• Membrane Journal
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• v.32 no.6
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• pp.456-464
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• 2022

Hydrogen permeation performance was analyzed by manufacturing Pd and Pd-Cu membranes through electroless plating. As a support for the Pd and Pd-Cu membranes, α-Al₂O₃ ceramic hollow fiber were used. Pd-Cu membrane was manufactured through sequential electroless plating, and then annealing was performed at 500°C, for 18 h in a hydrogen atmosphere to make Pd and Cu alloy. After annealing, the Pd-Cu membrane confirmed that the alloy was formed through EDS (Energy Dispersive X-ray Spectroscopy) and XRD (X-ray Diffraction) analysis. In addition, the thickness of the Pd and Pd-Cu plating layers were measured to be about 3.21 and 3.72 µm, respectively, through SEM (Scanning Electron Microscope) analysis. Hydrogen permeation performance was tested for hydrogen permeation in the range of 350~450°C and 1~4 bar in hydrogen single gas and mixed gas (H₂, N₂). In a single hydrogen gas, Pd and Pd-Cu membranes have flux of up to 54.42 and 67.17 ml/cm²⋅ min at 450 °C and 4 bar. In the mixed gas, it was confirmed that the separation factors of 1308 and 453 were obtained under the conditions of 450 °C and 4 bar.

• Korean Journal of Materials Research
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• v.11 no.2
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• pp.76-81
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• 2001

In order to recover Au and Pd from the leaching solution of various electronic wastes by electrowinning, the electrochemical behavior of Au and Pd in hydorchloric acidic solution was investigated by means of voltammetry. The reduction potential of Au ion was 800mV and the limiting current appeared at 470mV in electrolytic solution of gold. The reduction potential of Pd ion was 500mv and the limiting current appeared at 150mV in electrolytic solution of Palladium. However, in Au-Pd electrolytic solution, the Potentials for reduction and the limiting current of Au decreased as the content of Pd in electrolyte increased, and the potentials for the limiting current of Au and Pd closed nearest together when percentage of Pd electrolytic solution was 37v71% in Au-Pd electrolyte.

• Analytical Science and Technology
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• v.36 no.6
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• pp.324-331
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• 2023

Latent fingerprints on wet paper cannot be developed using amino acid reaction reagents. Therefore, physical developer (PD) or lipid staining reagents like oil red O (ORO) should be utilized. However, ORO is not very effective in developing fingerprints that are older than approximately 4 weeks. On the other hand, PD performs well in developing older fingerprints, but it cannot do so for relatively fresh fingerprints. Additionally, PD has the disadvantage of taking a long time to develop fingerprints. In this study, in order to overcome the limitations of PD, we attempted to increase its reactivity by applying Ag-PD, which involves depositing silver onto paper using vacuum metal deposition (VMD), and compared this with fingerprints developed using ORO and PD. As a result, Ag-PD showed superior fingerprint development compared to ORO and PD on wet paper stored for 2~8 weeks, and the fingerprint development time for PD was significantly reduced to 90~150 seconds.

• Journal of Biomedical Engineering Research
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• v.20 no.4
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• pp.443-449
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• 1999

현재 시판되고 있는 치과용 76.5%Pd-11.6%Cu-7.2^%GarP 합금의 주조상태 및 임상열처리에 따른 미세조직의 변화를 X-선 회절기, 광학현미경, 시차열분석기를 이용하여 관찰하였다. 주조상태, 탈개스 및 세리믹소성처리 후 미세조직은 Pd고용체와 금속간화합물 Pd2Ga으로 구성되어 나타났고, 이들 상들은 열처리에 따라 상당한 변화를 보였다. 또한 Pd은 아르곤 분위기 내의 산소와 반응하여 산화물 형성 및 분해로 인해 질량변화곡선(TG)이 변하였고, 시차열분석(DTA)에서는 약 815$^{\circ}C$ 정도에서 Pd2Ga에 기인하는 흡열피크를 확인하였다. 이러한 실험의 결과들은 Cu가 이원계 Pd-Ga 합금의 Ga의 고용량을 낮추어 공정반응이 저 Ga 쪽으로 이동하기 때문인 것으로 설명하였다. 그러나 앞으로 보다 명확한 상변태 규명을 위해서 TEM등의 분석장비를 사용하여 체계적인 연구가 요구된다.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.243-248
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• 1998

This study investigated the separation and the property of palladium precipitate formed by ascorbic acid in a simulated radioactive liquid waste, which was composed of 10 elements((Pd, Ru, Rh, Nd, Cs, Sr, Fe, Ni, Zr, Mo). Pd was separated selectively by using reduction characteristics of metal ions contained in the simulated waste with ascorbic acid. When the nitric acid concentration was 0.5 M, the Pd over 99.5% was precipitated by adding 0.04 M ascorbic acid. Nitric acid concentration is important at the reduction reaction of Pd ion. The precipitation yield of Pd was decreased as the concentration of nitric acid was increased. The Pd precipitate was re-dissolved in reaching at an equilibrium when the concentration of nitric acid was high and ascorbic acid was added with a small amount. The Pd precipitate formed by ascorbic acid was Pd metal and was aggregated by particles less than $1.0{\mu}m$.

