The Experts below are selected from a list of 150246 Experts worldwide ranked by ideXlab platform
Jun Wang - One of the best experts on this subject based on the ideXlab platform.
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the structure and properties of chromium nitride coatings deposited using dc pulsed dc and modulated pulse power magnetron sputtering
Surface & Coatings Technology, 2010Co-Authors: Jianliang Lin, John J Moore, William D Sproul, Brajendra Mishra, Jun WangAbstract:Abstract The time averaged Ion Energy distributIons and Ion fluxes of continuous dc magnetron sputtering (dcMS), middle frequency pulsed dc magnetron sputtering (PMS), and modulated pulse power (MPP) magnetron sputtering plasmas were compared during sputtering of a Cr target in an Ar/N 2 atmosphere in a closed field unbalanced magnetron sputtering system. The results showed that the dcMS plasma exhibited a low Ion Energy and Ion flux; the PMS plasma generated a moderate Ion flux of multiple High Ion Energy regIons; while the MPP plasma exhibited a significantly increased number of target Cr + and gas Ions with a low Ion Energy as compared to the dcMS and PMS plasmas. Cubic CrN coatings were deposited using these three techniques with a floating substrate bias. The structure and properties of the coatings were characterized using X-ray diffractIon, scanning electron microscopy, transmissIon electron microscopy, nanoindentatIon, microscratch and ball-on-disk wear tests. It was found that the depositIon rate of the MPP CrN depositIons was slightly lower than those of the dcMS depositIons, but Higher than in the PMS depositIons at similar average target powers. The coatings deposited in the dcMS and PMS conditIons without the aid of the substrate bias exhibited large columnar grains with clear grain boundaries. On the other hand, the interruptIon of the large columnar grain growth accompanied with the renucleatIon and growth of the grains was revealed in the MPP CrN coatings. The MPP CrN coatings exhibited a dense microstructure, fine grain size and smooth surface with High hardness (24.5 and 26 GPa), improved wear resistance (COF = 0.33 and 0.36) and adhesIon, which are the results of the low Ion Energy and High Ion flux bombardment from the MPP plasma.
M Kiuchi - One of the best experts on this subject based on the ideXlab platform.
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the formatIon of chromium nitrogen phases by nitrogen Ion implantatIon during chromium depositIon as a functIon of Ion to atom arrival ratio
Surface & Coatings Technology, 1997Co-Authors: W Ensinger, M KiuchiAbstract:Abstract Nitrogen-containing phases of chromium can be formed when chromium films deposited from the vapor phase are bombarded with an intense beam of nitrogen Ions. In the present paper, formatIon of Cr/N-phases with Ion bombardment with a comparatively High Ion Energy is discussed. Chromium was electron beam evaporated onto silicon during bombardment with 30 keV nitrogen Ions. Ion flux and atom depositIon rate were varied over a wide range. At low I/A (Ion-to-atom) arrival ratio, nitrogen-containing chromium films were formed. At High I/A-ratios, monophase CrN was obtained. In the transitIon between these phases, phase mixtures of Cr(N), Cr 2 N and CrN were formed. The results show that phase formatIon is mainly due to Ion implantatIon. By contrast to titanium nitride, reactIons with adsorbed gases do not play a role. It turns out that phase formatIon follows the equilibrium phase diagrams and is a direct functIon of the I/A-ratio. The regIons of existence of the different phases in the depositIon rate / Ion current density diagram are separated by iso-I/A-lines.
Alain Billard - One of the best experts on this subject based on the ideXlab platform.
