• 한국결정성장학회지
• /
• 제29권6호
• /
• pp.359-364
• /
• 2019

서스펜션 플라즈마 스프레이 법은 미세한 분말을 용사 공정에 적용함으로써 전통적인 플라즈마 스프레이 법의 단점을 극복하고자 개발된 코팅법이다. 본 연구에서는 고밀도의 Y₂O₃ 코팅막을 제조하기 위해 서스펜션 플라즈마 스프레이법을 이용하여 플라즈마 건의 전류량과 총 가스 유량을 공정변수로 하여 코팅막을 제조하였으며, 그에 따른 코팅막 특성에 대한 연구를 하였다. 코팅막의 미세구조 및 물리적 특성 평가 결과 플라즈마 건 전류량 200 A, 총 가스 유량 220 L/min의 조건에서 층상 결함 없이 0.2 vol%의 매우 낮은 기공률을 갖는 고밀도의 Y₂O₃ 코팅막을 제조할 수 있었다.

• 한국표면공학회지
• /
• 제49권1호
• /
• pp.87-91
• /
• 2016

The development of high performance transparent electrode with flexibility have been required for flexible electronics. Here, we demonstrate the silver nanowire and reduced graphene oxide hybrid transparent electrode for replacing brittle indium-tin-oxide electrode by spray coating technique and plasma reduction. The spray coating system is applied to deposit silver nanowire and over coated graphene oxide films and it has a great potential to scale-up. The resistance of silver nanowire transparent electrode is reduced by 10% and the surface roughness is decreased after graphene oxide coating. The over-coated graphene oxide is successfully reduced by $H_2$ plasma treatment and it is effective in increasing the environmental stability of electrode. The lifetime of silver nanowire and reduced graphene oxide hybrid electrode at $85^{\circ}C$ of Celsius degree of temperature and 85% of relative humidity has much increased.

• 한국분무공학회지
• /
• 제13권4호
• /
• pp.193-199
• /
• 2008

Spray coating is a versatile surface modification technology in which coating is built-up based on the successive deposition of micron-scaled particles. Depending on the coating materials, the coatings can meet the required mechanical properties, corrosion resistance, and other properties of base materials. Spraying processes are mainly classified into thermal and kinetic spraying according to their bonding mechanism and deposition characteristics. Specifically, thermal spraying process can be further classified into many categories based on the design and mechanism of the process, such as frame spraying, arc spraying, atmospheric plasma spraying (APS), and high velocity oxygen-fuel (HVOF) spraying, etc. Kinetic spraying or cold gas dynamic spraying is a newly emerging coating technique which is low-temperature and high-pressure coating process. In this paper, overall view of thermal and kinetic spray coating technologies is discussed in terms of fundamentals and industrial applications. The technological characteristics and bonding mechanism of each process are introduced. Deposition behavior and properties of technologically remarkable materials are reviewed. Furthermore, industrial applications of spray coating technology and its potentials are prospected.

• 한국표면공학회지
• /
• 제41권5호
• /
• pp.220-225
• /
• 2008

In this study, two kinds of Fe-based bulk metallic glasses (BMG) powder were built-up through atmospheric plasma spray (APS) technique. The microstructure of two coatings was analyzed through X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Crystallization and oxidation in coatings were affected by chemical composition and initial powder size. Then, both of them influenced the tribological property.

