• 연구논문집
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• 통권28호
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• pp.219-227
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• 1998

In order to investigate the interfacial structure between TiN and iron nitride, an AISI 4140 steel was nitrided to form a layer of thickness 15$\mum$ by DC ion nitriding, then the surface was bombarded with Ti ions and subsequently coated a TiN film of 5$\mum$ by arc ion plating method. The interfacial microstructure between TiN and iron nitride was characterized by optical microscope, SEM and XRD. So called black layer was observed in the duplex treatment. It was resulted from the decomposition of iron nitride during the bombardment. Its thickness was increased with increasing bombardment time at high bias voltage. But the thickness was greatly decreased when the iron nitride was bombarded with a nitrogen gas or at a reduced bias voltage. The adhesion strength of the top TiN coating was decreased with increasing thickness of the black layer. Furthermore, the reduced adhesion strength in this system was discussed in view of the interfacial structural relationship between TiN and iron nitride.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
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• pp.324-326
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• 2004

l2wt%Cr Steel has been applied on turbine bucket and nozzle partition material of power plant. Turbine bucket and nozzle get damaged by solid particle within steam, therefore they are protected by surface treatments such as ion nitriding, boriding and chrome carbide HVOF spray coating. In this study, solid particle erosion(SPE) characteristics after these surface treatments are examined at operating temperature 540$^{\circ}C$ and 590$^{\circ}C$ of fossil power plant and the mechanism of damage was studied. Erosion of 12wt%Cr steel is originated by micro cutting and that of boriding and chrome carbide HVOF spray is originated by these mechanism - repeating collision, crack initiation and propagation. As the results of SPE test at 540$^{\circ}C$ and 30$^{\circ}$ impact angle that is the most commonly occurred in power plant, Boriding had the best SPE -resistance property, Cr$_2$C$_3$-25(Ni20Cr) HVOF spayed and ion nitrided samples were also better than bare metals(l2wt%Cr Steels). At 590$^{\circ}C$ and 30$^{\circ}$ impact angle, Boriding had also the most superior characteristic and HVOF spay sample was better than bare metal.

• Design & Manufacturing
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• 제13권1호
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• pp.13-18
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• 2019

The size and prospects of the domestic semiconductor equipment market are increasing every year. In the case of various parts used inside semiconductor equipments, high durability such as high strength and abrasion resistance is demanded. Particularly, the gases used in semiconductor production processes are toxic. In order to prevent such toxic gas leakage, a precision processing technique and a surface treatment technique for preventing corrosion are required. Electro-polishing is an electro-chemical method of polishing a metal surface to make it smooth and polished. Electro-polishing is mainly used in the finishing process of metal surface. Unlike mechanical polishing, electro-polishing is used in many fields, such as fine chemical etching equipment, since no damaged layer or burr, fine polishing groove and particles are generated. However, in order to withstand the gas used in the semiconductor equipment, the parts must have high corrosion resistance. However, the surface hardness generally become lowered through electro-polishing. Therefore, in this study, surface hardness were experimentally observed before and after electro-polishing. Then, a method of improving hardness by preparing a nitrided layer by plasma ion nitriding treatment.

• 한국융합학회논문지
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• 제10권11호
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• pp.241-246
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• 2019

STS 630에 이온질화를 통한 기계적 특성 및 세포독성을 고찰하여 의료기구용으로 활용중인 STS 420 소재의 대체 가능성을 융합적으로 고찰하고자 하였다. STS 630 합금을 $480^{\circ}C$에서 1시간 시효처리 후 온도, 시간, 압력, 질소투입량의 변화를 통하여 이온질화 최적조건을 선정하고, 미세조직, 경도, 인장강도 등 기계적 특성의 변화와 섬유아세포(IGF cell)를 이용한 MTT 세포독성 시험을 수행하였다. STS 630의 경도는 시험결과 $400^{\circ}C$에서 질화시간 3시간 이상일 때 시간에 따라 증가하며, 질소가스 투입량에 비례하여 질화층의 두께와 표면경도가 증가함을 알 수 있었다. STS 630의 인장강도는 시효처리와 이온질화에 의해 34%의 향상이 되었으며, 의료기구로서의 적합성을 확인하기 위하여 섬유아세포(IGF cell)를 이용한 MTT 세포독성 시험의 경우에는 대조군(STS 420)에서만 세포 독성이 관찰되고, STS 630의 경우에는 세포독성이 나타나지 않아 의료기구로서의 적합성은 있는 것으로 판단된다.

• 대한기계학회논문집
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• 제9권2호
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• pp.240-249
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• 1985

여러 가지 조건하에서 한쪽면만 이온질화 처리된 SCM4 의 평판을 모델로 하여 질화층의 기계적 성질과 잔류응력을 연구하였다. 질화층에서의 재료의 성질은 질소함량분포에 비례하여 변할 것이 라는 가정하에 외팔보의 굽힘과 온도-곡률의 관계를 구하는 이론적 모델을 정립하고 이에 따른 간접적 실험방법을 제시하였다. 질화층 표면에서의 선팽창 계수는 질화되지 않은 코어의 값에 비 해 2내지 12% 증가를 보였고 탄성계수는 50내지 700%증가를 보였다. 질화로 인한 축방향 팽창은 변형도로 약 0.002를 얻었다. 상온에서의 코어의 최대인장 잔류응력은 2내지 25Kg/mm$^{2}$이 며, 질화층표면에서 일어나는 최대압축잔류응력은 질화조건에 따라 50내지 300Kg/mm$^{2}$을 얻었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.328-331
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• 1988

Sealed Interface Local Oxidation (SILO) technology has been investigated using a nitride/oxide/nitride three-layered sandwich structure. P-type silicon substrate was either nitrided by rapid thermal processing, or silicon nitride was deposited by LPCVD method. A three-layered sandwich structure was patterned either by reactive ion etch (RIE) mode or by plasma mode. Sacrificial oxidation conditions were also varied. Physical characterization such as cross-section analysis of field oxide, and electrical characterization such as gate oxide integrity, junction leakage and transistor behavior were carried out. It was found that bird's beak was nearly zero or below 0.1um, and the junction leakages in plasma mode were low compared to devices of the same geometry patterned in RIE mode, and gate oxide integrity and transistor behavior were comparable. Conclusively, SILO process is compatible with conventional local oxidation process.