• Journal of the Korean Magnetics Society
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• v.6 no.6
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• pp.405-410
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• 1996

Valence band photoemission spectroscopy (PES) measurements have been performed for $Co_{x}Pd_{100-x}$ alloy films using synchrotron radiation (x = 0, 25, 40, 65). Then the partial spectral weight distributions (PSW's) of Co 3d and Pd 4d electrons have been determined. The Co 3d PSW's exhibit some structures which are quite different from those of the Co film for x < 25 %, whereas they become very similar to those of the Co film for x > 40 %. For x < 25 %, the peak near the Fermi level ($E_F$) and a shoulder around 2 eV binding energy in the Co 3d PSW reflect large hybridization between Pd 4d and Co 3d electrons, suggesting that the hybridization might play an inportant role in determining perpendicualr magnetic anisotropy. The Pd 4d PSW's in Co-Pd alloy films are found to have larger FWHM's (full widths at half maximum), larger binding energies of the main peaks, and larger spectral intensities at $E_F$ than the PES spectrum of the Pd film. The FWHM of the Pd 4d PSW increases with decreasing Pd concentration, which are considered to reflect the disordering effect in the alloy formation or the change in the Pd 4d electronic structure due to hybridization between Co 3d and Pd 4d electrons.

• Membrane Journal
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• v.32 no.2
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• pp.116-125
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• 2022

In this experiment, an α-Al₂O₃ ceramic hollow fiber was used as a support, and a hydrogen membrane plated with Pd and Pd-Ag was manufactured through electroless plating. The Pd-Ag membrane was annealed at 500℃ for 10 h to form an alloy of Pd and Ag. It was confirmed that it became a Pd-Ag alloy through EDS (Energy Dispersive X-ray Spectroscopy) analysis. Also, the thickness of the Pd, Pd-Ag plating layer was measured to be about 8.98 and 9.29 ㎛ through SEM (Scanning Electron Microscope) analysis respectively. Hydrogen permeation experiment was performed using the H₂ gas and mixed gas (H₂ and N₂) in the range of 350~450℃ and 1-4 bar using the prepared hydrogen membrane. Under the H₂ gas condition, the Pd and Pd-Ag membrane has a flux of up to 21.85 and 13.76 mL/cm²·min and also separation factors of 1216 and 361 were obtained in the mixed gas at 450℃ and 4 bar conditions respectively.

• Journal of IKEEE
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• v.22 no.2
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• pp.356-361
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• 2018

We investigated a hydrogen gas sensor which is available in a high temperature atmosphere. The hydrogen sensors were fabricated into a metal-oxide-semiconductor (MOS) structure made of $Pd/Ta_2O_5/SiC$, and the thin tantalum oxide ($Ta_2O_5$) layer was fabricated by rapid thermal oxidation (RTO). In the experiment, we made three types of sensors with different palladium (Pd) patterns to evaluate the effect of Pd electrode on response characteristics. As the result, the response characteristics in capacitance were improved further when the filled area of the Pd electrode became larger.

• Transactions of the Korean hydrogen and new energy society
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• v.8 no.4
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• pp.145-154
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• 1997

The $H_2$ and $H_2S$ sensing characteristics of Pd and Pd-Rh gate MOS sensor and the effect of Pd deposition condition on the hydrogen sensing performance of Pd gate MOS sensor was investigated. The increase of rf power and deposition temperature led to the decrease in the sensitivity and the initial response rate. The deposition temperature gave more effects on the decrease of the sensitivity and the initial response rate than the rf power. The sensitivity of Pd-Rh sensor gave better performance than pure Pd sensor. As the concentration of Rh in the gate increased, the sensitivity decreased. For Pd-Rh sensor, the sensitivity to $H_2$ was higher than that to $H_2S$. It was demonstrated that rf power, deposition temperature had an important role in the sensor performance.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.4 s.37
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• pp.323-330
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• 2005

We fabricate PIN PD (Positive Intrinsic Negative Photo-Diode) for CWDM optical repeater and optical transmission system, and analyze theoretically the characteristics to verify the capability of device fabricated. Furthermore, we integrate CWDM filter into PD package to enhance the cost and the performance when compared to the conventional system, in which CWDM filter and PD package are linked by optical fusion splicing. The integrated CWDM PD is fabricated by three steps as follows: CWDM filter design, PD packaging, and product assembly and test. The results of measurement for PD fabricated reveal 0.5 dB bandwidth of 17 nm, isolation over 60 dB at transmission port and over 20 dB at reflection port. Also, the IMD3 for wireless communication is over 63 dBc, and the responsivity of PD presents over 0.9 A/W for 20 samples of the total 23 PD. The total insertion loss reduces about 0.4${\~}$0.7 dB due to the integrated assembly of CWDM and PD.