• Journal of Surface Science and Engineering
• /
• v.40 no.4
• /
• pp.170-174
• /
• 2007

High Velocity Oxygen Fuel (HVOF) thermal spray coating of nano size WC-Co powder (nWC-Co) has been studied as one of the most promising candidate for the possible replacement of the traditional hard plating in some area which causes environmental and health problems. nWC-Co powder was coated on Inconel 718 substrates by HVOF technique. The optimal coating process obtained from the best surface properties such as hardness and porosity is the process of oxygen flow rate (FR) 38 FMR, hydrogen FR 57 FMR and feed rate 35 g/min at spray distance 6 inch for both surface temperature $25^{\circ}C\;and\;500^{\circ}C$. In coating process a small portion of hard WC decomposes to less hard $W_2C$, W and C at the temperature higher than its decomposition temperature $1,250^{\circ}C$ resulting in hardness decrease and porosity increase. Friction coefficient increases with increasing coating surface temperature from 0.55-0.64 at $25^{\circ}C$ to 0.65-0.76 at $500^{\circ}C$ due to the increase of adhesion between coating and counter sliding surface. Hardness of nWC-Co is higher or comparable to those of other hard coatings, such as $Al_2O_3,\;Cr,\;Cr_2O_3$ and HVOF Tribaloy 400 (T400). This shows that nWC-Co is recommendable for durability improvement coating on machine components such as high speed spindle.

• Journal of Surface Science and Engineering
• /
• v.49 no.6
• /
• pp.580-586
• /
• 2016

Cr-Si-Al-N coating with different Si content were deposited by hybrid physical vapor deposition (PVD) method consisting of unbalanced magnetron (UBM) sputtering and arc ion plating (AIP). The deposition temperature was $300^{\circ}C$, and the gas ratio of $Ar/N_2$ were 9:1. The CrSi alloy and aluminum targets used for arc ion plating and sputtering process, respectively. Si content of the CrSi alloy targets were varied with 1 at%, 5 at%, and 10 at%. The phase analysis, composition and microstructural analysis performed using x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) including energy dispersive spectroscopy (EDS), respectively. All of the coatings grown with textured CrN phase (200) plane. The thickness of the Cr-Si-Al-N films were measured about $2{\mu}m$. The friction coefficient and removal rate of films were measured by a ball-on-disk test under 20N load. The friction coefficient of all samples were 0.6 ~ 0.8. Among all of the samples, the removal rate of CrSiAlN (10 at% Si) film shows the lowest values, $4.827{\times}10^{-12}mm^3/Nm$. As increasing of Si contents of the CrSiAlN coatings, the hardness and elastic modulus of CrSiAlN coatings were increased. The morphology and composition of wear track of the films was examined by scanning electron microscopy (SEM) and energy dispersive spectroscopy, respectively. The surface energy of the films were obtained by measuring of contact angle of water drop. Among all of the samples, the CrSiAlN (10 at% Si) films shows the highest value of the surface energy, 41 N/m.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2007.04a
• /
• pp.103-104
• /
• 2007

Cr-Mo-Si-N 코팅막은 AISI D2 모재와 Si 모재위에 $Ar/N_2$ 혼합기체를 사용하여 AIP (arc ion plating) 방법과 마그네트론 스퍼터링 (DC magnetron sputtering) 방법을 결합시킨 하이브리드 코팅시스템을 이용하여, 증착하였다. XRD, HRTEM, XPS 등의 분석장비를 이용하여 Cr-Mo-Si-N 코팅의 미세구조를 관찰하였다. Cr-Mo-Si-N 코팅의 경도는 Si함량이 12.1 at.%에서 약 50 GPa의 최고치를 나타냈으며, 평균 마찰계수는 Si 함량이 증가할수록 감소하였다.

• Journal of Surface Science and Engineering
• /
• v.38 no.3
• /
• pp.95-99
• /
• 2005

Quaternary Ti-Cr-Si-N coatings were synthesized onto steel substrates (SKD 11) using a hybrid method of arc ion plating (AIP) and sputtering techniques. For the Syntheses of Ti-Cr-Si-N coatings, the Ti-Cr-N coating process was performed substantially by a multi-cathodic AIP technique rising Cr and Ti targets, and Si was added by sputtering Si target during Ti-Cr-N deposition. In this work, comparative studies on microstructure and evaluation of mechanical properties between Ti-Cr-N and Ti-Cr-Si-N coatings were conducted. As the Si was incorporated into Ti-Cr-N coatings, the Ti-Cr-Si-N coatings showed largely increased hardness value of approximately 42 GPa than one of 28 GPa for Ti-Cr-N coatings. The average friction coefficient of Ti-Cr-N coatings largely decreased from 0.7 to 0.35 with increasing Si content up to 20 at. $\%$. In addition, wear behavior of Ti-Cr-N coatings against steel ball was much improved with Si addition due to the surface smoothening effect and tribe-chemical reaction.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2009.10a
• /
• pp.200-200
• /
• 2009

아크이온플래이팅 기술과 DC 마그네트론 스퍼터링 기술이 결합된 하이브리드 코팅 시스템을 이용하여 STS 304와 Si 기판에 4성분계 CrAlCxN1-x 코팅을 증착하였다. 합성된 CrAlCxN1-x 코팅은 주로 유도결합형로 f구성되었다. CrAlCxN1-x 코팅의 carbon 함량이 0.17 at.%일 때 약 34 GPa을 나타내었으며 마찰계수는 carbon 함량이 0에서 1 at.%로 증가함에 따라 0.82에서 0.38까지 크게 감소하였다. 이는 코팅 표면과 steel 볼 사이에 amorphous carbon layer가 형성되어 고체윤활제로 작용한 것으로 사료된다.

