Al-Si-Cu-Ni低熔点钎料中合金元素对其性能的影响

Al-Si钎料因具有良好的润湿性、流动性、钎焊接头的抗腐蚀性和可加工性，应用非常广泛，但其熔点较高，很难用于低熔点的铝合金的钎焊。以Cu、Ni作为主要的添加元素，通过正交试验的方法研究了合金元素Cu、Ni、Si对铝基钎料熔点的影响。结果表明，影响的主次顺序为Cu、Si、Ni，同时得出：随着合金元素Cu、Si的含量的增大，其熔点大大降低；合金元素Ni的含量对钎料熔点的影响较小。钎料Al-20Cu-3.3Ni-10Si的熔点最低，达到535.8℃，同时该钎料的铺展性能极佳。     

微量Cu元素对Au-24Ag-3.25Si钎料合金组织和焊接性能的影响

通过分析相图,配制成分分别为Au-24Ag-3.25Si、Au-24Ag-3.25Si-1.5Cu、Au-24Ag-3.25Si-2.0Cu、Au-24Ag-3.25Si-2.5Cu4种合金,中频感应真空熔铸法制备铸锭,在流动氢气保护管式电阻炉中进行焊接实验,基板采用纯Ni片,焊接温度为550℃.使用微量型DTA差热分析仪测定钎料合金的熔化温度,并通过金相观察和扫描电镜观察结合X射线能谱分析对钎料合金的组织和焊接性能进行研究.结果表明,添加适量的Cu元素能降低Au-24Ag-3.25Si钎料合金的熔点,减小固液相间隔:Cu元素的加入使Au-24Ag-3-25Si钎料合金的显微组织发生了显著变化,有新固溶体的形成,使得钎料合金的硬度随之升高;Au-24Ag-3.25Si-1.5Cu钎料合金与Ni焊接后铺展形貌良好,润湿角较小,其焊接界面组织形貌与未添加Cu元素前基本一致,仍然有金属间化合物层(IMC)出现,能谱分析和线扫描结果显示,该IMC层由Ni和Si的金属间化合物组成,Cu元素的添加没有明显改善Au-24Ag-3.25Si钎料合金与Ni的焊接性能.     

Cu,Sn,Ni对Al-Si基钎料性能的影响

Si元素和Cu元素对钎料液相线温度的影响最大,两者的加入会明显降低钎料熔点。随合金元素含量的增大,合金由非一致性熔化逐渐转变为一致性熔化,进而减小了熔化温度范围。在钎料中添加Sn元素会显著降低其耐蚀性,而Ni元素则会提高钎料的耐蚀性能和力学性能,其质量分数在2%左右为宜。对钎料的组织分析说明,其中主要相为α(Al)相、θ(CuAl_2)相和块状初晶Si相。Ni的加入起到了细化晶粒的效果,并会提高钎料的耐蚀性和力学性能,θ(CuAl_2)相和Al_6Cu_3Ni相则会因为Cu含量的增加而增多。     

镍对Ag20CuZnSnP钎料铺展润湿性和接头抗剪强度的影响

通过在Ag20CuZnSnP钎料合金的基础上添加不同含量的元素Ni,研究并分析了不同含量的Ni元素对钎料铺展性能和钎焊接头抗剪强度的影响。结果表明,当钎料合金中Ni元素的含量超过2．0％时,钎料在1Cr18Ni9Ti不锈钢上的铺展面积可大大提高;当钎料中Ni元素含量为2．0％时,同种和异种母材钎焊接头的抗剪强度均达到最大值。对钎料微观组织分析表明,在钎料合金中加入元素Ni可以明显细化钎料合金中粗大树枝晶状的锡青铜组织,而元素Ni会夺取金属间化合物Cu3P中的P元素,在钎料中主要以金属间化合物Ni3P的形式存在。     

LD2铝合金真空钎焊用铝基钎料的制备及性能研究

利用快速凝固技术制备了8种A1-Si-Cu-Ni四元合金钎料,研究了合金元素对铝基钎料性能的影响。实验结果表明:随着Cu含量的增加,钎料的熔点大大降低,且钎料的铺展面积和抗拉强度都呈现先增加后降低的趋势;随着Si含量的增加,钎料的熔点和抗拉强度皆为先增加后降低,同时钎料的铺展面积明显增加。     

