Tribological studies of different bioimplant materials for orthopedic application using Taguchi experimental design

In this research ball on disc wear tests have been carried out with ASTM G-99 standard at room temperature in simulated body fluid. The tribological property such as the coefficient of friction and wear weight loss was studied by using the Taguchi design of experiments. The design of the experiment was done using L8 orthogonal array to determine the collective contribution of the wear parameters. An analysis of variance demonstrated that the individual contribution of type of material factor was 97.15% and 66.66% for the coefficient of friction and wear weight loss respectively, which is the highest individual contribution as compared to other factors. It was concluded that the coefficient of friction and wear weight loss is mainly influenced by type of material factor. The analysis of the signal-to-noise ratio shows that the optimal coefficient of friction and wear weight loss was obtained with CoCrMo material at an applied normal load of 5 N with a sliding velocity of 0.05 m/s for a track diameter of 30 mm. To check the accuracy of results a confirmation test was carried out which indicates that predicted values are very close to the experimental values and the model is significant to predict the coefficient of friction. The results showed that the coefficient of friction and wear weight loss increases with increasing the applied load and sliding velocity. The microstructure of all substrates materials was analyzed using a scanning electron microscope. Wear track study showed that adhesive dominant wear mechanism for all four different substrate materials.

On the tribology of complex 2D/3D composites bearing

In the present work, a hierarchical braided polymer composite consists of Polytetrafluoroethylene (PTFE) fibers, reinforcement fibers, and epoxy resin was designed as a self-lubricant composite and bearing. Different reinforcements such as glass, carbon, and Kevlar fibers were employed to investigate the effect of reinforcement on the wear characteristics of composites. Besides, the influence of 2D/3D braid fabric was examined on the wear behavior of samples. Also, 90 and 120 N loads were applied to assess the load impact. Results illustrated that compared to glass and Kevlar, carbon could lead to a greater wear weight loss and friction coefficient. However, PTFE tribofilm was observed according to scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDS) analysis. Moreover, with the increase of load, the wear stability of the composites faded significantly. Furthermore, the tribological features became inappropriate with the deployment of the 3D braid structure. Finally, the modeling of tribological parameters was carried out using response surface methodology-based D-optimal design. The adequacy of the models was checked by analysis of variance. Results implied that there is an excellent correlation between the model and the experiments.

Superior wear performances of one-step forming TiCp/Ni3Al-Ni3Al multi-coating on powder metallurgy master alloy substrate

One-step forming TiCp/Ni3Al-Ni3Al multi-coating on powder metallurgy 316L stainless steel substrate was fabricated by vacuum hot-pressing sintering technology and its wear performances at different loads and ambient temperatures were investigated. The wear weight loss of TiCp/Ni3Al-Ni3Al multi-coating increased with the increase in the applied load and a mild-to-severe wear transition occurred. Inversely, the coating’s wear weight loss decreased as the ambient temperature increased. The high wear resistance at elevated temperatures was mainly attributed to high work-hardening capacity and high temperature strength of Ni3Al matrix. Besides, the mechanically mixed layer with dispersed TiC particulates prevented the substrate from plastic deformation and thermal softening, which were conducive to improve the wear resistance of the coating.

A study on the microstructures and three–body abrasive wear behaviors of Fe–B alloy under different Fe2B boride orientation

Purpose The directional solidification Fe-B alloy was prepared. The microstructures and three-body abrasive wear behaviors of directional solidification alloy were investigated. Design/methodology/approach Fe-B alloy was melted in medium frequency induction furnace. The hardness was measured on HRS-150 Rockwell-hardness tester and HXD-1000TMC tester. The wear characteristic of the alloy was examined with a block-on-ring geometry. The worn surface of the alloy was investigated by scanning electron microscopy and laser scanning microscopy. Findings The wear weight loss and worn surface roughness increase with the increasing contact load in wear tests. When the worn surface is perpendicular to the boride growth direction, the highest hardness plane of the boride can resist abrasive effectively under the surrounding and supporting of the martensite matrix. Originality/value The relation between boride growth direction and wear direction will cause different boride breaking tendency and wear weight loss.

