Effects of Trace Elements Ag, Bi and Ni on Solid–Liquid Electromigration Interface Diffusion in Solder Joints

2021 ◽  
Author(s):  
Xuemei Li ◽  
Zihao Liu ◽  
Cheng Li ◽  
YuXin Guo ◽  
Dawei Wang ◽  
...  
Keyword(s):  
Trace Elements ◽  
Solder Joints ◽  
Interface Diffusion ◽  
Solid Liquid

Solid/liquid partition coefficients to model trace element critical loads for agricultural soils in Canada

2007 ◽  
Vol 87 (Special Issue) ◽  
pp. 189-201 ◽  
Author(s):  
M I Sheppard ◽  
S C Sheppard ◽  
C A Grant
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Best Management Practices ◽  
Management Practices ◽  
Agricultural Land ◽  
National Level ◽  
Trace Element Content ◽  
Crop Productivity ◽  
Multiple Sources ◽  
Solid Liquid

Canadian consumers are demanding a sustainable agricultural industry as well as products delivered under Best Management Practices (BMPs). Trace element accumulation in soils may influence crop productivity, food quality and ecosystem and human health. Canada’s feed and foodstuff export industry has already faced cases of penalties for high trace element content [cadmium (Cd) in durum wheat]. Thus, it is imperative to be able to estimate the accumulation and potential short- and long-term impacts of trace elements in soil. A national-level Trace Element Indicator (TEI) based on present loadings of trace elements to agricultural land is in progress. An Expert Panel including Canadian, American and Australian experts guided the assembly of a proposed methodology for this TEI. The proposed TEI, described briefly here, is a critical load approach with a single expression of the risk of impact from single or multiple trace elements from multiple sources (manures, biosolids, effluents and fertilizers and natural processes), invoked in a stochastic manner. Two key data requirements are the current background levels of trace elements in soil, and the leachability of these trace elements. A survey of total and soluble concentrations of 54 elements in up to 112 soils was completed. Although preliminary in scope, these represent key soil series in Canada. From this, a database of the solid/liquid partition coefficient, Kd, was computed. These Kd values will be used to characterize the leachability of the trace elements. Key words: Cadmium, copper, zinc, lead, nickel, uranium, metals, Kd, distribution coefficient

Influence of ultrasounds on interfacial microstructures of Cu-Sn solder joints

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xu Han ◽  
Xiaoyan Li ◽  
Peng Yao ◽  
Dalong Chen
Keyword(s):  
Design Methodology ◽  
Solder Joints ◽  
Nucleation And Growth ◽  
Content Type ◽  
Reaction Stage ◽  
Interfacial Imcs ◽  
Soldering Process ◽  
Liquid Reaction ◽  
Ultrasonic Assisted ◽  
Solid Liquid

Purpose This study aims to investigate the interfacial microstructures of ultrasonic-assisted solder joints at different soldering times. Design/methodology/approach Solder joints with different microstructures are obtained by ultrasonic-assisted soldering. To analyze the effect of ultrasounds on Cu6Sn5 growth during the solid–liquid reaction stage, the interconnection heights of solder joints are increased from 30 to 50 μm. Findings Scallop-like Cu6Sn5 nucleate and grow along the Cu6Sn5/Cu3Sn interface under the traditional soldering process. By comparison, some Cu6Sn5 are formed at Cu6Sn5/Cu3Sn interface and some Cu6Sn5 are randomly distributed in Sn when ultrasonic-assisted soldering process is used. The reason for the formation of non-interfacial Cu6Sn5 has to do with the shock waves and micro-jets produced by ultrasonic treatment, which leads to separation of some Cu6Sn5 from the interfacial Cu6Sn5 to form non-interfacial Cu6Sn5. The local high pressure generated by the ultrasounds promotes the heterogeneous nucleation and growth of Cu6Sn5. Also, some branch-like Cu3Sn formed at Cu6Sn5/Cu3Sn interface render the interfacial Cu3Sn in ultrasonic-assisted solder joints present a different morphology from the wave-like or planar-like Cu3Sn in conventional soldering joints. Meanwhile, some non-interfacial Cu3Sn are present in non-interfacial Cu6Sn5 due to reaction of Cu atoms in liquid Sn with non-interfacial Cu6Sn5 to form non-interfacial Cu3Sn. Overall, full Cu3Sn solder joints are obtained at ultrasonic times of 60 s. Originality/value The obtained microstructure evolutions of ultrasonic-assisted solder joints in this paper are different from those reported in previous studies. Based on these differences, the effects of ultrasounds on the formation of non-interfacial IMCs and growth of interfacial IMCs are systematically analyzed by comparing with the traditional soldering process.

