A facile method to enhance the uniformity and adhesion properties of water-based ceramic coating layers on hydrophobic polyethylene separators

Lee, Hoogil,Jeon, Hyunkyu,Gong, Seokhyeon,Ryou, Myung-Hyun,Lee, Yong Min Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.427 No.1

<P><B>Abstract</B></P> <P>To enhance the uniformity and adhesion properties of water-based ceramic coating layers on hydrophobic polyethylene (PE) separators, their surfaces were treated with thin and hydrophilic polydopamine layers. As a result, an aqueous ceramic coating slurry consisting of Al<SUB>2</SUB>O<SUB>3</SUB> particles, carboxyl methyl cellulose (CMC) binders, and water solvent was easily spread on the separator surface, and a uniform ceramic layer was formed after solvent drying. Moreover, the ceramic coating layer showed greatly improved adhesion properties to the PE separator surface. Whereas the adhesion strength within the bulk coating layer (<I>F</I> <SUB>mid</SUB>) ranged from 43 to 86Nm<SUP>−1</SUP> depending on the binder content of 1.5–3.0wt%, the adhesion strength at the interface between the ceramic coating layer and PE separator (<I>F</I> <SUB>sepa-Al2O3</SUB>) was 245–360Nm<SUP>−1</SUP>, a value equivalent to an increase of four or five times. Furthermore, an additional ceramic coating layer of approximately 7μm did not degrade the ionic conductivity and electrochemical properties of the bare PE separators. Thus, all the LiMn<SUB>2</SUB>O<SUB>4</SUB>/graphite cells with ceramic-coated separators delivered an improved cycle life and rate capability compared with those of the control cells with bare PE separators.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Polydopamine-treated PE separators were used for ceramic-coated separators (CCSs). </LI> <LI> Polydopamine (PDA) facilitated the uniform water-based ceramic coating layers. </LI> <LI> PDA-PE/CCS improved adhesion strength between PE and ceramic coating layers. </LI> <LI> PDA-PE/CCS improved thermal stability compared to bare PE. </LI> <LI> PDA-PE/CCS improved rate and cycle retention abilities of full cells. </LI> </UL> </P>

Non-stick Ceramic Coating for Pottery by Incorporation of Cellulose Nanofibers

신은애,김계현,이창기 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

Ceramic coating is not only eco-friendly and harmless but also thermally and chemically durable. However, foods easily adhere to the cookware on cooking due to hydrophilic coating layer from numerous hydroxyl groups on silica surface. To solve such problem, we prepared ceramic coating solution with enhanced non-stick property. This hydrophobic coating was materialized by rough surface from nanofibers added into ceramic solution. Cellulose nanofibers (CNFs) contained in silica colloidal solution for ceramic coating made the surface of coating irregularly and rough. The average roughness of ceramic coating surface increased when CNFs were added according to the results from 3D microscope. Also, ceramic coating incorporated CNFs was more thermally stable so its thermal degradation temperature also increased compared to that of base ceramic solution. We anticipate that the non-stick and thermally stable pottery can be fabricated by applying this CNF-incorporated ceramic coating.

