Polyaniline coating electrochemical properties improvement after roughened platinum substrate and its anti-wear performance study

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1477-1483
Author(s):  
Wenguang Zhang ◽  
Wei Li ◽  
Xiaowen Sun

In order to improve the electrochemical performance of the neural electrode the polyaniline coatings were modified on roughened Pt (PANI/rPt1) electrodes using electrochemical method. The roughness factor (fR up to 424) of Pt surfaces increased significantly through electrochemical roughening processing. PANI/rPt electrodes showed excellent interfacial properties. Specifically, about 5.6-fold increase in the charge density of PANI/rPt (fR = 424) was observed, while the interfacial impedance (103.5 Ω) was reduced by 50% compared to that of PANI coatings on the smooth Pt surfaces (PANI/sPt2). The results indicate the potential application of PANI/rPt as an efficient and stable future neural interface. In addition, the wear test shows that the coating did not fail during the wearing period and holds an excellent wear resistance ability.

2020 ◽  
pp. 002199832095740
Author(s):  
S Dhanalakshmi ◽  
K ShanmugaSundaram ◽  
TR Tamilarasan ◽  
R Rajendran

Aluminium matrix composites (AMC) are gaining wide popularity in various sectors due to their excellent properties which are synergic. Apart from strength, wear resistance of a material is also an essential criterion for the number of applications. Extensive studies are being carried out on the secondary processing of these materials to enhance the suitability of the AMC for engineering applications. In this study, initially, Al 2014 base alloy and their composites with 5, 10, and 15 wt.% SiCp fabricated by stir casting route were subjected to wear test. Based on the encouraging wear performance, the Al-10 wt.% SiC composite was further subjected to extrusion. Pin-on-disc sliding wear tests on the as-cast & extruded base alloy and the composite samples were carried out at a constant load of 20 N for a total sliding distance of 1000 m with a velocity of 2 m/s. Microhardness and porosity measurements were carried out besides the study of wear performance, such as coefficient of friction and wear by weight loss. The worn surfaces were analyzed both by optical and scanning electron microscopes. The effect of particle addition, extrusion, porosity, and microhardness on the wear performance of the samples was discussed. Among the samples studied, the Al-10 wt.% SiC composite extruded at a ratio of 8:1 is found to have the highest wear resistance.


Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 660
Author(s):  
Qun Wang ◽  
Yingpeng Zhang ◽  
Xiang Ding ◽  
Shaoyi Wang ◽  
Chidambaram Seshadri Ramachandran

In order to investigate the effect of WC grain size on coatings’ properties and abrasive wear performance, a few WC-20Cr3C2-7Ni coatings with three different WC grain sizes were deposited by the high-velocity oxy-fuel (HVOF) thermal spray process. The phase compositions, microstructures, and mechanical properties of the coatings were investigated. Furthermore, the two- and three-body abrasive wear performances of the three coatings were tested by using SiC and SiO2 abrasives, respectively. The results show that all the three coatings were composed of WC, Cr3C2, and the Ni binder as well as the (W,Cr)2C phase. The abrasive wear resistance of the WC-20Cr3C2-7Ni coating monotonously increased with increasing WC grain size when the SiC abrasive was used in the two- and three-body abrasive wear tests. However, the wear resistance trend was reversed when the SiO2 abrasive was used in the three-body abrasive wear test. The specific wear rate of the WC-20Cr3C2-7Ni coating exposed to the SiC abrasive under the two-body abrasive wear test was the largest. The wear resistance of the coatings was more significantly affected by the hardness of the abrasive particles than the size of carbides present within the coating. The high hardness of SiC can cut both the carbide and the binder phase of the WC-based cermet coatings, resulting in a high wear rate, whereas the low hardness of SiO2 cuts and/or scratches the binder initially, and then it dislodges the carbides from the matrix. The dislodged carbides which were subsequently pulled out from the matrix by the repeated impact of the SiO2 abrasives result in a milder wear rate.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Zhu Weixin ◽  
Kong Dejun

Abstract NiMo-5%TiC, NiMo-15%TiC, and NiMo-25%TiC coatings were prepared on GCr15 steel by laser cladding (LC). The microstructure and the phases of the obtained coatings were analyzed using ultra-depth-of-field microscopy (UDFM) and X-ray diffraction (XRD), respectively. A ball-on-disk wear test was used to analyze the friction-wear performance of the substrate and the NiMo-TiC coatings under grease-lubrication condition. The results show that the grain shape of NiMo-TiC coatings is dendritic. The wear resistance of NiMo-TiC coatings is improved by the addition of TiC, and the depths of the worn tracks on the substrate and on the NiMo-5%TiC, NiMo-15%TiC, and NiMo-25%TiC coatings are 4.183 μm, 2.164 μm, 1.882 μm, and 1.246 μm, respectively, and the corresponding wear rates are 72.25 μm3/s/N, 32.00 μm3/s/N, 18.10 μm3/s/N, and 7.99 μm3/s/N, respectively; this shows that the NiMo-25%TiC coating has the highest wear resistance among the three kinds of coatings. The wear mechanism of NiMo-TiC coatings is abrasive wear, and the addition of TiC plays a role in resisting wear during the friction process.


