• 한국주조공학회지
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• 제13권3호
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• pp.238-247
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• 1993

Microstructure, hardness and wear characteristics of $SiC_p/Al-6.5wt%Si-1.7wt%Mg$ alloy composites fabricated by the method of rheo-compocasting and hot pressing are investigated in this study. The dispersion of SiC particles in the composites is homogeneous and the hardness improves as additional amount increases. The wear amount of the matrix metal increases highly as wear rates increase, for the wear mechanism changes from adhesive wear to melt wear, and the matrix metal was coated on the surface of revolving disc and its weight increases. In the 5vol% composites, Fe is adhered on the surface of specimen by the projection of the dispersed hard SiC particles which have net-work structure and the coating layer is about $300{\mu}m$. But in the composite more than 20vol%, the wear amount of composite decreases because the SiC particles which have superior hardness, wear resistance and heat resistance properties resist wear, the abrasive wear turn out predominant wear mechanism and so the wear amount of revolving disc increases.

• 한국재료학회지
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• 제7권4호
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• pp.310-316
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• 1997

The effects of carbide and matrix structures on the abrasion wear resistance of multi-component white cast irons with 3.0 mass%C have been studied in this paper. Four different heats were poured in order to obtain the specimens with different combinations of the carbide structures: a basic iron(3.0 mass%C-5.0 mass%Cr-5.0 mass%V-5.0 mass% Mo-12.5mass%W)for M$_{6}$C and M$_{7}$C$_{3}$ carbides, and a Cr free iron(3.0 mass%C-5.0 mass%V-2.5mass%Mo-12.5 mass%W) for MC and M6C carbides. A conventional high Cr free free iron(3.0 mass%C-5.0 mass%V-2.5 mass%Mo-12.5 mass%W) for MC and M6C carbides. A conventional high Cr white cast iron was also poured to compare its wear resistance with those of the multi-component white cast irons. In the as-cast condition, the range of abrasive wear rate(Rw=mg/min) was from 4.15 to 5.98 . The lowest Rw, which means the highest wear resistance, was obtained in the basic iron with nodular MC, lamellar M$_{2}$C and cellular M$_{7}$C$_{3}$ carbides. On the other hand, the Rw of the high Cr white cast iron ranked between the basic iron and the Mo and W free iron. In each alloy, the Rw of air hardened or tempered specimen was lower than that of the as-cast one because of the change of matrix structures by the heat treatments. The Rw of the hear treated speci-mens increased in the order Mo and W free iron, basic iron, Cr free iron, high Cr iron, and V free iron.n.n.n.

• 한국주조공학회지
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• 제20권6호
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• pp.377-385
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• 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.

• Elastomers and Composites
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• 제46권4호
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• pp.335-342
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• 2011

비산회를 첨가한 폐 PE의 직접적인 재활용 및 용도 개발을 위하여 재생 폴리에틸렌 수지와 순수 HDPE를 기본으로 비산회(fly ash)와 블렌드하여 비산회/재생 PE 복합재료를 치합형 동방향 회전 이축 압출기(fully intermeshing co-rotating twin screw extruder)를 이용하여 각 조성별로 제조하였다. 본 연구에서는 플라스틱 수지(재생 PE, HDPE)와 비산회의 혼합비를 (0~40) wt.%로 하였고 비산회의 함량 변화에 따른 물성을 비교하였다. 세 종류의 PE 모두 비산회 함량이 증가할수록 항복인장강도가 감소하고, 파단신율이 감소한다. 내마모성 시험 결과는 사포 거칠기가 증가할수록 내마모성이 떨어지고 거칠기가 감소할수록 충전제의 함량에 따라 내마모성이 증가한다. Notched Constant Ligament Stress 시험에서는 신재 PE와 재생 PE의 경우 하중의 변화에 따라 파괴 시간이 짧아지는 결과를 나타냈고, 비산회가 혼합된 KRPE 복합체는 신재 PE, 폐 PE 그리고 신재 PE 복합체 및 JRPE 복합체와 비교할 때 상대적인 파괴 시간은 짧게 나타나지만 매설용 구조물에 대한 한국산업표준에서 정하는 20% 노치 깊이, 15%의 하중에서 24시간 이상의 저속 균열저항성을 나타내어 지하매설용 구조체로서 하수 이음관/받침대와 옥외구조물로서 가로수 보호의자와 같은 구조물에 적용할 수 있을 것으로 판단한다.

