Surface modification of titanium by plasma nitriding (original) (raw)
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Treatment of Surface Properties of Titanium with Plasma (Ion) Nitriding
Defect and Diffusion Forum, 2009
In order to improve the poor surface hardness and the wear resistance, titanium has been nitrided with plasma (ion) nitriding which is one of the methods to treat surface properties of titanium alloys. The increment at surface hardness and so the wear resistance of nitrided titanium alloys has been provided by means of compound layer (ε-Ti 2 N+δ-TiN) and diffusion zone (α-Ti) occurred by plasma ion nitriding. The goal of the present paper is to investigate effects of nitriding temperature and nitriding time on the microstructure and hardness value of nitrided surface layers. A systematic study was undertaken with specimens of commercial pure Ti and Ti-6Al-4V alloy. As treatment parameters, we have used; nitriding time (from 2 to 9 hour), nitriding atmosphere (H 2 -80%N 2 ), total pressure (1 kPa) and cathode temperature (from 600 to 800 o C). The Vickers indenter was used for analysis of the micro hardness measurements. The thin hardened layer at the nitrided surface was characterized by glancing-angle X-ray difractometer. X-ray diffraction analysis has confirmed the formation of ε-Ti 2 N and δ-TiN phases on the nitrided specimens. Experimental details and characterization of plasma (ion) nitrided titanium have reported and discussed.
Near-surface composition and tribological behaviour of plasma nitrided titanium
Journal of Physics D: Applied Physics, 2003
Near-surface composition and tribological behaviour of plasma nitrided commercially pure (CP) Ti have been investigated using x-ray diffraction, nuclear reaction analysis, scanning electron microscopy, wear assays with stainless steel Gracey scaler and sonic apparatus, and friction coefficient measurements. The total wear behaviour can be divided into two steps. The first step is the growth of an oxynitride layer. The second step is the breakdown of the oxynitride layer during which debris is produced, increasing the friction coefficient. Each sample exhibits features that correlate with the near-surface composition. For instance, the presence of thin layers of ε-Ti 2 N and δ-TiN precipitating on the near-surface region control the transition from the first to the second step.
2013
One of potential metals to be used in biomechanical applications is the commercially pure (cp) titanium. This material requires a process to improve the mechanical properties of the surface, because it is relatively soft. The purpose of this study is to determine the effect of plasma nitro carburizing process to cp titanium surface hardness. In this study, cp titanium plasma nitro carburizing process is conducted at different temperatures, i.e., at 350°C for 3, 4, and 5 h, and at 450°C for 2, 3, and 4 h, respectively. Hardness tests are then performed on each specimen. The depth of penetration in the hardness test is also recorded; the microstructure captures are also taken using an optical microscope. The results show that the longer processing time, the higher the hardness value. In higher temperature, the hardness values correspond to the increasing temperature. In terms of the depth direction, there is a reduction in hardness value compared to the raw material.
Surface modification of titanium by radio frequency plasma nitriding
Thin Solid Films, 2006
Radio frequency (RF) plasma nitriding using different input plasma processing powers (250-600 W) improves the surface of titanium by forming hard phases of TiN, Ti 2 N, and Ti (N) into the surface. The characteristics of the compound layer have been investigated by optical microscopy, microhardness measurements, and X-ray diffraction. The effect of plasma power on the sample temperature, electron temperature, and plasma density was studied using Langmuir double probe. The measured surface hardness value of the compound layer is 2190 HV 0.1 for treated sample at plasma power 500 W. The compound thickness continuously increases as the plasma power increases. The highest nitriding rate of 5.88 Am 2 /s was recorded when the input plasma power was adjusted at 550 W. This high nitriding rate of treated titanium samples is ascribed to the high concentration of active nitrogen species in the plasma atmosphere and the formed microcracks near to the surface of the sample during the plasma processing. We have proposed that at low input plasma power (low temperature) the interstitial diffusion is the main mechanism. However, vacancy-controlled diffusion for high input plasma power (high temperature) is probably the one needed to surmount the energy barrier.