Taguchi optimization of tribological properties of Al/Gr/B4C composite

Purpose – The purpose of this paper is to develop hybrid aluminum metal matrix composite by stir casting process, reinforced with graphite and hard boron carbide particles to enhance the wear resistance. An attempt is made to optimize the wear (weight loss) and coefficient of friction (COF) by considering three factors, i.e. normal load, track diameter and sliding speed which were varied at three different levels. Design/methodology/approach – The effect of graphite and boron carbide on microhardness was studied by adding them in varying percentages. After determining the best combination of hybrid reinforcements, optimization of wear (weight loss) and COF was carried out at various levels of considered factors. Taguchi design of experiments was used using the software “Minitab 16.1”. ANOVA was used to analyze the effect of various parameters on wear and COF. To validate the results, mathematical modeling was carried out in terms of regression equations and results obtained by regression equations. Findings – The results revealed that the lower weight percentage of graphite (3 per cent) and boron carbide (1 per cent) significantly improved microhardness of developed composites. Results of ANOVA revealed that normal load was the main contributing factor for wear and COF. The results obtained by regression equations and confirmatory tests were within the results obtained by ANOVA. Originality/value – To the best of the author’s knowledge, very less work has been reported on optimization of wear and COF using hybrid reinforcement particles of graphite and boron carbide.

Preparation and Tribological Behavior of Ni-P-B4C Electroless Coatings

In this research, micro-hardness and wear resistance of two types of electroless coatings were investigated including Ni-P and Ni-P-B4C composite coatings. Dispersible B4C particles and electroless Ni-P alloy were codeposited on carbon steel by electroless plating and then heat treated at 200, 400 and 600 °C for 1 h, respectively. The cross-section morphology and microstructure of the composite coatings were characterized. Meanwhile, the micro-hardness and tribological behavior of composite coatings were evaluated. The results showed that the Ni-P-B4C composite coating presents better wear resistance in comparison with that of Ni-P coating. The Ni-P-B4C composite coating with heat treated at 400 °C exhibits high micro-hardness and good wear resistance, which the highest hardness is 1200 HV, the minimum wear weight loss is 0.12 mg and the lowest friction coefficient is 0.2054.

Study of Friction and Wear Behavior of Ni-P-β-SiC Composition Coating on Aluminum Alloy

Ni-P-β-SiC was prepared using different granularity β-SiC and rolling electroless plating technology. The test results show that β-SiC particles in composite coating are uniform, and the thickness and hardness of composite coating are 17~25μm and 520~620HV, respectively. At the same time, the friction and wear behavior of Ni-P-β-SiC composition coating have been studied. The results show that the wear weight loss decrease and the friction coefficient increase with the increase of β-SiC granularity.

Effect of Carbon Content on Microstructure, Mechanical Properties and Wear Resistance of Ti(C,N)-Based Cermets

Ti(C,N)-based cermets with three carbon contents are prepared by sintering in vacuum. The effects of carbon content on the microstructure, mechanical properties and wear resistance of Ti(C,N)-based cermets were investigated. The results show that the grains refine gradually and the hard phase core becomes smaller when the carbon contents increases. The mechanical properties closely relates to the carbon content. With the increase of carbon content, the furrows created by grains cutting are getting narrower and more intensive. When the carbon content reaches 0.8%, a large quantity of wear debris bonding blocks are attached on the wearing surface. In this condition, the Ti(C,N)-based cermets are of the minimum wear weight loss and the best comprehensive mechanical property.

Microstructure and Mechanical Properties of Al/AlN Surface Composite Fabricated via Multi-Pass Friction Stir Processing

The AlN particles reinforced composite was fabricated on the surface of aluminum 6061-T6 alloy rolled plate by five passes friction stir processing (FSP). Microstructure of FSPed sample was characterized by optical microscope and scanning electron microscope. AlN particles in composite were verified by EDS and XRD. Microhardness and resistance to wear were also investigated. Results show that grains in composite were refined by dynamic recrystallization and uniformly dispersed AlN particles. Composite region bonded with the Al substrate well. No reaction occurred at the interface between AlN and Al matrix. By comparison with base metal, the FSP-produced composite exhibited improved microhardness and substantial wear weight loss reduction.

Preparation and Performance of Electrodeposited Cr-Pr Coating

Cr-Pr coating was prepared by electrodeposition method. The microhardness, wear weight loss and friction coefficient of Cr-Pr coating were studied respectively. The Cr-Pr coating were characterized with ICP-AES, EDAX, XRD and SEM techniques, respectively. The microhardness and the wear weight loss, friction coefficient of the Cr-Pr coatings are higher and lower respectively than that of the Cr coating. The microhardness of the Cr-Pr is as high as 805.2 HV, which is higher 3.74% than that of the Cr coating (776.2 HV). The wear weight loss of Cr-Pr is lower 1.33 times than that of Cr coating. The friction coefficient of Cr coating and Cr-Pr coating are 0.884 and 0.723 respectively. There are crystalline CrC in Cr-Pr coating. The nodules on Cr-Pr coating surface are smaller than that of Cr coating surface, and furrows and spalling are lower on the worn surface of Cr-Pr coating than that of the Cr coating.