scholarly journals Improvement of Mechanical, Tribological, and Fricative Reduction Properties of Pure Titanium by Boriding

2021 ◽  
Vol 11 (11) ◽  
pp. 4862
Author(s):  
Tong Chen ◽  
Shinji Koyama ◽  
Lihua Yu
Keyword(s):  
Room Temperature ◽  
Present Report ◽  
High Surface ◽  
Pure Titanium ◽  
Surface Hardness ◽  
Hardened Layer ◽  
Layer Growth ◽  
Different Temperatures ◽  
The Difference ◽  
Hardened Layer Thickness

Surface boriding of pure titanium was performed using dissolved salt impregnation to modify the surface hardness and improve wear performance. The effect of boriding temperature (950–1150 °C) on the microstructure, composition, and room-temperature tribological properties of the borided samples was investigated by X-ray diffraction, scanning electron microscopy, and ball-on-disc tribometry, respectively. Gibbs free energy was also calculated to evaluate the compounds generated during the boriding at different temperatures. After a detailed analysis of the crystal structures and the growth morphologies of TiB, the diffusion mechanisms for B atoms in TiB and TiB2 were discussed in the present report. The boriding temperature had a large effect on the microstructure, mechanical properties, and room-temperature tribological behavior of the borided samples, attributed to the changes in the composition and the increased hardened layer under elevated boriding temperature. The modeling of layer growth kinetics was also discussed in this paper. The actual value of hardened layer thickness was compared to the calculated value, and the difference was analyzed. The fricative value of the borided samples showed a minimum value of 88.9 dB for a boriding temperature of 1050 °C. The depth and width of the wear tracks decreased gradually with increasing boriding temperature. The worn surface of the samples borided at higher temperatures showed very good wear resistance. A boriding condition of 1050 °C was considered optimal, as it provided sufficiently high surface hardness and a low fricative value to reduce vibrations during practical use.

Structure and Phase Composition of a Ti Film–Al Substrate System Irradiated with an Intense Pulsed Electron Beam

2018 ◽  
Vol 781 ◽  
pp. 101-107
Author(s):  
Yurii Ivanov ◽  
Olga V. Krysina ◽  
Pavel Moskvin ◽  
Elizaveta A. Petrikova ◽  
Olga V. Ivanova ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Electron Beam ◽  
High Surface ◽  
Pure Titanium ◽  
Surface Hardness ◽  
Vacuum Arc ◽  
High Wear Resistance ◽  
Commercially Pure Titanium ◽  
Plasma Cathode ◽  
Commercially Pure

Commercially pure A7 aluminum was exposed to surface modification in a single vacuum cycle which included vacuum arc evaporation and deposition of commercially pure titanium and intense electron beam irradiation and melting of the film–substrate system using a plasma-cathode pulsed electron source. The deposited Ti film thickness was 0.5 and 1 μm. The irradiated Ti–Al system revealed a multilayer multiphase structure consisting of submicro-and nanosized elements with intermetallic inclusions Al3Ti, Al2Ti, and TiAl3. The Ti film during irradiation broke up into fragments with their immersion in the molten Al surface layer to a depth of 20 μm. The modified material surpassed the initial aluminum in wear resistance by a factor of 2.4 and in microhardness by a factor larger than 4. The main cause for the high surface hardness and high wear resistance of the modified aluminum was likely the formation of both the intermetallic particles and the Ti-hardened transition layer.

scholarly journals The Effect of Heating on Surface Microhardness of Resin-based Materials for Direct Restoration

2018 ◽  
Vol 55 (4) ◽  
pp. 584-589
Author(s):  
Simona Stoleriu ◽  
Gianina Iovan ◽  
Irina Nica ◽  
Galina Pancu ◽  
Andrei Victor Sandu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Vickers Microhardness ◽  
Composite Resin ◽  
Heating Temperature ◽  
Surface Hardness ◽  
Mean Value ◽  
Direct Restoration ◽  
Different Temperatures ◽  
Materials Used ◽  
Hardness Values

