• Title/Summary/Keyword: Critical scratch load

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A Study on Friction and Wear of TiN Film for the Wear-life Prediction (마모수명평가를 위한 TiN 경질박막의 마찰 및 마모특성에 관한 연구)

  • 정기훈;이영제
    • Tribology and Lubricants
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    • v.13 no.3
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    • pp.28-32
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    • 1997
  • Indentation, scratch and sliding tests were carried out in this paper to predict the critical loads and the failure modes of TiN-coated specimen. The test specimens were S20C steels with three different substrate hardness, roughness and coating thickness. The scratch test shows that the coating thickness has more dominant effect on the critical load of coated disk than the hardness and the roughness. Using the percent contact load, the ratio of sliding load to the critical scratch load, the cycles to failure are measured to predict the wear-life of TiN film. On the wear-life diagram the percent loads and the cycle to failure show the good linear relation on semi-log coordinate. With decreasing loads, the diagram shows the wear-limit at which the coated disk survives more than 4000 cycles.

Life Evaluation of CrN Coatings due to Wear Using Friction and Acoustic Emission Sensor (마찰 및 음향방출 신호를 이용한 CrN 코팅의 마모수명 평가)

  • 조정우;이영제
    • Tribology and Lubricants
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    • v.15 no.4
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    • pp.328-334
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    • 1999
  • Acoustic emission (AE) sensor was used to evaluate the wear-life of CrN-coated steel disks with 1 $\mu\textrm{m}$ and 4 $\mu\textrm{m}$ coating thickness. The relationship between Af and friction signal from scratch test and sliding test was investigated. The first spatting of CrN film was detected by AR signals in the early stage of coating failures, and overall failures by friction signals. Therefore, the conservative design for coating-life should be done using the results of AE signals. Using the percent contact load, the ratio of sliding normal load to the critical scratch load and the number of cycles to failure was measured to predict the wear-life of CrN film. On the wear-life dia-gram the percent contact loads and the number of cycles to failure showed a good linear relationship on the log coordinate. As the load percentage was decreased, the diagram showed that the wear-limits, at which the coated steels survived more than 35,000 cycles, were about 4∼5% of the critical scratch loads.

Characteristics and Assessment of Printer Toner Adhesion (프린터 토너의 점착력 특성 및 평가 기법)

  • Lee, Jung-Eun;Kim, Kwang-Il;Kim, Hyun-Joon;Kim, Dae-Eun
    • Transactions of the Society of Information Storage Systems
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    • v.5 no.2
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    • pp.82-88
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    • 2009
  • Understanding the adhesion behavior and characteristics of toner film is required to achieve image and text printing with high quality resolution. Toner can be considered as a thin film coating on a media such as paper or polymer film. Quantitative measurement of adhesion characteristics of the thin film is important to assess the reliability of the system. In this work the main objective was to investigate the adhesion characteristic between the toner and the media by ramp loading scratch test method. The scratch test may be used to obtain quantitative information about the adhesion of the film to the substrate. In the scratch test a diamond tip was used to scratch the surface of the toner film under an increasing normal load until the toner detached or fractured. The critical load (LC) was obtained from the experimental results. Also, the relationship between the critical load and the adhesive strength of the interface between the substrate and the toner was obtained by measuring the normal and tangential forces during the scratch test. Finally, theoretical analysis of the toner scratch characteristics was performed based on Benjamin and Weaver theory, Plowing model, and Laugier model.

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Evaluation of Failure Modes and Adhesion of DLC Films by Scratch Test (스크래치 시험을 통한 DLC 박막 파손과 밀착 특성 평가)

  • Kim, Ju Hee;Park, Chanhyung;Ahn, Hyo Sok
    • Tribology and Lubricants
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    • v.33 no.4
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    • pp.127-133
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    • 2017
  • In order to characterize the adhesive properties and failure mechanisms of diamond-like carbon (DLC) films of two different thicknesses (130 nm and $1.2{\mu}m$), deposited by plasma-enhanced chemical vapor deposition on a Si substrate, scratch testing with a micro-indenter ($12.5{\mu}m$ tip radius) was performed under a linearly increasing load. These scratch tests were conducted under the same test conditions for both films. The critical load of each film was estimated from the scratch test results, based on a sharp increase in the coefficient of friction and a clear distinction of failure modes. The critical load was the basis for evaluating the adhesion strength of the films, and the $1.2{\mu}m-thick$ DLC film had superior adhesion strength. For better understanding of the failure modes, the following analyses were conducted: friction behavior and scratch tracks analysis using scanning electron microscopy, energy-dispersive spectroscopy, and 3-D profilometry. The scratch test results showed that failure modes were related to the thickness of the films. The 130 nm-thick DLC film underwent cohesive failure modes (cracks and chipping) before reaching to a gross failure stage. On the other hand, the thicker DLC film ($1.2{\mu}m-thick$) did not exhibit micro cracks before a sudden gross failure of the film together with the evidence of cracking and chipping of the Si substrate.

