• 열처리공학회지
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• 제24권4호
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• pp.209-216
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• 2011

Surface coatings were prepared on SKD11 core mold steel by plasma electrolytic oxidation (PEO). The coatings were investigated about the formation condition of core mold steel. SKD11 were coated by PEO in a mix solution of Sodium Aluminate $NaAlO_2$ (10 g/l), Sodium Silicate powder $Na_2SiO_3$ (0.5 g/l), Sodium tungstate dihydrate $Na_2WO_42H_2O$ (0.5 g/l) at less than $30^{\circ}C$. The electrical condition were voltage : 500~600 V; Pulse : 600~1800 Hz; current density 15~20 $A/dm^2$ various time : 3 min~40 min. The coatings surface morphology, cross-section, friction coefficient, hardness were investigated. The PEO coatings on SKD11 core mold steel showed the extended service life.

• 한국재료학회지
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• 제28권7호
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• pp.405-410
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• 2018

TiN and CrN thin films are among the most used coatings in machine and tool steels. TiN and CrN are deposited by arc ion plating(AIP) method. The AIP method inhibits the reaction by depositing a hard, protective coating on the material surface. In this study, the characteristics of multi-layer(TiN/CrN/TiN(TCT), CrN/TiN/CrN(CTC)) are investigated. For comparison, TiN with the same thickness as the multilayer is formed as a single layer and analyzed. Thin films formed as multilayers are well stacked. The characteristics of micro hardness and corrosion resistance are better than those of single layer TiN. The TiN/CrN peak is confirmed because both TCT and CTC are formed of the same component(TiN, CrN), and the phase is first grown in the (111) direction, which is the growth direction. However, the adhesion and abrasion resistance of the multilayer films are somewhat lower.

• 한국표면공학회지
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• 제24권3호
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• pp.119-124
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• 1991

Recently, the trend of research in hard coating is concentrate on developing the process of ionization rate under low operating pressure, to get the thin film with high adhesion and dense microstructures. In this study ionization rate enhancement type PVD process using permanent magnet is developed, which enhances the ionization rate by confining the plasma suppressing the wall loss of electron. By the result to investigate the characteristic of glow discharge, the ionization rate of this process is enhanced about twice as high as that of triod BARE process (about 26%), and more dense TiN microstructures are obtained in this process. Cylindrical ion energy analyzer is made and attached in front of a quadrupole mass filter for the analysis of the energy distribution of reactive gas and activated gas ions from the plasma zone. To analyze the operation mechanism of ion energy analyzer, computer simulation is performed by calculation the electric field environment using finite element method. By these analyses of ion energy distribution of outcoming ions from the plasma zone, it is found that magnetic field enhances ion kinetic energy as well as ionization rate. The other results of this study is that the foundation of feed-back system is constructed, which automatically control the partial pressure of reactive gas. In can be possible by recording the data of mass spectrum and ion energy analysis using A-D converter.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.155-158
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• 2007

Printed organic thin-film transistor(OTFT) to use as a switching device for an organic light emitting diode(OLED) were fabricated in the microcontact printing and direct printing processes at room temperature. The gate electrodes($5{\mu}m$, $10{\mu}m$, and $20{\mu}m$) of OTFT was fabricated using microcontact printing process, and source/drain electrodes ($W/L=500{\mu}m/5{\mu}m$, $500{\mu}m/10{\mu}m$, and $500{\mu}m/20{\mu}m$) was fabricated using direct printing process with hard poly(dimethylsiloxane)(h-PDMS) stamp. Printed OTFT with dielectric layer was formed using special coating system and organic semiconductor layer was ink-jet printing process. Microcontact printing and direct printing processes using h-PDMS stamp made it possible to fabricate printed OTFT with channel lengths down to $5{\mu}m$, and reduced the process by 20 steps compared with photolithography. As results of measuring he transfer characteristics and output characteristics of OTFT fabricated with the printing process, the field effect characteristic was verified.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2001년도 추계학술발표회 초록집
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• pp.56-56
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• 2001

