Microstructural characterization of as-cast biocompatible Co–Cr–Mo alloys

Giacchi, J.V.; Morando, C.; Fornaro, Osvaldo; Palacio, H.

doi:10.1016/j.matchar.2010.10.011

Cited by 143 publications

(78 citation statements)

References 18 publications

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“…The non-uniformity of the structure of the cast Co-Cr alloy was confirmed by the standard deviation of the Vickers microhardness value. Similar to the present result, a few studies reported that casting technique can lead to poor mechanical properties compared to other manufacturing processes such as powder metallurgy and forging [3,4]. The corrosion resistance of cast and milled Co-Cr alloys was determined in artificial saliva solution using potentiodynamic polarization tests as shown in Fig.…”

Section: Methodssupporting

confidence: 83%

Corrosion and Tribocorrosion Behavior of Cast and Machine Milled Co-Cr Alloys for Biomedical Applications

et al. 2016

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In this study, the electrochemical behavior and tribocorrosion performance of cobalt-chromium (Co-Cr) alloys produced by different fabrication methods (casting and CAD/CAM milling technique) have been investigated in the laboratory-simulated artificial saliva. The results have shown that the maximum tribocorrosion resistance was obtained for milled Co-Cr alloy because of higher corrosion resistance and hardness of milled Co-Cr alloy compared too those of cast Co-Cr alloy. Moreover, the lowest friction coefficient was achieved for milled Co-Cr alloy.

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Section: Methodssupporting

confidence: 83%

Corrosion and Tribocorrosion Behavior of Cast and Machine Milled Co-Cr Alloys for Biomedical Applications

et al. 2016

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“…and M7C3 carbides [20][21][22][23]. The resulting microstructure is a coarse dendritic structure as seen in Figure 2.2 and 2.3. represents the primary strengthening mechanism in the as-cast state [24].…”

Section: Research Objectives Summarymentioning

confidence: 94%

In-Vivo Corrosion and Fretting of Modular TI-6AL-4V/CO-CR-MO Hip Prostheses: The Influence of Microstructure and Design Parameters

González¹,

Luís²

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The purpose of this study was to evaluate the incidence of corrosion and fretting in 48 retrieved titanium-6aluminum-4vanadium and/or cobalt-chromium-molybdenum modular total hip prosthesis with respect to alloy material microstructure and design parameters. The results revealed vastly different performance results for the wide array of microstructures examined. Severe corrosion/fretting was seen in 100% of as-cast, 24% of low carbon wrought, 9% of high carbon wrought and 5% of solution heat treated cobaltchrome. Severe corrosion/fretting was observed in 60% of Ti-6Al-4V components.Design features which allow for fluid entry and stagnation, amplification of contact pressure and/or increased micromotion were also shown to play a role. 75% of prosthesis with high femoral head-trunnion offset exhibited poor performance compared to 15% with a low offset. Large femoral heads (>32mm) did not exhibit poor corrosion or fretting. Implantation time was not sufficient to cause poor performance; 54% of prosthesis with greater than 10 years in-vivo demonstrated none or mild corrosion/fretting. v Effect of heat treatments on Ti-6Al-4V microstructure. Effect of heat treatments on Ti-6Al-4V mechanical propertiesFracture toughness values for equiaxed and highly transformed microstructuresTi-6Al-4V ASTM mechanical and compositional requirements Summary of modular total hip prosthesis retrieval studies during the past 25 years. As-received prostheses catalogingGeneral prostheses feature cataloging Macroscopic Examination. Overall implant examination, i.e. non-surface specific. Porous Surface Coating TypesFemoral head and femoral stem dimensional variables Modular junction dimensional variablesCorrosion and Fretting Scoring Criteria Worst fretting or corrosion score distribution by moment arm length.Worst fretting/corrosion score distribution for either head or trunnion by implantation time in-vivo. Cobalt-Carbon phase diagram illustrating the lever rule principle that dictates the fraction AB/AC of the constituent phases which will be liquid at the sintering temperature AC. i.e. an increase in carbon content will decrease the temperature required for adhering porous coatings.Porous coated as-cast cobalt-chrome stem Effect of Cooling Rates and Highest Temperature on Ti-6Al-4V Microstructure Finite element analysis predicting greater wear at the trunnion surface as femoral head is increased from 32mm to 56mm.Material, contact conditions and environmental variables governing potential for fretting wear.Pitting corrosion phenomena and associated reactions and surface features. Ion channeling contrast enhanced image of taper subsurface at 6,000X magnification, revealing differences in morphology near the surface.FIB trench subsurface regions selected for energy dispersive spectroscopy analysis.Cobalt, chromium, and molybdenum elemental weight percent at different depths as determined by EDS.(Left to right) 1. FIB sample pull out of as-cast carbide in matrix. 2. Areas from which EDS and TEM diffraction patterns were taken. 3. TEM im...

