Wear Resistance Of Titanium Research Articles

Hard and wear-resistant titanium nitride films for ceramic cutting tools by pulsed high energy density plasma

High-quality and wear-resistant titanium nitride films were deposited onto silicon nitride ceramic cutting tools by pulsed high energy density plasma technique at ambient temperature. The adhesive strength of TiN film to the ceramic substrate has been satisfactory with very high critical load up to more than 80 mN measured by nanoscratch tester. The TiN films possess very high values of nanohardness and Young's modulus, which are near to 28 and 350 GPa, respectively. The wear resistance and edge life of the ceramic tools were increased greatly because of the deposition of titanium nitride coatings. The cutting performance of the silicon nitride ceramic tools with such TiN films could be optimized by varying the deposition conditions, including the (shot) number of pulsed plasma and the discharge voltage between the inner and outer electrodes, etc.

Characterisation of the palladium-modified thermal oxidation-treated titanium

A novel and cost-effective surface modification technique, namely palladium-modified thermal oxidation (PTO), has recently been developed, which can dramatically enhance corrosion and wear resistance of titanium. The present paper reports characterisation of the surface engineered (thermal oxidation and palladium-modified thermal oxidation) titanium, using X-ray diffraction (XRD), glow discharge spectrometry (GDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS). The surface case of the oxidised materials comprises a surface rutile TiO 2 layer and an underlying diffusion zone (Ti-O solid solution). It has been found that the palladium treatment can decrease the grain size of the surface oxide, improve the oxide layer adherence, and delay the stratification and spallation of the surface oxide.

Structural Wear-Resistant Sintered Materials Based on Titanium

A principle is proposed for increasing the wear resistance of structural titanium materials by addition (together with a moderate number of hard inclusions) of alloying elements which, without decreasing the strength and ductility of titanium, increase the wear resistance of the material thanks to the formation of oxide films during friction that prevent seizing of the contacting surfaces. Requirements for the hard inclusions and alloying additions were defined, the basic of which is a high affinity of the alloying elements for oxygen. Grades of wear-resistant structural titanium materials were created and recommended for use in the production of components operating in friction units at room temperature (IT20, IT15V) and at 250-550°C (IT16M). The mechanical properties and operating conditions (sliding rate, pressure, temperature, counterbody material, atmosphere) of the sintered titanium materials were investigated.

Air treatment of pure titanium by furnace and glow-discharge processes

The high oxygen affinity of titanium can be used to improve the surface hardness and wear resistance of titanium and titanium alloy components by means of thermal treatments. In the present paper a comparison of the effects of glow-discharge and furnace processes, carried out using air as treatment atmosphere, on the microstructure and mechanical properties of commercially pure titanium samples is reported. Both treatment types, performed at 973 and 1173 K for 0.5, 2 and 4 h, produce modified surface layers: the outer layer (compound layer) consists essentially of TiO 2 and small amounts of TiN x O y , while the inner layer (diffusion layer) consists of α-Ti crystals rich in interstitial atoms. The plasma treatment is shown to be more efficient in hardening titanium surface layers than the furnace process: by using the same treatment temperature and time, plasma treated samples have a thicker hardened layer, with higher hardness values than the furnace treated ones. A crystallographic characterisation of the α-Ti solid solution has also been performed and the a, c lattice parameters have been evaluated. Plasma treated samples show larger lattice parameters and c/ a values than the furnace treated samples, suggesting a higher concentration of interstitial atoms due to the plasma treatment.

Fretting wear and cracking in sintered metal matrix composites

A methodology, involving fretting tests, to develop wear and crack resistant materials for tribological applications for automotive valve train parts (e.g. cams, tappets) has been recently reported for high speed steels. Modifications to one of these sintered steels, M3 Class 2, were effected by additions, singly and in combination, of 5 wt.% of wear resistant titanium carbide and of solid lubricant manganese sulphide. In our fretting tests alternate displacements were imposed between the test material (plane) and a chromium steel or alumina ball. Running conditions fretting and material response fretting maps were constructed for the four materials. Two types of fretting damage were detected and analysed: cracking or particle detachment and wear through the tribologicaly transformed structure (TTS). Crack initiation, associated with porosity and interfaces, was detected when the maximum tensile stress in the contact reached 1.2 GPa. Cracking analyses were also carried out using static and fatigue mechanical tests and replica scanning electron microscopy. Crack growth and propagation were influenced by details of the microstructure, e.g. TiC was observed to arrest crack growth, whereas MnS made it easier. Wear analysis included the determination after each test of the wear volume, which could be related to the coefficient of friction and the cumulative dissipation energy during the fretting test.

