• 연구논문집
• /
• 통권30호
• /
• pp.137-145
• /
• 2000

Since the concept of osseointegration was introduced, titanium and titanium-based alloy materials have been increasingly used for bone-anchored metal in oralmaxillofacial and orthopedic reconstruction. Successful osseointegration has been attributed to biocompatibility and surface condition of metal implant among other factors. Although titanium and titanium alloys have an excellent over the metal ion release and biocompatibility, considerable controversy has developed over the metal ion and wear debris in vivo and vitro. In this study, nitrogen ion implantation technique was used to improve the corrosion resistance and wear property of titanium materials, ultimately to enhance the tissue reaction to titanium implants As ion implantation energy was increased, projected range of nitrogen ion the Ti substrate was gradually increased. Under condition of constant ion energy. atomic concentration of nitrogen was also increased with ion doses. The friction in Hank's solution was increased with ion doses. The friction coefficient of ion implanted specimens in HanK's solution was increased from 0.39, 0.47 to 0.52, 0.65 respectively under high energy and ion dose conditions. As increasing ion energies and ion dose, amount of wear was reduced.

• Journal of Advanced Marine Engineering and Technology
• /
• 제31권6호
• /
• pp.744-752
• /
• 2007

Recently a fuel oil of the diesel engine in the ship is being changed with low quality as the oil price is higher more and more. Therefore the wear and corrosion in all parts of the engine like cylinder liner ring groove of piston crown, spindle and seat ring of exhaust valve are increased with using of heavy oil of low quality In particular the degree of wear and corrosion in between valve spindle and seat ring are more serious compared to the other parts of the engine due to operating in severe environment such as the high temperature of exhaust gas and repeating impact. Thus the repair weld to the valve spindle and seat ring is a unique method to prolong the life of the exhaust valve in an economical point of view In this study. corrosion property of both weld metal zone and base metal was investigated with some electrochemical methods such as measurement of corrosion potential, cathodic and anodic polarization curves, cyclic voltammogram and polarization resistance etc. in 5% $H_2SO_4$ solution. in the case of being welded with some welding methods and welding materials to the exhaust valve specimen as the base metal. In all cases. the values of hardness of the weld metal zone were more high than that of the base metal. And their corrosion resistance were also superior to the base metal. The weld metal of A2F(AC SMAW: 2 pass welding with foreign electrode) showed a relatively good results to the corrosion resistance as well as the hardness compared to the ether welding methods and welding materials. Moreover it indicated that hardness of the weld metal by the domestic electrode was considerably high compared to that of the foreign electrode.

• 방사선산업학회지
• /
• 제5권2호
• /
• pp.145-149
• /
• 2011

Poly(butylenes terephthalate) have made large strides in applications of injection, extrusion, and molding material due to their excellent thermal resistance and appropriate mechanical properties. However, PBT was not hard polymer but a soft polymer which caused low absorption of external energy and the defect of being easily broken with the strong impact. Thus, the electron beam irradiation was carried out over a range of irradiation doses from 100 to 1,000 kGy for enhancing the properties. The decreases of $T_m$, $T_c$, and enthalpy were observed as increasing the absorbed dose in the results of DSC analysis. The improvement in the impact strength of PBT was clearly observed as the absorbed dose was increased. This was probably due to the 3-dimensional network structures, resulting in increasing the absorption of impact energy. In addition, the wear properties had increased at higher than 300 kGy. The negative deviation of weight loss confirmed the improvement of the wear properties of PBT, as evidenced by SEM observation on the wear surfaces.

• 한국재료학회지
• /
• 제13권12호
• /
• pp.839-845
• /
• 2003

The abrasion and impact wear resistance were investigated on the hardfacing weld dispersed with the recycled hard metal(HM). The HM was composed of the tungsten carbide(WC) reinforced metal matrix composite. The cored wire filled with the 25-35wt.% HM and 2-8wt.% of the alloying element, Fe-75Mn- 7C(FeMnC), was used for the gas metal arc(GMA) welding. By using the cored wire of the 25wt.% HM and FeMnC addition, the weld showed mostly constant wear loss for the abrasion as a function of the FeMnC content. This was due to the insufficient amount of the tungsten carbide formed during the GMA welding. The FeMnC addition to the 35wt.% HM did not improve the abrasion wear property since the amount of the tungsten carbide formed was decreased with respect to the FeMnC amount. The 6wt.% FeMnC addition to the 35wt.% HM exhibited the better impact wear resistance than the hardfacing weld by 40wt.% HM.

