• 마이크로전자및패키징학회지
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• 제24권1호
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• pp.45-50
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• 2017

본 연구에서는 Sn-0.7Cu-xZn 무연솔더와 OSP 표면처리 된 솔더접합부의 전단강도를 Zn 함유량에 따라 평가하였다. 다섯 종류의 Sn-0.7Cu-xZn (x=0, 0.5, 1.0, 1.5, 2.0 wt.%) 솔더페이스트를 제작한 뒤, OSP(organic solderability preservative) 표면처리 한 PCB(printed circuit board) 기판의 전극에 리플로우 공정으로 180 um 직경의 솔더볼을 형성하였다. 전단강도는 두 가지 조건의 전단속도(0.01, 0.1 m/s)로 고속전단시험(high speed shear test)을 통해 측정하였고, 고속전단시험 시에 측정된 F-x(Force-distance) curve를 통해 파괴에너지(fracture energy)를 계산하였다, SEM(주사전자현미경, scanning electron microscopy)과 EDS(energy dispersive spectroscopy) 분석을 통하여 단면과 파단면을 관찰하였고, 금속간 화합물(intermetallic compound, IMC) 층을 분석하였다. Zn 함유량이 증가함에 따라 금속간 화합물 층의 두께는 감소하였고, Zn 함유량이 0.5 wt.%일 때 가장 높은 전단 강도(shear strength)를 나타내었다. 전체적으로 높은 전단속도 조건의 전단강도 값이 낮은 전단속도 조건의 전단강도보다 높았다.

• Journal of Welding and Joining
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• 제23권6호
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• pp.93-98
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• 2005

The purpose of this study is to investigate the characteristics of pb-free $Zn-(3\~6)\%Al-(1\~6)\%Cu$ solder alloys for ultra high temperature(>573K) which applied to air craft, space satellite, automotive, oil, gas well exploration and data logging of geo-thermal wells. Melting range, solderability, electric resistivity, microstructure and mechanical properties were examined with solder alloys casted in Ar gas atmosphere. $Zn-4\%Al-(1\~3)\%Cu,\;Zn-5\%Al-(2\~4)\%Cu\;and\;Zn-6\%Al-(3\~5)\%Cu$ alloys satisfied the optimum melting range of 643 to 673k for ultra high temperature solder. A melting temperature increased with increasing Cu content, but decreased with increasing Al content. The spreadability was improved with increasing hi content. But the content of Cu had no effect on the spreadability. The electric resistivity was lowered with increasing Al and decreasing Cu content. In all Zn-Al-Cu solder alloys, primary dendritic $\varepsilon$ phase(Zn-Cu), dendritic $\eta$ phase(Zn-Cu-Al), $\alpha(Al-Zn)-\eta$ eutectic and eutectoid phase were observed. The addition of Al increased the volume fraction of eutectic and eutectoid phase and it decreased f phases. Also, the addition of Cu increased slightly the volume fraction of e, the eutectic and eutectoid phases. With increasing total content of Al and Cu, a hardness and a tensile strength were linearly increased, but anelongation was linearly decreased.

• 한국세라믹학회지
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• 제34권4호
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• pp.399-405
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• 1997

With the increase of ZnO content, heat of hydration decreased. For specimens containing ZnO more than 0.6 wt.%, the compressive stength of cement cured for 28 days could not be measured because setting was not occurred. With the increase of ZnO content, Blaine specific surface area of cement was decreased and the residue of 45 ${\mu}{\textrm}{m}$ and 90 ${\mu}{\textrm}{m}$ was increased when cement was ground. That is, grindability became worse as ZnO increased in clinker. The difference of color as a function of ZnO content could not be observed, but in the excess of amount of ZnO added, color became more white and reddish yellow.

• Asian-Australasian Journal of Animal Sciences
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• 제30권7호
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• pp.1006-1012
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• 2017