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nanostructured hard coatings deposited by cathodic arc depositIon from concepts to applicatIons
Surface & Coatings Technology, 2011Co-Authors: Frederic Sanchette, Cedric Ducros, Thomas Schmitt, Ph. Steyer, Alain BillardAbstract:Abstract The vacuum cathodic arc depositIon (CAD) process is now widely used on an industrial scale to prepare protective hard coatings on cutting tools, metal molds, etc.… It has been recognized that High IonizatIon levels of cathodic arc discharges and High Ion Energy can provide advantages such as enhanced adhesIon required for mechanical applicatIons involving High loads. CAD allows depositIon of a wide range of hard compounds as nitrides or carbonitrides. However, CAD is also often associated macrodroplet generatIon that degrades the surface roughness of coatings. The recent trend is to develop advanced nanostructured hard coatings in order to enhance properties as hardness, toughness, and oxidatIon resistance. This paper recalls the basic aspects of both CAD technology and nanostructured thin films synthesis. DepositIon and characterizatIon of both nanocomposite and nanolayered hard coatings are described. Mechanical behaviors of nitrides can be significantly enhanced by nanolayering. The first example deals with the development of hard nanolayered nitrides coatings for cutting tools protectIon. It is clearly shown in this example that TiN/AlTiN coatings perform better than CrN/AlTiN and TiN/CrN for the same periods and the best performance is reached for the thinnest periods. It is also shown, in a second example, how silicon additIon in CrN can lead to enhancement of oxidatIon resistance associated with the nanocomposite structure. Thus, relatIonships are established between depositIon conditIons, nanostructure and mechanical behaviors or oxidatIon resistance of the coatings. This short review recalls that CAD remains a powerful and industrial technology for nanostructured hard coatings depositIon.
D H C Chua - One of the best experts on this subject based on the ideXlab platform.
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review of metal oxide films deposited by filtered cathodic vacuum arc technique
Materials Science & Engineering R-reports, 2006Co-Authors: B K Tay, Zhen Wei Zhao, D H C ChuaAbstract:Cathodic vacuum arc is a depositIon technique which exhibits unique properties, such as High Ion Energy, High IonizatIon rate and multiple Ion charge states, depending on the cathodic materials. The drawback lies in the presence of macroparticles in the plasma thus preventing this technique from being widely applied. However, in the past decade, much effort had been focused on the eliminatIon of macroparticles and the most successful approach is the use of curved magnetic filters to effectively separate the plasma from the macroparticles. The filtered cathodic vacuum arc (FCVA) refers to the combined cathodic arc with the magnetic filters. This article reports on the fundamentals related to vacuum arc, and the basic concept behind the magnetic filters and its effectiveness in the removal of macroparticles. This promising technique has been further applied to the depositIon of metal oxide thin films, which is an important group of materials. The properties of various metal oxide thin films, such as titanium oxide, aluminum oxide, zinc oxide, zirconium oxide, transparent conducting oxides and other oxides, deposited by the FCVA are reviewed in this article. In additIon, some applicatIons of the metal oxide thin films will be discussed.
Jianliang Lin - One of the best experts on this subject based on the ideXlab platform.
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the structure and properties of chromium nitride coatings deposited using dc pulsed dc and modulated pulse power magnetron sputtering
Surface & Coatings Technology, 2010Co-Authors: Jianliang Lin, John J Moore, William D Sproul, Brajendra Mishra, Jun WangAbstract:Abstract The time averaged Ion Energy distributIons and Ion fluxes of continuous dc magnetron sputtering (dcMS), middle frequency pulsed dc magnetron sputtering (PMS), and modulated pulse power (MPP) magnetron sputtering plasmas were compared during sputtering of a Cr target in an Ar/N 2 atmosphere in a closed field unbalanced magnetron sputtering system. The results showed that the dcMS plasma exhibited a low Ion Energy and Ion flux; the PMS plasma generated a moderate Ion flux of multiple High Ion Energy regIons; while the MPP plasma exhibited a significantly increased number of target Cr + and gas Ions with a low Ion Energy as compared to the dcMS and PMS plasmas. Cubic CrN coatings were deposited using these three techniques with a floating substrate bias. The structure and properties of the coatings were characterized using X-ray diffractIon, scanning electron microscopy, transmissIon electron microscopy, nanoindentatIon, microscratch and ball-on-disk wear tests. It was found that the depositIon rate of the MPP CrN depositIons was slightly lower than those of the dcMS depositIons, but Higher than in the PMS depositIons at similar average target powers. The coatings deposited in the dcMS and PMS conditIons without the aid of the substrate bias exhibited large columnar grains with clear grain boundaries. On the other hand, the interruptIon of the large columnar grain growth accompanied with the renucleatIon and growth of the grains was revealed in the MPP CrN coatings. The MPP CrN coatings exhibited a dense microstructure, fine grain size and smooth surface with High hardness (24.5 and 26 GPa), improved wear resistance (COF = 0.33 and 0.36) and adhesIon, which are the results of the low Ion Energy and High Ion flux bombardment from the MPP plasma.