• 감성과학
• /
• 제10권2호
• /
• pp.177-186
• /
• 2007

골프의 대중화가 이루어짐에 따라 다양한 연령대가 골프웨어 시장에 흡수되면서 기존의 $50{\sim}60$대 고객 뿐 아니라 $30{\sim}40$대 전문직 종사자들과 20-30대의 젊은 새로운 소비자층이 형성되어 골프웨어에 대한 소비자의 요구도 다양화되어 가고 있다. 본 연구는 골프웨어에 대한 새로운 소비자 요구를 조사하고 분석하여 다양하고 폭넓어진 골프웨어 시장에서 차별화된 상품개발과 기획에 반영할 수 있는 자료를 제공하고자 하였다. 본 연구의 조사 대상자는 대전지역에 위치한 골프 연습장을 이용하고 있는 20세 이상의 남녀 150명으로 하였다. 조사방법은 설문지법(Questionnaire method)으로 설문지의 내용은 남녀 골프 참가자들의 인구 통계학적 특성과 운동습관 및 태도에 관한 문항, 현재 착용 중인 골프웨어의 특성에 관한 문항, 골프웨어에 대한 소비자 요구 사항 문항으로 총 45문항을 개발하여 조사를 실시한 결과. 다음과 같은 결론을 도출하였다. 조사대상자 들이 현재 착용하고 있는 골프웨어에 대한 특성을 살펴 본 결과, "착용쾌적감이 좋다", "신축성이 있어 활동적이다", "사이즈가 전반적으로 잘 맞는다", "촉감이 좋다"의 문항들에서는 3.5점 이상의 높은 평점을 나타냈으나, "적당한 가격이다", "보푸라기가 잘 생기지 않는다", "세탁후 수축, 신장, 탈색, 이염이 잘 일어나지 않는다"등의 문항들은 3점이하의 비교적 낮은 평가 결과를 나타내었다. 골프웨어에 대한 소비자 요구사항을 파악하여 제품개발에 반영할 수 있도록 하기 위하여 21개의 소비자 요구사항을 추출하였다. 골프웨어에 대한 소비자의 요구사항 중 "착용감"이 가장 중요하게 고려되는 항목으로 나타났으며, 그 다음으로는 "흡수성", "촉감", "신축성", "차외선 차단", "사이즈"등의 순으로 중요하다고 응답하였다. 골프웨어에 대한 소비자의 요구사항이 어떤 차원으로 구성되어 있는가를 밝히기 위해 요인분석을 실시한 결과, 유행/디자인 특성요인, 섬유소재 특성요인, 위생성능 특성요인, 체형보정 특성요인 등 4개의 요인이 추출되었다.

• 한국주조공학회지
• /
• 제20권6호
• /
• pp.377-385
• /
• 2000

Al matrix composites as the most promising MMCs can be expected to be excellent engineering materials in the nearest future. So as to improve material properties of composite, many manufacturing processes have been developed. Among them, squeeze casting process which offers fine microstructure and near-net-shape is one of the most successful MMCs manufacturing processes. But, in case of with subsieve size particles (under 44 ${\mu}m$), it is very difficult to homogeneously distribute particles in matrix of Al matrix composite by various casting processes, including squeeze casting used so far. Duplex process which was developed in previous study was used to distribute the particle of subsieve size more homogeneously in matrix of Al matrix composite. Microstructures, wear and heat resistance characterization of Al-Si-Cu-Mg-(Ni)/SiCp manufactured by duplex process were examined to clarify the effect of manufacturing conditions, particle size of reinforcement and alloying elements. Al matrix composites reinforced with SiCp(10 ${\mu}m$) have the lowest wear amount among composites reinforced with 3 ${\mu}m$, 5 ${\mu}m$ and 10 ${\mu}m$ SiCp. The wear amount of Al matrix composites with 10 wt.% SiCp(3, 5, 10 ${\mu}m$) was decreased according to the increase of the sliding speed because abrasive wear takes place at high sliding speed of 4m/s and worn debris with block type occurs at low sliding speed of 1m/s. As for heat resistance, it is made clear that remarkable heat resistance property can be obtained by addition of Ni element in Al matrix composites.

