Treatment of Surface Properties of Titanium with Plasma (Ion) Nitriding (original) (raw)
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Surface modification of titanium by plasma nitriding
Materials Research, 2003
A systematic investigation was undertaken on commercially pure titanium submitted to plasma nitriding. Thirteen different sets of operational parameters (nitriding time, sample temperature and plasma atmosphere) were used. Surface analyses were performed using X-ray diffraction, nuclear reaction and scanning electron microscopy. Wear tests were done with stainless steel Gracey scaler, sonic apparatus and pin-on-disc machine. The obtained results indicate that the tribological performance can be improved for samples treated with the following conditions: nitriding time of 3 h; plasma atmosphere consisting of 80%N 2 +20%H 2 or 20%N 2 +80%H 2 ; sample temperature during nitriding of 600 or 800 °C.
The Effect of Low Temperature Plasma Nitriding on Wear Resistance of Ti6Al4V Alloy
Acta Physica Polonica A, 2014
The eect of low temperature plasma nitriding on wear resistance of Ti6Al4V alloy were investigated. There have been several studies to investigate the low temperature plasma nitriding on Ti6Al4V alloy. Plasma nitriding processes under gas mixture of N2/H2 = 3 were performed at temperature 535 • C for duration of 4, 8 and 12 h. Adhesive wear tests were carried out by using a tribometer in block-on-ring conguration (ASTM G77), in sliding conditions, without lubricants and in air. Surface hardness of the plasma nitrided samples were measured by a Vickers hardness tester machine. Scanning electron microscopy studies were conducted to understand the wear mechanisms involved during the adhesive wear. Wear rate was calculated using weight loss per unit sliding distance. It was found that the wear resistance and surface hardness of the alloy improved considerably after plasma nitriding process. The wear resistance of the plasma nitrided samples were higher than of the unnitrided samples. Extension of nitriding times from 4 h to 12 h in the Ti6Al4V alloy improved remerkably the wear resistance and surface hardness.
Topography, Hardness, Elastic Modulus and Wear Resistance of Nitride Coatings on Titanium
Proccedings of International Scientific Conference "BALTTRIB 2017", 2017
The roughness, hardness and elastic modulus of the surface layers of c.p. titanium after thermodiffusion saturation with nitrogen at temperatures of α and β phase regions were investigated. It was established that the increasing temperature of gas nitriding provided a higher level of surface hardening (hardness, elastic modulus, depth of hardened layer) of the material but worsened the roughness of its surface. The tribological tests of hardened by nitriding c.p. titanium in pairs with 304L stainless steel showed lower friction coefficients in the period of rubbing, where the surface of the titanium was nitrided below the temperature of the transus temperature.
Proceedings of the Bulgarian Academy of Sciences
This study investigates and analyzes the influence of plasma gas nitriding with indirect plasmatron on the phase transformations, microstructure, surface microhardness, and corrosion resistance of titanium alloy Ti-10V-2Fe-3Al. In order to achieve this, the limits of the power used in this process are a minimum of 12 kW and a maximum of 35 kW. The thermochemical treatment time intervals are set at 5, 10, and 15 min. It is found that the phase composition of the surface layer after plasma gas nitriding consists of α-Ti, (N, O), TiN, and TiO2. Titanium oxides are detected only on the outermost surface of the nitrided layers. The measured hardness of the plasma gas nitrided layers obtained of Ti-10V-2Fe-3Al is up to 650 HK0.05. Potentiodynamic polarization analysis indicates that the subjects nitrided using 18 kW of power for 15 min have the lowest corrosion rate, while the highest corrosion rate is observed in those nitrided at 25 kW for 15 min.
Properties and structural-phase state of the surface layers of titanium after combined nitriding
Materials Science, 2007
We study the simultaneous nitriding of titanium alloys by two methods: thermodiffusion saturation and ion implantation. Prior to nitrogen implantation, a thin oxynitride film and a thick nitride one were formed on the surface of VT6 titanium alloy of the (α + β)-class (Ti-6Al-4V). We show that nitrogen implantation changes the state of the surface of titanium and increases the surface microhardness of nitride and oxynitride coatings. An increase in the hardness of the surface without loss of its quality is possible in the case of nitrogen implantation into a thin oxynitride film.
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.
Structure of Commercial Titanium Subjected to Low-Temperature Ion Nitriding
Mechanics of Machines, Mechanisms and Materials, 2022
The structural-phase state of commercial titanium of grades ВТ1-00 (VT1-00) and ВТ1-0 (VT1-0) has been studied in the initial state and after various types of low-temperature ion nitriding. In the initial state, the VT1-00 and VT1-0 alloys have a single-phase α-Ti structure with a hexagonal close-packed crystal lattice. The hardness of titanium is 140–150 HV 10. It has been shown that ion-beam nitriding of VT1-00 alloy at low temperatures of 350 and 450 °С leads to the formation of thin (up to 5 μm) nitrogen-hardened layers with a hardness of 160–180 HV 0.05. As a result of ion implantation at temperatures of 500 and 550 °C, a nitrogen-modified layer with a microhardness of 190–220 HV 0.05 is formed in the surface layers of the VT1-00 titanium alloy, containing a solid solution of nitrogen in the α-Ti matrix phase. Nitrogen implantation of the VT1-00 alloy at a temperature of 620 °C leads to the formation of titanium nitrides TiN0.26, ε-Ti2N, η-Ti3N2-x in the surface layer of titani...
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.
Mechanism of r.f. plasma nitriding of Ti-6A1-4V alloy
The objective of the current study was the gradual development of the formation of the nitride layer during inductive r.f. plasma nitriding. The study centers on characterization of refined layers and plasma diagnostics in the vicinity of the sample, and raises critical questions of how the layers and interracial microstructure might affect the near-surface properties. The composition of the plasma near the surface of the sample (plasma layer) was examined by optical emission spectroscopy and mass spectrometry during plasma nitriding and while sputtering the sample after the nitriding process. It was observed that during the nitriding process, the plasma layer contains Ti, NH,, species, N (or/and N +), H,, species (or/ and H +2). However, when the nitrided sample was exposed to argon plasma, Ti, A1 and NH were observed. It was found that two distinct sublayers, comprising d-TiN and &TiN + e-Ti~N phases, were formed with alloying elements in a segregated zone, followed by a solid solution of nitrogen in titanium. The formation of the uppermost sublayer (&TIN phase), containing H, NH, and N, in addition to Ti depleted of AI and V, has a strong effect on the diffusion of nitrogen into a-Ti and on the layer properties. This can be enhanced if hydrogen is present in the nitriding atmosphere and is prevented if hydrogen is replaced by argon. Therefore, the nitrogen content in the layer results in the formation of nitride phases and is accompanied by an improvement in mechanical properties.