• Title/Summary/Keyword: Surface Treatment

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Durability of Various Anti-Corrosive Organic Coatings in Marine Environment for Twelve Years

  • Yamamoto, Mashiro;Kajiki, Toshitaka;Kamon, Toshikuni;Yoshida, Kotaro
    • Corrosion Science and Technology
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    • v.3 no.1
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    • pp.20-25
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    • 2004
  • In order to clarify the durability of protective coatings for maritime steel structures, various anti-corrosive organic coated steel samples were exposed for twelve years in semitropical marine environment at Miyakojima Island, Okinawa, JAPAN. Samples were various organic coated steel pipes, 4.0 m in length and 150 mm in diameter. While the bare steel pipe entirely corroded in 4.5 mm thickness in four and half years, these organic coated steel pipes exhibited protective appearances after twelve-year-exposure except for the defect in the coatings. Polyethylene (PE) lining pipe exhibited a good protective performance. Urethane painted pipe was also good but some barnacles stuck to its surface. A combination of petrolatum tape and FRP cover showed sufficient corrosion resistance for steel surface. The correlation in results between exposure and laboratory acceleration test was examined. It was found that salt spray test (SST) results corresponded to rusted area of scratched portion and that adhesion change of coating layer corresponded to the rotating immersion test result. Among the on-site measured data, volume resistivity is utilized for the index of corrosion protection performance of organic coating.

Experimental study on improving bamboo concrete bond strength

  • Mali, Pankaj R.;Datta, Debarati
    • Advances in concrete construction
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    • v.7 no.3
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    • pp.191-201
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    • 2019
  • Bamboo concrete bond behaviour is investigated through pullout test in this work. The bamboo strip to be used as reinforcement inside concrete is first treated with chemical adhesive to make the bamboo surface impermeable. Various surface coatings are explored to understand their water repellant properties. The chemical action at the bamboo concrete interface is studied through different chemical coatings, sand blasting, and steel wire wrapping treatment. Whereas mechanical action at the bamboo concrete interface is studied by developing mechanical interlock. The result of pullout tests revealed a unique combination of surface treatment and grooved bamboo profile. This combination of surface treatment and a grooved bamboo profile together enhances the strength of bond. Performance of a newly developed grooved bamboo strip is verified against equivalent plain rectangular bamboo strip. The test results show that the proposed grooved bamboo reinforcement, when treated, shows highest bond strength compared to treated plain, untreated plain and untreated grooved bamboo reinforcement. Also, it is observed that bond strength is majorly influenced by the type of surface treatment, size and spacing of groove. The changes in bamboo-concrete bond behavior are observed during the experimentation.

Shear Bond Strength of Zirconia and Ceramics according to Dental Zirconia Surface Treatment (치과용 지르코니아 표면처리방법에 따른 지르코니아와 전장용 도재의 결합강도 관찰)

  • Lee, Gwang-Young;Choi, Sung-Min
    • Journal of Technologic Dentistry
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    • v.41 no.4
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    • pp.279-285
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    • 2019
  • Purpose: The dental CAD / CAM system has been popular with the development of the digital dental industry. Zirconia is a typical material in dental CAD / CAM systems. Zirconia crowns are classified into single layer and double layer. This study is about the double layer crown of zirconia. The surface roughness, bond strength and fracture patterns of the zirconia surface were observed. Methods: Zirconia blocks were cut using a low speed cutter. Sintered to form a plate shape (6mm × 6mm × 3mm). The prepared specimens were surface treated in four ways. Surface roughness and bond strength were measured. And the fracture pattern was observed. Results: Result of surface treatment of zirconia. The surface roughness test results were as ET 2.87 ㎛, ST 2.67 ㎛, LT 2.44 ㎛, AT 2.41 ㎛, CN 2.08 ㎛ order. Bond Strength results were as LT 25.09 MPa, AT 23.27 MPa, ST 21.27 MPa, ET 21.09 MPa, CN 16.12 MPa order. Fracture patterns showed cohesive failure of 25-50% of the bond area. Conclusion: Surface roughness, bond strength and fracture pattern of the zirconia surface were observed. Etching the surface treatment of zirconia materials has been shown to affect the surface roughness. Zirconia special binder treatment has been shown to affect the bond strength improvement.

