Papers by Keyword: Titanium Nitride

Abstract: A new and simple method is proposed to fabricate fully dense and single fcc phase of substoichiometric titanium nitride (TiNx). Powders mixture composed of titanium hydride (TiH2) and titanium nitride (TiN) was consolidated by using pulsed electric current sintering. All samples showed relative density values higher than 98% with larger grain size at lower nitrogen concentration. Lattice parameter increased linearly with increasing [N]/[Ti] ratio. In addition, TiNx with substoichiometric compositions was more easily densified than stoichiometric TiN. The addition of TiH2 improves the sinterability of the samples preserving the fcc phase characteristic of TiN.

Abstract: An approach by mixing laser and plasma to conduct nitriding treatment on the surface of titanium can improve the surface hardness, and the hardness of the surface in different nitriding depth is different. We wrote a program, by which we carried out Monte Carlo simulation calculation, in accordance with the model description by C language. In the calculation process, by changing laser power intensity, scanning velocity, nitrogen ion energy and angle of incidence, we got the distribution of nitrogen ions in iron under different conditions, and thus formed computer simulation diagram of titanium nitride process.

Abstract: In order to improve the photocatalytic efficiency, the N doped anodic titania film for photocatalyst was synthesized by anodic oxidation of TiN layer in sulfuric electrolyte, and the photocatalytic properties of N doped TiO₂ layer were investigated. During the oxidation process of the TiN layer, nitrogen was doped into the anodic titania film due to the change of the titanium nitride layer to TiO₂ layer film. In the evaluation of dye degradation, N doped titania catalyst shows much higher efficiency than non-doped titania film.

Abstract: In this work, new information on surface morphology, phase and local structure of titanium nitride (TiN) nanocrystal thin films grown with different nitrogen gas concentration by direct current (DC) magnetron sputtering is provided. Surface morphology of the thin films was studied by field emission scanning electron microscope (FE-SEM). Phase and local structure of the TiN nanocrystals were determined by X-ray diffraction spectroscopy (XRD) and X-ray absorption fine structure (XAFS). The TiN nanocrystals were prepared on silicon substrates. N₂/Ar gases were used as reactive gases for sputtering Ti target. The amount of these two reactive gases was varied at different ratios (N₂/Ar), i.e. 100:0, 75:25, 50:50 and 25:75 respectively. Our results suggested that sputtering Ti target with high N2/Ar gas ra_{Subscript text}tio (higher than 75%) provides good TiN layer while sputtering with low N₂/Ar gas ratio (lower than 25%) gives Ti layer instead of TiN. In addition, sputtering with 50% N₂/Ar gas ratio gives a multiphase system between TiN and Ti. Local structure parameters of these nanocrystal thin films are reported.

Abstract: The effect of titanium nitride addition on the microstructure, porosity and mechanical properties of Ti(C, N)-based cermets were investigated in this work. Results show that cermets have typical core-rim microstructure, the grain size of hard phase refines and the porosity increases with the addition of titanium nitride content. The transverse rupture strength reaches maximum at about 15wt.% titanium nitride. The hardness declines with the incremental titanium nitride content.

Abstract: To improve surface hardness of dental implant made of pure titanium (Ti), titanium nitride (TiN) coating was introduced. However, studies revealed that TiN only showed osseointegration similar or inferior to that of Ti. Therefore it is necessary to improve the biocompatibility of TiN for dental implant coating. In the present study, TiN coating was prepared on pure Ti substrates and hydrothermal treatment was conducted to modify its surface properties. It was found that, TiN surface was partially oxidized after treatment and calcium (Ca) was successfully combined onto its surface. Surface morphology, roughness and hardness were not affected after treatments below 140°C and wettability was obviously improved.

Abstract: Titanium nitride (TiN) is a hard material, often used as coating to improve the wear properties of titanium alloys in machining, implant and aerospace applications. Electron Beam Physical Vapor Deposition (EB-PVD) is a technique which a target anode is bombarded with an electron beam given off by a charged tungsten filament under high vacuum, producing a thin film in a substrate. In this work, results of TiN films depositions on Ti-13Nb-13Zr substrates by EB-PVD are studied. Titanium targets were obtained by a purified ingot and the substrates produced by powder metallurgy. Sintered samples of Ti-13Nb-13Zr and TiN layers were characterized by X-ray diffraction, scanning electron microscopy, Vickers microhardness and wear tests. The TiN films presented high hardness values, continuity and large thickness. The coatings improved the tribological properties of the substrate due to high adhesion and low wear rate.

Abstract: In this paper, the corrosion properties of AISI 301 stainless steel (SS) coated with 1-micron thick titanium nitride (TiN) hard coatings is investigated. TiN was deposited by pulsed magnetron sputtering resulting in different microstructure ranging from agglomerated crystallites to homogeneous film. Microstructure of the coatings was characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). Resistance to general and localized corrosion was evaluated by potentiodynamic polarization in NaCl 1% solution. It has been shown that the existence of columnar structure in the TiN film reduces significantly the resistance to localized corrosion due to infiltration of liquid through paths at the grain boundaries. Furthermore, by comparing the polarization curves of TiN coatings deposited on SS and glass, it was shown that the electrochemical response of TiN-coated SS at low potentials is the result of electrochemical activity at the coating/electrolyte interface whereas at high potentials the increase in the current is the result of pits generated at the substrate/electrolyte interface at defects/pores within the coating.

Abstract: This research is aimed to synthesize titanium nitride (TiN) thin films on stainless steel 304 using metal vacuum arc surface coating technique. A titanium rod is used as cathode. Plasma is generated by applying the arc pulse voltage of 450 V between the electrodes in N2 atmosphere. The pressure of N2 is varied from 10-5 to 10-3 torr when compare with uncoated-stainless steel 304. The bias voltage for substrate is -1 kV. Then the properties of the films are investigated. Firstly, microstructures of TiN thin films are indentified by X-ray diffraction method (XRD) and the cross-section scanning electron microscopy (SEM) is used to measure the thickness. Secondly, the corrosion resistance is examined by electrochemical test in 1 M H2SO4 solution at 25°C. The electrical resistivity is analyzed by interfacial contact resistance measurements.

Abstract: Using anatase and flake graphite as starting material, titanium nitride was prepared by carbothermal reduction nitriding method under nitrogen gas pressure 0.05 MPa and flow rate 0.3 m³/h, at 1673K(1400°C).The proportion of n_c and n_TiO2 are 1.5:1,2.0:1,2.2:1 and 2.5:1. The phase composition and microstructure of titanium nitride were investigated by XRD and SEM. The results show that: titanium nitride can be prepared with anatase and flake graphite by carbothermal reduction nitriding method. When the proportion of n_c and n_TiO2 is 2.2:1 the quantity of titanium nitride is the most. Because the reacting temperature is low and the contact area of the anatase and flake graphite is small the large grain size and uniform grain size titanium nitride can not be obtained.