• Title/Summary/Keyword: Surface Composite

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Characterization of Cr-P-C/MoS2 composite plating electro-deposited from trivalent chromium

  • Park, Jong-Kyu;Seo, Sun-Kyo;Byoun, Young-Min;Lee, Chi-Hwan
    • Journal of Ceramic Processing Research
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    • v.19 no.6
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    • pp.445-449
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    • 2018
  • Chromium plating is a common surface treatment technique extensively applied in industry due its excellent properties which include substantial hardness, abrasion resistance, corrosion resistance, surface color, and luster. In this study, the effect of $MoS_2$ particles of the composite coating was investigated. To improve the lubrication of mold, $Cr-P-C/MoS_2$ composite plating was studied by varying the $MoS_2$ content. The current efficiency of the composite plating incorporated $MoS_2$ particles was increased at $MoS_2$ contents of 0.5 and 1.0 g/l due to the incorporation of fine particles. On the other hand, when the content of $MoS_2$ is 1.0 g/l or more, the current efficiency is lowered due to an increase in impact on the cathode surface. In order to evaluate the mechanical properties of Scratch test were conducted. Scratch test confirmed the lubricity and abrasion resistance characteristics revealed that the composite plating with added $MoS_2$ had relatively low surface roughness and uniform surface modification to improve its properties.

Application of Friction Stir Process to Improve Surface Reliability of Light Weight Magnesium Alloy (경량 마그네슘 합금의 표면 신뢰성 향상을 위한 마찰교반공정의 적용)

  • Gil, Ung-Chan;Kim, Jae-Yeon;Hyun, Chang-Young
    • Journal of Applied Reliability
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    • v.16 no.2
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    • pp.155-161
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    • 2016
  • Purpose: Purpose of this study is to analyze the effect of particle size as well as number of pass on surface microstructure and hardness of SiC(p)/AZ31 surface composite fabricated by friction stir process (FSP). Method: SiC(p)/AZ31 surface composite containing different size of SiC particle (i. e., $2{\mu}m$ and $8{\mu}m$) was fabricated by multi-pass FSP. Microstructure was observed by scanning electron microscope and surface hardness was determined by Vickers hardness tester. Results: For all the FSPed specimens with and without hardening particles, grain size was refined due to dynamic recrystallization behavior. Surface hardness was observed to increase with decreasing particle size in the composite layer. Increasing number of FSP pass was effective for homogeneous distribution of the hardening particles and for resulting increase in surface hardness. Conclusion: FSP was effective to modify surface microstructure for improving surface hardness of SiC/AZ31 composite.

A STUDY ON THE GLOSS AND ROUGHNESS OF THE COMPOSITE RESIN (복합레진의 광택 및 표면조도에 관한 연구)

  • Cho, Seung-Joo;Lee, Myung-Jong
    • Restorative Dentistry and Endodontics
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    • v.15 no.1
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    • pp.67-80
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    • 1990
  • This study was performed for elucidating the effects on surface polishing of composite resins. In this study, Silux(microfilled), Graft(hybrid), Bisfil- I (hybrid posterior) and Hi-pol(conventional) were used. Sixty specimens were made with 4 brands of composite resins and Optilux system in $2.0{\times}1.3{\times}1.0cm$ resin block which has a cavity with 0.5cm diameter and 0.5cm depth. Polishing was done with #600 sand paper and Soflex, Super-snap, Micron finishing system, or Composite polishing kit. Final polished surfaces were measured by roughness tester(Kasaka Lab. Ltd., Japan) and image analyser(Omnimet Image Analyser, Buehler, USA). The results were as follows, 1. The celluloid strip produced the smoothest surfaces. 2. Light curing microfilled composite resin, Silux, had smoother surface than any others. 3. The surfaces polished by Soflex were smoothest. 4. Aluminum oxide disk, Soflex and Super-Snap, made smoother surface than diamond bur, M.F.S., or silicon point, Composite polishing kit. 5. The roughness values of surface polished by M.F.S. composed of diamond burs, were less than those of Composite polishing kit made from silicone points.

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A study on the improvement of impregnation on the surface of injection-molded thermoplastic woven carbon fabric composite (열가소성 직물탄소복합소재 사출 성형품의 표면 함침 개선에 관한 연구)

  • Jeong, Eui-Chul;Yoon, Kyung-Hwan;Lee, Sung-Hee
    • Design & Manufacturing
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    • v.15 no.3
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    • pp.39-44
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    • 2021
  • In molding of continuous fiber-reinforced thermoplastic composites, it is very difficult to impregnate between the reinforcements and the matrix since the matrix has a high melting temperature and high viscosity. Therefore, most of composite molding processes are divided in the manufacturing processes of intermediate materials called prepreg and the forming of products from intermediate materials. The divided process requires additional facilities and thermoforming, and they increase the cycle time and cost of composite products. These problems can be resolved by combining the continuous fiber-reinforced composite molding process with injection molding. However, when a composite material is manufactured by inserting woven fabric into the injection mold, poor impregnation occurs on the surface of the molded product. It affects the properties of the composites. In this paper, through an impregnation experiment using cores with different heat transfer rates and pore densities, the reason for the poor impregnation was confirmed, and molding experiments were conducted to produce composite with improved surface impregnation by inserting the mesh. And also, the surface impregnation and deformation of composites molded using different types of mesh were compared with each other.

