• 자원리싸이클링
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• 제27권2호
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• pp.32-37
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• 2018

본 연구는 금속 팔라듐 및 산화 팔라듐의 재활용을 위한 전 단계 연구로 수행되었다. 본 연구에서는 산화 팔라듐(PdO)의 형성을 위한 열역학적 수식들을 확립하였다. 또한 고상의 염화 팔라듐($PdCl_2$)을 염산 용액에 용해시킨 염화 팔라듐 용액을 원료용액으로 사용하였다. 이 원료 용액으로부터 분무열분해 공정에 의하여 평균입도 30 nm 이하의 산화 팔라듐 분체를 제조하였다. XRD 분석 결과 생성된 분체는 오직 PdO 상이었으며 TEM 분석결과 형성된 나노 PdO 입자들은 단결정 상임을 확인하였다. 또한 생성된 PdO 분말의 비표면적은 약 $32m^2/g$이었다.

• Bulletin of the Korean Chemical Society
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• 제16권5호
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• pp.398-400
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• 1995

Selective oxidation of cyclohexane in acetone solution has been studied using iron catalysts with hydrogen peroxide in-situ produced by palladium catalyst. Iron tetraphenylporphyrin chloride shows the highest activity among the tested chlorides and porphyrin complexes of some metals of the first transiton series. Iron chloride and iron tetraphenylporphyrin chloride were supported on four kinds of 4-vinylpyridine copolymer with styrene or divinyl-benzene. Nitrogen 1s photoelectron spectra give the evidence that pyridyl nitrogens of the 4-vinyl pyridine copolymer act as ligands to bind iron species. The copolymer with styrene is the most efficient support for the binding because its solubility in catalyst preparation solvent (methylene chloride) gives the pyridyl group advantage to contact with the iron catalysts. However, better catalytic activity per iron atom could be obtained with a rigid crosslinked polymer due to active site isolation.

• Corrosion Science and Technology
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• 제4권1호
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• pp.19-22
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• 2005

Two Au-Ag-Cu-Pd dental casting alloys (Au:12% and 20%) used. The test solutions used 0.9 % NaCl solution (isotonic sodium chloride solution), 0.9 % NaCl solution containing 1 % lactic acid, and 0.9 % NaCl solution containing 1 % lactic acid and 0.1 mol $dm^{-3}$ $Na_2S$. The surface of two samples in three sample solutions was not natural discoloration during one year. The alloy containing 12 % gold was easily alloyed and the composition was uniform comparing with the alloy containing 20 % gold. The rest potentials have not a little effect after three months. The kinds of metals could not definitely from the oxidation and reduction waves of metal on the cyclic voltammograms. The dissolutions of gold and palladium were 12 % Au sample in the 0.9 % NaCl solution containing 1 % lactic acid and 0.1 mol $dm^{-3}$ $Na_{2}S$. The pH of solution had an affect on dissolution of copper, and sulfur ion had an affect on dissolution of silver. The copper dissolved amount from 20 % gold sample was about 26 times comparing with that of 12 % gold sample in the 0.9 % solution containing 1 % lactic acid. Corrosion products were silver chloride and copper chloride in NaCl solution, and silver sulfide and copper sulfide in NaCl solution containing $Na_{2}S$.

• Bulletin of the Korean Chemical Society
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• 제31권7호
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• pp.1945-1950
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• 2010

Solvent extraction experiments of Pt(IV), Pd(II) and Rh(III) by Alamine336 were performed from the mixed chloride solutions. In the HCl concentration range from 1 to 5 M, most of Pt and Pd were extracted from the mixed solutions. However, the extraction percentage of Rh was much smaller than that of Pt and Pd. Lower concentration of Alamine336 in strong HCl solution led to higher separation factor of Rh from Pt and Pd. Adding $SnCl_2$ to the mixed solutions increased the extraction percentage of Rh, while the extraction percentage of Pt and Pd was little affected. Our results showed that selective separation of Rh or coextraction of the three platinum group metals from the mixed solution would be possible by adjusting the extraction conditions.

