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含稀土Sn-Zn-Bi系无铅钎料润湿性能的研究 总被引:7,自引:0,他引:7
通过向Sn-Zn-Bi系钎料合金中添加适量合金元素Ga,Cu和La,制备了对Cu母材具有较好润湿性能的Sn-8.9Zn-2.7Bi-1.0Ga-0.5Cu-0.2La无铅钎料,其润湿角为25.1°。同时,还研究了无铅钎料中稀土元素La以及合金元素Ga的微量变化对钎料的润湿性及与母材金属结合界面组织结构的影响。研究发现,La和合金元素Ga的含量对Sn-Zn-Bi系无铅钎料润湿性能有较大影响,适量添加无论是在空气中还是在氮气保护下,均可以改善钎料的润湿性。 相似文献
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Sn-In-Zn三元系相图和无铅钎料成分的探讨 总被引:6,自引:0,他引:6
Sn-In-Zn三元体系的液相限相图进行了实验和探讨,发现体系存在一个三元低共熔点E:46Sn-52ln-2Zn(100ω),其熔点为108℃.在相图研究的基础上,得出该体系作为无铅焊料的最佳组分为6.7Zn-8.0In-85.3Sn(100ω),其熔化温度为188℃。 相似文献
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探讨了电感耦合等离子体发射光谱法(ICP-AES)测定镍基钎料中硼的分析条件.试样经王水低温溶解,然后高温发硫酸烟,选择182.641 nm作为分析谱线,同时采用基体匹配法配制标准样品,不仅有效降低了基体效应,同时解决了无标校正的问题,校准曲线的线性范围为0~0.06 mg/mL,相关系数为0.999 98.方法应用于实际样品分析,方法检出限为3×10^(-5)mg/mL(n=11),方法相对标准偏差为0.32%~0.65%,回收率为99.2%~100.6%. 相似文献
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稀土对表面组装用Sn2.0Ag0.7CuRE钎料合金组织与性能的影响 总被引:10,自引:1,他引:10
对真空条件下制备的Sn2.0Ag0.7CuRE钎料合金显微组织、力学及物理性能进行了研究。结果表明:当稀土(RE)的添加量小于0.1%(质量分数)时,RE均匀地分布在钎料合金中,除铺展面积和延伸率与Sn37Pb钎料相当外,Sn2.0Ag0.7CuRE钎料合金的拉伸强度和导电性能均高于传统的Sn37Pb钎料;当RE添加量达到0.5%时,钎料合金中出现了明显的梅花状和点状RE化合相且弥散分布于晶界和相界附近,且拉伸强度、延伸率和铺展面积都出现了不同程度的下降。从综合性能和制造成本考虑,真空条件下制备Sn2.0Ag0.7CuRE钎料合金,RE的添加量应不大于0.1%。 相似文献
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针对大面积功率器件软钎料的失效问题,运用扫描电子显微镜(SEM)分析了SnPb软钎料的微观结构并运用能谱仪对其进行成分分析,找出了失效的主要原因:对软钎料进行刚玉抛光后,未能将残留在软钎料内的Al2O3成分完全去除,以至于器件的可焊性变差.根据分析提出了改进意见,较好地解决了SnPb软钎料的失效问题. 相似文献
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L. J. Wei J. X. Guo X. H. Dai L. Guan Y. L. Wang B. T. Liu 《Surface and interface analysis : SIA》2016,48(12):1337-1340
Adsorption energies and density of states for O atoms adsorption on the Ti3Al (0001) surface have been calculated using first‐principles calculations based on density functional theory. It is found that the order of O atom adsorption on the Ti3Al (0001) surface is associated with the adsorption energy as well as the distance of O atoms because of the interaction. The adsorption energy mainly depends on the bond number and bond strength between O and Ti atoms, and the adsorption site with rich‐Ti surface (HI and HCPAl) is first priority. The adsorption energy decreases with the increase of the oxygen coverage because of the characteristics of the valence d‐orbitals of transition metals surface. Furthermore, the density of states indicates that the hybridization peak of O and Ti atoms is mainly from the contribution of Ti 3d‐ and O 2p‐orbitals, and the hybridization peak of O and Al atoms from the contribution of Al 2p‐ and O 2p‐orbitals. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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采用F-S多体势对液态合金Al3Ni和Ni3Al在不同冷却速度下的微观结构及其转变机制进行了分子动力学模拟,得到了不同冷速下各温度的双体分布函数;采用HA键型指数法对其结构进行了分析,结果表明: Al3Ni在两种冷速下均以非晶的形式出现,只是慢冷时体系的有序度略有升高;而Ni3Al的结构及能量转变受冷速影响较大,快冷时形成非晶,而慢冷时出现明显结晶;同样冷速下Al含量较少的Ni3Al体系的有序度高,更易形成晶体,晶体的形成过程中有能量突变. 相似文献
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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献