Effect of Surface Treatment on Adhesive Strength Properties of Al/PC Adhesive Joints (Al/PC 접합재의 접착강도특성에 미치는 표면처리의 영향)

  • Seo, Do-Won;Yoon, Ho-Cheol;Yoo, Sung-Chol;Lim, Jae-Kyoo;Lutz Dorn
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.5
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    • pp.840-847
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    • 2003
  • The bonding of adhesive joints of adhesive joints is influenced by the surface roughness of the joining Parts. However, the magnitude of the influence has not yet been clarified because of the complexity of the phenomena. In this study, it is shown that surface treatment affects adhesive strength and durability of alumina/polycarbonate single-lap .joints, and leading speed affects tensile-shea strength of adhesive Joints. To evaluate effect of surface treatments on the adhesive strength, several surface treatment methods are used, that is, cleaning, grinding, SiC polishing and sand blasting. It is shown that an optimum value of the surface roughness exists with respect to the tensile-shea strength of adhesive joints. The adhesive strength shows linear relationship with the surface roughness and loading speed. And the mechanical removal of disturbing films of lubricants, impurities and oxides make adhesive strength increase significantly.

Properties of Concrete using Surface Treatment Recycled Aggregates and Steel Fibers (강섬유보강(鋼纖維補强) 표면처리(表面處理) 순환골재(循環骨材)콘크리트의 특성(特性))

  • Bae, Ju-Seong;Kim, Nam-Wook
    • Resources Recycling
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    • v.20 no.1
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    • pp.46-53
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    • 2011
  • The recycled aggregate produced from the waste concrete have the disadvantages in the quality for the natural aggregate. Therefore, in order to reuse the recycled aggregate widely it is a previous subject to improve the quality of recycled aggregate. We deduced the more effective surface treatment method using the colloidal silica solution for quality improvement of recycled aggregate. This study aimed to verify the influences of the deduced surface treatment method and the reinforcement of steel fiber to the properties of concrete. For this object, we inquired into the results of the strengths and the flexural failure tests for the five kinds of concrete specimens.

Surface Treatment Effect on the Toilet by Numerical Modeling and High Speed CCD Camera (수치모델과 고속 CCD 카메라를 이용한 세변기 표면 처리 효과 특성 해석)

  • Roh, Ji-Hyun;Do, Woo-Ri;Yang, Won-Kyun;Joo, Jung-Hoon
    • Journal of the Korean institute of surface engineering
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    • v.44 no.1
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    • pp.32-37
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    • 2011
  • Numerical analysis is done to investigate the effect of surface treatment of a toilet on the cleanness. The surface treatment using plasma for the super-hydrophobic surface expects the self-cleaning effect of the toilet seat cover for preventing the droplets with a great quantity of bacteria during the toilet flushing after evacuation. In this study, the fluid analysis in the toilet during the flushing was performed by an ultrahigh-speed CCD camera with 1,000 frame/sec and the numerical modeling. And the spattering phenomenon from the toilet surface during urine was analyzed quantitatively by CFD-ACE+ with a free surface model and a mixed model of two fluids. If the surface tension of the toilet surface is weak, many urine droplets after collision bounded in spite of considering the gravity. The turbulence generated by the change of angle and velocity of urine and the variation of the collision phenomenon from toilet surface were modeled numerically.

Heat and Surface treatments for the Longevity of Prehardened Steels (사출금형용 프리하든 강의 수명 향상 기술)

  • Kim, Sung Wan;Moon, Kyoung Il;Kim, Sang Gweon;Cho, Yong Ki
    • Journal of the Korean Society for Heat Treatment
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    • v.18 no.6
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    • pp.383-393
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    • 2005
  • 본 고에서는 사출금형소재로 널리 사용되는 프리하든 강의 수명을 극대화 시킬 수 있는 열 표면처리 기술에 대해 소개하였다. 이러한 열 표면처리 기술 및 기술 적용시 고려해야할 점을 다시 정리해 보면, 제조하는 대상물을 고려한 최적 금형 재료의 선택 (표 1~3) 선택된 금형의 물성을 최적으로 구현할 수 있는 열처리 선택 (표 4) 금형의 사용 환경을 고려한 최적 열 표면처리 선택 (표 5) 질화 열처리에 의한 수명 향상 피로 수명이 중요한 경우 : 질화층 $100{\mu}m$이내 열간 내마모성, 크립저항성이 요구되는 경우 : 질화층 $300{\sim}400{\mu}m$ TiN, CrN 등 세라믹 코팅에 의한 성능 향상 내식성 중요시 CrN, DLC의 적용 내마모성 및 초저마찰계수의 구현 : 방향성 코팅, 나노구조화 금형의 국제경쟁력을 향상시키기 위해서는 고품위 금형 제조 기술이 필요하고 이를 위하여, 표면개질처리가 필수불가결하다는 것이다. 또한, 열 표면처리에는 각각의 특징이 있고, 적용 상황의 미묘한 차이에 따라 특성이 바뀌기 때문에 고품위, 품질 금형을 얻고자 하면 어느 때보다 사용자, 금형기술자, 열 열 표면처리 기술자들과의 협력이 요구된다.

