Cu-Sn-Ti体系边际二元系界面反应的研究

Cu-Sn-Ti三元系及其相关的3个二元系均具有重要的实用价值.实验制备了Ti/Sn和Cu/Sn固-液扩散偶及Cu/Ti二元固相扩散偶,经电子显微和探针观测发现: Ti/Sn固-液扩散偶在873K下退火30～160min,只生成1个Sn3Ti2中间相; Cu/Sn固-液扩散偶在808K下退火10min时也只生成1个Cu3Sn中间相,但退火时间延长至30min时在Cu与Cu3Sn界面上生成Cu41Sn11,退火60min后在Cu与Cu41Sn11之间又生成了bcc-a2; Cu/Ti二元固相扩散偶在1023K下退火1000h后,在其界面处生成了CuTi2、CuTi、Cu4Ti3、Cu4Ti 4个化合物,而Cu3Ti2相并未在扩散偶中出现.还采用最大驱动力模型对上述3个二元系的界面反应过程进行了计算并成功解释了相应的实验现象.     

623K温度下SnxZn1-x/Ni扩散偶的界面反应

为研究Sn-Zn合金(无铅焊料的候选者)和Ni基体(Cu基上的扩散阻挡层)的界面反应,制备一系列原子分数x分别为14.8％、22％和31％的液固扩散偶Sn1-xZnx/Ni;在623 K温度下恒温退火后,用扫描电镜和电子探针检测与分析扩散偶的界面结构,研究退火时间和合金中的Zn含量对扩散层结构和形貌的影响.结果表明,S...     

Cu-Ni-Sn扩散偶的界面过渡层固相序列分析

铍铜合金性能优异,但潜存毒性危害,Cu-Ni-Sn合金是一种典型的调幅分解强化型弹性铜合金,凭借其高的强度、硬度、弹性和优良的抗应力松弛性能,广泛应用于电子、航天、航海等领域,是替代铍铜的候选材料之一。然而Cu-Ni-Sn合金体系复杂,不同成分合金的性能差异较大,传统的研究材料的方法,一次只能研究一种或几种成分的合金,因此本文选择了"扩散多元节"高通量实验方法对Cu-Ni-Sn合金进行研究。本文采用CALPHAD相图计算手段,计算了Cu,Ni和Sn元素在相变过程中的活度变化曲线,根据元素活度在合金相中的范围大小对Cu-Ni-Sn三元扩散偶的Cu-Ni,Cu-Cu35Sn和Ni-Cu35Sn各个界面的固相序列进行了理论优化。通过Cu-Ni-Sn三元扩散偶实验,获得了CuNi,Cu-Cu35Sn和Ni-Cu35Sn扩散界面的过渡层组织形貌,结合理论计算结果,得到了可能的界面固相序列。在650℃条件下,Cu-Ni界面处仅有fcc_A1相的过渡层;Cu-Cu35Sn界面过渡层固相序列自富Cu端为fcc_A1→D03_Cu3Sn/Cu3Sn;Ni-Cu35Sn界面的固相序列自富Ni端为fcc_A1+Ni3Sn_LT→fcc_A1+Ni3Sn2→Ni3Sn2+D03_Cu3Sn/Cu3Sn。     

Al/Ni/Fe界面扩散反应的实验研究

采用"铆钉法"制备了含有Al/Ni、Al/Fe和Ni/Fe两相界面的扩散偶,以及Al/Ni/Fe多相扩散偶,利用光学显微镜、电子探针分别对每组扩散偶的界面区域进行了观察分析.实验结果显示,固态扩散促使两相界面处生成扩散层,Al/Ni/Fe多层扩散偶中,由于混相层中不同产物的生长速率不同,促使界面不稳定生长,形成束集型的扩散层结构.     