• 전기화학회지
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• 제18권2호
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• pp.45-50
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• 2015

본 연구에서는 리튬 이온 전도성 세라믹 고체전해질($Li_{1+x+y}Al_xTi_{2-x}Si_yP_{3-y}O_{12}$, LATP)의 알칼라인 용액 내에서의 화학적 안정성을 증가시키기 위하여, 고체전해질 표면을 질화 공정 처리를 통해 개질하였다. LATP 고체전해질의 화학적 안정성 및 전기화학 특성과 관련된 고체전해질 표면 형상 및 구조 특성 등을 X-선 회절법, X-선 광전자 분광법, 주사 전자 현미경 및 임피던스 측정을 통하여 분석하였다. 질화 처리된 LATP 시료를 30일간 알칼라인 용액에 담지하여, 표면 처리하지 않은 시료와 비교시 향상된 화학적 안정성을 나타냈으며, 이를 하이브리드 리튬-공기 전지에 적용하여 비교시 개선된 충방전 분극 및 효율 특성을 보였다. 이러한 결과를 바탕으로 질화 처리 공정을 통한 표면 개질은 알칼라인 용액내에서의 세라믹 고체전해질의 화학적 안정성을 증가시키는데 효과적으로 도움이 될 것으로 판단된다.

• 대한치과보철학회지
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• 제42권2호
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• pp.210-225
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• 2004

Statement of problem: Implant screw loosening has been remained problem in restorative practices. Surface treatment of screw plays a role of preventing screw from loosening in implant screw mechanism. Purpose : The purpose of this study was to investigate surface characteristics of TiN and ZrN film ion plated screw with titanium and gold alloy screw and to evaluate wear resistance, surface roughness, and film adhesion on screw surface using various instruments. Material and methods : GoldTite screws and titanium screws provided by 3i (Implant Innovation, USA) and TorqTite screws or titanium screws by Steri-Oss (Nobel Biocare, USA) and gold screws and titanium screws by AVANA (Osstem Implant, korea) were selected. Ion plating which is much superior to other surface modification techniques was carried out for gold screws and titanium screws using Ti and Zr coating materials with nitrogen gas. Ion nitrided surface of each abutment screw was observed with field emission scanning electron microscopy (FE-SEM, micro-diamond scratch tester, vickers hardness tester, and surface roughness tester. Results : 1) The surface of gold screw and GoldTite is more smooth than ones of other kinds of non coated screw. 2) The ZrN and TiN coated surface is the more smooth than ones of other kinds of screw. 3) The hardness of TiN and ZrN coated surface showed higher than that of non coated surface. 4) The TiN coated titanium screw and ZrN coated gold screw have a good wear resistance and adhesion on the surface. 5) The surface of ZrN coated screw showed low surface roughness compared with the surface of TiN coated screw. Conclusion : It is considered that the TiN and ZrN coated screw which would prevent a screw from loosening can be applicable to implant system and confirmed that TiN and ZrN film act as lubricant on surface of screw due to decrease of friction for recycled tightening and loosening.

• 한국전기전자재료학회논문지
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• 제20권1호
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• pp.1-7
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• 2007

In this paper, two kinds of initial oxidation methods i.e., SLTO(Slow Low Temperature Oxidation: $700^{\circ}C$) and RTO(Rapid Thermal Oxidation: $850^{\circ}C$) are applied prior to the plasma nitridation for ultra thin oxide of RPNO (Remote Plasma Nitrided Oxide). It is observed that SLTO has superior characteristics to RTO such as lower SS(Sub-threshold Slope) and improved Ion-Ioff characteristics. Low frequency noise characteristics of SLTO also showed better than RTO both in linear and saturation regime. It is shown that flicker noise is dominated by carrier number fluctuation in the channel region. Therefore, SLTO is promising for nano-scale CMOS technology with ultra thin gate oxide.

• 열처리공학회지
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• 제7권3호
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• pp.184-189
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• 1994

The heat treatment charaterristic of SCM 440 and B 16 steels has been investigated in various condition(A, B and C) to the effect of heat treatment on mechanical properties, and the following results were obtained. 1. We are obtained a good nitriding characteristic in bainitic structure than other heat treatment cycle in our experiment. 2. Fatigue characteristic has shown in order of B)C)A condition as heat treatment cycle. 3. The effective hardening depth and fatigue characteristic has been excellented in B 16 than SCM 440 after the nitriding and Q. T for Band C condition. 4. Nitriding depth has been increased in addition of Cr, V and the nitriding efficiency is increased as easiness of banite formation to wide range of cooling rate by addition of Mo. 5. The depth of compound layer in parallel surface, notched slop plane and notched bottom has been varied to the nitriding depth of 5, 4 and 3 ${\mu}$ in relatively uniform pattern after 10h nitriding treatment for SCM 440 into A condition.