• Title, Summary, Keyword: Abrasive wear

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Tribology Research Trends in Chemical Mechanical Polishing (CMP) Process (화학기계적 연마(CMP) 공정에서의 트라이볼로지 연구 동향)

  • Lee, Hyunseop
    • Tribology and Lubricants
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    • v.34 no.3
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    • pp.115-122
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    • 2018
  • Chemical mechanical polishing (CMP) is a hybrid processing method in which the surface of a wafer is planarized by chemical and mechanical material removal. Since mechanical material removal in CMP is caused by the rolling or sliding of abrasive particles, interfacial friction during processing greatly influences the CMP results. In this paper, the trend of tribology research on CMP process is discussed. First, various friction force monitoring methods are introduced, and three elements in the CMP tribo-system are defined based on the material removal mechanism of the CMP process. Tribological studies on the CMP process include studies of interfacial friction due to changes in consumables such as slurry and polishing pad, modeling of material removal rate using contact mechanics, and stick-slip friction and scratches. The real area of contact (RCA) between the polishing pad and wafer also has a significant influence on the polishing result in the CMP process, and many researchers have studied RCA control and prediction. Despite the fact that the CMP process is a hybrid process using chemical reactions and mechanical material removal, tribological studies to date have yet to clarify the effects of chemical reactions on interfacial friction. In addition, it is necessary to clarify the relationship between the interface friction phenomenon and physical surface defects in CMP, and the cause of their occurrence.

CFD Analysis of Trap Effect of Groove in Lubricating Systems: Part II - Variation in Radius of Curvature of Groove Edge (그루브의 Trap 효과에 대한 CFD 해석: 제2부 - 그루브 모서리의 곡률반경 변화)

  • Hong, Sung-Ho
    • Tribology and Lubricants
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    • v.36 no.6
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    • pp.359-364
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    • 2020
  • Numerical investigation of the groove trap effect with variation in the groove-edge radius of curvature is presented here. The trap effect is evaluated in a two-dimensional sliding bearing using computational fluid dynamics (CFD). This simulation is based on the discrete phase model (DPM) and standard k - ε turbulence model using commercial CFD software, FLUENT. The numerical results are evaluated by comparisons with streamlines and particle trajectories in the grooves. Grooves are applied to various lubrication systems to improve their lubrication characteristics, such as load carrying capacity increment, leakage reduction, frictional loss reduction, and preventing three-body abrasive wear due to trapping effect. This study investigates the grove trapping effect for various groove-edge radius of curvature values and Reynolds numbers. The particle is assumed to be made of steel, with a circular shape, and is injected as a single particle in various positions. One-way coupling is used in the DPM model because the single particle injection condition is applied. Further, the "reflect" condition is applied to the wall boundary and "escape" condition is used for the "pressure inlet" and "pressure outlet" boundaries. From the numerical results, the groove edge radius is found to influence the groove trap effect. Moreover, the groove trap effect is more effective when applying the groove edge radius.

THE EFFECTS OF SEALING ON THE PLASMA-SPRAYED OXIDE-BASED COATINGS

  • Kim, Hyung-Jun;Sidoine Odoul;Kweon, Young-Gak
    • Proceedings of the KWS Conference
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    • pp.53-58
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    • 2002
  • Electrical insulation and mechanical properties of the plasma sprayed oxide ceramic coatings were studied before and after the sealing treatment of the ceramic coatings. Plasma sprayed A1$_2$O$_3$-TiO$_2$ coating as the reference coating was sealed using three commercial sealants based on polymer. Penetration depth of the sealants to the ceramic coating was evaluated directly from the optical microscope using a fluorescent dye. It is estimated that the penetration depth of the sealants to the ceramic coating is from 0.2 to 0.5 mm depending on the sealants used. The preliminary test results with a DC puncture tester imply that the dielectric breakdown voltage mechanism of plasma sprayed ceramic coatings has been determined to be a corona mechanism. Dielectric breakdown voltage of the as-sprayed and as-ground samples have shown a linear trend with regard to the thickness showing an average dielectric strength of 20 kV/mm for the thickness scale studied. It is also shown that grinding the coating before sealing and adding fluorescent dye do not agent the penetration depth of sealants. All of the microhardness, two-body abrasive wear resistance, bond strength, and surface roughness of the ceramic coating after the sealing treatment are improved. The extent of improvement is different from the sealants used. However, three-point bending stress of the ceramic coating after the sealing treatment is decreased. This is attributed to the reduced micro-crack toughening effect since the cracks propagate easily through the lamellar of the coating without crack deflection and/or branching after the sealing treatment.