• 한국진공학회지
• /
• 제7권s1호
• /
• pp.30-36
• /
• 1998

The plasma-spray technique is currently the most frequently used method to produce calcium phosphate coatings. Hydroxyapatite(HAp), one form of calcium phosphate, is preferred by its ability to form a direct bond with living bone, resulting in improvements of implant fixation and faster bone healing. Recently, concerns have been raised regarding the viable use and long-term stability of plasma-spray HAp coatings due to its nature of comparatively thick, porous, and poor bonding strength to metal implants. Thin layers (maximum of few microns) of calcium phosphate were formed by an e-beam evaporation with and without ion bombardments. The Ca/P ration of film was controlled by either using the evaporants having the different ration of Ca/P with addition of CaO, or adjusting the ion beam assist current. The Ca/P ration had great effects on the structure formation after heat treatment and the dissolution bahavior. The calcium phosphate films produced by IBAD exhibited high adhesion strength.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2005년도 추계학술발표회 및 workshop
• /
• pp.181-182
• /
• 2005

• Corrosion Science and Technology
• /
• 제5권2호
• /
• pp.77-83
• /
• 2006

The plasma electrolytic oxidation (PEO) process is a relatively new surface treatment technique that produces a chemically stable and environment-friendly electrolytic coating that can be applied to all types of magnesium alloys. In this study, the characteristics of oxide film were examined after coating the extruded AZ31 alloy through the PEO process. Hard ceramic coatings were obtained on the AZ31 alloy by changing the coating time from 10min to 60min. The morphologies of the surface and the cross-section of the PEO coatings were examined by scanning electron microscopy and optical microscopy, and the thickness of the coating was measured. The X-ray diffraction pattern of the coating shows that the coated layer consists mainly of the MgO and $Mg_2SiO_4$ phases after the oxidation reaction. The hardness of the coated AZ31 alloy increased with increasing coating time. In addition, the corrosion rates of the coated and uncoated AZ31 alloys were examined by salt spray tests according to ASTM B 117 and the results show that the corrosion resistance of the coated AZ31 alloy was superior to that of the un-coated AZ31 alloy.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
• /
• pp.1001-1004
• /
• 2003

We applied the spray pyrolysis technique to prepare fine $YBO_{3}$:Tb particles with high photoluminescence, which could be used in the plasma display device as a green phosphor. Several preparation conditions were investigated in order to tail the vacuum ultraviolet characteristics of $YBO_{3}$:Tb particles when they were prepared by the spray pyrolysis. As a result, the optimized $YBO_{3}$:Tb particles showed the high photoluminescence intensity as well as fine size in comparison with the commercial one.

• 세라미스트
• /
• 제9권6호
• /
• pp.24-29
• /
• 2006

Electron beam physical vapor deposition (EB-PVD) process has currently been applied to thermal barrier coatings (TBCs) for aircraft engines. Due to unique columnar structure, EB-PVD TBCs have advantages in resistances to thermal shock and thermal cycle for their applications, compared to films prepared by plasma spray By the EB-PVD equipment, we successfully obtained yttria-stabilized zirconia (YSZ) layer which has columnar and feather like structure including a large amount of nano size pores and gaps. The EB-PVD technique has been developed for coating functional perovskite type oxides such as (La, Sr)MnO3. Electrode properties have been improved by interface and structural control.

• 전기학회논문지
• /
• 제66권11호
• /
• pp.1600-1604
• /
• 2017

Mo-Cu alloys have been widely used for heat sink materials, vacuum technology, automobile and many other applications due to their excellent physical and electronic properties. Especially, Mo-Cu composites with 5~20 wt% copper are widely used for the heavy duty service contacts due to their excellent properties like low coefficient of thermal expansion, wear resistance, high temperature strength and prominent electrical and thermal conductivity. In most of the applications, high dense Mo-Cu materials with homogeneous microstructure are required for high performance, which has led in turn to attempts to prepare ultra-fine and well-dispersed Mo-Cu powders in different ways, such as spray drying and reduction process, electroless plating technique, mechanical alloying process and gelatification-reduction process. However, most of these methods were accomplished at high temperature (typically degree), resulting in undesirable growth of large Cu phases; furthermore, these methods usually require complicated experimental facilities and procedure. In this study, Mo-Cu alloying were prepared by planetary ball milling (PBM) and spark plasma sintering (SPS) and the effect of Cu with contents of 5~20 wt% on the microstructure and properties of Mo-Cu alloy has been investigated.