Papers by Keyword: TiN Coating

Abstract: Total hip prosthesis (THP) is the most success of the 20^th century in orthopaedic biomedical engineering. However due to difficult conditions within the human body its durability is generally limited to 15-16 years. THP is a bio-tribosystem, on which many mechanical, thermal, chemical and biological factors act. This paper presents the results of an analysis regarding the topography and tribological parameters of femoral heads structures before and after TiN coating. We report on the synthesis of TiN thin films on steel substrates by pulsed laser deposition (PLD) method for improving the mechanical characteristics of the structures. Adhesion resistance of the coating on the sub-layer was evaluated by scratching tests accompanied by Optical Microscopy (OM), Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). As a principal result, this work points out that TiN protective coatings deposited by PLD technique with the maximum number of pulses can represent an alternative technology to ensure adhesion and scratch resistance of TiN coatings on femoral heads.

Abstract: TiN coating as an interlayer in Ti/TiN/PbO₂ electrode and PbO₂ catalytic layer were fabricated by reactive plasma spray and electro-deposition, respectively. It is shown that because of good effect of the TiN interlayer, the Ti/TiN/PbO₂ electrode exhibits a higher oxygen evolution potential and much improved accelerated life compared with the Ti/PbO₂ electrode.

Abstract: In this paper, TiN coating as an interlayer was fabricated on Ti substrate by reactive plasma spray. Ti/TiN/Sb-SnO2 electrodes were prepared by SOL-GEL method and the influence of the TiN interlayer on the structure, oxygen evolution potential and service life of the electrodes was studied. It was shown that the surface of the Ti/TiN/Sb-SnO2 electrodes is more homogeneous and the oxygen evolution potential and accelerated life are both higher than those of the Ti/Sb-SnO2 electrodes.

Abstract: This paper wants to find one of the solutions to control the coated surface properties. The surface layers control is not easy. We have a very simple test like hardness test to get some important information of the surface, but in case of the coatings we need to do this test very circumspectly. The hardness test results always depend on the surface roughness, the coating microstructure, the layer thickness and the type and load of the hardness test. The chose method was the nanohardness test which gave the penetration depth us function of the very small load.

Abstract: Titanium Nitride (TiN) thin film was deposited on β-type Ti-15Mo-3Nb-3Al-0.2Si alloy plates by RF magnetron sputtering method. The effect of nitrogen flow rate on the structure and properties of the TiN thin films were studied. The preferred orientation of TiN thin films changed from (111) to (200) as the nitrogen flow rate increased due to the effect of the kinetic energy of the bombarding particles. The coating thickness was found to decrease with increasing nitrogen concentration, which also favors (200) orientation with increasing nitrogen flow rate. With increase of nitrogen flow, the morphology of the TiN thin films films changed from characteristic pyramidal shaped grains to columnar-shaped grains. The roughness analysis of the coating shows that the average roughness of the coating decreased with increasing nitrogen flow rate. The increase of hardness with increasing nitrogen flow rate is attributed to the decrease in grain size.

Abstract: In this paper TiN coating was prepared on stainless steel substrate using arc ion plating technique. The coating samples’ phases, surface morphology, micro-determination chemical composition, loss factor and damping ratio were tested. The phases of TiN coating were determined by X-ray diffraction (XRD) technique. The surface morphology and chemical composition of the TiN coating were analyzed by scanning electron microscope (SEM) and Energy Dispersive Spectrometer (EDS), respectively. The damping performance of the samples was measured by hammering activation according half power bandwidth method. The loss factor or damping ratio of samples were obtained according frequency response curve. The results showed that damping performance of samples was considerably improved by TiN coatings.

Abstract: TiN protective coating was prepared on NdFeB by DC magnetron sputtering to improve the corrosion resistance and scratch resistance of the magnetic. During deposition, the nitrogen/argon mixture gas was introduced into the chamber with the nitrogen partial pressure at 20 % and 10 % and the bias of 200 V was applied to subtract, respectively. At a lower nitrogen partial pressure of 10%, TiN coating was composed of many particles with an irregular shape. With increasing the nitrogen pressure to 20%, composing particles become small and show as the regular trihedron shape. All TiN coatings have a cubic structure. The bias makes the depositing TiN coating denser and preferential growth become no obvious. By the nitrogen partial pressure of 20 % and bias of 200 V, the dense TiN coating has best corrosion resistance and excellent wear resistance.

Abstract: The 2μm thick TiN coatings were deposited by arc ion plating on YW2 cemented carbide substrate, and the system of TiN/YW2 was treated with cryogenic treatment at -196°C for 30 hours. The change of the Rockwell indentation's morphology of the system (the form and density of cracks, the spalling state of the coating)before and after the treatment were investigated by means of the Rockwell hardness tester. With metallurgical microscope and SEM, the change of the microstructure of the substrate and its influence on the fracture toughness of the system were investigated. The results show that after the treatment, the density of the radiated cracks in the substrate were obviously reduced, but the main cracks hadn’t any change, the spalling of the TiN coating along the indentation was lightened. After the cryogenic treatment the dispersed granular γ phase obviously decreased or even disappeared, the pores became smaller and the microstructure of YW2 became more compact，and the microcracks were merged during the cryogenic treatment. These are beneficial to improve the fracture toughness of YW2 substrate and the coating/substrate system.

Abstract: In this paper TiN coating as an interlayer was fabricated on Q235 steel substrate by reactive plasma spray method and its microstructure and influences on the performance of the Fe/TiN/PO₂ electrode were investigated. It is shown that the TiN coating has a rough surface and layered cross-section structure. The coating consists of main TiN phase and a small quantity of Ti oxides. After heat-treated below 550°C the TiN coating is greatly densified due to the increase of Ti oxides, and however the electric resistance of the Fe/TiN samples is still lower than that of the Ti substrate. For the Fe/TiN/PbO₂ electrode a rougher surface and more micropores were observed in the active PbO₂ coating than on the surface of the Ti/PbO₂ electrode. Due to the presence of the TiN interlayer the Fe/TiN/PbO₂ electrode shows an accelerated life of 180h under the test condition, which is much longer than 28min of the Ti/PbO₂ electrode.

Abstract: In recent years, plasma-assisted chemical vapor deposition (PACVD) has been introduced as a suitable technique to deposit hard coatings on to tools of complex geometries. This study focuses on the influence of process parameters during plasma nitriding and TiN coatings, such as duty cycle, treatment time and temperature parameters on the properties of nanostructured binary layers. To improve performance and the quality of the samples, a duplex process combining a plasma nitriding (PN) pre-treatment and a plasma-assisted chemical vapour deposition (PACVD) was applied on the steel surface. A mixture of H2, N2, Ar and TiCl4 was used to deposit a thin film of TiN on H11 steel. The microstructural, mechanical and tribological properties of the coating were investigated using X-Ray diffraction, scanning electron microscopy, atomic force microscopy combined with nanoindentation and pin-on-disc measurements. The results indicate that the small grain size was obtained at low duty cycle (33%) and increased with increasing of the duty cycle to 60 %. Calculated roughness of surface for duty cycle 50 % was 72 nm.