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Effect of the Amount of a Lubricant and an Abrasive in the Friction Material on Friction Characteristics (자동차 제동시 나타나는 마찰특성에 관한 연구(I. 고체 윤활제($Sb_2S_3$)와 연마제($ZrSiO_4$)의 함량에 따른 영향)

  • Jang, Ho
    • Tribology and Lubricants
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    • v.13 no.1
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    • pp.34-41
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    • 1997
  • Frictional behavior of three automotive friction materials (brake pads) containing different amounts of antimony trisulfide ($Sb_2S_3$) and zirconium silicate ($ZRSiO_4$) were investigated using a front brake system. The friction materials were tested on a brake dynamometer (dyno) with gray cast iron rotors. The dynamometer(dyno) test simulated the dragging of a ehicle maintaining 70 km/h and vehicle stops from 100 km/h using 20 different combinations of initial brake temperature (IBT) and input pressure (IP). The results showed a strong influence of the relative amount of $Sb_2S_3$ and $ZrSiO_4$ in friction materials on friction characteristics. Friction stability was improved with the higher concentration of $Sb_2S_3$ in the friction material. Torque variation during drag cycle was increased with an increase of the $ZrSiO_4$ concentration in the friction material. Average friction coefficient and the wear rate of the friction material increased by using more aggressive friction materials containing more $ZrSiO_4$ and less $Sb_2S_3$. Generation of the disk thickness variation (DTV) increased when friction materials with higher concentration of $ZrSiO_4$ were used Careful examination of DTV change showed that aggressiveness of the friction material played an important role in determining torque variation.

Characteristics of Stainless Steel Composites with Nano-sized TiCxNy (Nano-sized TiCxNy를 함유한 STS 복합체의 특성)

  • Ban, Tae-Ho;Park, Sung-Bum;Jo, Soo-Jeong;Lee, Dong-Won;Turaev, Farkhod R.;Park, Yong-Il;Kim, Sung-Jin
    • Journal of Korean Powder Metallurgy Institute
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    • v.18 no.3
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    • pp.290-296
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    • 2011
  • Titanium carbonitride is more perspective materials compared to titanium carbide. It can be used in tool industry and special products because of its higher strength, abrasive wear-resistance and especially its strong chemical stability at high temperatures. We produced STS+TiCxNy composite by the spark plasma sintering for higher strength and studied the characteristics. The planar and cross-sectional microstructures of the specimens were observed by scanning electron microscopy. Characterizations of the carbon and nitride phases on the surface of composite were carried out using an X-ray diffractometer. During annealing TiCxNy particles diffusion into STS 430 was observed. After annealing, sintering isolations between particles were formed. It causes decreasing of mechanical strength. In addition when annealing temperature was increased hardness increased. Heterogeneous distribution of alloying elements particles was observed. After annealing composites, highest value of hardness was 738.1 MHV.

Fabrication of Organic-Inorganic Nanocomposite Blade for Dicing Semiconductor Wafer (반도체 웨이퍼 다이싱용 나노 복합재료 블레이드의 제작)

  • Jang, Kyung-Soon;Kim, Tae-Woo;Min, Kyung-Yeol;Lee, Jeong-Ick;Lee, Kee-Sung
    • Composites Research
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    • v.20 no.5
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    • pp.49-55
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    • 2007
  • Nanocomposite blade for dicing semiconductor wafer is investigated for micro/nano-device and micro/nano-fabrication. While metal blade has been used for dicing of silicon wafer, polymer composite blades are used for machining of quartz wafer in semiconductor and cellular phone industry in these days. Organic-inorganic material selection is important to provide the blade with machinability, electrical conductivity, strength, ductility and wear resistance. Maintaining constant thickness with micro-dimension during shaping is one of the important technologies fer machining micro/nano fabrication. In this study the fabrication of blade by wet processing of mixing conducting nano ceramic powder, abrasive powder phenol resin and polyimide has been investigated using an experimental approach in which the thickness differential as the primary design criterion. The effect of drying conduction and post pressure are investigated. As a result wet processing techniques reveal that reliable results are achievable with improved dimension tolerance.

Contact Analysis of a Spherical Particle Between Elastomeric Seal and Steel Surface (시일과 스틸면 사이에 구형입자가 있는 접촉문제의 해석)

  • Park, Tae-Jo;Jo, Hyeon-Dong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.2
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    • pp.161-166
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    • 2010
  • Elastomeric seals are widely used in dynamic seal applications, and it is well known that the sealing surfaces can be gradually worn out. Abrasive wear is known to be the most dominant factor; however, little research has been carried out on this problem until now. In this study, a new contact problem related to elastomeric seals-a small spherical particle and steel surface-was modeled and analyzed using MARC. Variations of von-Mises and residual stress distributions as well as deformed seal and steel surface shapes with seal materials and interferences are presented. The stress distribution and surface deformation are highly affected by the elastic properties of seal. For PTFE, the maximum von-Mises stress exceeds the yield strength, and plastic deformation occurs on the steel surface. Therefore, the sealing surface can also be worn down by sub-surface fatigue due to intervening hard particles in the sealing surfaces together with the well-known abrasion.