2011 ◽  
Vol 295-297 ◽  
pp. 256-259
Author(s):  
Jing Li ◽  
Jin Shan Zhao

Fe-28Al and Fe-28Al-10Ti alloys were prepared by mechanical alloying and hot pressed sintering. The mechanical properties and wear resistance were studied. The results show that Fe-28Al bulk material is mainly characterized by the low ordered B2 Fe3Al structure with some dispersed Al2O3 particles. The mechanical properties such as the hardness and strength of Fe-28Al-10Ti are significantly improved compared with Fe-28Al, which is attributed to the grain refinement and solid solution reinforcing with the addition of Ti element. The fracture mode is mainly the intergranular fracture. Fe-28Al-10Ti exhibits more excellent wear resistance than Fe-28Al, especially after long distance sliding wear test. There is difference in wear mechanisms of Fe-28Al and Fe-28Al-10Ti alloys. Under the load of 100N, there is obvious plastic deformation on the worn surface of Fe-28Al. Micro-crack and layer splitting occur on the surface of Fe-28Al. The main wear performance of Fe-28Al-10Ti is particle abrasion, the characteristics of which are micro cutting and micro furrows.


2009 ◽  
Vol 416 ◽  
pp. 443-448 ◽  
Author(s):  
Hui Min Chen ◽  
Liu Jie Xu ◽  
Shi Zhong Wei

The expansion curves during the procedure of continuous cooling which high vanadium high speed steel (HSS) was tempered with 250°C, 550°C and 600°C after 1050°C quenching were determined by the Gleeble-1500D thermal simulation test device, and the curves were analyzed subsequently. The hardness and microstructure of high vanadium HSS under different tempering temperatures were analyzed by means of SEM, TEM and X-ray diffraction, and the influence of tempering temperature on the hardness and retained austenite were discussed. At the same time, the wear resistance of the material at different tempering temperatures was studied by the HST-100 friction wear testing machine, and the influence of microstructure on wear resistance was analyzed further. The studies show that the structures are not transformed at 250°C tempering with cooling rate of 0.5°C/s; The retained austenite transformed to martensite at about 390°C when 550°C and 600°C tempering. Wear test shows that the abrasive wear performance is excellent with 550°C tempering after 1050°C quenching because of the decrease of the amount of retained austenite, therefore the heat treatment of 550°C tempering after quenching of high vanadium HSS is optimal.


2008 ◽  
Vol 591-593 ◽  
pp. 271-276 ◽  
Author(s):  
M.A. Martinez ◽  
R. Calabrés ◽  
J. Abenojar ◽  
Francisco Velasco

In this work, ultrahigh carbon steels (UHCS) obtained by powder metallurgy with CIP and argon sintered at 1150°C. Then, they were rolled at 850 °C with a reduction of 40 %. Finally, steels were quenched at 850 and 1000 °C in oil. In each step, hardness, bending strength and wear performance were evaluated. Obtained results are justified with a metallographic study by SEM. Both mechanical properties and wear resistance are highly favoured with the thermomechanical treatment that removes the porosity of the material. Moreover, final quenching highly hardens the material. The obtained material could be used as matrix for tool steels.


2005 ◽  
Vol 20 (5) ◽  
pp. 1122-1130 ◽  
Author(s):  
Y.X. Yin ◽  
H.M. Wang

Wear-resistant Cu-based solid-solution-toughened Cr5Si3/CrSi metal silicide alloy with a microstructure consisting of predominantly the dual-phase primary dendrites with a Cr5Si3 core encapsulated by CrSi phase and a small amount of interdendritic Cu-based solid solution (Cuss) was designed and fabricated by the laser melting process using Cr–Si–Cu elemental powder blends as the precursor materials. The microstructure of the Cuss-toughened Cr5Si3/CrSi metal silicide alloy was characterized by optical microscopy, powder x-ray diffraction, and energy dispersive spectroscopy. The Cuss-toughened silicide alloys have excellent wear resistance and low coefficient of friction under room temperature dry sliding wear test conditions with hardened 0.45% C carbon steel as the sliding–mating counterpart.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2112
Author(s):  
Saverio Affatato ◽  
Paolo Erani ◽  
Maurizio Fersini ◽  
Vincenzo Contaldi ◽  
Anna Rita Terrizzi ◽  
...  

