scholarly journals Effect of Electroless Ni–P Plating on the Bonding Strength of Bi–Te-Based Thermoelectric Modules

2017 ◽  
Vol 62 (2) ◽  
pp. 1225-1229
Author(s):  
S.S. Kim ◽  
I. Son ◽  
K.T. Kim

AbstractIn the present study, electroless Ni–P plating was applied to Bi–Te-based thermoelectric materials as a barrier layer and the effect of the Ni–P plating on the bonding strength of the thermoelectric module was investigated. The bonding strength of the n- and p-type modules increased after being subjected to the electroless Ni–P plating treatment. In the case of the thermoelectric module that was not subjected to electroless Ni–P plating, Sn and Te were interdiffused and formed a brittle Sn–Te-based metallic compound. The shearing mostly occurred on the bonding interface where such an intermetallic compound was formed. On the other hands, it was found from the FE-EPMA analysis of the bonding interface of thermoelectric module subjected to electroless Ni-P plating that the electroless Ni-P plating acted as an anti-diffusion layer, preventing the interdiffusion of Sn and Te. Therefore, by forming such an anti-diffusion layer on the surface of the Bi–Te based thermoelectric element, the bonding strength of the thermoelectric module could be increased.

2020 ◽  
Vol 985 ◽  
pp. 16-22
Author(s):  
Sung Hwa Bae ◽  
Joon Young Choi ◽  
Injoon Son

This study investigates a brazing method for manufacturing PbTe thermoelectric modules using a Ag-based filler metal with a melting point of about 650 °C. To improve the bonding strength between the Ag-based brazing layer and the PbTe thermoelectric module, an electroless Ni-P plating layer is formed on the surface of the thermoelectric module as a diffusion barrier layer. The bonding strength of the PbTe thermoelectric module manufactured by the electroless Ni-P plating and Ag-based brazing has a high value of approximately 8.3 MPa. No defects such as pores or cracks were observed at the bonding interface between the thermoelectric element and the brazing layer. Furthermore, because of the high bonding strength of the manufactured thermoelectric module, fractures occur inside the thermoelectric element rather than at the bonding interface. Accordingly, the electroless Ni-P plating and Ag-based brazing method proposed in this study is found to be effective in manufacturing PbTe-based thermoelectric modules with high bonding strength.


2021 ◽  
Vol 21 (8) ◽  
pp. 4503-4507
Author(s):  
Seong Min Yun ◽  
Injoon Son ◽  
Sung Hwa Bae

In thermoelectric modules, multiple n-type and p-type thermoelectric elements are electrically connected in series on a Cu electrode that is bonded to a ceramic substrate. Defects in the bond between the thermoelectric elements and the Cu electrode could impact the performance of the entire thermoelectric module. This study investigated the effect of plating layers on the bonding strength of p-type Bi–Te thermoelectric elements. Ni and Pd electroplating was applied to Bi–Te thermoelectric elements; further, electroless Ni–P immersion gold (ENIG) plating was applied to Cu electrodes bonded to ceramic substrates. Forming a Pd/Ni electroplating layer on the surface of thermoelectric elements and an ENIG plating layer on the surface of the Cu electrode improved the bonding strength by approximately 3.5 times. When the Pd/Ni and ENIG plating layers were formed on Bi–Te elements and Cu substrates, respectively, the solderability greatly increased; as the solderability increased, the thickness of the diffusion layer formed with the solder layer increased. The improved bonding strength of the Pd/Ni plated thermoelectric element bonded on the ENIG plated substrate is attributed to the enhanced solderability due to the rapid inter-diffusion of Pd and Au into the solder layer and the formation of a stable and non-defected solder reaction interface layer.


2005 ◽  
Vol 475-479 ◽  
pp. 967-970 ◽  
Author(s):  
Taek Kyun Jung ◽  
Hyouk Chon Kwon ◽  
Sung Chul Lim ◽  
Young Sup Lee ◽  
Mok Soon Kim

We investigated about the effects of core material(Pure Al, Al3003) on extrudability such as the maximum extrusion ratio and the bonding strength of Copper Clad Aluminum(CCA) by indirect extrusion. As a results of this experiment, the maximum extrusion ratio of Cu/Al3003 was 38, which was larger than 21.39 of Cu/Al(Cu/pure Al). It was because that the difference of flow stress between copper as the sheath material and Al3003 as the core material was smaller than that of between copper and pure aluminum under the same extrusion temperature of 623K. The bonding strength gradually increased when the extrusion ratio increased, on the other hand, the bonding strength of Cu/Al3003 was higher than that of Cu/Al under same extrusion conditions. The diffusion layer thickness that affected bonding strength was not affected by the kind of core material, but it gradually increased when the extrusion ratio increased. It was thought that Cu/Al3003 had a more intimate diffusion layer than Cu/Al had because the extrusion pressure of Cu/Al3003 was higher than that of Cu/Al under the same extrusion conditions.


