The effect of magnetron sputter parameter on fiber coating character (original) (raw)
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Journal of Materials Science, 1994
The vigorous interfacial reactions in SiC/Ti-6AI-4V composites at elevated temperatures lead to the deterioration of the mechanical properties of the composites. TiB 2 and TiC were selected as potential protective coatings for SiC fibres in titanium-based composites. These coatings were deposited on to fibres by the chemical vapour deposition technique. Comparisons and evaluations have been made of the effectiveness of these ceramics as protective coatings for SiC fibres by incorporating the coated fibres into a Ti-6AI-4V matrix using the diffusion bonding method. Emphasis has been placed on the chemical compatibility of the candidate coating with SiC and Ti-6AI-4V by examining the interfaces of the fibre/coating/matrix using microscopic methods and chemical analysis. A stoichiometric TiB 2 coating was found to be stable with SiC and has proved an effective barrier to prevent the SiC fibre from reacting with the Ti-6AI-4V. The TiC coating showed no apparent reaction with a titanium-alloy matrix under the conditions studied, but was found to react with the SiC fibre substrate.
Vacuum, 2010
Approximately 1.5e2.5 mm thick nanocomposite coatings of TiAlCrYN were deposited using a fourcathode reactive unbalanced pulsed direct current magnetron sputtering system from the sputtering of Ti, Al, Cr, and Y targets in Ar þ N 2 plasma. The TiAlCrYN nanocomposite coatings were deposited on various substrates such as high speed steel (HSS) drill bits, mild steel and silicon. TiAlCrYN coatings with almost similar mechanical properties but with different Ti, Al, Cr and Y contents were prepared to study their thermal stability and machining performance. The structural and mechanical properties of the coatings were characterized using X-ray diffraction and nanoindentation technique, respectively. The elemental composition, bonding structure, surface morphology and cross-sectional data were studied using energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy and field-emission scanning electron microscopy, respectively. Nanoscratch tests were performed to determine the adhesive strength of the coatings. The corrosion behavior of TiAlCrYN nanocomposite coatings on mild steel substrate was studied using potentiodynamic polarization in a 3.5% NaCl solution. Micro-Raman spectroscopy was used to characterize the structural changes as a result of heating of the nanocomposite coatings in air (600e 1000 C). TiAlCrYN coatings prepared at 17 at.% Ti, 13 at.% Al, 21 at.% Cr and 1 at.% Y exhibited thermal stability as high as 900 C in air (denoted as Sample 3). For the performance evaluation, the TiAlCrYN coated HSS drill bits were tested under accelerated machining conditions. With a drill speed of 800 rpm and a feed rate of 0.08 mm/rev the TiAlCrYN coated HSS drill bits (Sample 3) averaged 657 holes, while drilling a 12 mm thick 304 stainless steel plate under dry conditions, before failure. Whereas, the uncoated drill bits failed after drilling 50 holes under the same machining conditions. Results indicated that for the HSS drill bits coated with TiAlCrYN, the tool life increased by a factor of more than 12.
TiO 2 coatings on silicon carbide and carbon fibre substrates by electrophoretic deposition
Journal of Materials Science, 2000
Electrophoretic deposition (EPD) has been used to obtain TiO 2 coatings on three dimensional (3-D) SiC fibre (Nicalon R-type) and carbon fibre substrates. Colloidal suspensions of commercially available TiO 2 nanoparticles in acetylaceton with addition of iodine were used. The EPD parameters, i.e., deposition time and voltage, were optimised for each fibre type. Strongly adhered TiO 2 deposits with high particle packing density were obtained. Scanning electron microscopy observations revealed high penetration of the titania nanoparticles into the fibre preforms. The TiO 2 deposits were sintered at 800 • C for 1 h in order to produce relatively dense and uniform TiO 2 coatings covering completely the SiC or carbon fibres. For the carbon fibre/TiO 2 system, an effort was made to produce a 3-D titania matrix composite by further infiltration of the porous fibrous preform with TiO 2 by slurry dipping and subsequent pressureless sintering. The 3-D carbon fibre reinforced TiO 2 matrix composites fabricated contained residual porosity, indicating further infiltration and densification steps are required to produce dense composites of adequate structural integrity. For SiC fibre fabrics, oxidation tests in air established the effectiveness of the TiO 2 coating as oxidation protective barrier at 1000 • C. After 120 h the increase of weight due to oxidation of coated fibres was more than twice lower than that of the uncoated fibres. TiO 2 coated SiC fibre preforms are attractive materials for manufacturing hot gas filters and as reinforcing elements for ceramic matrix composites.
