Fabrication and thermal behavior of Al/Fe2O3 energetic composites for effective interfacial bonding between dissimilar metallic substrates

김지훈,조명훈,심홍민,김수형 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.78 No.-

Herein, the roles of an Al/Fe2O3 energetic composites as a heat energy source and a bonding medium forinterfacially bonding dissimilar Al/Cu metallic substrates are systematically investigated. Energeticmaterial (EM)/solder material (SM) bilayer pellets are assembled and ignited between the interfacial Al/Cu substrates for bonding. The upper EM layer comprising an Al microparticle (MP)/Al nanoparticle (NP)/Fe2O3 NP composite serves as a heat source for melting the lower SM layer comprising SAC305 MP forstrongly bonding the Cu substrate with the melted SM layer. The intermetallic compounds (AlxFey)formed during the aluminothermic reactions of the ignited EM layer play an important role as a bondingmedium between the Al substrate and the melted EM layer. The dissimilar Al/Cu substrates areinterfacially bonded using an EM layer with a fuel-to-oxidizer ratio of 1.97–4.44. The maximummechanical strength of the bonded Al/Cu substrates increases with the increase in the fuel-to-oxidizerratio owing to the supply of sufficient heat energy under fuel-rich conditions. The EM layer acts as aneffective heat energy source and mechanical bonding medium. The proposed interfacial bondingtechnique is simple, easy, and versatile for welding and joining dissimilar metallic substrates forindustrial applications.

3차원 소자 적층을 위한 BOE 습식 식각에 따른 Cu-Cu 패턴 접합 특성 평가

박종명,김수형,김사라은경,박영배,Park, Jong-Myeong,Kim, Su-Hyeong,Kim, Sarah Eun-Kyung,Park, Young-Bae 대한용접접합학회 2012 대한용접·접합학회지 Vol.30 No.3

Three-dimensional integrated circuit (3D IC) technology has become increasingly important due to the demand for high system performance and functionality. We have evaluated the effect of Buffered oxide etch (BOE) on the interfacial bonding strength of Cu-Cu pattern direct bonding. X-ray photoelectron spectroscopy (XPS) analysis of Cu surface revealed that Cu surface oxide layer was partially removed by BOE 2min. Two 8-inch Cu pattern wafers were bonded at $400^{\circ}C$ via the thermo-compression method. The interfacial adhesion energy of Cu-Cu bonding was quantitatively measured by the four-point bending method. After BOE 2min wet etching, the measured interfacial adhesion energies of pattern density for 0.06, 0.09, and 0.23 were $4.52J/m^2$, $5.06J/m^2$ and $3.42J/m^2$, respectively, which were lower than $5J/m^2$. Therefore, the effective removal of Cu surface oxide is critical to have reliable bonding quality of Cu pattern direct bonds.

Interfacial shear horizontal (SH) waves propagating in a two-phase piezoelectric/piezomagnetic structure with an imperfect interface

Huang, Y.,Li, X. -F.,Lee, K. Y. Taylor Francis 2009 Philosophical magazine letters Vol.89 No.2

<P> Shear waves propagating along the imperfectly bonded interface of a magnetoelectric composite consisting of Piezoelectric (PE) and Piezomagnetic (PM) phases are considered. An exact dispersion relation is obtained. It is found that the interfacial imperfection strongly affects the velocity of interfacial shear waves. The existence condition of the interfacial shear waves is derived. In particular, for certain combined magnetoelectric composites, interfacial shear waves do no exist for perfect interface and exist only for imperfect interface. Moreover, the corresponding waves are dispersive, and the range of the phase velocity is derived, lying between the smaller of the Bleustein-Gulyaev waves of two PE and PM materials and the interfacial waves for the perfect bonding. These findings are useful for PE/PM composites in the microwave technology.</P>

Simulation of Transverse Mechanical Properties Using Interfacial Shear Stress Ratio for CF-PEI Thermoplastic Composites at Elevated Temperatures

