The origin of driving force for the formation of Sn whiskers at room temperature

2007 ◽  
Vol 22 (11) ◽  
pp. 3226-3232 ◽  
Author(s):  
Shi-Bo Li ◽  
Guo-Ping Bei ◽  
Hong-Xiang Zhai ◽  
Zhi-Li Zhang ◽  
Yang Zhou ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Compressive Stress ◽  
Driving Force ◽  
Room Temperature ◽  
Whisker Formation ◽  
Sn Whisker ◽  
Spontaneous Growth ◽  
Sn Whiskers

Sn whiskers can form at room temperature on the agglomerated flakes produced by mechanical alloying (MA) of Ti, Sn, and C powders, whether the flakes are stored in air or water. The Sn whiskers forming in air are tens of micrometers to several centimeters in length and 0.5 to ∼10 μm in diameter. Whereas a large amount of Sn polyhedra forms on the flakes that are stored in water, a small amount of Sn whiskers forms on the polyhedra. The driving force for Sn whisker formation is the compressive stress induced by mechanical alloying (MA) and oxidation. The mechanism about the spontaneous growth of metal whiskers is discussed.

Spontaneous Tin (Sn) Whisker Growth from Electroplated Tin and Lead-Free Tin Alloys Coatings: A Short Review

2018 ◽  
Vol 280 ◽  
pp. 151-156 ◽  
Author(s):  
Aimi Noorliyana Hashim ◽  
Mohd Arif Anuar Mohd Salleh
Keyword(s):  
Driving Force ◽  
Room Temperature ◽  
Whisker Growth ◽  
Copper Substrate ◽  
Short Review ◽  
Hazardous Substances ◽  
Lead Free ◽  
Sn Whisker ◽  
Tin Alloys ◽  
Sn Whiskers

Since the environmental regulations of Reduction of Hazardous Substances (RoHS) directive came into effect in Europe and Asia on July 1, 2006, requiring the removal of any lead (Pb) content from the electronics industry, the issue of tin (Sn) whisker growth from pure Sn and SnPb-free alloys has become one of the most imperative issues that need to be resolved. Moreover, with the increasing demand for electronics miniaturization, Sn whisker growth is a severe threat to the reliability of microelectronic devices. Sn whiskers grow spontaneously from an electrodeposited tin coating on a copper substrate at room temperature, which can lead to well-documented system failures in electronics industries. The Sn whisker phenomenon unavoidably gives rise to troubles. This paper briefly reviews to better understand the fundamental properties of Sn whisker growth and at the same time discover the effective mitigation practices for whisker growth in green electronic devices. It is generally accepted that compressive stress generated from the growth of Cu6Sn5 intermetallic compound (IMC) is the primary driving force for Sn whisker growth during room temperature storage. It is, therefore, important to determine that the relationship between IMC growth and Sn whisker growth. Reduction of stress in the IMC layer can therefore reduce the driving force for whisker formation and be used as a means for whisker mitigation. To date, there are no successful methods that can suppress the growth of Sn whisker as efficient as Pb addition. It is hoped that the Sn whisker growth mechanisms are understood better in the future, with better measuring and monitoring methodologies and systems being developed, the real solutions may be eventually developed to eliminate or mitigate the Sn whisker problems of green reliability lead-free electronic assemblies.

Sn Whiskers Nucleation and Growth - Short Review

2018 ◽  
Vol 280 ◽  
pp. 175-180
Author(s):  
N. Mohd Mokhtar ◽  
Mohd Arif Anuar Mohd Salleh
Keyword(s):  
Compressive Stress ◽  
Whisker Growth ◽  
Microstructural Characterization ◽  
Short Review ◽  
Hazardous Substances ◽  
Lead Free ◽  
Whisker Formation ◽  
Sn Whisker ◽  
Sn Whiskers ◽  
Aerospace Applications

Sn whisker growth on Cu substrate Pb-free solder is a serious problem in electric and electronic devices and as well as in aerospace applications. Due to the concern on the toxicity of lead by Restriction of Hazardous Substances Directive (RoHS), new lead free materials have been developed, and this resulted in the resurfacing of Sn whisker. The compressive stress, corrosionand surface oxide have been identified as the driving force for Sn whisker formation induced by mechanical alloying and oxidation. In this paper, we report the study to understand the mechanism of Sn whisker growth that control whisker formation on Sn finished.Based on the review, a preliminary conclusion has been made, where the analysis of the topography and microstructural characterization can be determined by evaluating under various environmental influences.Furthermore, the whisker growth happening on lead-free soldered can be considerably reduced by controlling the compressive stress in the solder which initiates the growth of intermetallic compounds (IMCs).

Whisker Growth from Tin Coatings

2004 ◽  
Vol 467-470 ◽  
pp. 465-470 ◽  
Author(s):  
W. Bevis Hutchinson ◽  
James Oliver ◽  
Margareta Nylén ◽  
Joacim Hagström
Keyword(s):  
Free Energy ◽  
Grain Boundary ◽  
Driving Force ◽  
Room Temperature ◽  
Boundary Diffusion ◽  
Whisker Growth ◽  
Elastic Stress ◽  
Spontaneous Growth ◽  
Tin Coatings ◽  
Diffusion Controlled

Conditions favouring spontaneous growth of whiskers from tin coatings are discussed. Observations are reported concerning orientations and geometry of whiskers. The driving force for growth arises from elastic stress in the coating and can be expressed as a Gibbs free energy in terms of the decrease in pressure. An analysis of diffusion-controlled growth based on grain boundary diffusion seems to be capable of accounting for the fast growth kinetics that are observed in practice at room temperature.

