Ti-45at%AI-1.6at%Mn 금속간화합물의 장시간 및 반복산화특성

김영진,최문기,김목순,Kim, Young-Jin,Choi, Moon-Ki,Kim, Mok-Soon 한국재료학회 1998 한국재료학회지 Vol.8 No.1

Ti-45at%AI-1.6at%Mn 조성을 갖는 금속간화합물의 장시간 및 반복산화 거동을조사하기 위하여 반응소결법 및 플라즈마 아크 용해법으로 제조한 시편에 대하여 80$0^{\circ}C$에서는 반응소결재와 용제재 모두 등온 및 반복산화에 대하여 우수한 저항성을 나타내었다. 90$0^{\circ}C$에서는 반응소결재의 경우에는 등온 및 반복산화에 대하여 우수한 저항성을 보였으며, 중량변화와 산화피막의 박리는 극히 적었다. 이에 비해 용제재의 경우에는 등온 및 반복산화에 의해 중향이 크게 변하였으며 피막의 박리도 극심하였다. 90$0^{\circ}C$에 있어서 두 재료간의 이러한 산화거동 차이는 기지/산화물 계면 부근에 형성된 산화층의 차이에 기인하는 것으로 간주하였다. 반응소결재의 경우에는 계면 부근에 연속적인 AO$_{3}$O$_{3}$층이 형성되며, 이러한 층이 산화에 대한 보호막으로 작용하는데 비하여 용제재에 있어서는 계면 부근에 AO$_{3}$O$_{3}$와 TiO$_{2}$의 혼합층이 형성되었다. 용제재의 반복산화시에 보여진 피막의 박리는 냉각시에 TiO$_{2}$와 기지간의 열팽창계수 차이에 기인하여 발생하는 열응력을 TiO$_{2}$가 견디지 못하고 박리를 초래한 것으로 해석하였다.

플럭스 활성도 및 In 첨가에 따른 Sn-0.3Ag-0.7Cu 솔더 조성의 젖음 특성 변화

유아미,김준기,김목순,현창용,이종현,Yu, A-Mi,Kim, Jun-Ki,Kim, Mok-Soon,Hyun, Chang-Yong,Lee, Jong-Hyun 한국마이크로전자및패키징학회 2008 마이크로전자 및 패키징학회지 Vol.15 No.4

저 Ag 함유 Sn-Ag-Cu계 무연솔더 조성, 즉, Sn-0.3Ag-0.7Cu 조성의 젖음 특성과 반응 특성을 Sn-1.0Ag-0.5Cu 및 Sn-3.0Ag-0.5Cu 합금 조성의 결과와 비교, 분석하였다. 또한 Sn-0.3Ag-0.7Cu 조성의 용융 특성을 시차주사열량계(differential scanning calorimeter, DSC)로 측정하고, 인장시험을 통한 응력-변형률 곡선을 관찰하였다. 아울러 Sn-0.3Ag-0.7Cu 조성의 젖음 특성을 향상시키기 위해 halide의 함유량이 많은 플럭스(flux)를 적용하거나 Sn-0.3Ag-0.7Cu 조성에 0.2wt.%의 In을 첨가하여 그 젖음 특성의 개선 정도를 분석해 보았다. 그 결과 halide 함유량이 높은 플럭스를 사용한 경우보다 미량의 In을 첨가한 경우가 $230{\sim}240^{\circ}C$의 저온 영역에서 wettability의 향상에 보다 효과적임을 관찰할 수 있었다. In this paper, wetting and interfacial reaction properties for low Ag containing Sn-Ag-Cu Pb-free solder alloy, i.e., Sn-0.3Ag-0.7Cu were investigated and compared with those of Sn-1.0Ag-0.5Cu and Sn-3.0Ag-0.5Cu. Melting behavior and stress-strain curves of some Sn-xAg-xCu alloys were also measured using a differential scanning calorimeter(DSC) and a tensile test machine, respectively. In order to enhance insufficient wetting properties of Sn-0.3Ag-0.7Cu alloy, the improvement of wetting properties were analyzed by applying fluxes containing higher content of halide or indium adding of 0.2wt.% into the solder alloy. It was concluded that the small addition of indium is more effective for the improvement of wettability in low temperature range of $230{\sim}240^{\circ}C$ than applying flux containing higher content of halide.

Spark Plasma Sintering법에 의해 예비 성형된 Al-10Si-5Fe-1Zr 분말합금의 고온 압축변형 거동

박상춘 ( Sang Choon Park ),김목순 ( Mok Soon Kim ),김경택 ( Kyung Taek Kim ),신승용 ( Seung Young Shin ),이정근 ( Jeong Keun Lee ),류관호 ( Kwan Ho Ryu ) 대한금속재료학회(구 대한금속학회) 2011 대한금속·재료학회지 Vol.49 No.11

Compressive deformation behavior of Al-10Si-5Fe-1Zr (wt%) alloy preform fabricated by SPS(spark plasma sintering) of gas atomized powder was investigated in the temperature range from 380 to 480℃ and at strain rates from 1.0×10?3 to 1.0×100 s?1. Stress-strain curves showed a peak stress (σp) during initial stage of deformation, followed by a steady state flow at all temperatures and strain rates tested. The σp decreased with both increase in temperature and decrease in strain rate. Nearly full densification was found to occur in the compressively deformed specimens irrespective of test condition. TEM observation revealed a restricted grain growth during steady state flow.