이재철,김기영,정근성,Lin Ye 한국섬유공학회 2018 Fibers and polymers Vol.19 No.5

The mechanical properties of a fiber-reinforced composite are determined primarily by the physical properties of the fiber and the matrix and the bond strength between these two materials. The latter also depends on the manufacturing process. In this study, micromechanical analyses employing a finite element method were used to attain an understanding of these correlations. Most early models used in micromechanical analyses of fiber-reinforced composites assumed perfect interfacial bonding between the fiber and the matrix. However, in real fiber-reinforced composites, this bonding is incomplete. While the fiber/matrix interface has been an active area of study, most researchers have relied on assumptions for properties that cannot be measured. As a means of controlling stress transfer in our micromechanical analyses, a new method was devised employing the ratio between the measured interfacial sheer stress (IFSS) in single-fiber fragmentation (SFF) tests and the simulated IFSS assuming perfect interfacial bonding. In simulated transverse tensile tests, this method resulted in an error area that was 44.5 % less than that obtained under perfect bonding conditions because using the IFSS ratio reduces errors associated with the stress transfer at the fiber/matrix interface.

Bond Behavior Between Steel Fiber Reinforced Polymer (SRP) and Concrete

Xingxing Zou,Lesley H. Sneed 한국콘크리트학회 2020 International Journal of Concrete Structures and M Vol.14 No.5

Steel fiber reinforced polymer (SRP) composite materials, which consist of continuous unidirectional steel wires (cords) embedded in a polymeric matrix, have recently emerged as an effective solution for strengthening of reinforced concrete (RC) structures. SRP is bonded to the surface of RC structures by the same matrix to provide external reinforcement. Interfacial debonding between the SRP and concrete is a primary concern in this type of application. This study aimed to investigate the bond characteristics between SRP and concrete determined by single-lap direct shear tests with different composite bonded lengths and fiber sheet densities (cord spacings). Specimens with medium density fibers failed mainly due to composite debonding, whereas those with low density fibers failed due to fiber rupture. Results of specimens that exhibited debonding were used to determine the bond-slip relationship of the SRP-concrete interface and to predict the full-range load response, which was in good agreement with the experimental results. A database of SRP-concrete direct shear tests reported in the literature was also established. Four analytical equations derived for fiber reinforced polymer (FRP)-concrete debonding were evaluated based on the database results and were found to predict the maximum load within approximately 15% error on average, however, they all underestimated the effective bond length.

Bond-flexural behaviour of structural nano-synthetic fibre-reinforced cementitious composites

Lee, S.J.,Kim, S.H.,Won, J.P. Applied Science Publishers ; Elsevier 2016 COMPOSITE STRUCTURES -BARKING THEN OXFORD- Vol.152 No.-

Prior studies have shown that the bond properties of structural nano-synthetic fibre in a cement matrix improved as the shape of the fibres became more three-dimensional. The maximum pull-out resistance strength increased but improvement of interfacial toughness did not follow due to fibre fracture. In this study, cementitious composites containing structural nano-synthetic fibres that improved the bond properties were examined for their flexural properties. The relationship between the bond and flexural properties were studied as a function of fibre volume fraction and shape; the straight type of fibre was also examined as a control. It was found that the flexural toughness increased with increasing fibre volume fraction. For the twisted type of fibre, the maximum residual flexural strength decreased with increasing crack mouth opening. However, the twisted+crimped type of fibre displayed stable post-peak behaviour with continuously increasing residual strength.