• Bulletin of the Korean Chemical Society
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• 제30권9호
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• pp.1951-1955
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• 2009

A Thermodynamic study on the interaction of bovine calf thymus DNA with new designed Pd(II) complex (Ethylendiamine- 8-hydroxyquinolinato Palladium(II) chloride) was studied by using isothermal titration calorimetry (ITC) at 27 ${^{\circ}C}$ in Tris buffer solution at pH = 7.5. The enthalpies of Pd(II) complex + DNA interaction are reported and analysed in terms of the new solvation theory. It was indicated that there are three identical and non-cooperative sites for Pd(II) complex. The binding of a Pd(II) complex is endothermic with association equilibrium constants of 428.03 m$M^{-1}$ at 27 ${^{\circ}C}$. The binding of Pd(II) complex can cause some changes in the stability of the DNA at low and high Pd(II) complex concentrations. Our results suggested that this complex might interact with DNA as an intercalator, thus interfering with DNA replication and cell proliferation.

• 한국표면공학회지
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• 제48권6호
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• pp.253-259
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• 2015

The test equipment becomes more important with the development of semiconductor industry. MEMS probe is an important testing component to detect the defects from the generated electric signal when it contacts the metal pad of semiconductor devices. Ni-Pd alloy has been paid attention to as a candidate of MEMS probe material because of its high surface hardness and relatively low resistivity. In this study, electroplated Ni-Pd alloy has been prepared by using ethylene diamine as a complexing agent. Solid solution alloy coating could be formed when concentration of palladium chloride and current density were in the ranges of 1~5 mM and $0.2{\sim}1.5A/dm^2$, respectively. The increase of current density brought about an decrease in palladium content, which made both of lattice parameter and grain size smaller. As a result of grain refinement, high hardness could be obtained. However, surface cracking was observed due to residual stress when the current density was above $1.3A/dm^2$. When effects of heat treatment temperature on hardness and sheet resistance were investigated, the accompanied grain growth decreased both of them. The decrease of hardness remained stable at a temperature of $200^{\circ}C$. The sheet resistance was drastically reduced at $100^{\circ}C$. After that, it was found to become constant.

• 한국산학기술학회논문지
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• 제13권12호
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• pp.6187-6195
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• 2012

네오디뮴 폐자석 침출액으로부터 희유금속인 네오디뮴을 회수하기 위해서는 네오디뮴과 같이 침출되는 철의 부가가치를 높이는 연구가 필요하다. 본 연구에서는 네오디뮴과 같이 침출되는 철의 유용자원화를 위한 기초연구로 철 나노분말 제조하는 실험을 수행하였다. 본 연구는 $FeCl_3$ 용액을 철 분말 원료로, 분산제는 $Na_4O_7P_2$와 Polyvinylpyrrolidone를 이용하였고, 환원제로는 $NaBH_4$, 철 나노분말 핵생성 촉진제 시드(seed)로 염화팔라듐을 사용하였다. 제조한 철 나노분말을 XRD, 전자현미경(SEM) 및 PSA 등을 이용하여 분말의 형상 및 크기 등을 분석하였다. 철과 $NaBH_4$의 농도비가 1 : 5이며, 반응시간이 30분 이상인 경우에서 철 분말이 제조되었으며, 이때 철 분말은 구형이었으며, 입도는 약 50 nm ~ 100 nm 크기였다. 분산제 $Na_4O_7P_2$의 경우 100 mg/L에서 철이온의 제타포텐셜이 음의 값을 가지므로 100 mg/L로 일정하게 하고, PVP와 Pd의 농도를 다양하게 하였을 경우, $FeCl_3$와 PVP와 Pd의 질량비 1 : 4 및 1 : 0.001에서, 분산이 양호하고, 입도 100 nm 크기인 철 나노분말을 합성하였다.

• The Journal of Advanced Prosthodontics
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• 제7권1호
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• pp.56-61
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• 2015