플립칩용 에폭시 접착제의 저온 속경화 거동에 미치는 경화제의 영향

최원정,유세훈,이효수,김목순,김준기,Choi, Won-Jung,Yoo, Se-Hoon,Lee, Hyo-Soo,Kim, Mok-Soon,Kim, Jun-Ki 한국재료학회 2012 한국재료학회지 Vol.22 No.9

Various adhesive materials are used in flip chip packaging for electrical interconnection and structural reinforcement. In cases of COF(chip on film) packages, low temperature bonding adhesive is currently needed for the utilization of low thermal resistance substrate films, such as PEN(polyethylene naphthalate) and PET(polyethylene terephthalate). In this study, the effects of anhydride and dihydrazide hardeners on the low-temperature snap cure behavior of epoxy based non-conductive pastes(NCPs) were investigated to reduce flip chip bonding temperature. Dynamic DSC(differential scanning calorimetry) and isothermal DEA(dielectric analysis) results showed that the curing rate of MHHPA(hexahydro-4-methylphthalic anhydride) at $160^{\circ}C$ was faster than that of ADH(adipic dihydrazide) when considering the onset and peak curing temperatures. In a die shear test performed after flip chip bonding, however, ADH-containing formulations indicated faster trends in reaching saturated bond strength values due to the post curing effect. More enhanced HAST(highly accelerated stress test) reliability could be achieved in an assembly having a higher initial bond strength and, thus, MHHPA is considered to be a more effective hardener than ADH for low temperature snap cure NCPs.

Ball Grid Array 보드 어셈블리의 동적굽힘 신뢰성에 미치는 언더필의 영향

장재원,방정환,유세훈,김목순,김준기,Jang, Jae-Won,Bang, Jung-Hwan,Yoo, Se-Hoon,Kim, Mok-Soon,Kim, Jun-Ki 한국재료학회 2011 한국재료학회지 Vol.21 No.12

In this paper, the effects of conventional and newly developed elastomer modified underfill materials on the mechanical shock reliability of BGA board assembly were studied for application in mobile electronics. The mechanical shock reliability was evaluated through a three point dynamic bending test proposed by Motorola. The thermal properties of the underfills were measured by a DSC machine. Through the DSC results, the curing condition of the underfills was selected. Two types of underfills showed similar curing behavior. During the dynamic bending reliability test, the strain of the PCB was step increased from 0.2% to 1.5% until the failure circuit was detected at a 50 kHz sampling rate. The dynamic bending reliability of BGA board assembly using elastomer modified underfill was found to be superior to that of conventional underfill. From mechanical and microstructure analyses, the disturbance of crack propagation by the presence of submicron elastomer particles was considered to be mainly responsible for that result rather than the shear strength or elastic modulus of underfill joint.

연료전지 촉매의 입자크기가 내구성에 미치는 영향

민경원,김현종,한명근,류태우,김목순,주영환,Min, Kyoung-Won,Kim, Hyun-Jong,Han, M.K.,U, Yu-Tae,Kim, Mok-Soon,Chu, Young-Hwan 한국전기화학회 2008 한국전기화학회지 Vol.11 No.4

본 연구에서는 백금의 입자크기가 내구성과 활성에 미치는 영향을 고찰하였다. 상용 Pt/C의 열처리를 통해 백금 입자 크기를 $3.5{\sim}9\;nm$로 조절하였고, XRD와 TEM을 통해 이를 확인하였다. 촉매의 내구성 분석을 위해 가속 실험을 실시하였고, 촉매 활성 측정을 위해 산소환원반응 실험을 하였다. 백금의 입자크기를 증가시킬수록 내구성은 향상되었으나 촉매의 활성이 저하되었다. 즉 촉매의 내구성과 활성은 반비례관계가 성립된다는 것을 확인하였다. 그리고 저하된 촉매 활성과 내구성을 향상시키기 위해, 합금 촉매를 사용하였다.상용 Pt/C의 최대 전력 밀도는 약 $507.6\;mV/cm^2$ 이고, PtCo/C 합금촉매는 $585.8\;mV/cm^2$이었다. 전기화학적 표면적은 상용 Pt/C는 약 60%정도 감소하였고, PtCo/C 합금촉매는 약 24%정도의 감소율을 나타냈다. 따라서 백금의 입자 크기 조절과 합금화를 통해 백금의 내구성과 활성을 동시에 높일 수 있었다. The influence of the particle size of platinum(Pt) on the stability and activity was studied. The particle size of platinum was controlled in the range of $3.5{\sim}9\;nm$ by heat treatment of commercial Pt/C and confirmed by XRD and TEM. An accelerated degradation test was performed to evaluate the stability of platinum catalysts. Oxygen reduction reaction was monitored for the measurement of activity. As increasing the Pt particle size, the stability of Pt/C electrode was enhanced and the activity was reduced. It was confirmed that the stability of Pt/C electrode was in inverse proportion to the activity. PtCo/C alloy catalyst was used to improve the activity and stability of large-sized platinum particle. The maximum power density of commercial Pt/C was $507.6\;mV/cm^2$ and PtCo/C alloy catalyst was $585.8\;mV/cm^2$. The decrement of electrochemical surface area showed Pt/C(60%) and PtCo/C alloy catalyst(24%). It was possible to enhance both of stability and activity of catalyst by the combination of particle size control and alloying.

