Sliding friction and wear performance of the nano-bioceramic α -Al 2 O 3 prepared by high energy milling

The structural evolution and morphological changes of the nanostructured α-Al2O3 powder using different milling times (1, 8, 16 and 24 h) were studied. It is observed that the crystallite size of the particles reduced to 2 nm after milling for 24 h. Morphological studies of powder particles indicated that the powder particle size continuously decreases with increasing milling time. The sliding wear rate and wear coefficient of friction were lower in the nanocrystalline samples milled at 24 h at same applied load (3, 6 or 10 N). The improved friction and wear resistance is attributed to the finer microstructure of the sample milled for 24 h

FRICTION AND WEAR BEHAVIOUR OF Ti-6AI-7Nb BIOMATERIAL ALLOY

Titanium and its alloys have been used as implant materials due to their very good mechanical and corrosion resistance and biocompatibility [1,2]. The most used biomaterials were commercially pure titanium (CP-Ti} issued in clinics, although CP- Ti has been pointed out to have disadvantages of low strength, difficulty for polishing, and poor wear resistance. Therefore, Titanium is still insufficient for high-stress applications ; e.g., long spanned fixed prostheses and the frameworks of removable partial dentures.Ti-6Al-4V alloy, originally developped as an aeronautical material, has been tested as a replacement for CP-Ti, because of its high mechanical properties with sufficient corrosion resistance[3], however, the cytoxicity of elemental Vanadium is questionable. Subsequently, some researches prove that vanadium and aluminum ions released from this ternary alloy can induce cytoxic effects or neurological disorders, respectively [4]. Also, for long-term, this alloy has transferred in sufficient load to adjacent bones, resulting in good resorbption and eventual loosening of the implant. Another ternary alloy used as implants was vanadium free, a+ii alloy, especially Ti-6Al-7Nb alloy that revealed improved mechanical characteristics, corrosion resistance and biocompatibility , developed for orthopedics application as a wrought material, has been evaluated as a new alloy for total hip prostheses. Niobium exhibits a similar effect to vanadium instabilizing ii phase in the Ti-Nb binary system, which is necessary for providing the a -ii two-phase structure. Therefore, niobium was used as the ternary element to produce the desirable microstructure in the Ti-6Al-7Nb alloy. Ascompared with Ti-6Al-4 V alloy, in a tensile test, these alloy show slightly lower strength and about 40% higher elongation

Friction and Wear Behavior of Ti-6Al-7Nb Biomaterial Alloy

Titanium has been increasingly applied to biomedical application because of its improved mechanical characteristics, corrosion resistance and biocompatibility. However their application remains limited, due to the low strength and poor wear resistance of unalloyed titanium. The purpose of this study is to evaluate the friction and wear behavior of high-strength titanium alloys: Ti-6Al-7Nb used in femoral stem (total hip prosthesis). The oscillating friction and wear tests have been carried out in ambient air with oscillating tribotester in accord with standards ISO 7148, ASTM G99-95a, ASTM G 133-95 under different conditions of normal applied load (3, 6 and 10 N) and sliding speed (1, 15 and 25 mm·s−1), and as a counter pair we used the ball of 100C 6, 10 mm of diameter. The surface morphology of the titanium alloys has been characterized by SEM, EDAX, micro hardness, roughness analysis measurements. The behav-ior observed for both samples suggests that the wear and friction mechanism during the test is the same for Ti alloys, and to increase resistance to wear and friction of biomedical titanium alloys used in total hip prosthesis (femoral stems) the surface coating and treatment are required

Friction and Wear Performance of Biomaterials Alloy AISI 316L and Ti-6Al-7Nb

We became interested in this work to study the tribological behavior of two total hip replacements steel AISI 316L and titanium alloy Ti-6Al-7Nb tests performed in this work are essays with reciprocating movement. The tribological properties of wear by sliding (reciprocating) for the different samples were evaluated in the air on a tribometer with a tribotester software software following standards: ISO 7148, ASTM G99-95a, ASTM G 133-95, with a relative humidity of 33-38% at a temperature 24 to 27°C and a non-lubricated state. The ball 100C6 steel of 10 mm diameter, 835 HV hardness and Young’s modulus 310 GPa was chosen as the antagonist to prevent further chemical reactions. Three different speeds (1, 6 and 15 mms-1) and four normal forces (2, 4, 6 and 10 N) were applied, which allowed us to test twelve different conditions. The values of the friction coefficient obtained in this work are confirmed by the bibliographical results and meet the standards imposed by biomedical particularly at the joint surface state of hip prostheses

Tribological behavior of Ti-6Al-4V and Ti-6Al-7Nb Alloys for Total Hip Prosthesis

The aim of the study is to evaluate the friction and wear behavior of high-strength alloys Ti-6Al-7Nb used in femoral stem and compare it with a Ti-6Al-4V alloy cylindrical bar corresponding to ISO 5832-3 part 3/01-07-199 standard. The tribological behavior was investigated by wear tests, using ball-on-disc and pin-on-disc tribometers. These tests consisted of measuring the weight loss and the friction coefficient of samples. The oscillating friction and wear tests have been carried out in ambient with oscillating tribotester in accordance with standards ISO 7148, ASTM G99-95a, and ASTM G133-95 under different conditions of normal loads (3, 6, and 10 N) and sliding speeds (1, 15, and 25 mm·s−1). As counter pairs, a 100Cr6 steel ball with 10 mm in diameter was used. Results show that the two alloys had similar friction and wear performance, although their grain structures and compositions are different. Occurrence of large frictional occurred, is probably caused by formation and periodic, localized fracture of a transfer layer. Higher friction with larger fluctuation and higher wear rate was observed at the higher siding speed. The Ti-6Al-4V wear mechanism transforms from ploughing and peeling off wear at low sliding speed to plastic deformation and adhesive wear