Tribo-mechanical and electrochemical properties of plasma nitriding titanium
Titanium nitrides have good tribo-mechanical and biomedical properties. They are employed to harden and protect cutting and sliding surfaces for industrial purpose and as a non-toxic outer-surface for bio-medical applications. In this study, pure titaniumwas nitrided using RF plasma technique. Themicrostructural,mechanical, tribological, electrochemical and biomedical properties of nitrided titaniumwere investigated. The X-ray diffraction demonstrates the formation of ε-Ti2Nand the cubic δ-TiN phases after plasma nitriding. The microhardness of the nitride samples increases as the plasma-processing power increases up to 1300 HV0.1. That represents approximately 7-fold increment in the microhardness in comparison with the untreated titanium. High nitriding rate of 0.17 μm2/s was recorded for the sample that was treated at 650 W. The wear and corrosion resistance are improved after plasma nitriding.Moreover, the friction coefficient is reduced from nearly 0.75 for the untreated titanium to 0.25 for the nitride one. An enhancement in the biocompatibility of the nitrided titanium has been achieved. The number of grown mesenchymal stem cells was higher for nitrided substrates compared to that of the untreated titanium. The improved tribo-mechanical and electrochemical performance of the nitrided titanium can be attributed to the formation of super-hard titanium nitrided phases.
XIII-6 Plasma Nitriding of Titanium Alloys with Indirect Plasmatron
2017
This article presents an experiment which consists of plasma gas nitriding of titanium alloy TI-6Al-4V. The purpose of the experiment is to improve tribological properties of titanium alloys in working conditions under sliding contact. Data obtained from the experiment is necessary for creating a technology for obtaining surface layers of a certain thickness.
Acta Metallurgica Slovaca, 2022
Titanium tends to form nitrides and carbides. The plasma nitrocarburizing technique can generate these nitride and carbide compounds on the material's surface. The objective of this research is to use a plasma nitrocarburizing process to increase the hardness and corrosion resistance of commercially pure titanium. The generation of a thin layer with an average thickness of 1.88 μm was discovered using a Scanning Electron Microscope. The X-Ray Diffraction technique identifies this thin layer made of TiN and TiC compounds. The untreated commercially pure titanium hardness was 105.75 VHN, and the plasma nitrocarburized commercially pure titanium hardness was 312.68 VHN, according to the Vickers micro tester. After plasma nitrocarburizing, the corrosion rate of untreated commercially pure titanium decreased from 0.0061 mmpy to 0.00077 mmpy. The plasma nitrocarburizing process resulted in a 196 percent increase in hardness and an 87 percent reduction in corrosion rate.
Plasma Nitriding of CP Titanium Grade-2 and Ti-6Al-4V Grade-5
IOP Conference Series: Materials Science and Engineering, 2017
Titanium metal is considered to be asset material due to its high tribological properties. Since these tribological properties like hardness, roughness, wear resistance etc. are influenced by the surface properties of the material, so obviously any changes in the surface of the material has direct impact on the tribological properties too. Nitriding is a heat-treating process that diffuses nitrogen into the surface of a metal to create a case hardened surface. The main objective is that to implement the plasma nitriding process to both CP Titanium grade-2 and Ti-6Al-4V grade-5 and to observe the improvements in the tribological properties with respect to the parent materials.
Journal of Biomedical Science and Bioengineering, 2022
Nitriding has been carried out using plasma nitriding techniques for surface treatment of Titanium as a biomaterial component. The purpose of this study was to determine the effect of plasma nitriding on surface hardness that occurs in titanium. The material used is Titanium Alloy (Ti-6Al-4V) Grade 5 which is processed by plasma nitriding by varying nitrogen (N2) and argon (Ar) gases of (100% N2/0% Ar), (95% N2/5% Ar), (90% N2/10% Ar), (85% N2/15% Ar), (80% N2/20% Ar), and (75% N2/25% Ar), and temperature 400ºC, time 5 hours and a pressure of 1.6 bar. The test results show that the optimum hardness is found in the gas composition with a ratio of 95% N2: 5% Ar. Obtained a hardness of 371 HV/VHN or an increase of 159% of the raw material with hardness value of 143 HV/VHN