• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2016년도 추계학술대회 논문집
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• pp.194.1-194.1
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• 2016

The present study investigated the effect of zincate treatment time on the dissolution behavior and the deposition of copper by immersion process and electroplating process on AZ31 Mg alloy substrate in a copper pyrophosphate bath. Without zincate pretreatment, the AZ31 Mg substrate quickly dissolved in the copper pyrophosphate solution although an external cathodic current was applied. The copper layers deposited on non-zincate treated AZ31 Mg alloy substrate by both immersion and electroplating processes showed very porous structure and very poor adhesion. With increasing zincate treatment time up to 2 min, the dissolution of AZ31 substrate in pyrophosphate solution rapidly decreased and the deposited copper layer was less porous and exhibited stronger adhesion. The immersion of AZ31 Mg sample in zincate solution for 5 min was found as a critical time for producing a non-porous and adherent electrodeposited copper layer on AZ31 Mg alloy. The optimum zincating time can be determined by observing the open circuit potential (OCP) of AZ31 Mg alloy samples in a copper pyrophosphate electroplating bath. The OCP reached a stable value of about -0.10 V (vs. SCE) after 5 min of immersion in the copper pyrophosphate electroplating solution.

• 한국표면공학회지
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• 제48권1호
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• pp.1-6
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• 2015

Amino-carboxyl acid as a complexing agent in acid copper sulfate solution was utilized to improve the adhesion of immersion copper layer for steel wire. According to the tape test results, regardless of alloy composition of the wire, the adhesion of immersion copper layer was improved with the addition of amino-carboxyl acid. The incorporation of H and Fe in the plating layer was analyzed by TOF-SIMS. The H and Fe were detected at the entire coating layer without any addition of amino-carboxyl acid. However, with addition of amino-carboxyl acid, the H and Fe were scarcely detected at the coating layer.

• 한국표면공학회지
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• 제42권6호
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• pp.280-286
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• 2009

In this study, the corrosion property of copper alloy tubes in seawater has been investigated. Three copper alloys of nominal composition Cu-20Zn-2Al(Al-Brass), Cu-30Ni(CN70/30) and Cu-10Ni(CN90/10) were considered. The samples were immersed in 3%NaCl flowing solution at $90^{\circ}C$ for 30, 50 and 80 days. Corrosion rate of copper alloy tubes in 3%NaCl flowing solution was investigated by weight-loss measurements and electrochemical test. The CN70/30 showed lowest corrosion rate among three copper alloy tubes. Because of passive films formation, corrosion rates of three types of copper tubes were decrease with time. Surface characteristics of copper alloy tubes were analyzed by optical micrograph(OM), scanning electronic microscopy (SEM), energy dispersive X-ray analysis(EDAX) and X-ray diffraction patterns(XRD). CN70/30 showed partly pitting problem on the surface owing to high Fe content, even though having high resistant against corrosion. Cracks appeared on the surface of CN90/10 and CN70/30 after more than 50 days immersion, which could be derived from high nickel contents.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.151.1-151.1
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• 2017

This work studied the corrosion behavior of AZ31 Mg alloy galvanically coupled with Cu during immersion in 0.1 and 0.5 M NaCl solutions by in-situ observation and galvanic corrosion current measurement using a zero resistance ammeter. The corrosion behavior of AZ31 Mg alloy was also studied by salt spray test. The average galvanic corrosion density during 2 h immersion in 0.1 NaCl solution was found to decrease as an exponential function with increasing the surface area ratios between AZ31:Cu or with increasing the distance between AZ31 and Cu. The corrosion of electrodeposited Cu on AZ31 Mg alloy was concentrated at the area next to Cu (about 5 mm for immersion test and 2 mm for salt spray test) and pitting corrosion was accelerated at the area beyond the severely corroded area by the galvanic coupling effect.

• 한국식품과학회지
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• 제21권6호
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• pp.735-741
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• 1989

For the accurate prediction of freezing time, probably the most difficult factor to measure and major error source is the surface heat transfer coefficient. In this work, surface heat transfer coefficient were determined for still air freezing and immersion freezing methods by theory of the transient temperature method and confirmed by using a modification of plank's equation to predict the freezing time of ground lean beef. The results showed the cooling rate of immersion freezing was about 11 times faster than that of still air freezing method. A comparison of surface heat transfer coefficient of copper plate and ground lean beef resulted an difference of 25-30% because the food sample surface is not smooth as copper plate. Also, when h-values measured by ground lean beef were applicated to modified model, the accuracy of its results is very high as difference of about 8%.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.10-10
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• 2008