상아질에 대한 자가 산부식 접착제의 전단결합강도와 SEM 분석 비교

조영곤,노기선,김수미,이영곤,정진호,기영재 大韓齒科保存學會 2003 Restorative Dentistry & Endodontics Vol.28 No.3

The purpose of this study was to compare shear bond strength and interfacial pattern of composite bonded to dentin using self-etching adhesive systems. Sixty extracted human molars with exposed occlusal dentin were divided into four groups and bonded with four adhesives and composites: Single Bond/Filtek Z 250(SB), Tyrian SPE-One-Step Plus/Aelitefil(TY), Prompt L-Lpop/Filtek Z 250(LP), and one-Up Bond F/Palfique Toughwell(OU). The results of this study were as follows; 1. Shear bond strength for OU was significantly lowet than that of other groups(p<0.05). No significant difference was founded among SB, TY, and LP. 2. Failure modes to dentin showed adhesive and mixed for SB, TY, and LP, but them for OUT showed adhesive in all spceimens. 3. Dentin-resin interface showed close adaptation for SB, TY, and LP, but it showed gap for OU. 4. The hybrid layers for TY, LP, OU were thinner than that of SB. Adhesive layers were observed between composite and hybrid layer, which were 5 ㎛ thick for TY and 10 ㎛ thick for OU.

다양한 레이저 접합 공정 조건에 따른 Sn-57Bi-1Ag 솔더 접합부의 계면 및 기계적 특성

안병진,천경영,김자현,김정수,김민수,유세훈,박영배,고용호,Ahn, Byeongjin,Cheon, Gyeong-Yeong,Kim, Jahyeon,Kim, Jungsoo,Kim, Min-Su,Yoo, Sehoon,Park, Young-Bae,Ko, Yong-Ho 한국마이크로전자및패키징학회 2021 마이크로전자 및 패키징학회지 Vol.28 No.2

In this study, interfacial properties and mechanical properties of joints were reported after Cu pads finished with organic solderability preservative (OSP) on flame retardant-4 (FR-4) printed circuit board (PCB) and electronic components were joined with a Sn-57Bi-1Ag solder paste by using a laser bonding process. The laser bonding process was performed under various bonding conditions with changing a laser power and a bonding time and effects of bonding conditions on interfacial and mechanical properties of joints were analyzed. In order to apply for industry, properties of bonding joints using a reflow bonding process which are widely used were compared. When the laser bonding process were performed, we observed that Cu₆Sn₅ intermetallic compounds (IMCs) were fully formed at the interface although the bonding times were very short about 2 and 3 s. Furthermore, void formations of the joints by using the laser bonding process were suppressed at the joints with comparing to the reflow bonding process and shear strengths of bonding joints were higher than that by using the reflow bonding process. Therefore, in spite of a very short bonding time, it is expected that joints will be stably formed and have a high mechanical strength by using the laser bonding process. 본 연구에서는 레이저 접합 공정을 이용하여 flame retardant-4 (FR-4) 인쇄회로기판 (printed circuit board, PCB)의 organic solderability preservative (OSP) 표면처리 된 Cu pad와 전자부품을 Sn-57Bi-1Ag 저온 솔더 페이스트로 접합을 한 후 접합부의 계면 특성과 기계적 특성에 대하여 보고 하였다. 레이저 접합 공정은 레이저 파워 및 시간 등을 다르게 진행하여 접합 공정 조건이 접합부의 계면 및 기계적 특성에 미치는 영향을 살펴보았다. 레이저 접합 공정의 산업적 적용을 위하여 산업적으로 많이 이용되고 있는 리플로우 접합 공정을 이용한 접합부의 특성과도 비교 하였다. 레이저 접합 공정 적용 결과 2, 3 s의 짧은 공정 시간에도 계면에 Cu₆Sn₅ 금속간화합물 (intermetallic compound, IMC)를 생성하여 접합부를 안정적으로 형성함을 확인 하였다. 또한, 리플로우 공정과 비교해 보았을 때 레이저 접합 공정을 적용할 경우 접합부의 보이드 형성이 억제됨을 확인할 수 있었으며 접합부의 전단강도도 리플로우 공정 접합부보다 높은 기계적 강도를 나타냈다. 따라서, 레이저 접합 공정을 적용할 경우 짧은 접합 공정 시간에도 불구하고 안정적인 접합부 형성 및 높은 기계적 강도를 확보할 수 있는 것으로 기대된다.

