J.H. Lin

The cavitation-erosion phenomenon of chromium nitride coatings deposited using cathodic arc plasma deposition on steel

Abstract The cavitation-erosion behavior of chromium nitride (CrN) coatings on AISI 4140 steel in fresh water and 3.5% NaCl solution has been investigated using an ultrasonic vibration system. The CrN coatings were deposited by cathodic arc plasma deposition (CAPD) with and without an intermediate layer of electroplated hard chrome, i.e. CrN/AISI 4140 and CrN/Cr/AISI 4140. The composition and structure of the CrN coatings have been studied using X-ray diffraction (XRD), using θ/2θ diffraction mode and Schulz reflection methods, which revealed a preferred orientation of CrN(220) for CrN/Cr/AISI 4140. The microstructure and crystalinity of the CrN coatings have been examined using cross-sectional transmission electron microscopy (XTEM). Both CrN/AISI 4140 and CrN/Cr/AISI 4140 coatings exhibited strong microcolumnar structures, however, the shape and grain size of the coatings were approximately the same. In addition to the microstructural investigations, cavitation-erosion tests were conducted under free corrosion conditions in fresh water and in chloride containing water. Subsequent electrochemical evaluation was made to elucidate the mechanism of cavitation-erosion. The resulting mechanical damage has been assessed using weight loss measurements and scanning electron microscopy (SEM) observations. Notwithstanding a significant improvement in the cavitation resistance of the coated specimens in fresh water and NaCl solution, the damage resulting from the cavitation-erosion in the 3.5% NaCl solution exhibited a higher weight loss than those in freshwater.

Corrosion and tribological studies of chromium nitride coated on steel with an interlayer of electroplated chromium

Abstract The electrochemical and tribological behavior of CrN coatings on steel are investigated. A single layer of chromium nitride coating is compared with a double layer of the coating (CrN/Cr/steel) in which the interlayer chromium was produced by electroplating with the aim of improving the corrosion and tribological performance of the steel. The CrN coatings are deposited by using a reactive cathodic arc plasma deposition technology in an industrial scale, while the interlayer of chromium produced by electroplating. The coating assemblies have been compared in terms of hardness, wear and corrosion resistance. The composition and structure of the chromium nitride have been studied by X-ray diffraction (XRD), using both θ/2θ diffraction mode and the glancing-incidence X-ray diffraction mode. The surface morphology was examined by using SEM. The improvement in wear and corrosion resistance after cathodic arc plasma deposition with and without a hard chrome as an interlayer are discussed in considering the microstructure changes.

The effect of preferred orientation on the mechanical properties of chromium nitride coatings deposited on SKD11 by unbalanced magnetron sputtering

Abstract Chromium nitride coatings exhibit good mechanical, corrosion and oxidation protection properties and can have various orientations. Preferred orientations of CrN(200) and Cr 2 N(111) were successfully deposited on SKD11 by unbalanced magnetron sputtering. To compare with different orientations, several mechanical properties of deposited films were studied, e.g. hardness, adhesion and wear behavior. The structural characterization and surface morphology were investigated using atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The chemical composition and stoichiometry were determined using X-ray photoelectron spectroscopy (XPS). The cross-section morphology of CrN coating is a columnar structure and Cr 2 N is a denser structure. Of the two orientations CrN(200) and Cr 2 N(111), CrN(200) possesses stronger adhesion and lower hardness.

The effect of Cr interlayer on the microstructure of CrN coatings on steel

The effect of electroplated Cr interlayer on the microstructure of CrN coatings on AISI 4140 steel were investigated. Two types of CrN-coated specimens by cathodic arc plasmas were prepared with and without an intermediate layer deposited by electroplated hard chrome (CrN/steel and CrN/Cr/steel). The microstructure and crystallinity of chromium nitride have been investigated using X-ray diffraction (XRD), cross-sectional transmission electron microscopy (XTEM) and selected area diffraction (SAD). Both CrN/steel and CrN/Cr/steel coating assemblies exhibit microcolumnar morphologies. However, it is noted that the columnar structure of CrN coating directly on steel is less evident, strong, and upward in comparison with that deposited on electroplated chromium layer. For CrN/Cr/steel assembly, the preferred orientations of CrN(220) and Cr(200) are observed.

Optical properties of amorphous carbon nitride synthesized on si by ECR-CVD

Amorphous carbon nitride films have been synthesized on silicon using an electron cyclotron resonance chemical vapor deposition (ECR-CVD) system combined with a negative dc bias and a mixture of C2H2, N2 and Ar as precursors. The refractive index and extinction coefficient of the amorphous carbon nitride films are characterized by N&K analyzer. The optical band gap energy derived by Taucs equation decays with increasing substrate negative dc bias, ECR-power, flow rate ratio of N2/C2H2, nitrogen to carbon ratio (N/C) determined by X-ray photoelectron spectroscopy (XPS) and with the increase of graphitic content was examined by Raman spectroscopy.