Microstructural features of wear-resistant titanium nitride coatings deposited by different methods

Titanium nitride, TiN, is used as wear protective and decorative coatings in various applications. These coatings are deposited by standard industrial methods such as chemical and physical vapor deposition (CVD and PVD, respectively), including magnetron sputtering or its modifications [e.g. the plasma-enhanced magnetron sputtered deposition (PMD) method]. The coatings have different microstructures (size and morphology of grains, orientation, dislocation structure, residual stress, etc.) depending on the method used and the deposition regime. The results of comparative transmission electron microscopy (TEM) investigations of the microstructure of thin TiN coatings deposited by classical CVD and PVD, including PMD, are presented. The microstructure was studied in sections perpendicular and parallel to the coating surface. The grain size was estimated from dark field images and the residual stress was determined using the bend extinction contours in the bright field images. It was found that the coatings deposited by PVD and CVD methods have different grain microstructures and residual stresses. The CVD coatings have an equiaxed microcrystalline structure with very low levels of the local residual stress. The mean grain size is 0.4–0.6 μm. The PVD coatings (Balzers and Metaplas) have a non-equilibrium submicron grain structure with a high level of the local residual stress equal to 0.06–0.08 E, where E is Young's modulus, and a mean grain size of 0.1–0.2 μm in the section parallel to the coating surface. The PMD coating structure is highly non-equilibrium nanocrystalline, with a very high level of residual stress equal to 0.13 E and a much finer grain size of 0.06 μm.

Integration of wear-resistant titanium carbide coatings into MEMS fabrication processes

Microelectromechanical systems (MEMS) are a key technology for small-scale satellites, integrated sensors, and intelligent control systems. However, a major limitation for Si-based systems involving tribological components is their inability to withstand prolonged sliding surface contact that results in high wear and causes them to fail within minutes of operation. Our aim is to protect the Si surfaces with wear-resistant coatings. Due to practical limitations of coating fully released MEMS structures, we have addressed the integration of the coating into the MEMS processing sequence. This paper describes the direct integration of a pulsed-laser-deposited wear-resistant titanium carbide (TiC) coating into the Si MEMS fabrication process. The in situ deposited TiC layer also provides an ideal substrate to the various possible lubrication schemes proposed for moving MEMS.

Tribological Evaluation of Diamond Coating on Pure Titanium in Comparison with Plasma Nitrided Titanium and Uncoated Titanium

Titanium alloys are characterized by poor tribological properties, and the traditional use of titanium alloys has been restricted to nontribological applications. The deposition of a well adherent diamond coating is a promising way to solve this problem. In this study, the tribological properties of diamond-coated titanium were studied using a pin-on-disk tribometer, and the results were compared with those of pure titanium and plasma nitrided titanium. The tribological behavior of pure titanium was characterized by high coefficient of friction and rapid wear of materials. Plasma nitriding improved the wear resistance only under low normal load; however, this hardened layer was not efficient in improving the wear resistance and the friction properties under high normal load. Diamond coating on pure titanium improved the wear resistance of titanium significantly. Surface profilometry measurement indicated that little or no wear of the diamond coating occurred under the test conditions loads. The roughness of the diamond coating was critical because it controlled the amount of abrasive damage on the counterface. Reducing the surface roughness by polishing led to the reductions in both the friction and wear of the counterface.

Pulsed Electrode Surfacing of Steel with TiC Coating: Microstructure and Wear Properties

In the present study, pulse electrode surfacing (PES) technique was employed to deposit ultrahard and wear-resistant titanium carbide (TiC) coating on AISI 1018 steel. Wear resistance of the coated surface increased significantly. An attempt was made to correlate the thermodynamic predictions and experimental observations. A composite coating that is adherent, crack free, and defect free in nature was obtained, with TiC being the most stable phase. Islands of TiC of various shapes and sizes are present in the Fe-rich matrix in the coating. Microhardness measurements suggest high hardness values in the coating region. Tribological properties such as wear resistance and coefficient of friction were also measured. The coefficient of friction data do not show significant fluctuations. Wear and friction phenomena in such a coating have been explained on the basis of a model based on composite/multiphase material.