플립칩 본딩용 접착제 특성에 미치는 촉매제의 영향

민경은,이준식,유세훈,김목순,김준기,Min, Kyung-Eun,Lee, Jun-Sik,Yoo, Se-Hoon,Kim, Mok-Soon,Kim, Jun-Ki 한국재료학회 2010 한국재료학회지 Vol.20 No.12

The application of flip chip technology has been growing with the trend of miniaturization of electronic packages, especially in mobile electronics. Currently, several types of adhesive are used for flip chip bonding and these adhesives require some special properties; they must be solvent-free and fast curing and must ensure joint reliability against thermal fatigue and humidity. In this study, imidazole and its derivatives were added as curing catalysts to epoxy resin and their effects on the adhesive properties were investigated. Non-isothermal DSC analyses showed that the curing temperatures and the heat of reaction were dependent primarily on the type of catalyst. Isothermal dielectric analyses showed that the curing time was dependent on the amount of catalysts added as well as their type. The die shear strength increased with the increase of catalyst content while the Tg decreased. From this study, imidazole catalysts with low molecular weight are expected to be beneficial for snap curing and high adhesion strength for flip chip bonding applications.

공정 변수에 따른 Al 모재와 Fe계 합금 분말의 레이저 오버레이층 거동

유연곤,강남현,김철희,김정한,김목순,Yoo, Yeon-Gon,Kang, Nam-Hyun,Kim, Cheol-Hee,Kim, Jeong-Han,Kim, Mok-Soon 대한용접접합학회 2007 대한용접·접합학회지 Vol.25 No.1

A joining of dissimilar metal combination faces significant problems such as poor strength and cracking associated with brittle intermetallic compounds(IMC) formed. An application of laser allows low heat input; leading to less dilution and smaller heat affected zone. The $CO_2$ laser overlay was conducted on an AC2B alloy with feeding Fe-based powders. The overlay area was significantly influenced from the travel velocity rather than the powder feeding rate. The interface between the overlay and substrate consisted of the hard and brittle IMC($FeAl_3,\;Fe_3Al,\;Fe_2Al_5$), which initiating and propagating the crack. The reciprocating test for the slide wear was conducted on a multi-pass overlay experiment. Comparing with the multi-pass overlay with no overlap, the overlay with 50% overlap showed better wear resistance.

고출력 LED의 광효율 특성 향상을 위한 TiO₂ 나노복합 봉지재 연구

강민수(Min-Su Kang),김목순(Mok-Soon Kim),유세훈(Sehoon Yoo) 대한용접·접합학회 2016 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2016 No.4

X-선 투과검사를 이용한 저항 점용접부 품질평가기법

이종대,이소정,방정환,윤길상,김목순,김준기,Lee, Jong-Dae,Lee, So-Jeong,Bang, Jung-Hwan,Yoon, Gil-Sang,Kim, Mok-Soon,Kim, Jun-Ki 대한용접접합학회 2014 대한용접·접합학회지 Vol.32 No.6

For the resistance spot welds of CR1180 and GA1180 TRIP steels, the weld quality evaluation method using the digitalized X-ray transmission imaging apparatus was investigated in comparison with the crosssectional examination method. In the case of the resistance spot welding of CR1180, three circular regions, such as WZ(white zone), GZ(grey zone) and DZ(dark zone), appeared on X-ray image and they corresponded to the diameters of indentation mark, nugget and corona bond, respectively. The variation of X-ray transmission thickness due to the thickness variation of the weld seemed to be mainly responsible for the formation of those contrasts. The X-ray image contrast formed from the variation of transmission thickness at the outer border line of DZ could also enable the inspections of the notch shape, nonuniformity of the welding pressure and spatter from its sharpness, concentricity and the normal straight line, respectively. The X-ray image of the resistance spot weld of galvannealed GA1180 TRIP steel was very similar to that of CR1180 TRIP steel except the crown shaped outer border line of DZ which was considered to be due to the melting behavior of zinc having the boiling temperature even lower than the melting temperature of steel.