• Title/Summary/Keyword: Thermal plasma spray coating

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High functional surface treatments for rapid heating of plastic injection mold (급속가열용 플라스틱 사출금형을 위한 고기능성 표면처리)

  • Park, Hyun-Jun;Cho, Kyun-Taek;Moon, Kyoung-Il;Kim, Tae-Bum;Kim, Sang-Sub
    • Design & Manufacturing
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    • v.15 no.3
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    • pp.7-12
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    • 2021
  • Plastic injection molds used for rapid heating and cooling must minimize surface damage due to friction and maintain excellent thermal and low electrical conductivity. Accordingly, various surface treatments are being applied. The properties of Al2O3 coating and DLC coating were compared to find the optimal surface treatment method. Al2O3 coating was deposited by thermal spray method. DLC films were deposited by sputtering process in room temperature and high temperature PECVD (Plasma enhanced chemical vapor deposition) process in 723 K temperature. For the evaluation of physical properties, the electrical and thermal conductivity including surface hardness, adhesion and wear resistance were analyzed. The electrical resistance of the all coated samples was showed insulation properties of 24 MΩ/sq or more. Especially, the friction coefficient of high temp. DLC coating was the lowest at 0.134.

Wear Resistance Characteristics of Thermal Sprayed AlSiMg/SiC Composite Coatings on Aluminum Engine Cylinder Bores (Aluminum Engine Cylinder Bore 적용 AlSiMg/SiC 복합 용사피막의 내마모 특성)

  • 양병모;변응선;박경채
    • Journal of Welding and Joining
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    • v.17 no.6
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    • pp.62-69
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    • 1999
  • The advantages of Thermal sprayed coatings as a replacement for cast iron liners are reduced weight, better heat transfer and reduced cost. One of the most important performance attributes of a cylinder bore coating is its wear resistance, since it must survive the abrasive sliding of both the piston rings and the piston skirt. In this study, composite powders were prepared by ball milling of Al-13Si-3Mg(wt%) alloy with SiC particles. The concentrations of SiC were 40 and 60wt%. The composite powders were sprayed using Metco-9MB plasma torch. Plasma sprayed coatings were heat-treated at 500℃ for 3 hours. The wear resistances of the plasma sprayed coatings were found to improve with heat treatment and superior to the commercially available G.C.I.(gray cast iron). AlSiMg-40SiC heat-treated coatings showed the best wear resistance in this study.

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The Experimental Study of Thermal Stress at Supersonic Nozzle (초음속 노즐의 열구조 안전성에 관한 실험적 연구)

  • Kim, Seong-Jin;Han, Hyeok-Seop;Lim, Jae-Hyock;Park, Eui-Yong;Baek, Ki-Bong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.11a
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    • pp.497-500
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    • 2011
  • The experimental study of thermal stress in the solid rocket engine nozzle with two different materials, SCM-440 and STS-630, was evaluated. SCM-440 has lager temperature increasing rate and higher temperature at the nozzle expansion region than STS-630. Thermal barrier efficiency and endurance of Zirconia coating were evaluated after making two more nozzles coated by Zirconica. Both coated materials showed about 70 percent higher thermal barrier efficiency than uncoated nozzles. Therefore, Zirconia coating using plasma spray method was useful in thermal safety at supersonic nozzle.

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A study on the high temperature properties of CoNiCrAlY coating fabricated by HVOF and LPPS process (LPPS용사법과 HVOF 용사법으로 제조된 CoNiCrAlY 코팅의 고온물성에 관한 연구)