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“…The good mechanical properties of implants are also related to the contact of the implant and human hard tissues. Even though, basic requirement of an implant material is to have good hardness, excellent corrosion and erosion resistance with good wear resistance, interaction between the tissues-implant interfaces is also play an important role (Mas Ayu et al, 2017;Giacchi et al, 2011;Geetha et al, 2010;Guocheng and Hala, 2010;Paital and Dahotre, 2009). Hence, surface modification of biomaterial implants is always aimed at modifying the material while still maintaining the bulk mechanical properties of the implant.…”

Section: Introductionmentioning

confidence: 99%

Thermal oxidation process improved corrosion in cobalt chromium molybdenum alloys

Ayu

Daud²,

Shah³

et al. 2017

Int. j. adv. appl. sci.

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The corrosion phenomena are always give bad impact to any metal products including human implants. This is due to the corrosion impacts are harmful for hard tissues and soft tissues. There are many methods to prevent the process of corrosion on implant materials such as coating with bioceramic materials and modify the implant surface with surface modification techniques. However, until now there is still no gold standard to overcome this problem and it is remain in researching process. Thus, the aim of this research is to investigate the potential and economical surface modification method to reduce the corrosion effects on Cobalt-Chromium-Molybdenum (Co-Cr-Mo) based alloy when insert in human body. The thermal oxidation process was selected to treat Co-Cr-Mo surface substrate. Firstly, Co-Cr-Mo alloy was heated in muffle furnace at constant temperature of 850°C with different duration of heating such as 3 hours and 6 hours in order to analyze the formation of oxide layer. The corrosion behaviours of untreated sample and oxidized sample were investigated utilizing potentiodynamic polarization tests in simulated body fluids (SBF). The Vickers hardness after corrosion testing was measured in order to evaluate the effect of thermal oxidation in reducing corrosion rate. Based on the results obtained it is clearly showed that substrates undergone thermal oxidation with 6 hours duration time performed better than 3 hours duration, with the hardness value 832.2HV vs. 588HV respectively. Dense oxide layer and uniform thickness formed on the oxidized substrates able to help in reducing the corrosion effects on Co-Cr-Mo alloy without degraded its excellent mechanical properties. The microstructures of oxidized substrates before and after corrosion test were also analyzed using FESEM images for better observations. It was determined that corrosion resistance of Co-Cr-Mo substrate can be increased with oxide layer formed on the alloys using thermal oxidation process.

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Microstructural characterization of as-cast biocompatible Co–Cr–Mo alloys

Cited by 143 publications

References 18 publications

Corrosion and Tribocorrosion Behavior of Cast and Machine Milled Co-Cr Alloys for Biomedical Applications

Corrosion and Tribocorrosion Behavior of Cast and Machine Milled Co-Cr Alloys for Biomedical Applications

In-Vivo Corrosion and Fretting of Modular TI-6AL-4V/CO-CR-MO Hip Prostheses: The Influence of Microstructure and Design Parameters

Thermal oxidation process improved corrosion in cobalt chromium molybdenum alloys

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