scholarly journals Electromigration-induced Pb and Sn whisker growth in SnPb solder stripes

2008 ◽  
Vol 23 (7) ◽  
pp. 2017-2022 ◽  
Author(s):  
C.C. Wei ◽  
P.C. Liu ◽  
Chih Chen ◽  
K.N. Tu
Keyword(s):  
Compressive Stress ◽  
Whisker Growth ◽  
Accelerated Tests ◽  
Sn Whisker ◽  
Growth Orientation ◽  
Sn Whiskers ◽  
Snpb Solder

Electromigration at 5 × 104 A/cm2 and 100 °C was conducted to grow composite Pb/Sn whiskers from SnPb solders, in which a Pb whisker grows first and then a whisker of Sn grows. In some cases, small Sn islands are embedded in Pb whiskers. The diameter of a composite whisker is <1 μm, which is much smaller than that of spontaneous Sn whisker growth on leadframes. The growth orientation of Pb whiskers was in the [110], [1¯11], and [112] directions. This investigation proposes that compressive stress generated by electromigration at the anode provides the force driving whisker growth. Therefore, accelerated tests of whisker growth at higher temperatures using electromigration are feasible.

Mechanical Alloying Behavior in the Nb-Si, Ta-Si, and Nb-Ta-Si Systems

1988 ◽  
Vol 133 ◽  
Author(s):  
K. S. Kumar ◽  
S. K. Mannan
Keyword(s):  
High Temperature ◽  
Mechanical Alloying ◽  
Mechanical Milling ◽  
Room Temperature ◽  
Crystalline Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Α Phase

ABSTRACTThe mechanical alloying behavior of elemental powders in the Nb-Si, Ta-Si, and Nb-Ta-Si systems was examined via X-ray diffraction. The line compounds NbSi2 and TaSi2 form as crystalline compounds rather than amorphous products, but Nb5Si3 and Ta5Si3, although chemically analogous, respond very differently to mechanical milling. The Ta5Si3 composition goes directly from elemental powders to an amorphous product, whereas Nb5Si3 forms as a crystalline compound. The Nb5Si3 compound consists of both the tetragonal room-temperature α phase (c/a = 1.8) and the tetragonal high-temperature β phase (c/a = 0.5). Substituting increasing amounts of Ta for Nb in Nb5Si3 initially stabilizes the α-Nb5Si3 structure preferentially, and subsequently inhibits the formation of a crystalline compound.

Temperature-induced structural phase transitions in RERhSn (RE = Y, Gd-Tm, Lu)

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Simon Engelbert ◽  
Rolf-Dieter Hoffmann ◽  
Jutta Kösters ◽  
Steffen Klenner ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Phase Transitions ◽  
Driving Force ◽  
Room Temperature ◽  
Structural Phase ◽  
Structural Phase Transitions ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray

Abstract The structures of the equiatomic stannides RERhSn with the smaller rare earth elements Y, Gd-Tm and Lu were reinvestigated on the basis of temperature-dependent single crystal X-ray diffraction data. GdRhSn crystallizes with the aristotype ZrNiAl at 293 and 90 K. For RE = Y, Tb, Ho and Er the HP-CeRuSn type (approximant with space group R3m) is already formed at room temperature, while DyRhSn adopts the HP-CeRuSn type below 280 K. TmRhSn and LuRhSn show incommensurate modulated variants with superspace groups P31m(1/3; 1/3; γ) 000 (No. 157.1.23.1) (γ = 3/8 for TmRhSn and γ = 2/5 for LuRhSn). The driving force for superstructure formation (modulation) is a strengthening of Rh–Sn bonding. The modulation is expressed in a 119Sn Mössbauer spectrum of DyRhSn at 78 K through line broadening.

Degradation mechanism of room temperature Na/Ni3S2 cells using Ni3S2 electrodes prepared by mechanical alloying

2013 ◽  
Vol 244 ◽  
pp. 764-770 ◽  
Author(s):  
Ho-Suk Ryu ◽  
Jong-Seon Kim ◽  
Jinsoo Park ◽  
Jin-Young Park ◽  
Gyu-Bong Cho ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Room Temperature ◽  
Degradation Mechanism

Preparation of Cu-Cr-Zr/AlN Nanocomposites and their Mechanical and Conductive Properties

2011 ◽  
Vol 239-242 ◽  
pp. 2756-2759
Author(s):  
Yong Qiang Qin ◽  
Yu Cheng Wu ◽  
Yan Wang ◽  
Yu Hong ◽  
Jing Quan Deng ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Wear Resistance ◽  
High Temperature ◽  
Powder Metallurgy ◽  
Mechanical Alloying ◽  
Room Temperature ◽  
Copper Alloys ◽  
Morphology Characterization ◽  
Conductive Properties ◽  
Conductivity Behavior

Copper and copper alloys had various applications in tremendous areas due to their unique properties, such as good conductivity, good thermal conductivity and so on. However, applications of copper and copper alloys were severely restricted as the result of the limited strength at room temperature and poor wear-resistance at high temperature. In this paper, we investigated the preparation of Cu-Cr-Zr/AlN nanocomposites by mechanical alloying process and then powder metallurgy technology. XRD and SEM were performed for the phase and morphology characterization. The conductivity properties were also tested and the results showed that Cu-Cr-Zr/AlN nanocomposites exhibited excellent conductivity behavior.

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