铜/钢扩散复合界面分析

用扫描电镜观察、能谱分析、电子探针和显微硬度测定等方法对铜／钢双金属棒扩散复合界面附近的组织、成分和硬度进行了分析。结果表明，铜／钢双金属通过扩散复合可使界面实现良好的冶金结合。随扩散温度的提高，两种金属的结合强度大大提高；随扩散时间的延长，结合强度先增加后趋于稳定，与一定的扩散温度相对应。扩散退火过程中，界面两侧的原子发生了互扩散。从扫描电镜和电子探针结果中可以确定铜／钢界面附近的氧化物为Fe2O3。     

TiNi合金轴向压缩动载荷下的超弹性研究

以高温固溶时效和中温退火处理过的Ti-50．7at％Ni合金为研究对象，考察了合金在试验温度为20℃，加载速率分别为3mm／min、15mm／min、30mm／min、50mm／min作用下的轴向压缩应力-应变行为。结果表明：2种热处理方式处理过的Ti-50．7at％Ni合金具有约4．5％～5．0％的非线性超弹性，高温固溶时效处理的合金由于析出相强化提高了合金母相强度，因而相变超弹性能比中温退火的合金要好，在相同试验条件下，高温固溶时效处理合金的加载-卸载曲线包围面积比中温退火的大，但随着加载速率的增加而减小；在较高加载速率下，中温退火的合金表现出近乎线性超弹性。     

Nb-Ti-Si三元系1 173 K等温截面的测定

运用扩散偶技术并结合电子探针微区成分分析方法，对Ni-Ti-Si三元扩散偶进行了相分析，测得了Ni-Ti-Si三元系1173K下所生成的7个扩散层，即TiSi2、TiSi、Ti5Si4、Ti5Si3、Ti3Si、Nb5Si3和NbSi2；未发现在元化合物。根据实验所得的结线数据并结合扩散偶中的相区分布规则，得出了Nb-Ti-Si三元系1173K下的等温截面。     

Fe-x%Mn/Super Dyma扩散偶中Fe-Al合金层的生长行为

Super Dyma锌铝镁硅合金镀层具有优良的耐腐蚀性能,在热浸镀锌工业中备受关注。为弄清锰元素对热浸镀Super Dyma合金镀层组织的影响,将Fe-x%Mn/Super Dyma固-液扩散偶在500, 550, 600和650℃分别进行10, 15, 20, 25和30 min的扩散退火,采用扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)等仪器研究了该扩散偶中合金层的相组成及其生长规律。研究结果表明:Fe-x%Mn/Super Dyma固-液扩散偶中的合金层由Fe_2Al_5相和FeAl_3相组成, Fe-Al合金层呈现抛物线生长规律,其生长受铁和铝原子扩散控制;随着扩散反应温度的提高, Fe-Al合金层的厚度明显增加;铁基合金中的锰元素具有抑制Fe-x%Mn/Super Dyma固-液扩散偶中Fe-Al合金层生长的作用,当锰含量为0.9%(质量分数)时,锰元素对扩散偶中Fe-Al合金层生长的抑制作用最明显。在热浸镀Super Dyma合金镀层时,最佳热浸镀温度温度为550～600℃。为得到合适的镀层厚度,可依据热浸镀温度确定合适的热浸镀时间和钢中的锰含量。     

基于钒铬渣钙化焙烧过程的V2O5/Cr2O3-CaO体系固相反应扩散行为

为探究钒铬渣钙化焙烧过程钒、铬组元与钙反应能力的差异,在热力学分析基础上,以V_2O_5、Cr_2O_3、CaO纯物质为原料,采用恒温焙烧法分别制备出V_2O_5-CaO与Cr_2O_3-CaO扩散偶。利用扫描电镜与能谱仪观测不同恒温时间后扩散界面的微观形貌以及产物层元素分布,分析恒温时间对固相界面反应的影响,并利用wagner方程对体系互扩散系数进行计算。结果表明:在空气气氛中873 K恒温焙烧9 h后,V_2O_5-CaO扩散偶界面产物层清晰,厚度与时间的平方根存在线性关系,说明该固相反应由扩散控速,产物以CaV_2O_6为主。而相同焙烧条件下,Cr_2O_3-CaO间未见明显的界面产物层,说明V_2O_5-CaO间固-固界面反应能力更强,其互扩散系数量级为10-10 cm~2·s~(-1)。     