  • 강현욱;권현옥;송요승
    • Journal of the Korean institute of surface engineering
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    • v.34 no.2
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    • pp.161-168
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    • 2001
  • A Thermal Barrier Coating (TBC) can play an important role in protecting parts from harmful environments at high temperatures such as oxidation, corrosion, and wear in order to improve the efficiency of aircraft engines by lowering the surface temperature of the turbine blade. The TBC can increase the life span of the product and improve the operating properties. Therefore, in this study the mechanical and thermal properties of the TBC such as oxidation, fatigue and shock at high temperatures were evaluated. A samples of a bond coat (CoNiCrAlY) produced by the High Velocity Oxygen Fuel (HVOF) and Low Pressure Plasma Spray (LPPS) method were used. The thickness of the HVOF coating layer was approximately $450\mu\textrm{m}$ to 500$\mu\textrm{m}$ and the hardness number of the coating layer was between 350Hv and 400Hv. The thickness of the LPPS coating was about 350$\mu\textrm{m}$ to 400$\mu\textrm{m}$ and the hardness number of the coating was about 370Hv to 420Hv. The X-ray diffraction analysis showed that CoNiCrAlY coating layer of the HVOF and LPPS was composed of the $\beta$and ${\gamma}$phase. After the high temperature oxidation test, the oxide scale with about l0$\mu\textrm{m}$ to 20$\mu\textrm{m}$ thickness appeared at the coating surface on the Al-depleted zone was observed under the oxide scale layer.

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Influence of Subsurface Layer on the Indentation Damage Behavior of YSZ Thermal Barrier Coating Layers Deposited by Electron Beam Physical Vapor Deposition (전자 빔 물리적 증착(EB-PVD)법으로 코팅된 YSZ 열차폐층의 압흔손상 거동에 대한 하부층의 영향)

  • Heo, Yong-Suk;Park, Sang-Hyun;Han, In-Sub;Woo, Sang-Kuk;Jung, Yeon-Gil;Paik, Un-Gyu;Lee, Kee-Sung
    • Journal of the Korean Ceramic Society
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    • v.45 no.9
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    • pp.549-555
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    • 2008
  • The thermal barrier coating must withstand erosion when subjected to flowing gas and should also maintain good stability and mechanical properties while it must also protect the turbine component from high temperature, hot corrosion, creep, and oxidation during operation. In this study we investigated the influence of subsurface layer, $Al_2O_3$ or NiCrCoAIY bond coat layer, on the indentation damage behavior of YSZ thermal barrier coating layers deposited by electron beam physical vapor deposition (EB-PVD). The bond coat is deposited using different process such as air plasma spray (APS) or spray of high velocity oxygen fuel (HVOF) and the thickness is varied. Hertzian indentation technique is used to induce micro damages on the coated layer. The stress-strain behaviors are characterized by results of the indentation tests.

Thermal Durability of 4YSZ Thermal Barrier Coating Deposited by Electron Beam PVD (전자빔을 이용한 물리기상증착법으로 제조된 열차폐용 4 mol% YSZ 코팅의 내열특성)

  • Park, Chanyoung;Yang, Younghwan;Kim, Seongwon;Lee, Sungmin;Kim, Hyungtae;Lim, Daesoon;Jang, Byungkoog;Oh, Yoonsuk
    • Journal of Powder Materials
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    • v.20 no.6
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    • pp.460-466
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    • 2013
  • 4 mol% Yttria-stabilized zirconia (4YSZ) coatings with $200{\mu}m$ thick are fabricated by Electron Beam Physical Vapor Deposition (EB-PVD) for thermal barrier coating (TBC). $150{\mu}m$ of NiCrAlY based bond coat is prepared by conventional APS (Air Plasma Spray) method on the NiCrCoAl alloy substrate before deposition of top coating. 4 mol% YSZ top coating shows typical tetragonal phase and columnar structure due to vapor phase deposition process. The adhesion strength of coating is measured about 40 MPa. There is no delamination or cracking of coatings after thermal cyclic fatigue and shock test at $850^{\circ}C$.

