• Journal of the Microelectronics and Packaging Society
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• v.24 no.4
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• pp.1-7
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• 2017

Aluminum alloys have been widely used in many fields such as electronic, structure, aero-space and vehicle industries due to their outstanding thermal and electrical conductivity as well as low cost. However, they have some difficulties for using in brazing process because of the strong oxide layer of $Al_2O_3$ on the surface of Al alloy. In addition, their melting point is similar to that of brazing filler metal resulting in thermal damage of Al alloys. Therefore, it is very important to understand the brazing principles, filler metal and its properties such as wetting, capillary flow and dissolution of base metal in the Al brazing process. This paper reviews the brazing principles, aluminum alloys, and brazing fillers. In the case of brazing principle, some formula was used for calculation of capillary force and the dissolution to obtain the best condition of Al brazing. In addition, the advanced research trends in Al brazing were introduced including thermal treatment, additive for improving property and decreasing melting point in Al brazing process.

• Journal of Ocean Engineering and Technology
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• v.15 no.3
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• pp.49-57
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• 2001

One of the most important considerations to braze Cu-Al dissimilar materials is control of brittle metallic compound which makes it difficult to obtain a sound brazed joint. Nowdays, several attempts were made to control the metallic compound. But effective method for controlling metallic compound was not established. In this point of view, commercially pure aluminum and copper were used as base metal and Al-Si-X and Zn-Al-X alloy systems were developed as filler metal. Brazing was carried out to find optimum conditions for Cu-Al dissimilar joint. The results obtained in this study were summarized as follows: 1) The joint brazed by Al-Si-X filler metal showed good brazeability and mechanical properties. The tensile strength of the joint brazed over solidus temperature was more than 90% of Al base metal. Especially, the joint brazed at liquidus temperature was fractured in the Al base metal. 2) Fluorides fluxes(a mixture of potassium fluoro-aluminates) were used to improve surface cleanliness of base metal and wettability of Al-Si-X filler metal. It was melted at the temperature about 1$0^{\circ}C$ lower than that of the filler metal, and made appropriate brazing environment. Therefore, it could be a proper selection as flux.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.253-254
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• 2009

본 연구는 다결정 알루미나 소결체와 사파이어웨이퍼(sapphire wafer)의 견고한 접합을 위해 활성금속 Ti가 함유된 Active Filler Metal을 사용하였고, 이를 브레이징한 후 접합 반응층과 Ti 거동 특성에 관한 것이다. 브레이징 (brazing)은 Ar 분위기 종에 $850^{\circ}C$에서 이행하였으며. 이때 다결정 알루미나, 사파이어와 Active Filler Metal 사이의 접합 반응층을 확인하였다. Active Filler Metal 내어| 존재하는 Ti가 접할 반응층의 양계면에 집중되는 것을 SEM을 이용하여 확인하였다. 또한 EDS Line Scanning을 실시하여 접합부에서 원소들의 분포를 관찰하였다.

• Journal of the Microelectronics and Packaging Society
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• v.18 no.3
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• pp.1-7
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• 2011

Active brazing of ceramic to metal is reviewed in this paper. As one of the key aspect in joint techniques, active brazing has been developed to simplify the manufacturing procedure of brazed joints between ceramic and metal. The active filler metal includes Ag-Cu-Ti series, Cu-Ti series, Co-Ti series and so on. The active filler metal which supplies the chemical bonds between ceramic and metal, enhances the wetting of filler metal on ceramic surface and eliminates the need for metallization treatments. The residual stress caused by difference of coefficient of thermal expansion between ceramic and metal, holds a direct influence on the bonding strength and even results in a fracture. Good joints of ceramic to metal promote the miniaturization and simplicity of electronic components with multifunction.