플라즈마 스프레이를 이용한 세라믹 코팅층의 부식특성에 관한 연구

김동화,송요승,윤종구,채경선,안준홍 한국 항공대학교 항공산업기술연구소 1999 航空宇宙産業技術硏究所 硏究誌 Vol.9 No.-

여러 산업체에선 한계된 금속의 성질을 필요한 용도에 맞게 합금원소를 첨가하므로써 개선해 왔으나, 이는 제한된 범위를 가지고 있으며, 그 효과가 작다. 최근에는 금속표면에 피막을 입혀 효율적으로 제품을 개선하여 생산하고 있다. 피막을 입히는 기술로는 용사법을 비롯하여 CVD, PVD, 양극산화법, 전기 및 화학도금등 그 종류는 다양하다. 금속위에 표면처리를 하여 세라믹피막을 얻으므로써 단열피복, 내마모성, 내식성, 내열성, 열전도 차폐등 물리적, 기계적 성질을 개선하고 있다. 이번 연구에서는 표면에 세라믹 보호 피막을 생성하는 process로 plasma spray법을 이용하여 Titanium 모재위에 Cr₂O₃-TiO₂, Al₂O₃-TiO₂,그리고 NiCoCrAlYO₂의 4종류의 세라믹 powder로 용사층을 형성, 물리적 특성을 분석하였고, 또한 bond coating 재료로는 NiCoCrAlYO₂분말을 사용하여 bond coating을 형성시키기 전과 후의 물성을 비교하였다. 특히 세라믹 피막의 기공도시험, 표면거칠기시험등을 통하여 피막의 내식성향상에 어떠한 영향을 주는지 XRD, SEM, 전기화학적 분극시험을 통해 중점적으로 연구하였다. 연구 결과 Al₂O₃-TiO₂피막층과 NiCoCrAlYO₂(bond coating layer)+Al₂O₃-TiO₂피막층이 우수한 내식성을 나타내며, 대체적으로 bond coating layer가 존재하지 않는 피막의 기공도와 표면거칠기의 평균값이 낮게 나오며, 내식성 역시 우수한 것으로 확인하였다. The ceramic material coating is used to protecting the underground pipe, ship, and water tank from corrosion environment. Recently, an advanced nation has made a lot of study to develop the semi-permanent insoluble cell using ceramic coating on valve metal(substrate). Therefore in this study the plasma spray method was used to make the protection coating. The ceramic materials for coatings were Cr₂O₃-TiO₂, Al₂O₃-TiO₂and the bond coating materials for bond strength was NiCoCrAlYO₂. As a results, the Al₂O₃-TiO₂ coating without bond coating(NiCoCrAlYO₂) represent the excellent anticorrosion property against corrosion environment.

세라믹 피막 모재의 표면거칠기가 미시적 마모에 미치는 영향

양경욱,문봉호,김현태 여수대학교 1999 論文集 Vol.14 No.2

The ceramic is a material with the Ceramic coating by CVD makes a boundary region between coating and substrate. The delamination is occurred at the boundary region. The control of boundary region is important for improving wear resistance of ceramic coating. The surface roughness of substrate changes for the control of boundary region. This study clarifies that the surface roughness of substrate influences on wear at the ceramic coating. In order to know the microscopic wear mechanism of CVD TiN coating, the wear process was observed in-situ during sliding in a SEM.VTR tribosystem. Three wear steps observed for CVD TiN coating With thickness of 1.5㎛. We propose a surface working method of substrate for increasing wear resistance of ceramic coating.

단결정형 세라믹 브라켓의 재접착 시 tribochemical silica coating이 전단접착강도에 미치는 영향

전영미(Young-Mi Jeon),손우성(Woo-Sung Son),강상욱(Sang-Wook Kang) 대한치과교정학회 2010 대한치과교정학회지 Vol.40 No.3

본 연구는 탈락된 세라믹 브라켓을 tribochemical silica coating하고 nano-filled flowable composite resin (Transbond Supreme LV, 3M Unitek, Monrovia, Calif, USA)을 이용하여 재접착하였을 때 교정치료에 충분한 접착강도를 얻을 수 있는지 평가하기 위해 시행하였다. 총 60개의 소구치를 준비하여 다음의 4개 군으로 나누었다: Tribochemical silica coating (TC) + Transbond Supreme LV (LV), TC + Transbond XT (XT), Sandblast treatment (SA) + LV, SA + XT. 재처리된 세라믹 브라켓은 각각의 접착제를 이용하여 치아에 부착하였다. 시편들을 상온의 생리식염수에 1주일간 보관한 뒤 열순환을 시켰다. 만능시험기로 전단접착강도를 측정한 뒤 파절양상을 평가하였다. TC군은 임상적으로 충분한 강도를 보였다(TCLV: 10.82 ± 1.82 MPa, TCXT: 11.50 ± 1.72 MPa). 하지만 SA군은 TC군에 비하여 유의하게 낮은 전단접착강도를 보였다(SALV: 1.23 ± 1.16 MPa, SAXT: 1.76 ± 1.39 MPa, p < 0.05). LV군과 XT군의 전단접착강도는 유의한 차이가 없었다. TCLV, TCXT군 모두 시편의 77%가 접착제에서의 파절을 보였고, 각 군당 1개씩의 시편에서 법랑질 파절이 관찰되었다. SA군은 모든 파절이 브라켓과 접착제 계면에서 발생하였다. LV군과 XT군의 탈락양상에는 유의한 차이가 없었다. 이상의 연구 결과에서 보면 nano-filled flowable composite resin과 tribochemical silica coating 처리를 이용하여 세라믹 브라켓을 재접착하면 충분한 전단접착강도를 얻을 수 있다. 단 법랑질 파절의 가능성이 있으므로 탈접착 시 적절한 기구와 기술을 이용해 주의깊게 브라켓을 제거해야 한다. Objective: The purpose of this study was to investigate the effect of tribochemical silica coating on the shear bond strength (SBS) of rebonded ceramic brackets using nano-filled flowable composite resin. Methods: A total of 60 premolars were prepared and divided into 4 equal groups as follows: Tribochemical silica coating (TC) + Transbond XT (XT), TC + Transbond supreme LV (LV), Sandblast treatment (SA) + XT, SA + LV. Treated ceramic brackets were rebonded on the premolars using each adhesive. All samples were tested in shear mode on a universal testing machine. Results: SBS of silica coated groups were high enough for clinical usage (TCLV: 10.82 ± 1.82 MPa, TCXT: 11.50 ± 1.72 MPa). But, SBS of the sandblast treated groups had significantly lower values than the tribochemical silica coated groups (SALV, 1.23 ± 1.16 MPa; SAXT, 1.76 ± 1.39 MPa; p < 0.05). There was no difference between the shear bond strength by type of adhesive. In the silica coated groups, 77% of the samples showed bonding failure in the adhesive. In the sandblast treated group, all bonding failures occurred at the bracket-adhesive interface. Conclusions: The result of this study suggest that newly introduced nano-filled flowable composite resin and tribochemical silica coating application on debonded ceramic bracket bases can produce appropriate bond strengths for orthodontic bonding.