The aim of this study was to evaluate and to compare the surface hardness of three types of resin-based materials used for direct restoration after heating at different temperatures. A giomer (Beautifil II, Shofu Dental), a compomer (Dyract eXtra, Dentsply Sirona) and a hybrid composite resin (Gaenial Posterior, GC Corporation) were selected for this study. Twenty disk-shaped specimens of each material were heated at room temperature (21�C), at 37�C, at 50�C and at 60�C. Vickers microhardness test was performed on top and bottom surfaces using digital microhardness tester (Micro-Vickers Hardness System CV- 400DMTM, CV Instruments Namicon). The top and bottom surfaces VHN was calculated as a mean value of five determinations. Also, the microhardness ratio was calculated by dividing the top mean VHN value by bottom mean VHN value. Increased mean hardness values were recorded after heating, irrespective of resin-based tested materials. The highest hardness values were recorded after heating all three materials at 60�C, followed by the hardness recorded at 50�C, 37�C and 21�C. For top surfaces, the lowest hardness value was recorded in Dyract eXtra group when samples were warmed at room temperature and the highest hardness value was obtained in Beautifil II group when samples where heated at 60�C. For the bottom surfaces, Dyract eXtra specimens heated at 21�C presented the lowest hardness values and Beautifil II samples heated at 60�C presented the highest hardness values. On top and on bottom surfaces Dyract eXtra showed the lowest hardness values, followed by G-aenial Posterior and Beautifil II, irrespective the heating temperature.

Formation of Hydroxyapatite Layer on Ti–6Al–4V ELI Alloy by Fine Particle Peening

2017 ◽  
Vol 11 (6) ◽  
pp. 915-924 ◽  
Author(s):  
Shoichi Kikuchi ◽  
Yuki Nakamura ◽  
Koichiro Nambu ◽  
Toshikazu Akahori ◽  
◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Fine Particle ◽  
Room Temperature ◽  
Treatment Time ◽  
Surface Hardness ◽  
Hardened Layer ◽  
Fatigue Properties ◽  
X Ray ◽  
Short Period ◽  
Stress Ratios

Fine particle peening (FPP) using hydroxyapatite (HAp) shot particles can form a HAp layer on room-temperature substrates by the transfer and microstructural modification of the shot particles. In this study, FPP with HAp shot particles was applied to form a HAp surface layer and improve the fatigue properties of Ti–6Al–4V extra-low interstitial (ELI) for use in bio-implants. The surface microstructures of the FPP-treated specimens were characterized by micro-Vickers hardness testing, scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffraction, and X-ray photoelectron spectroscopy. FPP with HAp shot particles successfully formed a HAp layer on the surface of Ti–6Al–4V ELI in a relatively short period by shot particle transfer at room temperature; however, the thickness and elemental composition of the HAp layer were independent of the FPP treatment time. The original HAp crystal structure remained in the surface-modified layer formed on Ti–6Al–4V ELI after FPP. Furthermore, FPP increased the surface hardness and generated compressive residual stresses at the treated surface of Ti–6Al–4V ELI. Four-point bending fatigue tests were performed at stress ratios of 0.1 and 0.5 to examine the effect of FPP with HAp shot particles on the fatigue properties of Ti–6Al–4V ELI. The fatigue life of the FPP-treated specimen was longer than that of the un-peened specimen because of the formation of a work-hardened layer with compressive residual stress. However, no clear improvement in the fatigue limit of Ti–6Al–4V ELI occurred after FPP with HAp shot particles because of subsurface failures from characteristic facets.

The Influence of Plasma Nitrocarburizing Process Temperature to Commercially Pure Titanium Surface Hardness

2013 ◽  
Vol 315 ◽  
pp. 700-704 ◽  
Author(s):  
Agung Setyo Darmawan ◽  
Waluyo Adi Siswanto ◽  
Tjipto Sujitno
Keyword(s):  
Pure Titanium ◽  
Surface Hardness ◽  
Process Time ◽  
Commercially Pure Titanium ◽  
Process Duration ◽  
Hardness Tester ◽  
Commercially Pure ◽  
Different Temperatures ◽  
Plasma Nitrocarburizing ◽  
Hardness Values

Commercially pure (cp) titanium is a relative soft metal and easily broken on friction-wear applications. To improve the hardness of the surface while maintaining the original properties, plasma nitrocarburizing process has been conducted. The effects of the treatment in different temperatures to the surface harness are then studied. In this study, cp titanium plasma nitrocarburizing process is conducted at different temperatures with different process time, i.e. at 350 °C for 3, 4, and 5 hours, and at 450 °C for 2, 3, and 4 hours respectively. Hardness tests are then performed on each specimen by using Micro Vickers Hardness Tester. The hardness values for the plasma specimens nitrocarburizing processes at temperature of 350 °C for process duration of 3 hours, 4 hours, and 5 hours are 74.16 HV, 92.25 HV and 94.41 HV, respectively, while for processes at temperature of 450 °C, the hardness values are 103.70 HV, 121.31 HV, and 126.17 HV for process duration of 2 hours, 3 hours, and 4 hours respectively. Hardness value of specimens which are resulted from the plasma nitrocarburizing process at temperature of 450 °C is higher compared with specimens that are processed at temperature of 350 °C.

scholarly journals Influence of Oxidation Processing Temperature on the Structure, Mechanical and Tribological Properties of Titanium Using Carbon Sheets