• Journal of Mechanical Science and Technology
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• v.16 no.9
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• pp.1078-1083
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• 2002

Ceramics are significantly used in many industrial applications due to their excellent mechanical and thermal properties such as high temperature strength, low density, high hardness, low thermal expansion, and good corrosion resistive properties, while their disadvantages are brittleness, poor formability and high manufacturing cost. To combine advantages of ceramics with those of metals, they are often used together as one composite component, which necessiates reliable joining methods between metal and ceramic. Direct brazing using an active filler metal has been found to be a reliable and simple technique, producing strong and reliable joints. In this study, the fracture characteristics of Si$_3$N$_4$ ceramic joined to ANSI 304L stainless steel with a Ti-Ag-Cu filler and a Cu (0.25-0.3 mm) interlayer are investigated as a function of strain rate and temperature. In order to evaluate a local strain a couple of strain gages are pasted at the ceramic and metal sides near joint interface. As a result the 4-point bending strength and the deflection of interlayer increased at room temperature with increasing strain rate. However bending strength decreased with temperature while deflection of interlayer was almost same. The fracture shapes were classified into three groups ; cracks grow into the metal-brazing filler line, the ceramic-brazing filler line or the ceramic inside.

• Journal of Advanced Marine Engineering and Technology
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• v.17 no.1
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• pp.66-72
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• 1993

The brazing of Al to Al using Al-Si alloy filler metal was performed under different bonding conditions such as ratio of lap length to plate thickness, surface roughness and joint clearance of the lap joint. The adopted thickness of the base metal in this experiments were two kinds of 4mm and 7mm which were most commonly used in various field. Influence of several bonding conditions of Al/Al joint was quantitavely evaluated by bonding strength test, and microstructural analysis at the interlayer were performed by optical microscope. From above experiments, the optimum bonding conditions of the brazing bonding of Al/Al using Al-Si alloy filler metal was determined. The major results obtained are as follows. 1) The fracture occurs at brazed joint in the conditions of that the ratio of lap length to plate thickness is less than 2 in case of 7mm plate thickness. 2) The ratio of lap length to plate thickness which the fracture occurs at base metal is decreased with the decreasing of the plate thickness. 3) The joint strength is not affected by the surface roughness and joint clearance of the brazed part. 4) The heat-treatment of the brazed joint contribute to eliminate the boundary between the base metal and filler metal. However, the joint strength is not affected by the heat-treatment.

• Proceedings of the KWS Conference
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• 1999.10a
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• pp.259-262
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• 1999

• Transactions of Materials Processing
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• v.21 no.8
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• pp.506-511
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• 2012

Aluminum brazing normally requires a careful control of temperature due to the small interval between brazing and melting temperatures for base materials. Unsuitable processing conditions, including brazing temperature outside admissible range, gap between brazed materials or inadequate flux feeding, can lead to joining defects. In this study, A357 was used as a filler metal for the brazing of pure aluminum base materials and brazed at temperatures in the semi-solid state. Interface microstructures with base materials were observed using optical metallography(OM) and scanning electron microcopy(SEM) with energy dispersive spectroscopy(EDS), and compared to conventional aluminum brazing.

• Korean Journal of Materials Research
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• v.26 no.7
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• pp.376-381
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• 2016

For the development of a low-melting point filler metal for brazing aluminum alloy, we analyzed change of melting point and wettability with addition of Sn into Al-20Cu-10Si filler metal. DSC results showed that the addition of 5 wt% Sn into the Al-20Cu-10Si filler metal caused its liquidus temperature to decrease by about 30 oC. In the wettability test, spread area of melted Al-Cu-Si-Sn alloy is increased through the addition of Sn from 1 to 5 wt%. For the measuring of the mechanical properties of the joint region, Al 3003 plate is brazed by Al-20Cu-10Si-5Sn filler metal and the mechanical property is measured by tensile test. The results showed that the tensile strength of the joint region is higher than the tensile strength of Al 3003. Thus, failure occurred in the Al 3003 plate.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.1
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• pp.47-52
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• 2003

The metallurgical and mechanical experiments of Titanium frame were conducted to investigate the optimum brazing and the improved brazed joints by filler metals has been developed by using other filler metals at brazing process. The filler metal is used in form of a metallic glass. The optimum brazing conditions were obtained from microstructural observation of brazed joints chemical analysis by means of X-ray micro-analysis and heating method.