• 대한기계학회논문집
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• 제19권4호
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• pp.968-980
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• 1995

Al/Al$_{2}$O$_{3}$/C hybrid metal matrix composites are fabricated by the direct squeeze infiltration method. From the microstructure of Al/Al$_{2}$O$_{3}$/C composites, uniform distribution of reinforcements and good bondings are found. Optimum processing conditions for preforms and squeeze castings are suggested. Mechanical properties, such as elastic modulus, elongation, 0.2% offset yield strength and ultimate tensile strength are obtained. Through the abrasive were test and wear surface analsis, wear behavior and its mechanism of AC2B aluminum and Al/Al$_{2}$O$_{3}$/C composites can be characterized under various sliding speed conditions. Tensile strenght elongation of Al/Al$_{2}$O$_{3}$/C composites are decreased with increasing the addition of carbon fiber. On the contrary, elastic modulus of Al/Al$_{2}$O$_{3}$/C composites is slightly improved compared with that of the unreinforced matrix alloy. The addition of carbon fiber to al/al$_{2}$O$_{3}$/C composites gives rise to improvement of the wear resistance. Specially, carbon chopped fibers play an important role in interfering sticking between the counter material and metal matirix composites. Al/Al$_{2}$O$_{3}$/C composites are suitable to high speed due to solid lubication of carbon. And wear model of Al/Al$_{2}$O$_{3}$/C composites is suggested by the examination of worn surfaces.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.136-139
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• 2003

Copper has attractive properties as a multi-level interconnection material due to lower resistivity and higher electromigration resistance as compared with Alumina and its alloy with Copper(0.5%). Among a variety of agents in Copper CMP slurry, $H_2O_2$ has commonly been used as the oxidizer However. $H_2O_2$ is so unstable that it requires stabilization to use as oxidizer Hence, stabilization of $H_2O_2$ is a vital process to get better yield in practical CMP process. In this article the stability of Hydrogen Peroxide as oxidizer of Copper CMP slurry has been investigated. When alumina abrasive was used, $\gamma$-particle Alumina C had a better stability than $\alpha$-particle abrasive. As adding KOH as pH buffering agent, $H_2O_2$ stability in slurry decreased. Urea hydrogen peroxide was used as oxidizer, an enhanced stability was gotten. When $H_3PO_4$ as $H_2O_2$ stabilizer was added, the decrease of $H_2O_2$ concentration in slurry became slower. Even though adding $H_2O_2$ in slurry after bead milling lead to better stability than in advance of bead milling, it had a lower dispersibility.

• Nano
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• 제13권12호
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• pp.1850144.1-1850144.13
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• 2018

A nano-$MoS_2$/montmorillonite K-10 (K10) composite was prepared and characterized. The composite contains two types of 2H-$MoS_2$ nanoparticles. One is the hollow spherical $MoS_2$ with a size range of 75 nm, and the other is the spherical nano cluster of $MoS_2$ with a size range of 30 nm. The two kinds of nano-$MoS_2$ were formed via assembly of numerous $MoS_2$ nano-platelets with a size of ~10 nm. A tribological comparison was then made among nano-$MoS_2$/K10, K10, nano-$MoS_2$ and a mechanical mixture of K10 and nano-$MoS_2$. K10 reduced the wear but slightly increased the friction. Nano-$MoS_2$ remarkably reduced both friction and wear. The mechanical mixture demonstrated better wear resistance than nano-$MoS_2$, indicating a synergistic anti-wear effect of nano-$MoS_2$ and K10. The synergistic effect was reinforced using nano-$MoS_2$/K10 instead of the mechanical mixture. A part of the $MoS_2$ in the contact region always lubricated the friction pair, and the rest formed a tribofilm. K10 segregated the friction pair to alleviate the ablation wear but magnified the abrasive wear. S-$MoS_2$ protects K10 and they together function as both a lubricant and an isolating agent to reduce the ablation and abrasive wear.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.342-345
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• 2009

Electro galvanized steel is electroplated cold roller steel for improving corrosion resistance and paintability, and is widely used in automobiles and home appliances. In the electroplating line for manufacturing electro galvanized steel if plating process is carried out with impurity on conductor roll surface, the defects in manufacturing process occurs because of steel fault. For quality, polishing is always required to separate impurity on surface of conductor roll. In this study, finite element analysis of wear for polisher brush is carried out for replaced time of it.

• 한국산업융합학회 논문집
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• 제15권4호
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• pp.103-109
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• 2012

To enhance the cutting performance of high speed steel(HSS) endmill, single and multilayer coating is applied on the substrated of the HSS endmill. Coating material reduces cutting force and enhances resistance against abrasive wear. This paper presents the physical vapour deposition(PVD) coating technology and evaluate the PVD coated HSS endmill. The performance of coated HSS endmills are fifteen times better than uncoated HSS endmill on proposed cutting conditions. The TiAlN monolayer coated endmills(futura nano coating) are better than those of multilayer coated endmills(futura coating) on machined surface and tool wear.

• 한국안전학회지
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• 제14권3호
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• pp.110-119
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• 1999

This study was conducted to invent brake of non-steel material without using asbestos and disc pad added $ZrSiO_4$ was made. The physical properties and friction characteristics were investigated by varying methods. The physical properties were inspected of shear strength, hardness, heat expansion, specific gravity, % of gashole, thickness variation, weight variation and pH variation. The friction stability was measured by friction coefficient on variations of speed, temperature and deceleration condition. It was found that the physical properties were in general excellent. According to the friction characteristics tests, $ZrSiO_4$ had an abrasive property. As a results, the friction materials containing $ZrSiO_4$ 3~5vol% showed better resistance to fading and improved friction stability than the materials without ZrSiO$_4$.