无铅钎料的抗氧化性能研究（一）

用无铅钎料替代传统锡铅钎料的形势已十分紧迫。波峰焊是电子组装的主要焊接方法，主要采用Sn-Cu合金钎料。无铅钎料在波峰焊时，熔融钎料长期暴露在大气环境中，钎料的抗氧化性能对电子组装产品的质量及组装焊接生产成本有重要影响。本文主要研究在Sn0．7Cu合金中添加微量元素对其抗氧化性能的影响，在Sn0．7Cu合金中添加微量元素P、Ge、Ni进行了抗氧化性能的研究。在实验中，每一种元素被添加到SnCu合金中，在炉中280℃下氧化48h，得出单独添加0．01％-0．05％Ge或0．005％-0．008％P的具有最好的抗氧化效果。最后通过测量其润湿角和铺展面积对其润湿性能进行评估；通过DSC测试其熔点；并对其进行金相组织观察。实验结果表明，添加微量元素的P或Ge可以在一定程度上改善SnCu钎料合金的抗氧化性能，与此同时，对其物理机械性能并没有太大影响。     

无铅钎料的抗氧化性能研究（二）

用无铅钎料替代传统锡铅钎料的形势已十分紧迫。波峰焊是电子组装的主要焊接方法，主要采用Sn-Cu合金钎料。无铅钎料在波峰焊时，熔融钎料长期暴露在大气环境中，钎料的抗氧化性能对电子组装产品的质量及组装焊接生产成本有重要影响。本文主要研究在Sn0．7Cu合金中添加微量元素对其抗氧化性能的影响，在Sn0．7Cu合金中添加微量元素P、Ge、Ni进行了抗氧化性能的研究。在实验中，每一种元素被添加到SnCu合金中，在炉中280℃下氧化48h，得出单独添加0．01％-0．05％Ge或0．005％-0．008％P的具有最好的抗氧化效果。最后通过测量其润湿角和铺展面积对其润湿性能进行评估；通过DSC测试其熔点；并对其进行金相组织观察。实验结果表明，添加微量元素的P或Ge可以在一定程度上改善SnCu钎料合金的抗氧化性能，与此同时，对其物理机械性能并没有太大影响。     

合金元素对6063铝合金阶梯焊中温钎料性能的影响

运用正交试验法,通过改变Si,Cu,Ni元素以及混合稀土RE元素的配比,研究含量的变化对Al-Si-Cu-Ni-RE钎料的熔点、铺展性以及抗剪强度的影响,并通过扫描电镜及能谱分析了钎料内部显微组织;通过研究发现,钎料的成分及加热温度是影响铺展面积的主要因素;对钎料显微组织分析可知,钎料中黑色的脆性θ(CuAl2)相和区域偏析的絮状相不利于接头的性能,而具有面心立方固溶体的基体相α(Al)以及球状聚集的Si相,使得钎料的力学性能优良.结果表明,对钎料熔点的影响方面,Cu元素的影响最大,其次为Ni,Si,RE元素,钎料的熔点随着Cu元素含量的增加而急剧下降.     

Au-Ag-Si钎料合金的初步研究

针对目前熔点在450～500℃范围内的电子器件用钎料的空缺，通过分析Au-Ag-Si系三元相图，并根据其存在的共晶单变量线e1e2，制备了几种熔化温度在400～500℃的共晶钎料合金，并对其钎焊性和加工性能进行了初步的研究。DTA分析发现，合金的熔点在所选定的合金成分范围内随Ag含量的增加而升高。此钎料与Ni板浸润性较好；将钎料合金铸锭热轧后表明该合金作为可加工的实用钎料是合适的。同时，初步探讨了Cu元素对于Au-Ag-Si系合金的熔化特性和塑性变形能力的影响，结果表明Cu对于改善合金的加工性能和缩小固液相间距具有重要的意义。     

钎焊及其设备

合金元素对6063铝合金阶梯焊中温钎料性能的影响 运用正交试验法,通过改变Si,Cu,Ni元素以及混合稀土RE元素的配比,研究含量的变化对Al-Si-Cu-Ni-NH拉钎料的熔点、铺展性以及抗剪强度的影响,并通过扫描电镜及能谱分析了钎料内部显微组织;通过研究发现,钎料的成分及加热温度是影响铺展面积的主要因素;对钎料显微组织分析可知,     

Comparison of geometries and electronic structures of polyacetylene,polyborole, polycyclopentadiene,polypyrrole, polyfuran,polysilole, polyphosphole,polythiophene, polyselenophene and polytellurophene