AN EVALUATION OF WEAR CHARACTERISTICS OF LIGHT-CURED RESTORATIVE COMPOSITES ON ENAMEL SURFACE (광중합형 복합레진과 법랑질간의 마모특성 평가)

  • Baik, Byeong-Ju;Lee, Seung-Young;Lee, Doo-Cheol;Kim, Jae-Gon
    • JOURNAL OF THE KOREAN ACADEMY OF PEDTATRIC DENTISTRY
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    • v.28 no.2
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    • pp.261-270
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    • 2001
  • This study was performed to evaluate wear characteristics of light-cured composites when opposed by human enamel. Seven light-cured restorative composites were selected and enamel cusps sectioned from premolars. All samples were stored in distilled water at $37^{\circ}C$ for 10 days. 68.6 N of weight was loaded during the test. The measurements of vertical loss of enamel cusps, weight loss and volume loss of composites, and SEM observations of the polished and abraded surfaces were made after 30,000 cycles. The results obtained were summarized as follows; 1. The highest hardness value of 70.4 was observed in the Spectrum group and the lowest value of 19.8 was observed in the Heliomolar group. Results of Tukey test showed that an overall significant difference was indicated except the Spectrum, Z100 and Clearfil AP-X groups(p<0.05). 2. Enamel showed the good abrasion resistance against the Heliomolar group of microfilled composite and the Palpique Toughwell group containing the submicron hybrid type spherical fillers. 3. The abrasive wear resistance of hybrid composites was improved with the decrease of mean particle size and hybrid of submicron particle fillers. 4. SEM observation of worn surfaces revealed the protrusion, attrition and missing of fillers, cracks developing and delamination in the matrix.

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Abrasion-Resistant Road Markings for Improved Durability Lane to Wear Simulators Test (차선재료의 내구성 향상을 위한 내마모성 시험 적용 연구)

  • Lee, Chang-Geun;Park, Jin-Hwan;Oh, Heung-Un
    • International Journal of Highway Engineering
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    • v.13 no.3
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    • pp.75-82
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    • 2011
  • There is the uncertain period of the construction in case of the products meeting the quality standard of KS M 6080, the quality is degraded because of the abrasive loss of the paint caused by vehicle tires as the traffic amount increases and of the loss and detachment of the glass beads providing the retroreflective function. The abrupt degradation of visibility causes the high frequency of traffic accidents at night and increases the traffic accident rate. Additional supplementary construction induces the direct material and construction costs. As the more cost induction effect than the direct cost, the traffic jam caused by the additional construction increases the indirect social costs such as time cost and vehicle cost. Hence, the study is concerned with performing the abrasion resistance test based on the EN 1436 standard to check and improve the quality of various road marking materials resulting in improving the durability of road marking materials. However, even though the difference in the durability lifetime of resins(binders) is bibliographically or theoretically clear, there was no difference in the durability lifetime (retroreflectivity aspect) of the road marking paint using these binders. The reason is that the bonding of beads was very insufficient or that the cross density caused by crack or freshness was low. Moreover, the measured wet retroreflectivity was distributed as the Rw3 or higher class in average on the basis of EN 1436 but was very insufficient on the basis of the minimum wet threshold retroreflectivity with 100mcd/($m^2{\cdot}lx$) managed overseas.

A study on the surface characteristics of diamond wire-sawn silicon wafer for photovoltaic application (다이아몬드 코팅 와이어로 가공된 태양전지용 실리콘 웨이퍼의 표면 특성에 관한 연구)

  • Lee, Kyoung-Hee
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.21 no.6
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    • pp.225-229
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    • 2011
  • Most of the silicon cutting methods using the multi-wire with the slurry injection have been used for wafers of the crystalline solar cell. But the productivity of slurry injection cutting type falls due to low cutting speeds. Also, the direct contact with the metal wire and silicon block increases the concentration of metallic impurities in the wafer's surface. In addition, the abrasive silicon carbide (SiC) generates pollutants. And production costs are rising because it does not re-use the worn wire. On the other hand, the productivity of the cutting method using the diamond coated wire is about 2 times faster than the slurry injection cutting type. Also, the continuous cutting using the used wire of low wear is possible. And this is a big advantage for reduced production costs. Therefore, the cutting method of the diamond coated wire is more efficient than the slurry injection cutting technique. In this study, each cutting type is analyzed using the surface characteristics of the solar wafer and will describe the effects of the manufacturing process of the solar cell. Finally, we will suggest improvement methods of the solar cell process for using the diamond cutting type wafer.