Plasma-assisted water-based Al₂O₃ ceramic coating for polyethylene-based microporous separators for lithium metal secondary batteries

Jeon, Hyunkyu,Jin, So Yeon,Park, Won Ho,Lee, Hongkyung,Kim, Hee-Tak,Ryou, Myung-Hyun,Lee, Yong Min Elsevier 2016 ELECTROCHIMICA ACTA Vol.212 No.-

<P><B>Abstract</B></P> <P>To meet the high requirements of future lithium secondary batteries based on lithium metal anodes for large-scale applications, we develop a cost-effective and environmentally friendly water-based method to prepare inorganic/polymer composite coating layers on commercial hydrophobic polyolefin-based microporous separators. To this end, we utilize a plasma-treatment technique. After the plasma treatment, the surface of the polyethylene (PE) separators changes from hydrophobic to hydrophilic, and the pore structures of the separators widen. These changes improve the affinity of the PE separators for polar liquid electrolytes and their ionic conductivities compared to those of bare PE and other ceramic-coated control systems. The polar functional groups derived from plasma treatment interact with the hydroxyl groups of water-soluble polymeric binders in the ceramic (Al<SUB>2</SUB>O<SUB>3</SUB>) coating layers, thereby improving the adhesion strength between the PE substrate and the ceramic coating layer. This improvement impedes hydrophobic recovery phenomena. As a result, plasma-treated ceramic-coated separators (plasma CCSs) exhibit superior power capability and cycle performance (plasma CCS maintained 94.7% of the initial discharge capacity up to the 1000th cycle at C/2, whereas bare PE’s remained high only up to the 300th cycle) in unit cells based on lithium metal anodes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Plasma treatment technique realizes a 100% water-based ceramic coating process. </LI> <LI> Plasma treatment enhances the adhesion properties of ceramic coating layer. </LI> <LI> Al<SUB>2</SUB>O<SUB>3</SUB> coating layers impedes hydrophobic recovery after plasma treatment. </LI> <LI> Plasma-treated Al<SUB>2</SUB>O<SUB>3</SUB> layers improves cycle performance and rate capabilities. </LI> </UL> </P>

지하 콘크리트구조물의 열화 억제에 의한 내구성 증진에 관한 연구

천병식(Cheon Byeong Sig),최춘식(Choe Chun Sig),정원우(Jeong Won U) 한국지반공학회 2004 한국지반공학회논문집 Vol.20 No.3

Normally, coating is used for protecting reinforced concrete. For this purpose. both organic and inorganic coatings are used. The advantages of inorganic coatings are lower absorption of UV, non-burning etc. On the other hand, organic coatings have the advantage of low permeability of CO₂, SO₂and water. Organic coatings provide better protection for reinforced concrete, However, organic coatings such as epoxy, urethane and acryl reduce long-temi adhesive strength by the difference of their thermal expansion coefficients and elastic inodulus from those of concrete, and the formed coating cover of these is blistered by poor breathing. Also, when organic coatings are applied to the wet surface of concrete, they have a problem with adhesion. In this study, a new coating inaterial for protecting concrete was hybridized with polymer and ceramics. And tests were carried out on its physical and durable characteristics, and safety characteristic on elution. All results were compared with organic coating inaterials and epoxies and showed that the performance of the developed coating material was not inferior to that of other organic coatings in protecting concrete. On the other hand, safety characteristic on elution was superior to epoxies which were used i n this study. So, the developed coating material was considered as a suitable protecting coating material which have advantages of inorganic and organic coatings for protecting underground concrete structures, especially in contact with water.