Study on Metal Microfilter Coated with Ceramics by Using Plasma Thermal Spray Method (플라즈마 용사를 이용한 복합세라믹 미세필터 연구)

  • Song, In-Gyu;Lee, Young-Min;Shin, Hyun-Myung;Choi, Hae-Woon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.9
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    • pp.1035-1040
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    • 2011
  • This research was performed on a microfilter made of a hybrid material (ceramic + metal) that was coated with ceramics on the metal-filter surface by using the thermal spray method. The ceramic powders used were $Al_2O_3+40TiO_2$ powder with a particle size of $20{\mu}m$ and $Al_2O_3$ (98%+)powder with a particle size of $45{\mu}m$. The metal filters were filter-grade $20{\mu}m$, $30{\mu}m$, and $50{\mu}m$ sintered metal powder filters (SIKA-R 20 IS, 30 IS, 50 IS; Sinter Metals Filters) and filter-grade $75{\mu}m$ sintered mesh filter with five layers. Ceramic-coated filters that were coated using the thermal spray method had a great influence on powder material, particle size, and coating thickness. However, these filters showed a fine performance when used as micro-filters.

Chonbuk National University 60kW and 200kw ICP(RF) Plasma systems for Advance Material processing (전북대학교 소재공정용 60kW 및 200kW ICP(RF) 플라즈마 발생 장치 구축 현황)

  • Lee, Mi-Yeon;Kim, Jeong-Soo;Seo, Jun-Ho;Choi, Seong-Man;Hong, Bong-Guen
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.11a
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    • pp.781-783
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    • 2010
  • Chonbuk national university High-enthalpy plasma research center is under construction for 60kW and 200kw ICP(RF) Plasma system as Advance Material R&D and production equipment. The 60kW & 200kW ICP(RF) plasma systems will contribute to promote Korea's material industrial development and Thermal plasma technology.

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Effect of Oxidation of Bond Coat on Failure of Thermal Barrier Coating (Bond Coat의 산화가 Thermal Barrier Coating의 파괴에 미치는 영향)

  • 최동구;최함메;강병성;최원경;최시경;김재철;박영규;김길무
    • Journal of the Korean Ceramic Society
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    • v.34 no.1
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    • pp.88-94
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    • 1997
  • The oxidation behavior of the NiCrAlY bond coat and thermal fatigue failure in the plasma-sprayed thermal barrier coating system, ZrO2.8wt%Y2O3 top coat/Ni-26Cr-5Al-0.5Y bond coat/Hastelloy X superalloy substrate, in commercial use for finned segment of gas turbine burner were investigated. The main oxides formed in the bond coat were NiO, Cr2O3, and Al2O3. It divided the oxide distribution at this interface into two types whether an Al2O3 thin layer existed beneath ZrO2/bond coat interface before operation at high temperature or not. While a continuous layer of NiO was formed mainly in the region where the Al2O3 thin layer was present, the absence of it resulted in the formation of mixture of Cr2O3 and Al2O3 beneath NiO layer. Analyses on the fracture surface of specimen spalled by thermal cycling showed that spalling occurred mainly along the ceram-ic coat near ZrO2/bond coat oxide layer interface, but slightly in the oxide layer region.

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Evaluation of Defects of Thermal Barrier Coatings by Thermal Shock Test Using Eddy Current Testing (열차폐 코팅층의 고온 열충격 시험후 ECT를 이용한 결함 평가)

  • Heo, Tae-Hoon;Cho, Youn-Ho;Lee, Joon-Hyun;Oh, Jeong-Seok;Lee, Koo-Hyun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.29 no.5
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    • pp.450-457
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    • 2009
  • Periodical thermal shock can introduce defects in thermal barrier coating made by layers of CoNiCrAlY bond coating(BC) and $ZrO_2-8wt%Y_2O_3$ ceramic top coating(TC) on Inconel-738 substrate using plasma spraying. Thermal shock test is performed by severe condition that is to heat until $1000^{\circ}C$ and cool until $20^{\circ}C$. As the number of cycle is increased, the fatigue by thermal shock is also increased. After test, the micro-structures and mechanical characteristics of thermal barrier coating were investigated by SEM, XRD. The TGO layer of $Al_2O_3$ is formed between BC and TC by periodical thermal shock test, and its change in thickness is inspected by eddy current test(ECT). By ECT test, it is shown that TGO and micro-crack can be detected and it is possible to predict the life of thermal barrier coating.