Objective: This study was conducted to investigate effects of zinc (Zn) bearing palygorskite (ZnPal) supplementation on growth performance, hepatic mineral content, and antioxidant status of broilers at early age. Methods: A total of 240 1-day-old Arbor Acres broiler chicks were allocated into 5 treatments with 6 replicates of 8 chicks each. Birds in 5 treatments were fed a basal diet supplemented with 0 (Control group; Analyzed Zn content: 81 mg/kg), 20, 40, 60, and 80 mg/kg Zn as ZnPal for 21 days, respectively. Blood, liver and intestinal mucosa were collected at 21 days of age. Results: Treatments did not affect growth performance of broilers during the 21-day study (p>0.05). The contents of hepatic Zn and magnesium (Mg) were linearly increased (p<0.001) by ZnPal supplementation. ZnPal inclusion linearly (p = 0.007) reduced malondialdehyde (MDA) concentration in serum. The activity of total superoxide dismutase (T-SOD) in liver increased linearly (p = 0.001) with concentration of ZnPal in diet. ZnPal inclusion linearly (p = 0.036) and quadratically (p = 0.005) increased T-SOD activity, and linearly (p = 0.012) increased copper/zinc superoxide dismutase (Cu/Zn SOD) activity in jejunal mucosa. The maximum responses of hepatic and jejunal antioxidant enzymes activities (T-SOD and Cu/Zn SOD) were found when supplementing the basal diet with 60 mg/kg Zn as ZnPal. Furthermore, ZnPal supplementation quadratically (p = 0.001) increased Cu/Zn SOD activity in ileal mucosa, and its maximum activity was observed in the diet supplemented with 20 mg/kg Zn as ZnPal. Conclusion: ZnPal supplementation did not alter growth performance of broilers. Dietary ZnPal inclusion could increase concentrations of hepatic trace minerals (Zn and Mg) and inhibit lipid peroxidation by reducing serum MDA accumulation, with the optimal dosage of Zn from ZnPal being 80 mg/kg diet (analyzed Zn content in the diet: 165 mg/kg), and 60 mg/kg Zn as ZnPal (analyzed Zn content in the diet: 148 mg/kg) was the optimum dosage for broilers to achieve maximum antioxidant enzyme activities.

• 한국환경농학회지
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• 제4권2호
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• pp.71-77
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• 1985

아연광산(亞鉛鑛山) 주변(周邊)에서 답토양(畓土壤)과 현미(玄米) 36점을 채취(採取)하여 축차분별분석(逐次分別分析)에 의해 토양(土壤) 중(中) Cd, Zn, Cu 및 Pb의 각(各) 형태별(形態別) 함량비(含量比)를 구하고, 중금속(重金屬)의 형태(形態)에 미치는 토양(土壤) 특성(特性)과 수도(水稻)의 흡수(吸收)와 관계가 깊은 화학적(化學的) 형태(形態)를 밝히기 위해 실험(實驗)하였다. 토양(土壤) 중(中) Cd의 형태별(形態別) 함량(含量)은 치환태(置煥態), 유기태(有機態) 및 carbonate 태가(態) 거의 같았으며 전(全) Cd의 73.9%를 차지하였다. 토양 중(中) Zn,은 잔류성(殘留性) Zn이 63.8%로 가장 높았다. Cu와 Pb의 형태별(形態別) 함량비(含量比)의 순위(順位)는 비슷하였다. 토양(土壤)의 pH가 높을수록 치환태(置換態) Cd, Zn, 및, Pb는 감소(減少)하였으며, 유기태(有機態)와 carbonate 태(態), Cd, sulfide 태(態) Cd, Zn, 및 Pb는 증가(增加)했다. 토양(土壤) 중(中) 유기물함량(有機物含量)은 유기태(有機態) Cd, Zn, 및, Pb는 carbonate 태(態) Cu와 정(正)의 상관(相關)을 보였다. 양(陽)이온치환용량(置換容量)이 증가(增加)하면 치환태(置換態) Cd, Zn, Cu 및, Pb, 유기태(有機態) Cu는 감소(減少)하였으나 carbonate 태(態) Cd, sulfide 태(態) Cd, Zn, Cu 및, Pb, 잔류성(殘留性) Cu는 증가(增加)하였다. 현미(玄米) 中 Cd 함량(含量)은 토양(土壤) 중(中) 전(全) Cd, 유기태(有機態) Cd, carbonate 태(態), sulfide 태(態) Cd 및 잔류성(殘留性) Cd와 높은 정(正)의 상관(相關)을 보였다. 그러나 토양(土壤) 중(中) Pb는 어떠한 형태(形態)도 현미(玄米) 중(中) Pb 함량(含量)과 상관(相關)이 없었다. 토양(土壤) 중(中) 수용태(水溶態)와 치환태(置換態) Zn 함량(含量)은 현미(玄米) 중(中) Zn 함량(含量)과 높은 정(正)의 상관(相關)을 보였다.

• 한국자기학회지
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• 제5권1호
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• pp.15-20
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• 1995

연자성재료인 Mn-Zn 페라이트에 미량의 첨가물로 CaO(0.1 mol%), NiO(0.0~6.0 mol%) 그리고 CoO(0.0~0.8 mol%) 첨가하여 20 종류의 시료를 공침법으로 제조하여, 첨가물의 첨가량에 따른 Mn-Zn 페라이트의 자기적 성질을 연구하였다. NiO, CoO의 첨가량이 증가함에 따라 초기투자율은 감소하고, 반면 Curie 온도는 증가하였다. 보자력$(H_{c})$, 포화자화$(B_{s})$ 및 자기이력손실$(W_{h})$은 NiO의 첨가량이 증가함에 따라 증가하는 것으로 나타났다.