Geometries of monomers through hexamers of cylopentadiene, pyrrole, furan, silole, phosphole, thiophene, selenophene and tellurophene, and monomers through nonamers of borole were optimized employing density functional theory with a slightly modified B3P86 hybrid functional. Bandgaps and bandwidths were obtained by extrapolating the appropriate energy levels of trimers through hexamers (hexamers through nonamers for borole) to infinity. Bandgaps increase with increasing π-donor strengths of the heteroatom. In general, second period heteroatoms lead to larger bandgaps than their higher period analogs. Polyborole is predicted to have a very small or no energy gap between the occupied and the unoccupied π-levels. Due to its electron deficient nature polyborole differs significantly from the other polymers. It has a quinoid structure and a large electron affinity. The bandgaps of heterocycles with weak donors (CH₂, SiH₂ and PH) are close to that of polyacetylene. For polyphosphole this is due to the pyramidal geometry at the phosphorous which prevents interaction of the phosphorus lone pair with the π-system. The bandgap of polypyrrole is the largest of all polymers studied. This can be attributed to the large π-donor strength of nitrogen. Polythiophene has the third largest bandgap. The valence bandwidths differ considerably for the various polymers since the avoided crossing between the flat HOMO — 1 band and the wide HOMO band occurs at different positions. The widths of the wide HOMO bands are similar for all systems studied. All of the polymers studied have strongly delecalized π-systems.     

Acid-base behavior of cryptand 1, 4, 7, 10, 13, 16, 21, 24-octaaza-bicyclo [8, 8, 8] hexacosan-3, 8, 12, 17, 20, 25-hexone and complex formation

The bicyclic cryptand I, 4, 7, 10, 13, 16, 21,24-octaaza-bigcyclo [8, 8, 8] hexacosan-3, 8, 12, 17, 20, 25-hex-one (COBH) bearing diaminoethane groups along the eight-atom bridges was synthesized. The structure consists of discrete neutral macrobicyclic units; the two cycles share the two tertiary amine nitrogen atoms, which exhibit an endo-endo conformation. Three identical branches formed by I, 2-diaminoethane link the two tertiary amine groups. The protonation reactions ofcryptand (COBH) and its complex formation with copper (II) were investigated by potentiometry in water and in a DMSO/water (80: 20 in mass ratio) mixture as solvents. The cryptand acts as a bis-base through its two Nbridgehead and exhibits a strong cooperativity that favors the first protonation and makes the second one difficult (ΔpK≈5.0 ). An inward rotation of the amide groups to form hydrogen bonds accounts for this cooperativity. The interaction of COBH with copper (II) leads to several binuclear complex proton contents.     

Acid-base behavior of cryptand 1, 4, 7, 10, 13, 16, 21, 24-octaaza-bicycio[8, 8, 8] hexacosan-3, 8, 12, 17, 20, 25-hexone and complex formation

The bicyclic cryptand 1,4, 7, 10, 13, 16, 21, 24-octaaza-bigcyclo [8, 8, 8] hexacosan-3, 8, 12, 17, 20, 25-hexone (COBH) bearing diaminoethane groups along the eight-atom bridges was synthesized. The structure consists of discrete neutral macrobicyclic units; the two cycles share the two tertiary amine nitrogen atoms, which exhibit an endo-endo conformation. Three identical branches formed by 1, 2-diaminoethane link the two tertiary amine groups. The protonation reactions ofcryptand (COBH) and its complex formation with copper (Ⅱ) were investigated by potentiometry in water and in a DMSO/water (80: 20 in mass ratio) mixture as solvents. The cryptand acts as a bis-base through its two Nbridgehead and exhibits a strong cooperativity that favors the first protonation and makes the second one difficult (pK 5.0 ). An inward rotation of the amide groups to form hydrogen bonds accounts for this cooperativity. The interaction of COBH with copper (Ⅱ) leads to several binuclear complex proton contents.     

Supplemental Literature Review of Binary Phase Diagrams: Cs-In, Cs-K, Cs-Rb, Eu-In, Ho-Mn, K-Rb, Li-Mg, Mg-Nd, Mg-Zn, Mn-Sm, O-Sb, and Si-Sr

Recent literature on Cs-In, Cs-K, Cs-Rb, Eu-In, Ho-Mn, K-Rb, Li-Mg, Mg-Nd, Mg-Zn, Mn-Sm, O-Sb, and Si-Sr phase diagrams is reviewed in this article in order to update the 1990 compilation Binary Alloy Phase Diagrams, 2nd edition, by T.B. Massalski, et al. For some systems reaction tables and crystal structure data have been included, as well. Diagrams have been checked for consistency with rules for phase diagram construction and modified when necessary. In addition, diagrams needing more work have been identified.