• Title/Summary/Keyword: Nanodiamond

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Tribological Characteristics of Paraffin Liquid Oil with Nanodiamond and Effects of Surface Hardness on Wear Properties (나노다이아몬드를 첨가한 오일의 트라이볼로지 특성 및 이에 미치는 표면 경도의 영향)

  • Lee, Gyu-Sun;Kim, Hyun-Soo;Lee, Jeong-Hoon;Park, Tae-Hee;Lee, Jung-Suk;Lee, Young-Ze
    • Tribology and Lubricants
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    • v.27 no.6
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    • pp.321-325
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    • 2011
  • Nanodiamond was dispersed in paraffin liquid oil to investigate the effects of nanodiamond at the marginally lubricated condition. Scuffing test and immediate loading sliding wear test were conducted using the fabricated nanodiamond oil. As a result, dispersion of nanodiamond in oil leads to increase in scuffing life, and nanodiamond contents affects the scuffing life. In case of immediate loading sliding wear test, the result was different according to hardness of specimen. If hardness of specimen was low, abrasion of nanodiamond occurred actively. If hardness of specimen was increased, however, nanodiamond can act as a spacer or rolling between contacting surfaces.

Comparison of Chemicophysics Properties of the Detonation Monocrystalline and Synthetic Polycrystalline Nanodiamond (폭발 단결정과 합성 다결정 나노다이아몬드의 물리화학적 특성 비교)

  • Kang, Soon-Kook;Chung, Myung-Kiu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.10
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    • pp.4689-4695
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    • 2011
  • Nanodiamond is a relatively new nanomaterial with broad prospects for application. In this paper, a variety of methods were used to analyze comprehensively chemicophysics properties of the detonation monocrystalline and synthetic polycrystalline nanodiamond, XRD spectroscopy, EDS, HRTEM, FTIR, Raman spectroscopy, TGA-DTA and BET. The results show that the monocryctalline detonation nanodiamond particles are spherical or elliptical shape of 4nm ~ 6nm grain size and the polycryctalline synthetic nanodiamond particles are angular shape of 80nm ~ 120nm grain size. The surface of the monocrystalline and polycrystalline nanodiamond contain hydroxy, carbonyl, carboxyl, ether-based resin, and other functional groups. The phase transition temperature of the monocrystalline detonation nanodiamond in the $N_2$ is about $650^{\circ}C$.

Effect of Lubricant with Nanodiamond Particles in Sliding Friction

  • Adzaman, M.H.;Rahman, A.;Lee, Y.Z.;Kim, S.S.
    • Tribology and Lubricants
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    • v.31 no.4
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    • pp.183-188
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    • 2015
  • This paper presents the experimental effects of lubricant with nanodiamond particles in sliding friction. In order to improve the performance of lubricants many additives are used, such as MoS2, cadmium chloride, indium, sulfides, and phosphides. These additives are harmful to human health and to the environment, so alternatives are necessary. One such alternative is nanodiamond powder, which has a large surface area. In order to investigate the effect of nanodiamonds in lubricants under sliding friction, they are dispersed in the lubricant at a variety of concentrations (0 wt%, 0.1 wt%, 0.3 wt%, 0.5 wt%, and 1 wt%) using the matrix synthesis method. Friction and wear tests are performed according to the ASTM G99 method using a pin-on-disc tester at room temperature. The specimens used in this experiment are AISI 52100 ball bearings and AISI 1020 steel discs. During the test, lubricant mixed with nanodiamond is supplied constantly to keep the two bodies separated by a lubricant film. To maintain boundary lubrication, the speed is set to 0.18 m/s and a load of 294 N is applied to the disc through the pin. Results are recorded by using workbench software over the test duration of 10 minutes. Experimental results show that when the concentration of nanodiamond increases, the coefficient of friction decreases. However, above a nanodiamond concentration of 0.5 wt%, both the coefficient of friction and wear volume increase. From this experiment, the optimum concentration of nanodiamond showing a minimum coefficient of friction of 0.09 and minimum wear volume of 0.82 nm2 was 0.5 wt%.

Tribology Properties of Nanodiamond Dispersed Engine Oil (나노다이아몬드가 분산된 엔진오일의 마찰공학 특성)

  • Jun, S.H.;Uhm, Y.R;Rhee, C.K.
    • Journal of Powder Materials
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    • v.18 no.5
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    • pp.417-422
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    • 2011
  • Hydrophobic nanodiamond (ND) were dispersed in engine oil (Helix Oil, Shell co.) as an additives to improve tribology properties. In this study, nanodiamond prepared by an explosive method was used. Tribology properties of both pure Helix oil and engine oil containing ND additive were evaluated. The rotating disks were made of Gray Cast Iron (240 Hv) and SKD11 (710 Hv). Surface topographies of the disks' wear tracks and friction coefficient were compared. The results show that nanodiamond-dispersed lubricants are capable of reducing these metals' wear loss. The friction coefficient is strongly affected to the hardness of wear track.

A Study on the Characteristics of Nanodiamond Films with the Gas Flow Control (가스 유량제어에 의한 나노다이아몬드 박막의 특성연구)

  • Kim, Tae-Gyu;Kim, Chang-Hoon
    • Journal of the Korean institute of surface engineering
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    • v.39 no.4
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    • pp.153-159
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    • 2006
  • Nanodiamond films were deposited on Si substrate by introducing a time dependent on/off modulation of $CH_4\;and\;O_2$ flows in a vertical-type microwave plasma enhanced chemical vapor deposition system. Surface morphology and diamond quality of the film were investigated as a function of the on/off modulation time interval. The diamond nucleation density on the substrate was enhanced under low temperature and low pressure condition. In addition, the diamond nucleation density was enhanced by increasing the on/off modulation time interval. Enhanced diamond quality was noticeable under the condition of a longer on/off modulation time interval. It was suggested that the nanodiamond nuclei formed the cluster formation.