Surface & Coatings Technology, 2011
Laser processing of Ti–SiC composite coating on titanium was carried out to improve wear resistance using Laser Engineered Net Shaping (LENS™) — a commercial rapid prototyping technology. During the coating process a Nd:YAG laser was used to create small liquid metal pool on the surface of Ti substrate in to which SiC powder was injected to create Ti–SiC metal matrix composite layer. The composite layers were characterized using X-ray diffraction, scanning and transmission electron microscopy equipped with fine probe chemical analysis. Laser parameters were found to have strong influence on the dissolution of SiC, leading to the formation of TiSi2, Ti5Si3 and TiC with a large amount of SiC on the surface. Detailed matrix microstructural analysis showed the formation of non-stoichiometric compounds and TiSi2 in the matrix due to non-equilibrium rapid solidification during laser processing. The average Young's modulus of the composite coatings was found to be in the range of 602 and 757 GPa. Under dry sliding conditions, a considerable increase in wear resistance was observed, i.e., 5.91 × 10− 4 mm3/Nm for the SiC reinforced coatings and 1.3 × 10−3 mm3/Nm for the Ti substrate at identical test conditions.► LENS™ was used to create Ti–SiC composite coatings on titanium. ► Laser parameters found to have measurable influence on the dissolution of SiC and resultant intermetallics. ► Microstructural analysis showed nonstoichiometric compounds due to rapid solidification. ► Considerable increase in wear resistance was observed for Ti–SiC composite coatings.
1998
The microstructures and compositions of multicomponent Ti-B-N, Ti-Si-B-N, Ti-Si-C-N, and Ti-Al-C-N films deposited by reactive magnetron sputtering using composite targets and produced by self-propagating high-temperature synthesis (SHS) have been investigated by means of transmission electron microscopy. Auger spectroscopy, and X-ray diffraction. Depending on the chemical composition of the film deposited, different single-phase crystalline films were observed. The sputtering process included sputter cleaning prior to the DC magnetron sputter deposition of Ti and TiN interlayers prior to DC magnetron sputter deposition of the multicomponent films from multicomponent targets. The films produced were characterized in terms of their microhardness, wear resistance, high-temperature oxidation conducted in air. and corrosion resistance in a solution of 5NH2SO4 at room temperature.
Journal of Applied Research and Technology, 2020
Thermogravimetric analysis (TG) is a rapid method for the determination of protecting the ability of thin film coatings in addition to oxidation kinetics. Boron carbide (B4C) reinforced Ti-6Al-4V thin films were deposited through the magnetron sputtering coating technique. The effect of 0, 2, 4, 6 and 8 Wt. % of B4C adding on microstructure, thermal behaviour and hardness of Ti-6Al-4V-B4C coatings were investigated. Thermal analysis of Ti-6Al-4V-B4C coatings with varying percentage of B4C resulted in the establishment of an exothermic peak, for the reason that reduction in the oxidation of coating. The thermal behaviour of coating was improved by B 4C addition; those coatings are recommended for practical application. It was proven that the addition of B 4C not only alters the thermal stability but also transforms the mechanism of oxidation. It was absolutely unconcealed that the Ti-6Al-4V-B4C film oxidization may be a multi-staged procedure subject on the heating rate. An occurrenc...
Interfacial reactions in a Ti6Al4V based composite: role of the TiB 2 coating
Journal of Materials Science, 1993
The characterization of TiB2/C-coated SiC fibres and their interface region in a Ti-6Al-4V based composite has been performed by using scanning electron microscopy (SEM), energy-dispersion X-rays (EDX) and Auger electron spectroscopy (AES). The features of the as-received fibre and the reactivity between fibre and matrix occurring during preparation of the composite have been studied in this paper. The interaction of the TiB2 external coating of the fibre with both the adjacent carbon layer and the titanium-based matrix is already appreciable in the as-received composite: TiB needles grow from TiB2 towards the matrix and a new layer containing C, Ti and B appears between TiB2 and C. The thicknesses of the original carbon and TiB2 fibre coatings decrease in the composite from 1000 nm to 400 and 800 nm, respectively. The TiB2 inhibits the reaction between SiC and Ti: there is no evidence of Six Tiy brittle phases.
Preparation of a titanium carbide coating on carbon fibre using a molten salt method
Carbon, 2008
A method for preparing protective titanium carbide (TiC) coatings on carbon fibres has been developed using a molten salt synthesis method. The TiC coatings were formed on the surface of carbon fibres in a reaction medium consisting of Ti powder in a mixture of molten LiCl-KCl-KF salts under an argon atmosphere at 900 and 950°C. The structure and morphology of the TiC coatings were characterized by XRD, SEM and energy dispersive X-ray (EDX) analyses. The coatings consisted of homogeneous single phase cubic TiC with thicknesses in the range of 60-800 nm. Variation of the synthesis time and reaction mixture was found to significantly affect the thickness and integrity of the TiC coating although variation of the reaction temperature had little effect. The coating thickness was closely related to the composition of the molten salts and to the molar ratio between the carbon fibre and titanium. (X. Li). C A R B O N 4 6 ( 2 0 0 8 ) 3 0 5 -3 0 9 a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c a r b o n