Structural and mechanical properties of Cr–Zr–N coatings with different Zr content

Cr–Zr–N films have been synthesised using R.F reactive magnetron sputtering system on Si (100) wafer and XC100 steel substrate without heating. The structural, mechanical and friction coefficient evolution as a function of the Zr content were investigated by XRD, (EDS, WDS), WPS, XPS, SEM, AFM, nanoindentation, Scratch adhesion and pin-on-disc sliding wear tests. The results show, that, with increasing Zr content, the film structure changed with the coexistence of (Cr–N, Zr–N) crystallographic orientation mixture. The films formed a (Cr, Zr) N solid solution where Zr atoms substitute Cr atoms. CrN lattice parameter increased from 4.17 to 4.32 Å with the crystallite size refinement. The mechanical parameters (H, σ, E, H/E and H3/ E2) were significantly improved in comparison to binary films, especially at 29 at.-% Zr. The friction and wear behaviour of the Cr–Zr (29 at.-% Zr)–N coating also showed a significant improvement

Effect of Replacing Vanadium by Niobium and Iron on the Tribological Behavior of HIPed Titanium Alloys

This study aims to examine the effect of replacing vanadium by niobium and iron on the tribological behavior of hot-isostatic-pressed titanium alloy (Ti–6Al–4V) biomaterial, using a ball-on-disk-type oscillating tribometer, under wet conditions using physiological solution in accordance with the ISO7148 standards. The tests were carried out under a normal load of 6 N, with an AISI 52100 grade steel ball as a counter face. The morphological changes and structural evolution of the nanoparticle powders using different milling times (2, 6, 12 and 18 h) were studied. The morphological characterization indicated that the particle and crystallite size continuously decrease with increasing milling time to reach the lowest value of 4 nm at 18-h milling. The friction coefficient and wear rate were lower in the samples milled at 18 h (0.226, 0.297 and 0.423; and 0.66 × 10−2, 0.87 × 10−2 and 1.51 × 10−2 µm3 N−1 µm−1) for Ti–6Al–4Fe, Ti–6Al–7Nb and Ti–6Al–4V, respectively. This improvement in friction and wear resistance is attributed to the grain refinement at 18-h milling. The Ti–6Al–4Fe samples showed good tribological performance for all milling times

Characterisation of R.F. magnetron sputtered Cr-N, Cr-Zr-N and Zr-N coatings

Binary Cr-N, Zr-N and Cr-Zr-N films were synthesised using a R.F. reactive magnetron sputtering technique by co-sputtering Cr and Zr. The crystalline structure, morphology, mechanical and tribological properties of the films as a function of Zr content were characterised by X-ray diffraction, microanalysis X (WDS, EDS), X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy, nanoindentation, scratch adhesion and pin-on-disc sliding wear tests. The residual stress was calculated with the Stoney formula. The Cr-Zr-N films exhibit a two-phase microstructure, containing a cubic (CrN, ZrN) with hexagonal (Cr2N, Zr2N) phases, as shown by X-ray diffraction. As the Zr content increased, a columnar and compact structure is developed with a low surface roughness. The results reveal that the mechanical and tribological properties of the films were found to depend on the Zr content and the hardness (maximum 26.3 GPa) is greatly improved in comparison with CrN and ZrN films, especially at 31 at.-% Zr. In the scratch test, the hardest film (Cr0.18Zr0.31N0.47) exhibited an adhesive failure at Lc2 = 34.3 N

Synthesis, microstructural and tribological characterization of calcined nano-bioceramic α- al2o3, sintered at different temperatures

The current research was undertaken to study the improvement of the tribological behavior of nanocrystalline bioceramic, α-alumina sample, produced by the calculations of gibbsite at different temperatures (300 to 1200°C), followed by uniaxial pressing, sintering and HIP treatment. The improved friction and wear resistance is attributed to the fine microstructure of the sample calcined at 1400 °C

Effect of Zr content on friction and wear behavior of Cr‐Zr‐N coating system

Nanostructured Cr‐Zr‐N thin film with different Zr content (0 to 48.8 at.%) was deposited, using an RF magnetron‐sputtering technique. The structural evolution and morphological changes were performed. The tribological performances were evaluated, using a ball‐on‐disk type Oscillating tribometer. The tests were carried out under normal loads of 2, 4 and 6 N, respectively, with an alumina ball (Al2O3) as a counter face. The results showed that the crystallite size of the Cr‐Zr‐N system was reduced to 10.8 nm at 31.8 at.% Zr content. Morphological studies of the films showed that the roughness continuously decreased with increasing Zr content, exhibiting a value of 11.2 nm at 31.8 at.% Zr. The wear rate tends to decrease with the increasing of Zr content to reach a lowest value of 1.95 × 10‐2 μm3.N.μm‐1 at 31.8 at.% Zr. The wear rate and friction coefficient were lower in the samples with 31.8 at.% Zr content. The improved friction and wear resistance were attributed to the grain refinement strengthening mechanism at 31.8 at.% of Zr