Novel interfacial bonding layers with controlled gradient composition profile for hydrocarbon-based membrane electrode assemblies

Jeong, Hwan Yeop,Yang, Dae-Soo,Han, Jae Hee,Lee, Jang Yong,So, Soonyong,Suh, Dong Hack,Hong, Sung Kwon,Hong, Young Taik,Kim, Tae-Ho Elsevier 2018 Journal of Power Sources Vol.398 No.-

<P><B>Abstract</B></P> <P>We develop a novel approach to improve the robustness of the interface between the hydrocarbon (HC) membrane and the perfluorosulfonic acid (PFSA) ionomer-based catalyst layer (CL) in membrane electrode assemblies (MEAs). This approach involves the creation of a gradient-composition interfacial bonding layer, in which the HC and PFSA contents are gradually varied along the thickness direction. The layer is fabricated using a simple spray-coating method, in which HC and PFSA ionomer mixtures with different compositions are sprayed stepwise onto both sides of the HC membrane surface. The interfacial structure developed in this process minimizes the chemical incompatibility between the HC and PFSA polymers. Owing to the tightly bound sublayers resulting from the intertwined HC and PFSA microdomains, the gradient-composition bonding layer provides a significantly improved interfacial adhesion strength (14 times higher than that of the pristine membrane without bonding layer) between the HC membrane and the PFSA-based CL. Finally, the fabricated MEA exhibits a >433% higher durability in humidity cycling tests compared with the pristine MEA without interfacial bonding layer, together with a better retention of its initial performance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel interfacial bonding layer for hydrocarbon-based MEA in PEMFC is developed. </LI> <LI> Bonding layer with a compositional gradient can be fabricated by a spraying method. </LI> <LI> 14 times improved interfacial adhesion strength is obtained. </LI> <LI> Excellent MEA durability is achieved via the stable membrane-electrode interface. </LI> </UL> </P>

Effect of Ar Plasma Treatment for Surface of Insert Metal on Property of TLP Bonding Joint for Power Module

Baek Seungju,Yu Dong-Yurl,Son Jun-Hyuk,Bang Junghwan,Kim Jungsoo,Kim Min-Su,Lee Han-Bo-Ram,고용호 대한용접접합학회 2020 대한용접·접합학회지 Vol.38 No.4

In this study, we investigated the effect of plasma treatment for the surface of an insert bonding metal on the prop�erties of a transient liquid phase (TLP) bonding joint for a power module. Sn preforms, as the insert bonding metal for the TLP bonding, were used with and without Ar plasma treatment. To investigate the effect of Ar plasma treat�ment, the TLP bonding for two structures of Cu-finished Si chip/Sn preform/organic solderability preservative (OSP)-finished direct bond copper (DBC) substrate (Cu/Sn/Cu), and Ni-finished Si chip/Sn preform/Ni(P)-finished DBC substrate (Ni/Sn/Ni) was performed with 1 MPa at 300 ℃ and the bonding times were 10, 30, and 60 min, respectively. After the TLP bonding, we observed interfacial reactions and formations of intermetallic compounds (IMCs) under various bonding conditions. To evaluate mechanical properties, a shear test was also performed. Compared to the TLP bonding joint that used bare Sn preforms without Ar plasma treatment, growth of IMCs at the bonding joint that used Sn preforms with Ar plasma treatment occurred faster, and the IMCs could be formed through the entire joint despite the bonding time of 10 min. Meanwhile, by increasing the bonding time, Cu6Sn5 and Cu3Sn were formed at the Cu/Sn/Cu TLP bonding joint, whereas Ni3Sn4, Ni-Sn-P, and Ni3P were observed at the Ni/Sn/Ni joint. In the case of the Cu/Sn/Cu joint, we observed that increasing Cu3Sn formation while increasing the bonding time could be beneficial to the shear strength of the joint. Further, shear strengths of the joint were not sig�nificantly changed under the bonding conditions after Ni3Sn4, Ni-Sn-P, and Ni3P IMCs were formed at the entire joint of the Ni/Sn/Ni.