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 585
Author(s):  
Tong Chen ◽  
Shinji Koyama ◽  
Shinichi Nishida ◽  
Lihua Yu
Keyword(s):  
Tribological Properties ◽  
Pure Titanium ◽  
Surface Hardness ◽  
High Hardness ◽  
Hardened Layer ◽  
Processing Temperature ◽  
X Ray Diffraction ◽  
Mechanical And Tribological Properties ◽  
Carbon Sheet ◽  
Worn Surface

Surface processing of pure titanium was performed using a carbon sheet to increase the surface hardness and improve tribological property. The effect of processing temperature (750–950 °C) for 2 h on the structure, mechanical and room-temperature tribological properties of the treated samples was investigated using X-ray diffraction, scanning electron microscopy, and ball-on-disk tribometry, respectively. The Gibbs free energy was also calculated to evaluate the compounds generated at different processing temperatures. As a result of the examination, the hardened layer was mainly composed of titanium oxide and titanium carbide. With the increasing processing temperatures, the thickness of the hardened layer increased first and then decreased gradually. It was also revealed that the surface hardness was increased first and then decreased as the processing temperature increased. The fricative value of the treated samples showed a minimum value of 84.1 dB for a processing temperature of 850 °C. The depth and width of the wear tracks increased first and then decreased gradually with the increasing processing temperatures. The worn surface of the treated samples at higher temperatures showed a very good wear resistance. A processing temperature at 850 °C is considered optimal as it provides sufficiently high hardness and a low coefficient of friction to reduce fricative during practical use.

Isocyanide insertion reactions into the Ta—C bonds of cationic and zwitterionic tantalocenes

2003 ◽  
Vol 81 (11) ◽  
pp. 1137-1148 ◽  
Author(s):  
Kevin S Cook ◽  
Warren E Piers ◽  
Brian O Patrick ◽  
Robert McDonald
Keyword(s):  
Ground State ◽  
Room Temperature ◽  
Structural Changes ◽  
Ion Pairs ◽  
Activation Parameters ◽  
Insertion Reactions ◽  
H Nmr ◽  
Agostic Interaction ◽  
Different Temperatures ◽  
The Difference

The insertion of isonitriles R' NC (R' = t-Bu, C6H11, CH2C6H5) occurs exclusively into the Ta—CH2 bonds of the zwitterionic compounds (C5H4R)2Ta[CH2B(C6F5)3]CH3 (R = H, 1a; R = CH3, 1b) at relatively slow rates at room temperature to form N-out isomers as the sole kinetic products. By comparison, insertion of the same isonitrile substrates into a Ta—CH3 bond of the non-zwitterionic analogs [(C5H4R)2Ta(CH3)2][A] (R = H, A = B(C6F5)4, 3a; R = CH3, A = BF4, 3b) occurs much more rapidly, again to form N-out isomers exclusively under kinetic conditions. The difference in rate is attributed to the presence of a ground state α-agostic interaction in the zwitterionic compounds, which is not featured in the dimethyl ion pairs. All of the N-out isomers formed undergo thermal and irreversible conversion to the corresponding N-in isomers at rates that are conveniently followed by 1H NMR spectroscopy. The rates were studied at different temperatures to obtain activation parameters for each transformation. The rate and activation trends for this isomerization were analyzed as a function of the structural changes in the compounds. It was found that the rate decreased as the steric bulk of the isonitrile substitutent R' increased and that the rates were faster for the series that incorporated the more electron-donating C5H4CH3 ancillary ligand. Furthermore, isomerization rates for the zwitterionic N-out compounds were faster than those found in the non-zwitterionic series. This study represents one of the more extensive kinetic analyses of the rate of N-out to N-in isomerization as a function of structural changes. The observations are consistent with the mechanistic picture that has been developed for this process, involving dissociation of the η2 iminoacyl ligand, rotation about the M—Ciminoacyl bond and recoordination to the inside site of the metallocene wedge. Key words: cationic metallocenes, isocyanide insertion, agostic interactions, tantalum.