Investigation of the Deposition and Integration of Hard Coatings for Moving MEMS Applications

AbstractMicroelectromechanical systems (MEMS) have been identified as a key technology for small-scale satellites, integrated sensors, and intelligent control systems. Using methods developed for highly integrated electronics, mechanical components are co-fabricated on planar wafers and subsequently etched free for mechanical movements in three dimensions. A major design limitation for these systems is their inability to withstand prolonged sliding surface contact. The fundamental problem is that the surface properties of silicon and poly-silicon, two of the most widely used materials for MEMS, are highly unsuitable for moving MEMS devices, resulting in high wear during operation. This work explores the feasibility and benefits of depositing thin, wear-resistant, low-friction coatings on silicon or poly-silicon. To achieve this goal, three-dimensional test silicon microstructures have been fabricated. Wear-resistant titanium carbide (TiC) coatings are deposited on these test structures using a novel non-line-of-sight pulsed laser deposition (PLD) process. In parallel, this paper addresses the integration of the TiC coating directly into the MEMS fabrication processes and its compatibility with standard silicon processing.

Coefficient of friction under dry and lubricated conditions of a fracture and wear resistant P/M titanium-graphite composite for biomedical applications

Recent studies have shown that aseptic loosening of orthopaedic implants is a biomechanical phenomenon initiated mechanically and propelled by biological responses to the presence of wear debris released from the biomaterial. A triphasic composite, fabricated by the heterogeneous sintering of titanium and graphite powders was developed to address the fracture and wear performance of titanium. The composite is designed to smear graphite on both articulating surfaces and hence reduced wear and maintained a low friction tribosystem with fracture properties better than conventional bioceramics. The composite is made up of ductile titanium and a colony of hard, wear resistant titanium carbide produced by the controlled sintering of titanium and graphite particles. Free graphite is present in varying quantities depending upon compaction pressure and initial graphite composition. Initial graphite content composites of 4% and 8% were made with different compaction pressure to give a range of porosities from 10% to 45%. The coefficient of frictional was measured on a pin-on-disc (hardened steel) configuration. Under dry state, the coefficient of friction was observed to reduce with increasing porosity. Graphite smearing and the entrapment of debris by the pores contributed to the reduction of the wear components which in turn reduced the coefficient of friction. Under lubricated conditions, the sintered titanium and its composites were observed to be independent of porosity and pore size. The frictional behaviour of the titanium-8% graphite composites showed first, a titanium carbide dominated-wear stage and the second, a free graphite smearing stage. The results proved the concept that the coefficient of friction of titanium-graphite composites approaches that between graphite-graphite surfaces after the running-in period. This proof of concept is the first realisation of a biomaterial that could reduce the coefficient of friction on both articulating surfaces, a step closer to the development of fracture and wear resistant biomaterials that also protects the other counter surface.

Influence of the PACVD process parameters on the properties of titanium carbide thin films

Wear-resistant titanium carbide (TiC) coatings were deposited by plasma-assisted chemical vapour deposition on high-speed steel. The influence of the partial pressure ratio of methane and titanium tetrachloride ( p CH 4 / p TiCl 4 ), the plasma voltage and the pulse/pause ratio on the composition and properties of the TiC coatings have been investigated. Small partial pressure ratios p CH 4 / p TiCl 4 up to about 15 result in nearly stoichiometric TiC coatings at high plasma voltage. Higher partial pressure ratios cause excess carbon, which is bound as C-C or C-H. An increasing carbon content was found also for both increasing plasma voltage and increasing pulse/pause ratio. The layer hardness was found to decrease with increasing excess carbon. No significant influence of composition on the friction coefficient has been detected.