退火对Ni80Fe20/Al2O3/Ag/Al2O3/Ni80Fe20平面自旋阀中自旋积累的影响

使用电子束蒸发镀膜方法在覆有掩膜板的SiO2/Si基片上制备了Ni80 Fe20/Al2 O3/Ag/Al2 O3/Ni80 Fe20结构平面自旋阀,研究了不同退火温度对Ni80 Fe20/Al2O3/Ag/Al2 O3/Ni80Fe20平面自旋阀中自旋积累的影响.使用非局域测量方法分别测量制备态以及300,400和500℃不同退火温度下Ni80 Fe20/Al2O3/Ag/Al2O3/Ni80Fe20平面自旋阀中Ag层中自旋积累信号的大小.实验结果表明:自旋积累信号在制备态下为1.3 mΩ;随着退火温度的升高,自旋积累信号也随着增大,并在500℃退火30 min后达到极大值(～14.5 mΩ),比制备态提高了一个数量级;进一步提高退火温度到600℃时,由于Ag层会凝聚成岛状结构而破坏Ni80 Fe20/Al2 O3/Ag/Al2 O3/Ni80 Fe20平面自旋阀中Ag层的连续性,使Ag层断裂,从而使测量到的自旋积累信号为0 mΩ.研究认为,Ni80 Fe20/Al2 O3/Ag/Al2O3/Ni80 Fe20平面自旋阀中自旋积累信号的增强主要是高的界面自旋极化率以及长的自旋扩散长度共同作用的结果.Ni80 Fe2/Al2O3/Ag/Al2 O3/Ni80 Fe20平面自旋阀中的铁磁/非磁金属界面处Al2O3插层的平整度在退火后得到改善,有效地提高了界面自旋极化率;同时,样品表面的Al2 O3保护层退火后对Ag层中自旋电子的散射作用的增强,提高了Ag中自旋电子的扩散长度.     

Diffusion of63Ni in the intermetallic B82-alloys in the systems Ni/Sn and Ni/In

The self-diffusion of⁶³Ni has been investigated in single crystals of the ordered intermetallic compounds Ni₆₁Sn₃₉, Ni₆₂Sn₃₈ and Ni₆₄In₃₆. The activation energies for diffusion perpendicular and parallel to the hexagonal c-axis are nearly the same and the values are between 2.14 and 2.34 eV. Moreover the D₀-values are direction dependent and range from 0.5 to 0.8 cm²/s for Ni/Sn and from 65 to 110 cm²/s for Ni/In. The experimental values of D_⊥/D_∥ are between 1.13 and 1.68 for Ni/Sn and between 0.87 and 0.79 for Ni/In, depending on temperature. These values are to be compared with theoretical values for the different diffusion mechanisms. The majority mechanism should be a site change of the tracer atom between the Ni-chains in c-direction and the double tetraeder interstices (DTI) with a further jump to another chain. Moreover two other mechanisms as minority mechanisms are possible. With rising temperature and filling the DTI's the part of minority mechanisms increases.     

The diffusion of hydrogen in liquid Ni,Cu, Ag,and Sn

The rates of absorption of hydrogen in stagnant liquid Ni, Cu, Ag, and Sn have been measured using 1) an unsteady-state gas-liquid metal diffusion cell technique similar to that used by El-Tayeb and Parlee for iron and 2) a steady-state diffusion cell technique recently developed in this laboratory. The rates of absorption are considered to be controlled by diffusion in the liquid. On this basis the chemical diffusion coefficients of hydrogen (D _H) in liquid Ni, Cu, and Ag, calculated from the rate data, can be described by:D _H ^Ni =7.47×10^?3 exp(?8550±1114/RT) cm²/secD _H ^Cu =10.91×10^?3 exp(?2148±349/RT) cm²/secD _H ^Ag =4.54×10^?2 exp(?1359±207/RT) cm²/sec In the above equations, the uncertainty in the activation energy (Q _H) corresponds to the 90 pct confidence level. No reliable Arrhenius equation could be obtained forD _H ^Sn , but theD _H values in tin are greater than for the other three metals. The following interesting and possibly significant correlations are observed betweenD _H,Q _H, and the hydrogen solubility (S _H):D _H ^Ni <D _H ^Fe <D _H ^Cu <D _H ^Ag <D _H ^Sn , andQ _H ^Ni >Q _H ^Fe >Q _H ^Cu >Q _H ^Ag , andS _H ^Ni >S _H ^Fe >S _H ^Cu >S _H ^Ag >S _H ^Sn .     

