W-Cu alloy is attractive to thermal managing materials in microelectronic devices because of its good thermal properties. The metal injection molding (MIM) of W-Cu systems can satisfy the need for mass production of the complex shaped W-Cu parts in semiconductor devices. In this study, the application of MIM process of the mechanically alloyed (MA) W-Cu composite powders, which had higher sinterability were investigated. The MA W-Cu powders and reduction treated (RT) powders were injected by using of the multicomponent binder system. The multi-stage debinding cycles were adopted in and atmosphere. The isostatic repressing treatment was carried out in order to improve the relative density of brown parts. The brown part of RT W-Cu composite powder sintered at 110 had shown the higher sinterability compared to that of MA powder. The relative sintered density of all specimens increased to 96% by sintering at 120 for 1 hour. The relationship between green density and the sintering behavior of MA W-Cu composite powder was analyzed and discussed on the basis of the nanostructured characteristics of the MA W-Cu composite powder.

본 연구에서는 기지금속과의 고상이나 액상의 고용한이 거의 없는 금속-카본(carbon)계에서 고에너지 볼밀공정을 이용하여 고체 윤활 청동베어링용 Cu-C-X계 나노복합금속분말을 제조하고자 하였다. Cu-10wt.%C-5wt.%AI과 Cu-10wt.%C-5wt.%Fe의 혼합분말을 이르곤 분위기의 attritor내에서 기계적 합금화한 후 Cu-C-X의 나노복합금속분말의 미세조직 특성을 조사하였다. AI, Fe를 첨가하였을 때 10시간 이상의 MA공정에서부터 약 10μm이하의 미세한 Cu-C-X나노복합금속분말을 얻을 수 있었으며, MA 시간에 따른 분말의 형상과 미세구조 변화는 금속-금속계의 MA 과정과 유사하게 진행되는 것을 알 수 있었다. Cu-C-X 나노복합금속분말의 X-선 회절시험 결과, MA 시간에 따라 Cu와 C분말의 회절피크의 폭은 넓어지고 회절강도는 감소하였으며, 특히 흑연피크의 MA시간에 따른 소멸은 흑연의 낮은 원자산란계수 때문에 의한 X-선 흡수 영향으로 고찰하였다. Williamson-Hall식으로 계산된 Cu-C-X 나노복합금속분말내의 Cu의 결정립은 15시간 이상의 MA공정에서부터 약 10nm이하의 크기를 가졌으며, TEM 분석결과로는 불규칙한 형상의 약 10-30nm 크기로 복합화된 Cu결정립을 확인할 수 있었다.

Ti-45at%AI-1.6at%Mn 조성을 갖는 금속간화합물의 장시간 및 반복산화 거동을조사하기 위하여 반응소결법 및 플라즈마 아크 용해법으로 제조한 시편에 대하여 800˚C에서는 반응소결재와 용제재 모두 등온 및 반복산화에 대하여 우수한 저항성을 나타내었다. 900˚C에서는 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. 900˚C에 있어서 두 재료간의 이러한 산화거동 차이는 기지/산화물 계면 부근에 형성된 산화층의 차이에 기인하는 것으로 간주하였다. 반응소결재의 경우에는 계면 부근에 연속적인 AO3O3층이 형성되며, 이러한 층이 산화에 대한 보호막으로 작용하는데 비하여 용제재에 있어서는 계면 부근에 AO3O3와 TiO2의 혼합층이 형성되었다. 용제재의 반복산화시에 보여진 피막의 박리는 냉각시에 TiO2와 기지간의 열팽창계수 차이에 기인하여 발생하는 열응력을 TiO2가 견디지 못하고 박리를 초래한 것으로 해석하였다.

In order to investigate the trace metals in Korean foods, the contents of Magnesium, Zinc, Manganese, Molybdenum and Selenium are studied in this paper. As show in the Table 1; a total of 250 samples of 25 species were analyzed by neutron activation analysis. The results obtained were as follows; 1. The overall ranges and mean (mg/100 g) were; Mg, 12.212-151.346 (55.164); Zn, 0.045-38.180 (2.473); Mn, 0.003-0.796 (0.225); Mo, ND-0.035 (0.007); Se, ND-0.069 (0.016). 2. The levels of all metals except Mo in shell fishes were high and the level of Mo in spices .was higher than that in other foods. 3. The levels of Zn and Mo in oyster were higher than another spcies.

중금속 이온이(Cd2+, Hg2+, Cu2+, Pb2+) 산개구리 여포난자의 성숙에 미치는 영향을 알아보기 위해 배양액에 일정 농도의 이온들을 첨가한 후 여포난자들을 일정시간 배양하였다. 여포난자의 성숙을 유도하기 위하여 FPH(Frog pituitary homogenate: 0.1p.e./ml)를 사용하였으며 여포난자의 성숙율은 난자의 핵막 붕괴율로부터 구하였다. 실험결과 Cd2+은 0.1ppm의 농도부터 여포난자의 성숙을 억제하였으며 Hg2+과 Cu2+는 1ppm부터, Pb2+는 5ppm에서 현저히 억제효과를 나타내기 시작하였다. 이들 중금속 이온 작용의 가역성을 조사하기 위해 3시간 동안 여포난자들을 중금속 이온에 노출시킨 후 보통 배양액으로 옮겨 계속 배양을 해 본 결과 Cd2+은 1ppm에서 가역성을 나타내었으나 2.5ppm에서는 비가역적인 손상을 주었다. Hg2+, Cu2+, Pb2+의 효과는 2.5ppm에서는 비가역성을 나타냈다. 위 결과로부터 개구리 여포난자의 배양계는 환경오염물질의 독성 검정에 요긴하게 사용할 수 있을것으로 생각되었다.