• Journal of Surface Science and Engineering
• /
• v.34 no.2
• /
• pp.125-134
• /
• 2001

($Ti_{1-x}$ $Cr_{x}$ )N coatings were deposited by an ion-plating method in a reactor with two separate metal sources, Ti and Cr. Ti was evaporated using an electron beam, while Cr evaporation was carried out by resistant heating. The Ti and Cr concentrations in the coatings were controlled by the Ti and Cr evaporation ratio. The coating hardness increased with increasing the Cr content(x) and showed a maximum value of 6,000 HK at around x=0.8. The critical load of the coatings, measured by the scratch test, was around 30 N. The wear resistance properties of the ($Ti_{1-x}$$Cr_{ x}$)N coatings were evaluated using a CSEM pin-on-disk type tribometer. A Cr-steel ball as well as a SiC ball, which had hardness values of 590 HK and 2,600 HK respectively, were used as the pin. After the wear test, the surface morphology, roughness and the concentration of the coatings were investigated, with the main focus being on the effect of wear debris and the transferred layer on the wear behavior.

• Journal of the Korean Ceramic Society
• /
• v.54 no.6
• /
• pp.511-517
• /
• 2017

With different working pressures and substrate biases, Cr-Al-N coatings were deposited by hybrid physical vapor deposition (PVD) method, consisting of unbalanced magnetron (UBM) sputtering and arc ion plating (AIP) processes. Cr and Al targets were used for the arc ion plating and the sputtering process, respectively. Phase analysis, and composition, binding energy, and microstructural analyses were performed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscopy (FESEM), respectively. Surface droplet size of Cr-Al-N coatings was found to decrease with increasing substrate bias. A decrease of the deposition rate of Cr-Al-N films was expected due to the increase of substrate bias. The coatings were grown with textured CrN phase and (111), (200), and (220) planes. X-ray diffraction data show that all Cr-Al-N coatings shifted to lower diffraction angles due to the addition of Al. The XPS results were used to determine the $Cr_2N$, CrN, and (Cr,Al)N binding energies. The compositions of the Cr-Al-N films were measured by XPS to be Cr 23.2~36.9 at%, Al 30.1~40.3 at%, and N 31.3~38.6 at%.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2004.11a
• /
• pp.75-78
• /
• 2004

Engine power cylinder parts are faced with more severe wear and friction environment. For instance, emission gas recirculation (EGR), one of the most valid technologies related to emission legislation, is known to accelerate wear of piston ring and cylinder liner. Therefore, advanced materials and surface treatments have been developed and adopted successively so that a need exists for an accurate and repeatable friction and wear bench test for various combination of piston ring and cylinder liner that more closely relates to engine test result. This paper introduces accelerative bench wear test method for piston ring and cylinder liner, presents the experimental result of friction and wear properties of piston ring surface treatments that noticed in substitution for hard chrome plating.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2015.05a
• /
• pp.125-125
• /
• 2015

Ti-Al-Cr-N thin layer was prepared on Fe-Si thin sheet by arc ion plating to improve corrosion and mechanical properties. The compositions ratios of Fe : Cr : Al : Ti : Si : N of the thin layers at $500^{\circ}C$ was 1.24 : 0.56 : 36.82 : 32.72 : 0.59 : 28.07 [wt.%], respectively. The higher arc ion plating temperature was, the higher corrosion resistance and nano-hardness were observed due to chromium content. Corrosion potential and corrosion rate in artificial sea water of the coating layer were in the range of $-39mV_{SHE}$ and $2mA/cm^2$, respectively. Passivity was not observed in the artificial sea water. Nano-hardnesses of the thin layers was increased by adding Cr from 23.6 to 25.8 [GPa]. The friction coefficients and fatigue limits of the layers were 0.388, 0.031, respectively.

• Corrosion Science and Technology
• /
• v.20 no.3
• /
• pp.112-117
• /
• 2021

Inductively coupled plasma magnetron sputtering (ICPMS) has the advantage of being able to dramatically improve coating properties by increasing the plasma ionization rate and the ion bombardment effect during deposition. Thus, this paper presents the comparative results of CrN films deposited by direct current magnetron sputtering (dcMS) and ICPMS systems. The structure, microstructure, and mechanical and corrosive properties of the CrN coatings were investigated by X-ray diffractometry, scanning electron microscopy, nanoindentation, and corrosion-resistance measurements. The as-deposited CrN films by ICPMS grew preferentially on a 200 plane compared to dcMS on a 111 plane. As a result, the films deposited by ICPMS had a very compact microstructure with high hardness. The nanoindentation hardness reached 19.8 GPa, and 13.5 GPa by dcMS. The corrosion current density of CrN film prepared by ICPMS was about 9.8 × 10^-6 mA/cm², which was 1/470 of 4.6 × 10^-3 mA/cm², the corrosion current density of CrN film prepared by dcMS.