Thermal Oxidation of CP-Ti at Different Temperatures

2010 ◽  
Vol 146-147 ◽  
pp. 1536-1539 ◽  
Author(s):  
Jing Hu ◽  
Yan Wang ◽  
Da Yue Wang
Keyword(s):  
Corrosion Resistance ◽  
Thermal Oxidation ◽  
Pure Titanium ◽  
Surface Hardness ◽  
Commercially Pure Titanium ◽  
Tio2 Layer ◽  
Air Atmosphere ◽  
Wide Range ◽  
Different Temperatures ◽  
Cp Ti

Thermal oxidation tends to improve surface performance of titanium and its alloys by thickening the native passive oxide layer. In the present work, investigation of thermal oxidation in a wide range of treating temperatures between 500-850°C was carried out for commercially pure titanium (CP-Ti) to determine the optimum thermal oxidation parameters by evaluating the corrosion resistance. Characterization of modified surface layers was made by X-ray diffraction analysis and surface hardness measurements. The results showed that the rutile TiO2 layer was formed on the surface of specimens, and the thickness of the TiO2 layer and the surface hardness increased with the treating temperature. Evaluation of corrosion resistance indicated that the optimum thermal oxidizing temperature was 700°C under air atmosphere.

scholarly journals Mechanical Properties and Frictional Wear Characteristic of Pure Titanium Treated by Atmospheric Oxidation

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3196
Author(s):  
Tong Chen ◽  
Shinji Koyama ◽  
Shinichi Nishida ◽  
Lihua Yu
Keyword(s):  
High Surface ◽  
Pure Titanium ◽  
Surface Hardness ◽  
Treatment Temperature ◽  
Atmospheric Oxidation ◽  
Wear Testing ◽  
Research Report ◽  
Processing Temperature ◽  
Wear Depth ◽  
Scratch Testing

Pure titanium was treated by atmospheric oxidation, and the effect of the treatment temperature on its performance was studied. X-ray diffraction, scanning electron microscopy, wear testing, and scratch testing were used to evaluate the performance of the treated specimens. In order to evaluate the difficulty of compound formation during the different processing temperatures, Gibbs free energy was calculated. The experimental results show that the surface hardness of the sample can be improved at a certain oxidation treatment temperature. When the processing temperature is 850 °C, the surface hardness reaches the maximum value. The results of the scratch testing show that the hardened layer produced at this processing temperature has excellent peeling resistance. In addition, the wear depth and wear width are also at their minimum values at this processing temperature. Since the specimen treated at a processing temperature of 850 °C provides sufficiently high surface hardness and wear resistance in this research report, it is considered to be the optimal condition during practical application.

Reciprocating Wear Behaviour of Two Dimensionally Reinforced Carbon-Phenolic and Carbon-Epoxy Composites

2011 ◽  
Vol 1 (4) ◽  
pp. 46-57
Author(s):  
Sourav Sarkar ◽  
V.G. Sekaran ◽  
E. Badisch ◽  
Manish Roy ◽  
R. Mitra
Keyword(s):  
Friction Surface ◽  
Room Temperature ◽  
Epoxy Composites ◽  
Wear Behaviour ◽  
Reciprocating Wear ◽  
Different Temperatures ◽  
The Difference ◽  
Surface Morphologies ◽  
Low Amplitude ◽  
Scanning Electron

A comparative study has been carried out on performance of two-dimensionally reinforced carbon/phenolic (C/P) and carbon/epoxy (C/E) composites, subjected to low amplitude reciprocating wear at different temperatures. The C/P composite has shown greater wear rate than the C/E composite, with the difference being modest at room temperature, and larger at 250 °C. The values of coefficient of friction, surface roughness, and depths of craters on worn surfaces have been measured, which along with surface morphologies examined by scanning electron microscope have been correlated to both amount of weight loss and mechanisms of damage by wear.

FERROMAGNETISM IN SEMICONDUCTOR C–Ni FILMS AT DIFFERENT ANNEALING TEMPERATURE

2016 ◽  
Vol 23 (03) ◽  
pp. 1650002 ◽  
Author(s):  
VALI DALOUJI ◽  
SMOHAMMAD ELAHI
Keyword(s):  
Coercive Field ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Composite Films ◽  
Nickel Concentration ◽  
Maximum Value ◽  
Different Temperatures ◽  
The Difference ◽  
Quartz Substrates ◽  
Microstructure And Magnetic Properties

In this work, the microstructure and magnetic properties of carbon–nickel (C–Ni) composite films annealed at different temperatures (300–1000[Formula: see text]C) were investigated. The films were grown by radio frequency magnetron sputtering on quartz substrates at room temperature. The nickel concentration in the films are affected by changing of the value of evaporation nickel atoms and measured by Rutherford backscattering spectroscopy (RBS). Values of coercive field were measured under both increasing and decreasing applied magnetic field. It is shown that the coercive field of films strongly dependent on the annealing temperature and at 500[Formula: see text]C films has maximum value of 93.67[Formula: see text]Oe. The difference in the coercive fields increased for films annealed from 300 to 500[Formula: see text]C and then decreased from 500 to 1000[Formula: see text]C. The ID/IG ratio of Raman spectra would indicate the presence of higher sp2 bonded carbon in the films annealed at 800[Formula: see text]C.

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