• 한국융합학회논문지
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• 제9권10호
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• pp.271-276
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• 2018

강의 부식을 방지하기 위해서 희생양극의 원리를 이용한 아연도금이 사용된다. 순수아연도금은 몇가지 문제점을 가지고 있어 얇으면서 내식성을 증가시키기 위한 방안의 하나로 Zn-Mn 합금도금이 연구되어지고 있다. Zn-Mn 합금도금은 도금 단가가 높음에도 불구하고 고내식성을 요구하는 자동차 부품 등에 적용이 가능하다. 본 연구에서는 산성 염화용액에서 Zn-Mn 합금도금을 전착하였다. 이때 염화욕에서 합금도금의 조성에 미치는 전해조건의 영향을 조사하였다. 전류밀도가 증가함에 따라 Zn함량이 감소하고 Mn함량은 증가하였다. 전해액의 온도가 증가함에 따라 Zn함량이 감소하고 Mn함량은 증가하였으며, 음극 분극곡선을 가지고 결과를 설명하였다.

• 한국재료학회지
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• 제23권2호
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• pp.98-103
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• 2013

$Mg_{3-x}Zn_xSb_2$ powders with x = 0-1.2 were fabricated by mechanical alloying in a planetary ball mill with a speed of 350 rpm for 24 hrs and then hot pressed under a pressure of 70 MPa at 773 K for 2 hrs. It was found that there were systematic shifts in the X-ray diffraction peaks of $Mg_3Sb_2$ (x = 0) toward a higher angle with increasing Zn for both the powder and the bulk sample and finally the phase of $Mg_{1.86}Zn_{1.14}Sb_2$ was formed at the Zn content of x = 1.2. The $Mg_{3-x}Zn_xSb_2$ compounds had nano-sized grains of 21-30 nm for the powder and 28-66 nm for the hot pressed specimens. The electrical conductivity of hot pressed $Mg_{3-x}Zn_xSb_2$ increased with increasing Zn content and temperature from 33 $Sm^{-1}$ for x = 0 to 13,026 $Sm^{-1}$ for x = 1.2 at 323 K. The samples for all the compositions from x = 0 to x = 1.2 had positive Seebeck coefficients, which decreased with increasing Zn content and temperature, which resulted from the increased charge carrier concentration. Most of the samples had relatively low thermal conductivities comparable to the high performance thermoelectric materials. The dimensionless figure of merit of $Mg_{3-x}Zn_xSb_2$ was directly proportional to the Zn content except for the compound with Zn = 1.2 at high temperature. The $Mg_{3-x}Zn_xSb_2$ compound with Zn = 0.8 had the largest value of ZT, 0.33 at 723 K.

• 한국환경보건학회지
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• 제16권2호
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• pp.83-87
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• 1990

This study was carried out to investigate the pollution of heavy metals in soil of seven stations from the upper spot (Yeungchun Dam) of Kumho River to the downstream(Gangchang Bridge). The results obtained were as follows: 1. The content of heavy metals in soil of Kumho River basin was highest at Gangchang Bridge [expresed in $\mu$g/g : Mn(246.0), Cd(1.90), Fe(551.2), Cu(108.2), Zn(86.4), Cr(80.2), respectively]. Whereas, the content of heavy metals expect for Mn, Cu was lowest at Yeungchun Dam [Cd(0.40), Fe(548.0), Zn(30.7), Cr(6.2), respectively] Also, the content of Cr, Zn was increased when the sampling areas are changed from upstream to downstream except for Hayang Bridge, and Hayang Bridge was the diverging point of the heavy metals content. 2. There were relatively correlated between Mn : FE, Cu, Zn, Cr, Fe : Cu, Zn, Cr(0.40 < $\left$\mid${r}\right$\mid$$ < 0.70), and were high correlated between Cd : Mn, Fe, Cu, Zn, Cu : Zn, Zn : Cr(0.70 < $\left$\mid${r}\right$\mid$$ < 0.90). Particularly, there was higest correlated between Cd : Cr, Cu : Cr(0.90< $\left$\mid${r}\right$\mid$$ < 1.0)

• 한국융합학회논문지
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• 제9권11호
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• pp.285-290
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• 2018

강은 자동차 제조업체 및 전기 제품에 많이 사용되고 있으나 부식으로 많은 문제점이 발생한다. 이러한 부식문제를 해결하기 위해 강 위에 아연전기도금을 두껍게 하고 있다. 그러나 아연 도금의 두께가 두꺼워지면 부품 제조 시 크렉이 발생하기 쉬우며, 이로 인해 부식이 더욱더 악화될 수 있다. 이러한 부식 문제를 해결하기 위해 아연과 크롬합금도금에 관심이 집중되고 있다. 본 연구에서는 염화욕에서 합금도금의 조성에 미치는 전해조건의 영향을 조사하였다. 전류밀도가 증가함에 따라 Zn함량이 감소하고 Cr함량은 증가하였다. 전해액 온도가 증가함에 따라 Zn함량이 감소하고 Cr함량은 증가하였으며, 그 결과는 음극분극곡선으로 가지고 해석되었다.