Volume Shrinkage Induced by Interfacial Reaction in Micro-Ni/Sn/Ni Joints

Experiments are carried out to measure the volume shrinkage during solid-state reaction in micro-joints for three-dimensional integrated circuit applications. Surface profilometer is employed to measure the volume shrinkage for the reaction between Ni and Sn. The shrinkage is correlated with the microstructural evolution during the reaction. It is found that the volume shrinkage is released through both joint height reduction and void formation. The resulting internal stress and the void formation might post potential reliability issues.     

Equilibrium distribution of Fe,Ni, Sb,and Sn between liquid Cu and a CaO-rich slag

Equilibrium measurements of the distribution of Fe, Ni, Sb, and Sn between a liquid Cu-O solution and a CaF₂-CaO-MgO-SiO₂ were carried out at 1500 K in a magnesia crucible. The results show that the studied solutes were in the states Fe(III), Ni(II), Sb(III), and Sn(IV), in the slag, for metal O contents ranging from 100 ppm to saturation at 2.1 pct. The Cu oxide solubility in the slag was also measured in absence of the solute elements. Its maximum solubility is about 4 ± 1 mass pct Cu₂O. The compositions at equilibrium allow determination of the activity coefficients (referred to pure oxide) of the four solute oxides in the slag. These values, expressed in round figures to take into account the experimental uncertainties, are 10 for Fe₂O₃, 20 for NiO, 10 for SnO₂, 1.6 10⁻² for SbO_1.5, and 60 for Cu₂O.     

Microstructural development in NiAl/Ni-Si-B/Ni transient liquid phase bonds

A transmission electron microscopy (TEM) based investigation of microstructural development during transient liquid phase bonding of near-stoichiometric NiAl to commercial purity nickel is presented in this article. The work described employed Ni-4.5 wt pct Si-3.2 wt pct B (BNi-3) melt-spun interlayers. The precipitation of both Ni-Al based phases and borides within the joint and adjacent substrate regions is discussed. The article considers martensite formation (within the NiAl substrate) and the precipitation of Ll₂ type phases (both within the joint and at the interface with the NiAl substrate). The relative roles of the two substrate materials (NiAl and Ni) in the isothermal resolidification process are identified. The preferential formation of Ni₃B boride phases in the Ni substrate near the original location of the Ni substrate-joint interface is discussed and contrasted with the absence of similar events in the NiAl substrate.     

Thermodynamic measurements in liquid Sn−Ag Alloys

The reversible galvanic cell: $$ Sn(l), SnO_2 (s)/CaO - ZrO_2 /Sn - Ag(1),SnO_2 (s) $$ electrolyte was employed to determine the thermodynamic properties of liquid Sn?Ag Alloys in the range ofX _Sn from 0.2 to 0.9 and in the overall temperature range of 825° to 1111°K. The data are consistent with the phase diagram. At 900°K, tin shows both positive and negative deviations from Raoult’s law, anda _Sn values agree well with the determinations of Frantik and McDonald but not with those of Laurieet al. At 1100°K, both tin and silver exhibit negative deviations from Raoult’s law lines.     

Interdiffusion of Sn and Pb in liquid Pb-Sn alloys

Coefficients for the interdiffusion of Sn in Pb-rich alloys and Pb in Sn-rich alloys were established using 1.5-mm-diameter capillaries and the semi-infinite rod technique. Interdiffusion coefficients are presented for the entire concentration range from pure Pb to pure Sn, for temperatures from 668 to 1031 K. The concentration dependence of the interdiffusion coefficients was determined by establishing the concentration along the length of the capillaries and calculating the coefficients using a finite-difference technique. The interdiffusion of Sn in Pb, extrapolated to 0 at, pct Sn, is given by