Ni-W alloy deposit is one of the best alternatives to hard chromium plating because of its good mechanical properties (high hardness, high strength, and good wear resistance). Ni-W alloy is deposited from weakly acidic or alkaline electrolytic bath with nickel sulfate, sodium tungstate or APT, and some kinds of organic hydroxy-acid complex and ammonia salts. W content of the deposit can be changed from 0 to 5Owt% and the coating with high W content is more attracted. But, meanwhile, the deposited layers are always found high internal stress, which cause them to become brittle and to bond insufficiently with the substrate. On the second hand, as the W content is incresed, the current efficiency reduced, which results in large quantities of hydrogen evolution and then produces bubbles on surface and pitting appearance In this paper, the influence of some additives on Ni-W alloy electroplating was investigated by means of compositional analysis and SEM. The initial results showed that 2-butyne-1,4-diol was the best brightener for Ni-W plating process. It could brighten and level deposit, but decreased the cathodic current efficiency. Its optimum concentration range is from O.lgjL to 0.5gjL. Besides, three kinds of additives including 2-butyne-1,4-diol were examined with Dagguchi method.

• 한국표면공학회지
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• 제19권3호
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• pp.83-91
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• 1986

Codeposited of boron nitride(BN) particle dispersed into electroless nickel-phosphours (Ni-P) and nickel-boron(Ni-B) platings were studied for the purpose of developing the wear resistance and lubricity. BN can be codeposited from electroless nickel plating bath with $NaH_2PO_2$ and $NaBH_4$ as the reducing agents. Most dispersolids were distributed uniformly in the Ni-P and Ni-B matrix. Abrasion loss decreased with increasing amount of codeposits and reached a constant value 2.4 percent by volume percent of BN particle. The wear resistance and the friction coefficient of the heat treated BN composite coatings were improved about three times than that of as-coatings. The BN composite coatings were more wear resistance than hard chromium. Ni-B-BN composite coatings showed lower wear resistance and friction coefficient than Ni-P-BN. The BN content of the deposite was found to be 2.4 v/o for these optium conditions.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2011년도 춘계학술대회 및 Fine pattern PCB 표면 처리 기술 워크샵
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• pp.141-141
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• 2011

DLC(Diamond Like Carbon) 박막은 높은 경도, 낮은 마찰계수, 내화학성 등의 우수한 트라이볼로지적 특성을 가지고 있기 때문에 다양한 산업분야에서 적용되고 있다. 이러한 DLC 박막은 합성기구나 구조의 관점에서 몇 가지 다른 이름으로 불려지기도 한다. 밀도와 경도가 높기 때문에 경질탄소(Hard Carbon)라고도 불려지며, 수소를 함유한 경우에는 수소함유 비정질 탄소(Hydrogenated Amorphous Carbon)이라는 이름이 사용되며, 고밀도 탄소(Dense Carbon) 또는 고밀도 탄화수소(Dense Hydrocarbon)라고 불리기도 한다. 이렇듯 DLC 박막은 합성방법에 따라 함유된 수소와 탄소의 결합구조의 차이가 있다. 수소 함유한 DLC 박막은 20~50%까지 수소를 함유하며, DLC막의 기계적, 광학적, 전기적 특성들이 수소함량과 밀접한 관계를 가지고 있는 것으로 알려져 있다. 그러나 함유된 수소가 $300^{\circ}C$ 이상의 온도에서는 쉽게 결합에서 이탈되면서 흑연화와 더불어 마찰마모시 코팅층의 파손이 발생한다고 보고되고 있고, 또한 수소량이 증가함에 따라 DLC 박막의 경도는 감소하게 되는데, 이는 수소에 의해 dangling bond가 Passivation되면 탄화수소의 3차원적인 Crosslinking은 그만큼 감소하게 되기 때문이라고 알려져 있다. 본 연구에서는 PECVD를 이용하여 여러 가지 공정에 따른 DLC 박막을 증착시켰으며, 수소함유량에 따른 DLC막의 구조와 그에 따른 경도 변화를 살펴보았다. FTIR(Furier Transform Infrared Spectroscopy)과 Raman Spectroscopy을 이용하여 DLC막의 수소의 결합상태를 관찰하였으며, Nano Indentation을 사용하여 미소경도를 측정하였고, FE-SEM을 이용하여 표면과 단면을 관찰하였다. 막의 두께 측정에는 ${\alpha}$-Step을 사용하였으며, Ball-on-Disk 타입의 Tribo-meter을 이용하여, 모재의 경도에 따른 마찰계수 변화를 관찰하였다.

