrate by unbalanced magnetron sputtering technique in order to evaluate mechanical properties for machine tools and automotive applications. Microstructure, chemical composition, surface morphology and phase analysis were carried out using field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force microscopy and X-ray diffraction, respectively. Both single and gradient layer of (Cr, Ni) N coatings show a significant increment in mechanical properties such as hardness, adhesion strength and surface roughness along with the reduction of friction coefficient. Mechanical tests revealed that the hardness of the gradient layer increased up to 3.1 times due to the formation of Cr₂N and Ni phase whereas single layer showed the least friction. Single layer CrNiN layer exhibited 27.2% less surface roughness (R_a) in comparison with gradient layer. High values of surface roughness, hardness, thickness and friction could be correlated with high film-to-substrate adhesion (L_c2) for the gradient layer.     

三牙轮钻头材料Ni65的冲蚀磨损机制研究

针对三牙轮钻头流道内实际工况,研究了钻头材料N i65和对比材料N i67和N i60 35%WC的冲蚀磨损特性。结果表明:N i65和N i67的冲蚀磨损阶段分为跑合期和稳定期,N i65磨损机制主要是微切削,而N i67的磨损机制主要是疲劳损伤和微切削;而N i60 30%WC的冲蚀磨损阶段为跑合期与周期性的稳定磨损和严重磨损期,其磨损机制主要是硬质点的脱落和疲劳点蚀。在试验过程中均伴有空蚀磨损。     

Cryo-X-ray analysis-A novel tool to better understand the physicochemical reactions at the bioglass/biological fluid interface

The present study deals with the short-term physicochemical reactions at the interface between bioactive glass particles [55SiO(2)-20CaO-9P(2)O(5)-12Na(2)O-4MgO. mol%] and biological fluid (Dulbecco Modified Eagle's Medium (DMEM)). The physicochemical reactions within the interface are characterized by scanning transmission electron microscopy (TEM) (STEM) associated with Energy-dispersive X-ray spectroscopy (EDXS). Microanalysis of diffusible ions such as sodium, potassium, or oxygen requires a special care. In the present investigation the cryo-technique was adopted as a suitable tool for the specimen preparation and characterization. Cryosectioning is essential for preserving the native distribution of ions so that meaningful information about the local concentrations can be obtained by elemental microanalysis. The bioglass particles immersed in biological fluid for 24 h revealed five reaction stages: (i) dealkalization of the surface by cationic exchange (Na(+), Ca(2+) with H(+) or H(3)O(+)); (ii) loss of soluble silica in the form of Si(OH)(4) to the solution resulting from the breakdown of Si--O--Si bonds (iii); repolymerization of Si(OH)(4) leading to condensation of SiO(2)); (iv) migration of Ca(2+) and PO(4) (3-) to the surface through the SiO(2)-rich layer to form CaO-P(2)O(5) film; (v) crystallization of the amorphous CaO-P(2)O(5) by incorporating OH-- or CO(3) (2-) anions with the formation of three different surface layers on the bioactive glass periphery. The thickness of each layer is approximately 300 nm and from the inner part to the periphery they consist of Si--OH, which permits the diffusion of Ca(2+) and PO(4) (3-) ions and the formation of the middle Ca--P layer, and finally the outer layer composed of Na--O, which acts as an ion exchange layer between Na(+) ions and H(+) or H(3)O(+) from the solution.     

激光熔覆Ni/TiC复合涂层组织与性能

采用激光熔覆技术在45钢样品表面制备了Ni/TiC复合涂层,利用光学显微镜、SEM,EDS,XRD、显微镜硬度计及摩擦磨损试验机等检测设备研究了Ni/TiC复合涂层的组织和性能。试验结果表明：Ni/TiC复合涂层没有出现裂纹、孔洞等缺陷,涂层与基体之间具有良好的冶金结合,涂层显微硬度沿层深皆呈明显的阶梯状分布,最外表面的熔覆层硬度最高,约为800 HV;熔覆试样的比磨损率比基体试样的比磨损率下降了86.5％,表明Ni/TiC复合涂层具有较好的耐磨性能。