Effect of metal vapor vacuum arc Cr-implanted interlayers on the microstructure of CrN film on silicon

c Abstract The effect of metal vapor vacuum arc (MEVVA) Cr-implanted interlayers on the microstructure of CrN films on the silicon wafer was investigated.Two types of the CrN-coated specimens (CrNySi and CrNyCrySi) by cathodic arc plasma deposition were prepared with and without a MEVVA Cr-implanted interlayer.The diffraction patterns of the coated specimens revealed the presence of CrN, and the (220) preferred orientation for both CrNySi and CrNyCrNySi.The CrN coating thicknesses for CrN y Si and for CrNyCrySi were 0.3 mm and 1.3 mm, respectively.Secondary ion mass spectrometry proved the high quality of the films on silicon substrates.Transmission electron microscopy micrographs and selective area diffractions revealed the presence of a large number of nano-scale Cr resulting from the interlayer of MEVVA Cr with a background of single crystal silicon spots. Furthermore, in situ stress measurement demonstrated that the presence of a Cr interlayer between CrN and Si could drastically reduce the residual stress in the CrNyCrySi assembly. 2003 Elsevier Science B.V. All rights reserved.

The effect of MEVVA implanted Cr on the corrosion resistance of CrN coated low alloy steel by cathodic arc plasma deposition

Abstract Metal vapor vacuum arc (MEVVA) source implantation is a novel and profitable surface modification process. Cathodic arc plasma deposition of CrN coating has been applied on an industrial scale to improve the corrosion resistance of AISI 4140 steel. The effect of the Cr implanted by MEVVA (Cr/steel) on the corrosion behavior of CrN/steel through the surface modification was investigated. Both AISI 4140 steel and its coated assemblies of Cr/steel, CrN/steel and CrN/Cr/steel were evaluated in aerated 0.1 N HCl solution. The composition and structure of the MEVVA implanted Cr and cathodic arc plasma deposited CrN on steel were studied by X-ray diffraction and secondary ion mass spectrometer. The polarization resistance ( R p ) of all samples was measured and compared with d.c. polarization resistance and electrochemical impedance spectroscopy. The microstructure of corroded samples was also examined by scanning electronic microscopy and electron probe X-ray microanalyser. The results indicated that the corrosion resistance of CrN coated steel was significantly enhanced by the MEVVA implanted Cr in CrN/Cr/steel.

Optical and structural properties of the amorphous carbon nitride by ECR-plasma

Abstract Amorphous carbon nitride films have been synthesized on silicon using an electron-cyclotron-resonance chemical vapor deposition (ECR-CVD) system combined with a negative d.c. bias in a mixture of C2H2, N2 and Ar as precursors. The refractive index and extinction coefficient of the amorphous carbon nitride films were determined by the N&K analyzer. The optical band gap was derived according to Tauc’s equation. The optical constants (n, k) and structural properties of the amorphous carbon nitride films were studied as a function of the substrate negative d.c. bias, ECR-power, flow rate ratio (N2/C2H2), nitrogen to carbon ratio (N/C) by X-ray photoelectron spectroscopy (XPS), degree of graphitization (sp2 content) by Raman spectroscopy and the radicals’ density in the ECR-plasma by the optical emission spectrometer (OES). Through the relationship between OES measurements and the Raman studies with optical band gap, the result indicated that a progressive graphitization of the film occurs with increasing N2/C2H2, N/C, ECR-power and substrate negative d.c. bias. The optical constants (n, k) of the a-C:N films prove an unambiguous dependence of the optical band gap on the substrate negative d.c. bias for the ECR-power.

Palladium seeding on the tantalum-insulated silicon oxide film by plasma immersion ion implantation for the growth of electroless copper

Abstract The major aim of this study was to combine the techniques of using plasma immersion ion implantation (PIII) and electroless plating to implant Pd onto a Ta diffusion barrier layer as catalyst for the electroless Cu plating in order to accomplish the ULSI interconnection metallization. In our study, it has been demonstrated that the accelerating Pd + ions by 2 kV pulsed negative bias voltages produce an amorphous Pd layer on β-Ta. The outermost Pd forms an oxide to the chemisorption of oxygen on Pd in air, while innermost Pd does not react with β-Ta, but instead remains in the form of metallic Pd. The Pd doses in the range of 5.7×10 14 and 8.6×10 14 cm −2 invokes an excellent catalytic effect on the electroless Cu plating. This results in an extraordinary ability for filling the submicron holes for gaining high quality electroless plated Cu interconnects, and thus qualifies for the traditional wet activation by SnCl 2 and PdCl 2 solutions.

The effect of argon on the electron field emission properties of α-C:N thin films

Abstract Amorphous carbon nitride (α-C:N) thin films were synthesized on silicon as electron emitters by the electron cyclotron resonance chemical vapor deposition (ECR-CVD) system in which a negative dc bias was applied to the graphite substrate holder and a mixture of C2H2 and N2 was used as precursors. The addition of Ar combined with the application of a negative dc bias can increase nitrogen content (N/C) measured by X-ray photoelectron spectroscopy (XPS), eliminate the dangling bonds in the film determined by Fourier transform infrared (FTIR) spectroscopy, decrease the film thickness measured by field emission scanning electron microscope (FE-SEM), increase the film roughness measured by atomic force microscope (AFM) and raise the graphitic content examined by Raman spectroscopy. The result shows that the onset emission field of α-C:N with Ar addition to the precursors can be as low as 4.5 V μm−1 compared with 9.5 V μm−1 of the film without the addition of Ar.