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Martin J. Fay Andrew Proctor Douglas P. Hoffmann Marwan Houalla David M. Hercules 《Mikrochimica acta》1996,122(3-4):311-321
The structure of Ti/Al2O3 supports (0–14 wt% Ti) and Co/Ti/Al2O3 catalysts (3 wt% Co) was examined by EXAFS. The results indicated that the Ti was present primarily as a highly dispersed surface phase. The Ti EXAFS results indicated that the Ti species were octahedrally coordinated. Evidence of Ti—Ti interactions was found for all loadings (2–14 wt% Ti) suggesting that the Ti surface species are present as small clusters of TiO2.The Co EXAFS results showed evidence for several structurally different Co surface phases as a function of Ti loading. Evidence of a Co species interacting with the Ti surface phase was observed for the 3% Co/2% Ti-3%Co/6%Ti catalysts. At the highest loadings studied, 3%Co/8%Ti and 3%Co/14%Ti, evidence was found for a CoTiO3-like phase. 相似文献
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The Aurivillius oxides were originally of interest for their ferroelectric properties and have recently been explored in the field of oxide ion conductivity. Atomistic simulation methods have been carried out for Bi3TiNbO9, Bi4Ti3O12, BaBi4Ti4O15 and Ba2Bi4Ti5O18 doped with Pb, Al, Ga, In, Ta to determine defect energy in the materials by employing efficient energy minimization procedures. The calculations rest upon the specification of an interatomic potential model, which expresses the total energy of the system as a function of the nuclear coordinates. The Born model framework, which partitions the total energy into long‐range Coulombic interactions and a short‐range term to model the repulsions and van der Waals forces between electron charge clouds, is employed. This is embodied in the GULP simulation code. Dopant solution energy versus ion size trends are found for both isovalent and aliovalent dopant incorporation at Bi and Ta sites. Trivalent dopants (Al, Ga, In) and Pb are more favorable on the Bi site, whereas Ta dopants preferentially occupy the Ti site. 相似文献
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稀土对Al2O3陶瓷烧结温度、显微组织和力学性能的影响 总被引:20,自引:3,他引:20
研究了Y2O3, La2O3 等稀土氧化物对Al2O3陶瓷烧结温度、力学性能和显微组织的影响. 结果表明, 添加稀土氧化物可以降低Al2O3陶瓷的烧结温度, 改善显微组织, 提高力学性能. 添加复合稀土氧化物(Y2O3+La2O3)后, Al2O3陶瓷的抗弯强度和断裂韧性分别提高1.8倍和2.08倍. 其性能提高的主要原因是稀土氧化物对细晶强化、净化界面、固溶强化、自增韧补强等作用的贡献. 相似文献
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Al3Ti1B1RE细化剂对罐用铝材的细化效果及稀土的作用 总被引:6,自引:0,他引:6
采用XRD,OM,SEM,EDAX等探讨了一种新型Al3Ti1B1RE中间合金细化剂对罐用铝材的细化效果及RE的作用。结果表明,该细化剂对罐用铝材的细化效果优于进口和国产Al3Ti1B,且具有长效性,达6h后仍未见明显衰退,明显提高了该材料的强度和塑性;其细化效果及稳定性好的主要原因是:RE可降低铝液的表面能,增加铝液对细化核心(如TiAl3,TiB2)的润湿性,既充分发挥了异质形核作用,又防止了TiB2聚集沉淀倾向;RE也极易在结晶前沿富集造成成分过冷,阻碍了α-Al晶粒生长,并促进其在细化核心上形核;此外RE还兼有一定的净化、细化和变质作用,尤其是净化作用提高了该细化剂的冶金质量。 相似文献
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采用基于密度泛函理论的第一性原理,针对PbZr0.5Ti0.5O3无氧和含氢的顺电相和铁电相的二层超晶胞,分别计算了 Ti 沿 c 轴位移时体系总能量的变化、电子云密度分布和Ti-O、Zr-O和H-O的重叠布居数.结果表明,含氢铁电相的Ti-O键和Zr-O 键相埘无氢铁电相明显减弱,氢氧之间较强的轨道杂化使它们趋于形成共价键;晶格中氧氧键的钉扎效应使含氢情况下的顺电相能昔始终低于铁电相能量,说明氢的引入阻碍了PbZr0.5Ti0.5O3从立方顺电相到四方铁电相的相变,并推断其为含氧气氛退火过程中PbZr0.5Ti0.5O3铁电性能下降的主要原因之一.所得结果对于深入理解铁电材料在氮氢混合气氛退火后铁电件能下降的微观机制具有参考价值. 相似文献