Coatings ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 213
Author(s):  
Sung Bae ◽  
Sungsoon Kim ◽  
Seong Yi ◽  
Injoon Son ◽  
Kyung Kim ◽  
...  

In this study, electroless-plating of a nickel-phosphor (Ni–P) thin film on surface-controlled thermoelectric elements was developed to significantly increase the bonding strength between Bi–Te materials and copper (Cu) electrodes in thermoelectric modules. Without electroless Ni–P plating, the effect of surface roughness on the bonding strength was negligible. Brittle SnTe intermetallic compounds were formed at the bonding interface of the thermoelectric elements and defects such as pores were generated at the bonding interface owing to poor wettability with the solder. However, defects were not present at the bonding interface of the specimen subjected to electroless Ni–P plating, and the electroless Ni–P plating layer acted as a diffusion barrier toward Sn and Te. The bonding strength was higher when the specimen was subjected to Ni–P plating compared with that without Ni–P plating, and it improved with increasing surface roughness. As electroless Ni–P plating improved the wettability with molten solder, the increase in bonding strength was attributed to the formation of a thicker solder reaction layer below the bonding interface owing to an increase in the bonding interface with the solder at higher surface roughness.


2006 ◽  
Vol 15-17 ◽  
pp. 1001-1007 ◽  
Author(s):  
Jeong Won Yoon ◽  
Seung Boo Jung

The interaction between Cu/Sn-Ag and Sn-Ag/Ni interfacial reactions has been studied during isothermal aging at 150°C for up to 1000h using a Cu/Sn-3.5Ag/ENIG sandwich solder joint. A typical scallop-type Cu-Sn intermetallic compound (IMC) layer formed at the upper Sn-Ag/Cu interface after reflowing. On the other hand, a (Cu,Ni)6Sn5 IMC layer was observed at the Sn-Ag/ENIG interface. The Cu in the (Cu,Ni)6Sn5 IMC layer formed on the Ni side has to be contributed from the dissolution of the opposite Cu metal pad or Cu-Sn IMC layer. When the dissolved Cu arrived at the interface of the Ni pad, the (Cu,Ni)6Sn5 IMC layer formed on the Ni interface, preventing the Ni pad from reacting with the solder. Although a long isothermal aging treatment at 150°C was performed, any Ni was not detected in the Cu-Sn IMC layer formed on the Cu side. Compared to the single Sn-Ag/ENIG solder joint, the formation of the (Cu,Ni)6Sn5 IMC layer of the Cu/Sn-Ag/ENIG sandwich joint retarded effectively the consumption of the Ni from the electroless Ni-P layer.


2021 ◽  
pp. 2001003
Author(s):  
Zuoxiang Xie ◽  
Kai Feng ◽  
Yan Xiong ◽  
Xu Chen ◽  
Yudong Liang ◽  
...  

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 237 ◽  
Author(s):  
Yanni Wei ◽  
Hui Li ◽  
Fu Sun ◽  
Juntao Zou

The Cu/Al composites conductive head is widely used in hydrometallurgy as the core component of cathode plate. Its conductive properties directly affect the power consumption, and the bonding strength and corrosion resistance determine the conductive head service life. The Cu/Al conductive head prepared by explosion welding, cold pressure welding, and solid-liquid casting methods were investigated in this paper. The interface microstructure and compositions were examined by scanning electron microscope and X-ray energy dispersive spectrometry. The bonding strength, interface conductivity, and the corrosion resistance of three types of joints were characterized. The Cu/Al bonding interface produced by explosive welding presented a wavy-like morphology with typical defects and many of brittle compounds. A micro-interlocking effect was caused by the sawtooth structures on the cold pressure welding interface, and there was no typical metallurgical reaction on the interface. The Cu/Al bonding interface prepared by solid-liquid casting consisted mainly of an Al-Cu eutectic microstructure (Al2Cu+Al) and partial white slag inclusion. The thickness of the interface transition layer was about 200–250 µm, with defects such as holes, cracks, and unwelded areas. The conductivity, interfacial bonding strength, and corrosion resistance of the conductive head prepared by explosive welding were superior to the other two.


2016 ◽  
Vol 10 ◽  
pp. 00062
Author(s):  
Michał Musiał ◽  
Marcin Borcuch ◽  
Krzysztof Wojciechowski
Keyword(s):  

2008 ◽  
Vol 580-582 ◽  
pp. 243-246 ◽  
Author(s):  
Hiroshi Nishikawa ◽  
Akira Komatsu ◽  
Tadashi Takemoto

The reaction between Sn-Ag (-Co) solder and electroless Ni-P plating was investigated in order to clarify the effect of the addition of Co to Sn-Ag solder on the formation of intermetallic compound (IMC) at the interface and the joint strength at the interface. Sn-Ag-Co solder was specially prepared. The results show that there is little effect of the addition of Co to the Sn-Ag solder on the IMC formation and the thickness of the IMC at the interface. For the pull strength of the solder bump joint, the addition of Co to the solder didn’t strongly affect the pull strength of the solder joints, but it affected the fracture mode of the solder joints.


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