A Study on the Processing Technique to form Various Dimples on the Surface of Composite Parts (복합재료 부품 표면에 다양한 딤플을 형성하는 성형 방법)

  • Joe, C.R.;Byun, Gill-Jae
    • Composites Research
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    • v.26 no.1
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    • pp.42-47
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    • 2013
  • In this study, an economical and effective processing technique to form multiple dimples on the surface of a composite part, which are known to be useful to improve aerodynamic performance and heat dissipation. Forming dimples on the surface using molds is an expensive processing because forming multiple tiny positive spheres on the surface of the mold requires much time and effort. In this study, plates with multiple round holes are utilized as a core to form dimples on the carbon/epoxy composite skin covering the core. A vacuum bagging process is used to apply pressure on the surface while curing. Composite parts which have multiple dimples on the surface can be utilized in the field which needs high aerodynamic performance and heat dissipation ability such as high speed sports car bodies.

Properties of Ni-P-SiC Composite Coating Layers Prepared by Electroless Plating Method (무전해도금법으로 형성한 Ni-P-SiC 복합도금막의 특성)

  • Lee, Hong-Kee;Lee, Ho-Young;Jeon, Jun-Mi
    • Journal of the Korean institute of surface engineering
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    • v.40 no.2
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    • pp.70-76
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    • 2007
  • Ni-P-SiC composite coating layers were prepared by electroless plating method and their deposition rate, codeposition of SiC, morphology, surface roughness, hardness, wear and friction properties were investigated. The deposition rate was kept almost constant independent of the concentration of SiC in the plating solution and the codeposition of SiC in the composite coating layer increased with increased concentration of SiC in the plating solution except the early stage. Vickers microhardness increased with respect to the increased codeposition of SiC and the heat treatment at $300^{\circ}C$ in air for 1 hour. It was found that the wear volume decreased with increased up to 50 wt.% of SiC codeposition, and that friction coefficient increased gradually with increased codeposition of SiC. Considering the wear and the friction behaviors, the composite coating layer obtained by using 50 wt.% of SiC codeposition is desirable for the practical application for anti-wear and anti-friction coatings.

Effect of Ultrasonic Process of Electroless Ni-P-Al2O3 Composite Coatings

  • Yoon, Jin-Doo;Koo, Bon-Heun;Hwang, Hwan-Il;Seo, Sun-Kyo;Park, Jong-Kyu
    • Journal of the Korean institute of surface engineering
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    • v.54 no.6
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    • pp.315-323
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    • 2021
  • In general, surface treatments of electroless Ni-P coating are extensively applied in the industry due to their excellent properties for considerable wear resistance, hardness, corrosion resistance. This study aims to determine the effect of ultrasonic conditions on the morphology, alumina content, roughness, hardness, and corrosion resistance of electroless Ni-P-Al2O3 composite coatings. The characteristics were analyzed by Energy-dispersive X-ray spectroscopy (EDX), x-ray diffractions (XRD), and atomic force microscopy (AFM), etc. In this study, the effect of ultrasonic condition uniformly distributed alumina within Ni-P solution resulting in a smoother surface, lower surface roughness. Furthermore, the corrosion resistance behavior of the coating was analyzed using tafel polarization curves in a 3.5 wt.% NaCl solution at 25 ℃. Under ultrasonic, Al2O3 content in Ni-P composite solution increased from 0.5 to 5.0 g/L, Al2O3 content at 3.0 g/L was showed a significantly enhanced corrosion resistance. These results suggested that ultrasonic condition was an effective method to improve the properties of the composite coating.

Strain Analysis in GFRP Cross-Ply Laminates Using TR-EFPI Optical Fiber Sensor (광섬유 TR-EFPI 센서를 이용한 GFRP 직교 적층판의 변형률 해석)

  • 우성충;최낙삼;권일범
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2003.10a
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    • pp.150-153
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    • 2003
  • Longitudinal strains({$varepsilon}_x$) of the core and skin layers in glass fiber reinforced plastic(GFRP) cross-ply composite laminates have been studied using the embedded optical fiber sensor of totally-reflected extrinsic Fabry-Perot interferometer(TR-EFPI). Foil-type strain gauges bonded on both the upper and lower surfaces were used for the measurement of the surface strains. Both TR-EFPI sensor and strain gauge bonded on the specimen surface showed excellent agreement within -0.0086 ~ +0.0302% strain. It was shown that values of {$varepsilon}_x$ in the interior of the surface layer and the core layer measured by embedded TR-EFPI sensor was significantly higher than that of the specimen surface measured by strain gauges. The experimental results were ascertained with finite element analysis. Embedded TR-EFPI optical fiber sensor could measure accurately the internal strains which were different from the surface.

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Reliability Analysis of laminated Composite Panel using Response Surface Method (반응면 기법을 이용한 적층복합재료판의 신뢰성해석)

  • 방제성;김용협
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2001.10a
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    • pp.187-190
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    • 2001
  • Response surface method is applied to evaluate the reliability of laminated composite panels. Since the linear and nonlinear first-ply failure load are computed using deterministic finite element analysis, new probabilistic finite element analysis is not necessary. Tsai-Wu criterion is used to construct the limit state suface. Material properties, layer thickness and lamina strengths of laminated composite panel are treated as random design variables. feasibility and accuracy of current method is validated using Monte-Carlo method Which perform thousand times of finite element analysis directly.

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Preparation and Characterization of Flexible Optical Composite Films Based on Bragg-Structured Interferometer

  • Um, Sungyong;Sohn, Honglae
    • Journal of Integrative Natural Science
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    • v.6 no.4
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    • pp.244-250
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    • 2013
  • Three types of functionalized flexible optical composite films based on Bragg structure porous silicon interferometer have been successfully fabricated by casting a toluene solution of polystyrene onto the free-standing porous silicon. The optical properties of composite films are measured. Surface functionalization of porous silicon is determined by FT-IR measurement. Reflectance and transparence properties of composite films are measured for the possible application of tunable optical filter and indicate that the transmission peak occurred at the identical location where the reflection peak appeared.