Flip chip technology is keeping pace with the increasing connection density of the ICs and is capable of transferring semiconductor performance to the printed circuit board. One of the most general flip chip technology is CPB technology presented by Intel. The CPTB technology has similar benefits with CPB but has simpler process and better reliability characteristics. In this paper, process sequence and structure of CPTB are presented.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.27-28
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• 2021

The search for new corrosion inhibitors for different corrosive mediums is a never-ending task. In the present work, the corrosion inhibition behavior and adsorption mechanism of two novel synthetic thiazolidinedione derivatives noted MTZD and ATZD in 3.5 wt.% NaCl solution on copper were investigated. Electrochemical, scanning electron microscope (SEM), atomic force microscopy (AFM) techniques were used along with first-principles DFT calculations. At maximum inhibitor concentration i.e., 300 ppm corrosion inhibition efficiency reached maximum up to 90% and 96% for MTZD and ATZD, respectively, and thereby followed the order of ATZD > MTZD. The inhibition efficiency increased up to 24 h of immersion, and then decreased after 48h immersion. The potentiodynamic curves suggested that the inhibition action of tested compounds is a mixed type of inhibitor. The first-principles DFT calculations suggested that compounds under investigation formed covalent bonds with Cu(111) surface via reactive sites. SEM and AFM results confirmed the formation of protective barrier that prevent corrosion attack.

• 한국가구학회지
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• 제19권5호
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• pp.358-364
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• 2008

Wood-inorganic material composite (WIC) was prepared by impregnating wood with copper sulfate ($CuSO_4\;5H_2O$) solution and by immersed wood in sodium carbonate($Na_2CO_3$) solution in order to introduce insoluble copper compounds {copper carbonate hydroxide, $CuCO_3\;Cu(OH)_2$} into the wood to give fungicidal effects in treated-wood. The weight percent gains (WPGs) of treated wood reached maximum value by impregnation of 20% copper sulfate solution and immersion in about 15% sodium carbonate solution for 24 hrs. Inorganic substances were present mainly in the lumina and cross-field pitting of tracheides. These substances were proved to be the insoluble copper carbonate hydroxide against water by the energy dispersive X-ray analyzer in conjunction with a scanning electron microscope (SEM-EDXA). The treated specimens showed high preservative effectiveness because the weight losses were hardly occurred by the fungi degradation test.

• Restorative Dentistry and Endodontics
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• 제14권1호
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• pp.199-204
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• 1989

The purpose of this study was to observe the anodic polarization curve from 4 kinds of low copper amalgam (Fine cut alloy, Spheralloy, Aristalloy and Amalcap) and 4 kinds of high copper amalgam (Dispersalloy, Sybraloy Orosphere and Tytin) obtained by using the potentiostat. The specimen made as the direction of manufacturer was stored at room temperature for about 7 days. The standard surface preparation was routinely carried out. The 0.9% saline solution was used as electrolyte in pH 6.8-7.0 at $37^{\circ}C$. The open circuit potential was determined after 30 minutes' immersion of specimen. The scan rate was 1mV/sec and the surface area of amalgam exposed to the solution was 0.785$cm^2$ for each specimen. All potentials reported are with respect to Ag/AgCl eelctrode. The following results were obtained. 1. The corrosion potential of high copper amalgams was higher than one of low copper amalgams, and the current density of high copper amalgam was lower than one of low copper amalgams. 2. The low copper amalgams had the similar pattern of polarization curve, but the high copper amalgams had the different pattern one another. 3. The polarization curve of Orosphere amalgam which is the admixed type was similar to one of low copper amalgam.

• Nuclear Engineering and Technology
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• 제55권8호
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• pp.2742-2746
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• 2023

The corrosion behavior of copper immersed in dilute oxychloride solution (100 mM) was studied through surface investigation and in-situ monitoring of open-circuit potential. The copper corrosion was initiated with copper dissolution into a form of CuCl^-₂, resulting in mass decrease within the first 40 h of immersion. This was followed by a hydrolysis reaction initiated by the CuCl^-₂ at the copper surface, after which oxide products were formed and deposited on the surface, resulting in a mass increase. The formation of nucleation sites for copper oxide and its lateral extension during the corrosion process were examined using focused ion beam (FIB)-scanning electron microscopy (SEM). The presence of metastable compounds such as atacamite (CuCl₂·3Cu(OH)₂) on the corroded copper surface was revealed by X-ray photoelectron spectra (XPS) and transmission electron microscopy (TEM)-energy dispersive spectrometry (EDS) analysis.