intermetallics containing 0-6 wt% of Cu were made by reactive sintering (RS) under vacuum using elemental powder mixtures (Process 1), electro-pressure sintering (EPS) using RS'ed materials (Process2), and EPS using elemental powder mixtures (Process 3). Relatively low dense titanium silicides were gained by process 1, in which porosity decreased with increasing Cu content. For example, porosity changed from 42 to 19.4% with the increase in Cu content from 0 to 6 wt%, indicating that Cu is a useful sintering aid. The titanium silicides fabricated by Process 2 had a higher density than those by Process 1 at given composition, and porosity decreased with increasing Cu content. For example, porosity decreased from 38 to 6.8% with the change in Cu content from 0 to 6 wt%. A high dense titanium silicides were obtained by Process 3. In this Process, porosity decreased a little by Cu addition, and was almost insensitive to Cu content. Namely, about 9 or 7% of porosity was shown in 0 or 1-6 wt% Cu containing silicides, respectively. The hardeness increased by Cu addition, and was not changed markedly with Cu content for the silicides fabricated by Process 3. This tendency was considered to be resulted from porosity, hardening of grain interior by Cu addition, and softening of grain boundary by Cu-base segregates. All these results suggested that EPS using elemental powder mixtures (Process 3) is an effective processing method to achieve satisfactorily dense titanium silicides.

Engine valve-shaped TiAl-Mn intermetallics containing 43.5 to 47.5at%Al (Mn/Al=0.036) are successively fabricated by reactive sintering the elemental powder mixtures near-net shaped by extrusion and die forging. A duplex structure consisted of lamellar grains and equiaxed grains is developed for all compositions, and the areal fraction of the lamellar grains(or equiaxed grains) decreases (or increases) with increasing Al content. As Al content increased, the elongation increases with accompanying decrease in yield strength and ultimate tensile strength at both room temperature and 80. This indicates that the suitable composition is Ti-45at%Al-1.6at%Mn in considering the balance of ambient and elevated tensile properties. The reactive-sintered Ti-45Al-1.6Mn alloy shows superior oxidation resistance not only to the plasma arc melted one but also to the heat resistance steel STR35(representative exhaust valve head material for automotive engine). The reactive-sintered Ti-45Al-1.6Mn alloy coated with an oxidizing scale exhibits a better wear resistance than induction hardened martensitic steel STR11(representative exhaust valve tip material for automotive engine).

It is well known that the metallo-phthalocyanine(MPcs) are sensitive to toxic gaseous molecules such as NO2 and also chemically and thermally stable. Therefore, lots of MPcs have been studied for the potential chemical sensor for NO2 gas using quartz crystal microbalance or electrical conductivity. In this study, 2,3,9,10,16,17,23,24-[octa-(dodecyloxy)] copper phthalocyanine and 2,3,9,10,16,17,23,24-[octa-(octyloxy)] copper phthalocyanine were synthesized and their possibility of LB film preparation were tested. It was confirmed by using FT-IR, DSC, NMR, UV-Vis absorption spectroscopy and Elemental Analysis that CuPc derivatives were successfully synthesized. From the π-A characteristics and limiting areas of two CuPc derivatives it was found that the preparation of LB films with these CuPc derivatives is possible.

비정질 금속 Co66F e4Ni B14S i15 의 표면층 제거에 대한 자기임피턴스 효과는 시료의 길이방향에 평행한 일축자기장에 대하여 측정하였다. MIR(Magnetoimpedance Ratios)은 비정질 금속의 두께가 얇아짐에 따라 감소하고, 전류에 비례하여 증가하는 경향을 나타내었다. 인가전류 주파수에 대한 MIR과 자기장의 감도는 모든 시료에서 주파수에 비례하여 증가하며 수 MHz 부근에서 최대값을 가지고 점차 감소하는 경향을 나타내었다. 시료의 표면층제거에 기인한 이방성자기장의 변화는 MI RMax을 나타내는 외부 자기장을 감소시키지만, MIR은 표면층 제거에 따른 부피효과에 기인하여 감소하였다....

Joining of AIN ceramics to W and Cu by active-metal brazing method was tried with use of (Ag-Cu)-Ti alloy as insert-metal. Joints were produced under various conditions of temperature, holding time and Ti-content in (Ag-Cu) alloy Reaction and microstructural development in bonded interface were investigated through observation and analysis by SEM/EDS, EPMA and XRD. Joint strengths were measured by shear test. Bonded interface consists of two layers: an insert-metal layer of eutectic Ag- and Cu-rich phases and a reaction layer of TiN. Thickness of reaction layer increases with bonding temperature, holding time and Ti-content of insert-metal. It was confirmed that the growth of reaction layer is a diffusion-controlled process. Activation energy for this process was 260 KJ/mol which is lower than that for N diffusion in TiN. Maximum shear strength of 108 MPa and 72 MPa were obtained for AIN/W and AIN/Cu joints, respectively. Relationship between processing variables, joint strength and thickness of reaction layer was also explained.

In most of sintered metal powder compacts, the sintered density distribution is controlled to be as high and uniform as possible to ensure the required mechanical properties. In general, the density distribution in the compacts is not uniform and not easy to measure. In the present study, a method for measuring the density distribution was developed, based on the indentation force equation by which the hardness and the relative density were related. The indentation force equation, expressed as a function of strength constant, workhardening coefficient and relative density, was obtained by finite element analysis of rigid-ball indentation on sintered powder metal compacts. The present method was verified by comparing the predicted density distribution in the sintered Fe-0.5%C-2%Cu compacts with that obtained by experiments, in which the density distribution was directly measured by machining the compacts from the outer surface progressively.