Heat Treatment Characteristics of a Press Draw Mold by Using High Power Diode Laser (고출력 다이오드 레이저를 이용한 프레스 드로우금형의 열처리 특성)

  • Hwang, Hyun-Tae;So, Sang-Woo;Kim, Jung-Do;Kim, Young-Kuk;Kim, Byeong-Hun
    • Journal of the Korean Society for Heat Treatment
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    • v.22 no.6
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    • pp.339-344
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    • 2009
  • Recently, Laser surface treatment technologies have been used to improve wear charactenitics and fatigue resistance of metal molding. When the laser beam is irradiated on the surface and laser speed is appropriate, the laser focal position is rapidly heated and the thermal energy of surface penetrates the material after irradiation, finally imbuing it with a new mechanical characteristic by the process of self-quenching. This research estimates the material characteristic after efficient and functional surface treatment using HPDL, which is more efficient than the existing CW Nd:YAG laser heat source. To estimate this, microstructural changes and hardness characteristics of three parts (the surface treatment part, heat affect zone, and parental material) are observed with the change of laser beam speed and surface temperature. Moreover, the depth of the hardened area is observed with the change of the laser beam speed and temperature. From the results of the experiments, it has been shown that the maximum hardness is approximately 788Hv when the heat treatment temperature and the travel speed are $1150^{\circ}$ and 2 mm/sec, respectively.

Surface Treatment of ITO (Indium-Tin-Oxide) thin Films Prepared by Sol-Gel Process (졸-겔 공정에 의해 제조된 ITO (Indium-Tin-Oxide) 박막의 표면처리)

  • Jung, Seung-Yong;Yun, Young-Hoon;Yon, Seog-Joo
    • Journal of the Korean Ceramic Society
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    • v.44 no.6
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    • pp.313-318
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    • 2007
  • ITO (Indium-tin oxide) thin films have been prepared by a sol-gel spinning coating method and fired and annealed in the temperature range of $450-600^{\circ}C$. The XRD patterns of the films indicated the main peak of (222) plane and showed higher crystallinity with increasing an annealing temperature. The surface of the ITO thin films were treated with 0.1 N HCl 20% solution at room temperature. The effects of surface treatment on electrical properties and surface morphologies of the ITO films were investigated with the results of sheet resistance and FE-SEM, AFM images. The samples, subsequently treated with acidic solution for 40 sec showed the sheet resistance of $0.982\;k{\Omega}/square$. The surface treatment using acidic solution diminished the RMS (root mean square) value and the residual carbon content of the ITO films. It seemed that the acid-cleaning of the ITO thin films lead to the decrease of surface roughness and sheet resistance.

The study of Design Surface Treatment Obtained Metal Color in Magnesium Alloy

  • Lee, Jung Soon;Lee, Hee Myoung
    • Applied Science and Convergence Technology
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    • v.26 no.2
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    • pp.21-25
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    • 2017
  • The shape of the reflection spectrum is complex and appears to overlap with several signals, because the surface state is uneven due to the natural oxide film, so that the spectrum becomes a complicated signal shape divided into regions 1 and 2 due to diffuse reflection. On the other hand, it is seen that the reflection spectrum after PEO surface treatment is overlapped with several signals. In addition, the reflectance of the energy band varies from 1.32 to 1.46 eV. Usually, the MgO-type oxide film was observed at an energy band of ~4.2 eV. The thickness of the oxide film was increased as the DC voltage was increased by the thin film thickness meter (QuaNix; 7500M) after Plasma Electrolytic Oxidation (; PEO) surface treatment. This is because the higher the DC voltage, the easier the binding of the $OH^-$ ions in the solution solution and the $Mg^+$ ions of the magnesium alloy. An important part of the bonding of ordinary ions is the energy source (plasma) which can promote bonding. However, when a certain threshold voltage or more is applied, the material is adversely affected. The oxide film of the surface may be destroyed without increasing the thickness of the oxide film, that is, whitening of the material may occur.