• 한국표면공학회지
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• 제49권6호
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• pp.580-586
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• 2016

Cr-Si-Al-N coating with different Si content were deposited by hybrid physical vapor deposition (PVD) method consisting of unbalanced magnetron (UBM) sputtering and arc ion plating (AIP). The deposition temperature was $300^{\circ}C$, and the gas ratio of $Ar/N_2$ were 9:1. The CrSi alloy and aluminum targets used for arc ion plating and sputtering process, respectively. Si content of the CrSi alloy targets were varied with 1 at%, 5 at%, and 10 at%. The phase analysis, composition and microstructural analysis performed using x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) including energy dispersive spectroscopy (EDS), respectively. All of the coatings grown with textured CrN phase (200) plane. The thickness of the Cr-Si-Al-N films were measured about $2{\mu}m$. The friction coefficient and removal rate of films were measured by a ball-on-disk test under 20N load. The friction coefficient of all samples were 0.6 ~ 0.8. Among all of the samples, the removal rate of CrSiAlN (10 at% Si) film shows the lowest values, $4.827{\times}10^{-12}mm^3/Nm$. As increasing of Si contents of the CrSiAlN coatings, the hardness and elastic modulus of CrSiAlN coatings were increased. The morphology and composition of wear track of the films was examined by scanning electron microscopy (SEM) and energy dispersive spectroscopy, respectively. The surface energy of the films were obtained by measuring of contact angle of water drop. Among all of the samples, the CrSiAlN (10 at% Si) films shows the highest value of the surface energy, 41 N/m.

• 디자인학연구
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• 제13권4호
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• pp.233-242
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• 2000

1990년대는 유압굴삭기의 전통적 조형이 새롭게 모색 및 재해석되는 시기로 판단되었으며, 이는 2가지 방향으로 정리될 수 있다. 하나는 유압굴삭기의 전통적 이미지에 관한 부정적 해석에서 기인한 '탈(post-heavy equipment)중기적' 경향이며, 다른 하나는 고유성 유지와 개선이라는 긍정적 해석에서 기인한 '후기(late-)중기적' 경향이다. 이는 동일한 현상을 다양하게 바라볼 수 있는 패러다임과 관련하는 것으로 사료된다. 이 시기에 개발 및 시판된 8개 연구대상 모델 중 유압굴삭기의 조형 경향은, 일본 색채디자인연구소에서 개발한 이미지스케일 3상한에서 2상한으로 변화였으며, 예외적으로 코벨코는 1상한까지 이동하는 경향이 있었다. 이는 탈중기적 이미지를 디자인 전략으로 채택하고 있는 코벨코만의 경우였다. 아울러, 인적(入的)공간으로서의 캐빈의 변화는 장비 전체의 변화에서보다 좀더 1상한으로 이동하고 있는데, 이는 물적(物的)공간과 시각적 차별화를 위한 것으로 사료되었다.

• 공업화학
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• 제27권4호
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• pp.449-454
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• 2016

본 연구에서는 구형의 폴리스티렌 구슬을 틀로 사용하여, 크기분포가 좁으면서 속은 비어있고 벽이 다공성인 구조의 탄소 마이크로 캡슐을 합성하였다. 폴리스티렌의 표면은 무기물인 실리카졸이 쉽게 입혀질 수 있도록 폴리비닐피롤리돈(PVP)을 코팅하여 변조하였다. PVP가 코팅된 PS 마이크로 입자표면에 SBA-16 졸을 부착시킨 다음, 실리카층에 존재하는 중간 크기의 세공 내에 탄소원을 채워 넣는 음각식 형뜨기법을 적용함으로써 속이 빈 구조의 탄소 마이크로캡슐을 제조하였다. 탄화과정을 거치고 틀로 사용한 다공성 실리카입자를 HF로 용해하면, 좁은 입자크기분포를 갖는 중간세공이 함유된 계란껍질형의 탄소입자를 얻을 수 있었다. 계란껍질형 탄소 마이크로캡슐 입자의 다공성과 전기화학적 특성은 XRD, SEM, TEM, 질소분자 흡/탈착분석법 및 cyclic voltammetry법으로 평가하였다. 이들 탄소입자는 슈퍼캐패시터와 같은 전자재료로서 유효하게 사용될 만한 높은 전기전도도와 용량을 나타내었다.