Study on Wear Characteristics of Lubricants with Nano-diamond Additives (나노다이아몬드가 첨가된 윤활제의 마모 특성 연구)

  • Kim, Seung Taek;Kim, Seung Mok;Park, Tae Hee;Lee, JungSeok;Lee, YoungZe
    • Tribology and Lubricants
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    • v.30 no.5
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    • pp.291-294
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    • 2014
  • Multiple additives can help improve the performance of generally used lubricants. These additives include MoS2, cadmium, chloride, indium, sulfide, and phosphide, which are harmful to both humans and the environment. Thus, researchers in this industry have been trying to reduce the use of these additives by finding alternatives. Nanodiamonds are one of these candidates. Nanodiamond particles are very hard, chemically stable, and highly heat-conductive. This research involved uniformly dispersing nanodiamond particles in marine engine oils via a matrix synthesis method at various concentrations (0, 0.1, 0.3, 0.5, and 1.0 wt). Friction and wear tests involved constant loads on ball-on-disk specimens, where the ball was AISI 51200 steel, the disk was AISI 1020 steel, and the sliding speed was 0.217 m/s. The lowest wear occurred at a suitable concentration of nanodiamonds (0.3 wt). However, excessive amounts of nanodiamonds caused them to act as abrasive debris because of their hardness, which increased the wear amount. The friction coefficient decreased as the nanodiamond concentration increased because their octagonal, almost spherical shape caused them to act as rolling contact elements between two surfaces.

High Performance Materials for Ophthalmic Hydrogel Lens Containing Nanoparticles

  • Kim, Duck-Hyun;Sung, A-Young
    • Journal of Integrative Natural Science
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    • v.9 no.1
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    • pp.16-22
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    • 2016
  • The optical and physical and characteristics of hydrogel ophthalmic lens polymerized with addition of 2,6-difluoropyridine, SiPc(silicon 2,9,16,23-tetra-tert-butyl-29H31H-phthalocyanine dihydroxide) and nanodiamond in the basic hydrogel material were evaluated. In particular, the utility of 2,6-difluoropyridine, SiPc and nanodiamond as a hydrogel ophthalmic lens material was investigated. 2,6-difluoropyridine, SiPc and nanodiamond were used as additives. And also, 2-hydroxyethyl methacrylate, acrylic acid, methyl methacrylate and a cross-linker EGDMA were copolymerized in the presence of AIBN as an initiator. The refractive index of 1.4348~1.4361, water content of 33.30~34.02%, UV-B transmittance of 4.77~67.50%, UV-A transmittance of 1.45~89.19% and visible transmittance of 32.12~92.21% were obtained. The results of hydrogel lens containing 2,6-difluoropyridine (add 5%) showed antibiosis for staphylococcus aureus. The produced copolymer is suitable for hydrogel soft ophthalmic lenses with antibiotic and anti-UV effect.

Effect of hydrogenation surface modification on dispersion and nucleation density of nanodiamond seed particle (수소화 표면 개질이 나노다이아몬드 seed 입자의 분산 및 핵형성 밀도에 미치는 영향)

  • Choi, Byoung Su;Jeon, Hee Sung;Um, Ji Hun;Hwang, Sungu;Kim, Jin Kon;Cho, Hyun
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.29 no.6
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    • pp.239-244
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    • 2019
  • Two hydrogenation surface modifications, namely hydrogen atmosphere heat treatment and hydrogen plasma treatment, were found to lead to improved dispersion of nanodiamond (ND) seed particles and enhanced nucleation density for deposition of smooth ultrananocrystalline diamond (UNCD) film. After hydrogenation, the C-O and O-H surface functionalities on the surface of nanodiamond particles were converted to the C-H surface functionalities, and the Zeta potential was increased. As the degree of dispersion was improved, the size of nanodiamond aggregates decreased significantly and nucleation density increased dramatically. After hydrogen heat treatment at 600℃, average size of ND particles was greatly reduced from 3.5 ㎛ to 34.5 nm and a very high nucleation of ~3.9 × 1011 nuclei/㎠ was obtained for the seeded Si surface.

Structural Modification of Nanodiamond Induced by Ion Irradiation

  • Seok, Jae-Gwon;Im, Won-Cheol;Chae, Geun-Hwa;Song, Jong-Han;Lee, Jae-Yong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.195.2-195.2
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    • 2014
  • Nanodiamond (ND) is composed of inner diamond core and outer graphite shell. The size of ND used in this study was about 5 nm. The ND solution was dropped on silicon substrate and dried in air. Dried ND sample was purified by using annealing method in air. Then, 40 keV Fe ion was irradiated into the sample. The dose was varied from $1{\times}10^{14}$ to $1{\times}10^{16}ions/cm^2$. The post annealing was performed at 1073 K in the vacuum to recover diamond structure. The annealing at 873 K in air was performed to remove the outer graphite shell. The structure of ND was confirmed by X-ray diffraction (XRD) and Raman spectroscopy. We will present the detailed data and results in the conference.

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