A water-based Al₂O₃ ceramic coating for polyethylene-based microporous separators for lithium-ion batteries

Jeon, H.,Yeon, D.,Lee, T.,Park, J.,Ryou, M.H.,Lee, Y.M. Elsevier Sequoia 2016 Journal of Power Sources Vol.315 No.-

To develop an environmentally friendly and cost-effective water-based inorganic coating process for hydrophobic, polyolefin-based microporous separators, the effect of surfactants in an aqueous inorganic coating solution comprising alumina (Al<SUB>2</SUB>O<SUB>3</SUB>) on polyethylene (PE)-based microporous separators is investigated. By using a selected surfactant, i.e., disodium laureth sulfosuccinate (DLSS), the aqueous Al<SUB>2</SUB>O<SUB>3</SUB> coating solution maintained a dispersed state over time and facilitated the formation of a uniform Al<SUB>2</SUB>O<SUB>3</SUB> coating layer on PE separator surfaces. Due to the hydrophilic nature of the Al<SUB>2</SUB>O<SUB>3</SUB> coating layers, the as-prepared, ceramic-coated PE separators had better wetting properties, greater electrolyte uptake, and larger ionic conductivities compared to those of the bare PE separators. Furthermore, half cells (LiMn<SUB>2</SUB>O<SUB>4</SUB>/Li metal) containing Al<SUB>2</SUB>O<SUB>3</SUB>-coated PE separators showed improved capacity retention over several cycles (93.6% retention after 400 cycles for Al<SUB>2</SUB>O<SUB>3</SUB> coated PE separators, compared to 89.2% for bare PE separators operated at C/2) and rate capability compared to those containing bare PE separators. Moreover, because the Al<SUB>2</SUB>O<SUB>3</SUB>-coated layers are more thermally stable, the coated separators had improved dimensional stability at high temperatures (140 <SUP>o</SUP>C).

패러린 컨포멀코팅 적용을 통한 고집적 전자장치의 진동 영향 및 내구성 연구

이창수,김해원,유민숙 국방기술품질원 2023 국방품질연구논집 Vol.5 No.2

Parylene coatings exhibit high mechanical strength. Therefore, we confirmed that the parylene coating has a positive effect on the reliability of electronic components mounted on PCBs (printed circuit boards) in a vibration environment. This study used Daisy chains of ceramic column grid array (CCGA) components to test the vibration environment of three sets of coatings: one set without the parylene coating, one set with 15 µm parylene coating, and one set with 30 µm parylene coating. The first random vibration of the x-axis consisted of six stages that were evaluated for 5 min each, and there was no special matter in all samples. In the case of the z-axis random vibration, under 2 grms conditions, the response sensor was 12.22 grms, confirming an instantaneous excitation of up to 1,000 times. Even under 5 and 10 grms conditions, excitations of more than 1,000 times were confirmed at 20.39 and 44.02 grms, respectively. Because of the Daisy chain, all uncoated samples were open under 20 grms conditions, and there were no special matters for the 30-µm-coated sample. In the cross section after the vibration test, visible cracks were confirmed in the uncoated sample, but the 30-µm-coated sample had either micro or no cracks. Consequently, it was experimentally verified that the uniform coating-film formation and parylene coating thickness were effective in relieving stress.

플라스마용사 세라믹 코팅재의 마멸특성

김귀식(Gui-Shik Kim),오맹종(Maeng-Jong Oh),박경석(Gyung-Seok Park),정동원(Dong-Won Jung) 한국해양공학회 1998 韓國海洋工學會誌 Vol.12 No.4

This paper is to investigate the wear behaviors of a thermal sprayed TiO₂ coating by a pin-on-disk type wear testing machine. The test specimens were to plasma sprayed TiO₂ coating on carbon st않I substrate (S45C) with Ni-4.5%Al alloy bond coating. And these were done heat treatment at 800℃ and 1000℃. Wear characteristics, which were friction force and friction coefficient, and wear rates, according to heat treatment temperature were conducted at the two kinds of load and wear environments at room temperature. The microhardness and wear of ceramic coating heat-treated were improved more than those of as-sprayed coating. The friction coefficient and wear amount of the heat-treated were remarkably decreased in the dry as well as the lubrication condition. Then, the anti-wear properties of the heat treatment at 1000℃ was better than that at 800℃. As increasing the load, the effect of the lubrication environment and heat treatment were decreased.