• 동력기계공학회지
• /
• 제20권5호
• /
• pp.29-36
• /
• 2016

Aluminum alloys have been widely used in engine materials, cold & hot-water storage vessels and piping etc., Furthermore, the aluminum alloy of AC8A have been widely used in mold casting material of engine piston for various vehicles because of its properties of temperature, wear and corrosion resistance. Therefore, it is considered that evaluation of corrosion resistance as well as wear resistance of AC8A material is also important to improve its property and to prolong its lifetime. In previous paper, the effect of solution($510^{\circ}C$:4hrs) and tempering($190^{\circ}C$: 16, 24, and 36 hrs)heat treatments to corrosion resistance and hardness were investigated using electrochemical method. In this study, in order to examine completely the effect of the tempering hours to hardness variation and corrosion resistance, the results of solution($510^{\circ}C$:4hrs) and tempering($190^{\circ}C$: 2, 4, 8 and 12hrs)heat treatments to hardness and corrosion resistance were investigated using electrochemical method. The hardness decreased with solution heat treatment compared to mold casting condition, but its value increased with tempering heat treatment. Furthermore, the corrosion resistance increased with decreasing of the hardness, and decreased with increasing of the hardness reversely. And the tempering heat treatment temperature at $190^{\circ}C$ for 8 hrs exhibited the highest value of the hardness and also indicated the highest corrosion current density. However, the values of hardness and corrosion current density was again increasingly decreased with increasing of tempering hours than 8 hrs, Consequently, it is suggested that decision of the optimum. tempering hours is very important to improve the corrosion or wear resistance.

• 전기화학회지
• /
• 제3권4호
• /
• pp.196-199
• /
• 2000

무전해 도금은 내식성, 내구성, 전도성 특별히 비전도성 물질의 도금이 요구되는 모든 재료에 폭 넓게 사용되는 우수한 표면 처리 방법이다. 무전해 니켈 도금은 비자성, 무정형 구조,내구성, 내식성 그리고 열정 안정성 등의 많은 장점을 갖는다. 본 연구에서는 무전해 니켈 도금의 열처리에 따른 무전해 니켈-인 도금의 경도와 내식성의 변화를 연구하였다. 가장 높은 경도 값은 $500^{\circ}C$열처리에서 얻어졌다. $300^{\circ}C$에서 열처리한 도금의 내식성이 60시간 동안 1몰의 황산 수용액에서 테스트 한 결과 가장 우수하였다.

• Journal of Welding and Joining
• /
• 제26권4호
• /
• pp.44-49
• /
• 2008

Generally, wear plate is steel plate having improved surface contact strength and impact strength by surface hardening which is welded using materials with good corrosion resistance, wear resistance and thermal resistance property. CFP GMAW(Compound Filler Plate Gas Metal Arc Welding) is the cladding method using GMAW with the CFP, which is bound with waterglass, on the substrate. It has advantages of reducing compound powder loss, uniform penetration, and preventing hardness decrease. To develope mass production technique of CFP GMAW process for production of high quality wear plate, the method for controling shallow penetration and increasing productivity is required. In this study, twin torch method applied to CFP GMAW process for increasing productivity. And the method was developed by controling penetration control, CFP dry time, gas formation flux and water glass concentration. As a result, applying twin torch method to CFP GMAW process was possible and high quality wide bead could be made without overlap joint.

• 폴리머
• /
• 제26권6호
• /
• pp.803-811
• /
• 2002

본 연구에서는 상이한 방법을 통하여 제조된 초고분자량 폴리에틸렌 (ultra high molecular polyethylene, UHMWPE)/카올린 복합재료의 마모 특성에 대하여 살펴보았다. 카올린 입자는 중합충전(in-situ polymerization)법과 분말 혼합법의 두 가지 상이한 방법을 통하 UHMWPE와 복합화되었으며 특히 분말 혼합법에서는 입자상으로 구성된 두 재료의 혼합 방법에 따른 입자 분산 및 마모 특성에 대하여 분석하였다. 제조된 복합재료의 마모실험에서 입자 충전에 의하여 내마모성이 크게 향상되었는데 연삭마모가 지배적인 마모기구였으며, 중합충전법이 내마모성 향상에 있어서 분말혼합법에 비하여 효과적이었다. 또한 충전된 입자의 분산 상태와 계면 특성이 내마모성 향상에 중요한 변수임을 확인할 수 있었다.