炭化物分散耐摩耗チタン合金の開発

炭化物分散耐摩耗チタン合金の開発

Laser boriding of titanium alloys

The low wear resistance of titanium and its alloys limits their use in machine building. Methods for the surface hardening of titanium and its alloys, which tend to enhance their antifriction properties. are of significant interest in this respect. Laser alloying is one of the most promising methods of improving the strength of the surface. In this study. we investigated the characteristic features of the structural formation of the surface layers of titanium alloy VT3-1 during laser alloying from dross coatings containing a mixture of boron carbide B4C and chromium.

The effects of chlorine content on the properties of titanium carbonitride thin film deposited by plasma assisted chemical vapor deposition

Wear resistant titanium carbonitride (TiCxNy) films were deposited onto high speed steel (AISI M2) by plasma assisted chemical vapor deposition using the gaseous mixture of TiCl4, CH4, N2, H2, and Ar. The effects of deposition conditions on the deposition rate and residual chlorine content were investigated. The influences of the chlorine on the crystallinity, microstructure, and mechanical properties of coatings were also studied. It was found that the residual chlorine content in the films greatly varied with the deposition conditions. Subsequently the crystallinity of the TiCxNy films deteriorated with the increase in the chlorine content. The microhardness and adhesion strength also decreased with the chlorine content. However, in spite of the low residual chlorine content, TiCxNy film deposited at high radio-frequency power shows inferior mechanical properties due to the micropore network structure.

チタンへの炭化物分散による耐摩耗性改善

チタンへの炭化物分散による耐摩耗性改善

The effect of reactant gas composition on the plasmaenhanced chemical vapour deposition of TiN

Wear-resistant titanium nitride (TiN) coatings could be obtained at a deposition temperature of 400 °C by r.f. glow discharge plasma-enhanced chemical vapour deposition (PECVD). TiN deposition was performed on tool steels and cemeted carbide cutting tools by the PECVD technique using a gaseous mixture of TiCl4, N2, H2 and argon in order to determine the effect of the reactant gas composition on the PECVD of TiN. The experimental results show a considerable difference in the deposition rates and the constituents of the deposits according to the inlet fractions of reactant gases as well as the substrate materials. However, the atomic ratio of the TiN deposited by PECVD is not affected by reactant gas composition unless the deposited layer incorporates iron. The deposited TiN layer contains chlorine, and its content can be reduced by increasing the H2 inlet fraction. At high N2 inlet fractions, the deposited layer contains iron and the atomic ratio of nitrogen to titanium is decreased. The surface of the deposited TiN is very uniform and the films are composed of extremely fine grains of TiN.

X-ray diffraction determination of stresses, texture, crystallite size, microstrain and composition in wear-resistant titanium carbide layers

X-ray diffraction determination of stresses, texture, crystallite size, microstrain and composition in wear-resistant titanium carbide layers

Abrasive wear resistance of titanium- and nitrogen-implanted 52100 steel surfaces

The wear resistance of titanium- and nitrogen-implanted 52100 bearing steels was measured by an abrasive wear technique with a depth resolution of 20–30 nm. Titanium-implanted surfaces were extremely resistant to wear against fine (1–5 microm) diamond abrasion, which suggests a very hard surface layer. Nitrogen-implanted surfaces, by contrast, wore at the same rate as non-implanted surfaces. Wear resistance versus depth profiles of titanium-implanted surfaces followed the concentration versus depth profile of the implanted titanium. Auger depth profiles indicated a large concentration of carbon (≈20 at.% maximum) distributed with a diffusion-like profile from the titanium-implanted surface into the bulk. The carbon was identified by Auger line shape analysis as a titanium carbide, and the wear resistance of the surface was attributed in part to its presence.

Growth of wear-resistant titanium carbide layers on hard metals

14. O. K. Teodorovich and L. I. Kostenetskaya, "Effects of a lubricating filler on the structure and properties of light-current sliding contacts," Poroshk. Metall., No. 12, 33-37 (1973). G. N. Braterskaya, L. I. Kostenetskaya, and O. K. Teodorovich, "Production and application of a silver-base electrical contact material with a liquid lubricant," Poroshk. Metall., No. i, 29-31 (1977). O. K. Teodorovich, I. M. D'yachenko, and S. M. Katsulukha, Composite Electrical Contact ~terials [in Russian], Tekhnika, Kiev (1974).