Solid–Liquid Interfacial Diffusion Reaction (SLID) Between Copper and Solder

2021 ◽  
pp. 91-103
Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7417
Author(s):  
Kaiyang Li ◽  
Tiance Zhang ◽  
Yuanzhi Zhu

Porous TiAl3 intermetallics were prepared by the thermal explosion (TE) and space holder method with different particle sizes of Ti and Al powders, and their reaction behaviors were investigated. The results showed that with the increase in the particle size of the Ti and Al powders, the interfacial contact between the particles decreased, resulting in low interfacial energy and reaction activity, making the process difficult to initiate. Meanwhile, the heat flow rose from 358.37 J/g to 730.17 J/g and 566.74 J/g due to the extension of the solid–liquid diffusion time. The TiAl3 structures obviously expanded, and the formation of connected pore channels promoted the porosity. Only when the Ti and Al particle sizes were both small did the solid–solid diffusion significantly appear. At the same time, the TE reaction weakened, so the product particles had no time to fully grow. This indicates that the particle size of the raw materials controlled the TE reaction process by changing the solid–liquid diffusion reaction time and the degree of solid-phase diffusion.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2483 ◽  
Author(s):  
Katarzyna Placha ◽  
Richard S. Tuley ◽  
Milena Salvo ◽  
Valentina Casalegno ◽  
Kevin Simpson

Over the past few years, significant progress towards implementation of environmentally sustainable and cost-effective thermoelectric power generation has been made. However, the reliability and high-temperature stability challenges of incorporating thermoelectric materials into modules still represent a key bottleneck. Here, we demonstrate an implementation of the Solid-Liquid Interdiffusion technique used for bonding Mmy(Fe,Co)4Sb12 p-type thermoelectric material to metallic interconnect using a novel aluminium–nickel multi-layered system. It was found that the diffusion reaction-controlled process leads to the formation of two distinct intermetallic compounds (IMCs), Al3Ni and Al3Ni2, with a theoretical melting point higher than the initial bonding temperature. Different manufacturing parameters have also been investigated and their influence on electrical, mechanical and microstructural features of bonded components are reported here. The resulting electrical contact resistances and apparent shear strengths for components with residual aluminium were measured to be (2.8 ± 0.4) × 10−5 Ω∙cm2 and 5.1 ± 0.5 MPa and with aluminium completely transformed into Al3Ni and Al3Ni2 IMCs were (4.8 ± 0.3) × 10−5 Ω∙cm2 and 4.5 ± 0.5 MPa respectively. The behaviour and microstructural changes in the joining material have been evaluated through isothermal annealing at hot-leg working temperature to investigate the stability and evolution of the contact.


Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 794
Author(s):  
Fuyue Wang ◽  
Xiangjie Wang ◽  
Qiang Yan ◽  
Jianzhong Cui

The influences of Li content on the corrosion behavior of TC4 (Ti6Al4V) titanium alloy were explored when the TC4 titanium alloy was immersed in Al–Li alloy melt containing 0%, 1%, and 2% lithium at 680 °C, 700 °C, and 720 °C for 0.5 h, 1 h, and 2 h. The structure and growth law of the diffusion reaction layer at solid–liquid interface were studied, and the growth kinetic equation of the diffusion reaction layer was established. In addition, Ti content in Al–Li alloy melt was determined and its dissolution rate was calculated. The results showed that with the increase of lithium content in the melt, the thickness of the diffusion reaction layer (DRL) between TC4 titanium alloy and the melt increased significantly, and the activation energies of the diffusion reaction obtained were 141.28 kJ·mol−1 in liquid Al, 86.62 kJ·mol−1 in liquid Al–1Li alloy, and 43.42 kJ·mol−1 in liquid Al–2Li alloy, respectively. The dissolution rate of Ti in Al–Li alloy melts increased with the increase of lithium content in melts. When the holding time reached 3 h in a TC4 crucible, the content of Ti dissolved in the Al–2Li alloy melt was 0.105 wt%.


Author(s):  
M. A. Kirk ◽  
M. C. Baker ◽  
B. J. Kestel ◽  
H. W. Weber

It is well known that a number of compound superconductors with the A15 structure undergo a martensite transformation when cooled to the superconducting state. Nb3Sn is one of those compounds that transforms, at least partially, from a cubic to tetragonal structure near 43 K. To our knowledge this transformation in Nb3Sn has not been studied by TEM. In fact, the only low temperature TEM study of an A15 material, V3Si, was performed by Goringe and Valdre over 20 years ago. They found the martensite structure in some foil areas at temperatures between 11 and 29 K, accompanied by faults that consisted of coherent twin boundaries on {110} planes. In pursuing our studies of irradiation defects in superconductors, we are the first to observe by TEM a similar martensite structure in Nb3Sn.Samples of Nb3Sn suitable for TEM studies have been produced by both a liquid solute diffusion reaction and by sputter deposition of thin films.


Author(s):  
J.A. Panitz

The first few atomic layers of a solid can form a barrier between its interior and an often hostile environment. Although adsorption at the vacuum-solid interface has been studied in great detail, little is known about adsorption at the liquid-solid interface. Adsorption at a liquid-solid interface is of intrinsic interest, and is of technological importance because it provides a way to coat a surface with monolayer or multilayer structures. A pinhole free monolayer (with a reasonable dielectric constant) could lead to the development of nanoscale capacitors with unique characteristics and lithographic resists that surpass the resolution of their conventional counterparts. Chemically selective adsorption is of particular interest because it can be used to passivate a surface from external modification or change the wear and the lubrication properties of a surface to reflect new and useful properties. Immunochemical adsorption could be used to fabricate novel molecular electronic devices or to construct small, “smart”, unobtrusive sensors with the potential to detect a wide variety of preselected species at the molecular level. These might include a particular carcinogen in the environment, a specific type of explosive, a chemical agent, a virus, or even a tumor in the human body.


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