Effect of Joint Size on Microstructure and Growth Kinetics of Intermetallic Compounds in Solid-Liquid Interdiffusion Sn3.5Ag/Cu-Substrate Solder Joints

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Ousama M. Abdelhadi ◽  
Leila Ladani
Keyword(s):  
Growth Rate ◽  
Intermetallic Compounds ◽  
Rate Constants ◽  
Solder Joints ◽  
Intermetallic Layer ◽  
Cu Substrate ◽  
Soldering Time ◽  
Diffusion Controlled ◽  
Solid Liquid ◽  
Intermetallic Layers

The effect of joint size on the interfacial reaction in the Sn3.5Ag/Cu-substrate soldering system was examined. An experiment was conducted in which parameters such as bonding time, temperature, and pressure were varied at multiple levels. The morphology and thickness of all intermetallic compounds (IMC) were analyzed using the scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) techniques. An examination of the microstructures of solder joints of different sizes revealed that the size of the solder joint has no effect on the type of IMCs formed during the process. It was found that the joint size significantly affected the thickness of the intermetallic layers. The Cu3Sn intermetallic layers formed in the smaller sized solder joints were found to be thicker than those in the larger sized solder joints. In all specimen sizes, the increase in the thickness of Cu3Sn intermetallic layers with soldering time was found to obey a parabolic relationship. Additionally, for the cases when eutectic solder is available in the joints, a similar soldering time and temperature dependency were found for the Cu6Sn5 IMC phase. The intermetallic growth of the Cu3Sn phase was under a volume-diffusion controlled mechanism. The growth rate constants and activation energies of intermetallic layers were also reported for different joint thicknesses. Furthermore, the growth rate constants of the Cu3Sn intermetallic layer were found to depend upon the size of the joints.

scholarly journals Leaching of trace elements from the rocks under action of organic acids

2017 ◽  
pp. 70-76
Author(s):  
A. V. Savenko ◽  
V. S. Savenko ◽  
A. V. Dubinin
Keyword(s):  
Crystal Structure ◽  
Trace Elements ◽  
Organic Ligands ◽  
Mass Ratio ◽  
Liquid Phases ◽  
Organic Complexes ◽  
Karymsky Volcano ◽  
Solid Liquid ◽  
Oxalic Acids ◽  
Acetic Acids

The experiments on studying leaching of trace elements (Li, Rb, Cs, Sr, Ba, V, Mn, Fe, Co, Ni, Cu, Tl, Y, La, Ce, Th, U) from unaltered ash of the Karymsky volcano (Kamchatka) under its interaction with 0.01 M solutions of oxalic, salicylic, tartaric, citric, and acetic acids at the different solid/liquid phases mass ratio were lead. Based on the obtained data it is drawn a conclusion that mobilization of trace elements occurs mainly as a result of demolition of crystal structure of rock-forming minerals, as well as (in case of oxalic acids) at reduction of Fe(III) and Mn(IV) oxyhydroxides to soluble Fe(II) and Mn(II) compounds. Organic complexes formation increases of the metals stability in solution and provides a possibility of achievement of much higher values of the dissolved forms concentration than for the lack of organic ligands.

Structural Size Effect on Mechanical Behavior of Intermetallic Material in Solder Joints: Experimental Investigation

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Leila Ladani ◽  
Ousama Abdelhadi
Keyword(s):  
Elastic Modulus ◽  
Solder Joints ◽  
Electron Backscatter Diffraction ◽  
Plastic Properties ◽  
Soldering Temperature ◽  
Nano Indentation ◽  
Soldering Process ◽  
Loading Direction ◽  
Solid Liquid ◽  
Backscatter Diffraction

The elastic and plastic mechanical properties of intermetallic compound (IMC) phases of a lead-free Sn3.5Ag/Cu-substrate soldering system are investigated in different sized joints using nano-indentation. The specimens were prepared using solid–liquid interdiffusion soldering process with joint sizes ranging from 15 to 450 μm. Solder joints were subjected to 360 °C soldering temperature for 20 min and then air cooled to room temperature to create testable IMCs thicknesses. Nano-indentation was used to extract the elastic and plastic properties of Cu6Sn5, Cu3Sn, and Ag3Sn IMCs and β-tin and copper materials. Cu–Sn IMCs formed in specimens with smaller joint size show higher elastic modulus, hardness, and yield strength and lower work hardening exponent. This was attributed to the dimensional constraints associated with decreasing joint size and the local stresses developed during fabrication in joints with different sizes. Local elastic modulus and hardness of single grains of Cu6Sn5 were obtained using a combination of nano-indentation and electron backscatter diffraction (EBSD) techniques. Grains with c-axis at a 45 deg angle with respect to the nano-indentation loading direction show higher elastic modulus (∼8.70% higher) and hardness (8.85% higher) compared to the grains that have a c-axis that is almost perpendicular to the nano-indentation loading direction.

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