PURPOSE. The purpose of this study was to evaluate the effects of the surface treatment and shape of the dental alloy on the composition of the prosthetic work and its metallic ion release in a corrosive medium after casting. MATERIALS AND METHODS. Orion Argos (Pd-Ag) and Orion Vesta (Pd-Cu) were used to cast two crowns and two disks. One of each was polished while the other was not. Two as-received alloys were also studied making a total of 5 specimens per alloy type. The specimens were submersed for 7 days in a lactic acid/sodium chloride solution (ISO standard 10271) and evaluated for surface structure characterization using SEM/EDAX. The solutions were quantitatively analysed for the presence of metal ions using ICP-MS and the results were statistically analysed with one-way ANOVA and a Tukey post-hoc test. RESULTS. Palladium is released from all specimens studied (range $0.06-7.08{\mu}g{\cdot}cm^{-2}{\cdot}week^{-1}$), with the Pd-Cu alloy releasing the highest amounts. For both types of alloys, ion release of both disk and crown pairs were statistically different from the as-received alloy except for the Pd-Ag polished crown (P>.05). For both alloy type, disk-shaped pairs and unpolished specimens released the highest amounts of Pd ions (range $0.34-7.08{\mu}g{\cdot}cm^{-2}{\cdot}week^{-1}$). Interestingly, in solutions submerged with cast alloys trace amounts of unexpected elements were measured. CONCLUSION. Shape and surface treatment influence ion release from dental alloys; polishing is a determinant factor. The release rate of cast and polished Pd alloys is between $0.06-0.69{\mu}g{\cdot}cm^{-2}{\cdot}week^{-1}$, which is close to or exceeding the EU Nickel Directive 94/27/EC compensated for the molecular mass of Pd ($0.4{\mu}g{\cdot}cm^{-2}{\cdot}week^{-1}$). The composition of the alloy does not represent the element release, therefore we recommend manufacturers to report element release after ISO standard corrosion tests beside the original composition.

• 자원리싸이클링
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• 제23권6호
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• pp.22-29
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• 2014

네오디뮴 폐자석 침출액으로부터 희유금속인 네오디뮴을 회수하는 연구와 함께 네오디뮴과 같이 침출되는 철의 부가가치를 높이는 연구가 필요하다. 본 연구에서는 네오디뮴과 같이 침출되는 철의 유용자원화를 위한 기초연구로 철 나노분말을 제조하는 실험을 수행하였다. 본 연구는 $FeCl_3$ 용액을 철 분말 원료로, 분산제는 $Na_4P_2O_7$와 Polyvinylpyrrolidone를 이용하였고, 환원제로는 $NaBH_4$, 철 나노분말 핵생성 촉진제 seed로 염화팔라듐을 사용하였다. 제조한 철 나노분말을 XRD, SEM을 이용하여 분말의 형상 및 크기를 분석하였다. Fe와 $NaBH_4$의 몰 비를 1 : 5로 조절하여 철 분말을 제조하였으며, 이 때 철 분말은 구형이었으며, 입도는 약 50 ~ 100 nm 였다. 분산제 $Na_4P_2O_7$의 경우 100 mg/L에서 철 이온의 제타포텐셜이 음의 값을 가졌고, $FeCl_3$ 과 PVP와 Pd의 질량비 1 : 4 : 0.001에서 분산이 양호하고, 입도가 100 nm 인 철 나노분말을 합성하였다. 같은 반응 조건에서 폐 Nd 침출액의 Fe 이온을 pH를 조절하여 슬러리화한 후 실험을 진행한 결과, pH 9에서 구형의 철 분말을 합성할 수 있었으며, 20 L 이상의 Scale-up 공정에서는 분산제 없이 환원제로 175 nm 크기의 철 분말을 합성할 수 있었다.

• 마이크로전자및패키징학회지
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• 제17권1호
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• pp.75-80
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• 2010

다공성 탄소전극기지 위의 무전해 니켈도금에 관한 연구를 하였다. 다공성 탄소전극기지로는 다공도가 20 ${\mu}m$ 이상인 것과 16~20 ${\mu}m$ 인 것을 사용하였다. 소수성인 탄소 표면은 $60^{\circ}C$ 이상의 암모니아 용액에 침적함으로써 그 표면 성질이 친수성으로 변화 되었고, 40분 이상 침적 시 접촉각이 $20^{\circ}$ 이하까지 측정 되었다. 도금욕의 pH가 증가됨에 따라 탄소기지 위에 도금된 니켈 도금층의 인의 석출량은 감소하였으며 니켈 도금층이 결정질 구조를 갖는 현상이 관찰되었다. 도금층의 두께는 pH가 증가함에 따라 증가하였다. 활성화 처리를 위한 $PdCl_2$의 농도에 따른 도금층의 두께 변화는 없었으나, 도금에 필요한 $PdCl_2$의 최소농도는 5 ppm 이상인 것으로 나타났다.