Effect of the WC particle size and Co content on the adhesion property between AIP-TiN coating and WC-Co substrate (AIP-TiN/WC-Co계에서 WC입자크기와 Co함량이 밀착력에 미치는 영향)

  • 한대석;류정민;권식철;김광호
    • Journal of the Korean institute of surface engineering
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    • v.35 no.3
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    • pp.165-171
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    • 2002
  • TiN coating were deposited onto different WC-Co substrates using arc ion plating (AIP) technique. The structure and morphology for the deposited coating were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). The adhesion behavior of the deposited TiN coating was investigated with a conventional scratch test. Effects of WC particle size and Co content on the adhesion strength between the deposited TiN coating and substrate were studied. During the scratch test, the value of critical load was dependent of WC particle size and Co content on substrate. As the WC particle size and Co content on substrate decreased, the critical load increased. The highest critical load, approximately 110N, was obtained at WC particle size of 1$\mu\textrm{m}$ and Co content of 10wt.%.

The Characteristics of Painted Coating on Aluminum Sheet by Sending Conditions (알루미늄 판재의 센딩조건에 따른 도장특성 평가)

  • Yoon, Han-Ki;Choi, Seok-In;Lee, Jong-Ho
    • Journal of Ocean Engineering and Technology
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    • v.25 no.1
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    • pp.44-48
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    • 2011
  • Researchers suggested painted coating characteristics of aluminum sheet by various sending condition. Painted coating is used to protect the surface of the blocks from the interior and exterior. It is also used to enhance the value of automobiles and ship materials. This process makes the materials surface for protection and elegance. Although analysis of the roughness and critical scratch load of painted coating is important, the effects of this material have not progressed much. In this study, the characteristics of painted coating in the other conditions of the polished aluminum sheet were investigated. The results of both various conditions and initial roughness values were almost similar to final values after painted coating.

The Morphology and Adhesion of TiCN Film formed by PECVD (PECVD 에 의해 형성된 TiCN 박막의 형상 및 밀착성)

  • Huh, J.;Nam, T.W.
    • Journal of the Korean Society for Heat Treatment
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    • v.15 no.3
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    • pp.118-126
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    • 2002
  • TiCN thin films were deposited on tool steels at $510^{\circ}C$ by PECVD from a $TiCl_4+N_2+CH_4+H_2+Ar$ gaseous mixture. The microstructures and preferred orientation were investigated. The micro-scratch tests were performed using a system equipped with an acoustic emission sensor. Critical loads were determined to evaluate the adhesion of TiCN to substrate. The influences of the microstructures of substrates, double layered coatings, and coatings after nitriding(duplex coating) were investigated. The experimental results showed that the microstructures of substrates and double layered coating did not affect the critical loads considerably. By the duplex coating, critical loads were not always increased. In some cases, duplex coatings decreased critical loads significantly despite of absence of black layer. In this study, we tried to relate the results of scratch test to the residual stress analysis. Nitriding before the coating reduces the tensile residual stress in the film, which gives rise to low critical load in scratch test.

Evaluation of Adhesion Properties of Arc PVD Coatings on Non-Nitrided and Nitrided Various Substrates (모재의 재질 및 질화층 형성에 따른 Arc PVD 코팅의 접합특성 평가)

  • Lee Jung-Min;Jun Sung-Jin;Ko Dae-Cheol;Kim Byung-Min
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.10 s.253
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    • pp.1179-1186
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    • 2006
  • This paper was designed to assess the adhesive properties of hard coatings on non-nitrided and nitrided various tool steels. Estimations of adhesion were done to scratch test which is mainly used in hard coating. The critical load$(L_c)$ between coating and substrate is defined through analysis of frictional load vs. normal load curve, signals of acoustic emission and optical observations. Coatings employed in this study are TiN, CrN and TiAlN, tools as substrates are STD11, STD61 and SKH51. It was classified to substrates with/without intermediate nitrided layer and hard coatings on substrate were deposited by arc PVD. Results showed that harder substrates and coatings give higher values of critical loads.

Evaluation of Adhesion properties of Arc PVD coatings for Micro Forming Die (미세성형용 금형 Arc PVD 코팅의 밀착력 평가)

  • Lee J. M.;Ko D. C.;Kim B. M.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.10a
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    • pp.186-189
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    • 2005
  • This paper was designed to assess the adhesive properties of hard coatings on non-nitrided and nitrided various tool steels. Estimations of adhesion were done to scratch test which is mainly used in hard coating. The critical load(Lc) between coating and substrate is defined through analysis of frictional load vs. normal load curve, signals of acoustic emission and optical observations. Coatings employed in this study are TiN, CrN and TiAlN, tools as substrates are STD11, STD61 and SKH51. It was classified to substrates with/without nitrided layer and hard coatings on substrate were deposited by arc PVD. Results showed that harder substrates and coatings give higher values of critical loads.

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