Success of total knee replacement (TKR) depends on the prosthetic design and materials. The use of metal components is well established with the disadvantage of allergic reactions. Ceramics have been recently proposed because of high wear resistance, excellent biocompatibility, wettability, and suitable mechanical properties. This study was aimed at investigating in vitro wear resistance of Zirconia Toughened Alumina (ZTA)/Ultra-high-molecular-weight polyethylene (UHMWPE) of TKR femoral components. An in vitro protocol was designed with the application of relevant load profile, 6-degrees-of-freedom knee simulator, and 8 × 105 cycles on the ZTA/UHMWPE configuration under bovine calf serum. Before and after wear test, the femoral components were investigated by using the Scanning Electron Microscope (SEM) and the X-Ray Diffraction (XRD) analyses, and stylus surface roughness measurements. The proposed pre-clinical test yielded repeatable results. In particular, gravimetric results showed that, after 8 × 105 cycles, the mean weight loss of the polyethylene mobile components is 5.3 ± 1.1 mg. The surface roughness measurements (Ramax) performed after the wear test showed no significant variation on the UHMWPE menisci. A slight increase of roughness has been found on the ZTA (0.02 µm before wear test, 0.28 µm after the test). SEM observations did not show significant modification of the surface morphology. Tetragonal to monoclinic phase ratio was measured by XRD before and after wear test to evaluate stability of tetragonal ZrO2 phase. Minimal conversion of tetragonal to monoclinic phase was found from 5.4 to 8%. Although this study is a preliminary evaluation limited to in vitro tests, it provides novel pre-clinical indications about the potential of ceramic TKR femoral components.


Author(s):  
L.-M. Berger ◽  
P. Vuoristo ◽  
T. Mäntylä ◽  
W. Kunert ◽  
W. Lengauer ◽  
...  

Abstract WC-Co-Cr represents an important composition for hardmetal-like coatings which is appHed when simuhaneous wear and corrosion resistance is required. In this paper five commercially available spray powders obtained by various production techniques (sintered and crushed as well as agglomerated and plasma-densified) of the composition WC-10%Co- 4%Cr have been thoroughly characterized and were sprayed by DCS, HVOF (CDS process) and APS. The microstructures of the coatings were characterized and their wear behaviour was investigated by means of an abrasion wear test. For the best of these powders the wear resistance was nearly equal for the DGS and HVOF coatings. Other powders show significant differences with respect to their processabilities in these spray processes. APS coatings from all powders, obtained with an Ar/H2 plasma showed inferior microstructures and significant lower wear resistance. The spray powder compositions, grain sizes and structures were found to determine the processability of the powders and the microstructure and properties of the coatings. COMPOSITE MATERIALS of the type hard phase - metallic binder with WC and CoCr as constituents are widely used for the preparation of hardmetal-like coatings. The chromium addition to the metallic binder is thought to improve its corrosion resistance in comparison with pure WC-Co. This has led to many applications of WC-CoCr coatings where simultaneous wear and corrosion resistance is required. Despite of its significant practical importance only a limited number of publications is devoted to detailed questions of structure and properties of WC-CoCr coatings (1-3). In some comparative studies such coatings have been investigated together with WC-Co and Cr3C2-NiCr coatings (4-8). However, systematic investigations of spray powder compositions and morphologies as well as investigations of the influence of different thermal spray processes on coating structures and properties which have repeatedly been provided for WC-Co (for example (9, 10)) are missing for WC-CoCr. In this paper a short survey of literature on the phase relationships in the WC-CoCr system and the effect of chromium additions on the properties of sintered parts and thermally sprayed coatings compared to WC-Co is given. In the experimental part a systematic study of the influence of the preparation process on composition and morphology of commercially available WC-10%Co-4%Cr spray powders was provided. These powders have been sprayed by DGS, HVOF and APS and the microstructure and basic properties of the coatings have been studied.


2011 ◽  
Vol 306-307 ◽  
pp. 425-428
Author(s):  
Jing Li ◽  
Xiao Hong Fan ◽  
De Ming Sun

Fe-28Al and Fe-28Al-10Ti alloys were prepared by mechanical alloying and hot pressing. The phases and dry sliding wear behavior were studied. The results show that Fe-28Al bulk materials are mainly characterized by the low ordered B2 Fe3Al structure with some dispersed Al2O3 particles. Fe-28Al-10Ti exhibits more excellent wear resistance than Fe-28Al, especially after long distance sliding wear test. There are obvious differences in wear mechanisms of Fe-28Al and Fe-28Al-10Ti alloys under different testing conditions. Under the load of 100N, there is plastic deformation on the worn surface of Fe-28Al. The main wear performance of Fe-28Al-10Ti is particle abrasion, the characteristics of which are micro cutting and micro furrows, but micro-crack and layer splitting begin to form on the surface of Fe-28Al. Under the load of 200N, serious plastic deformation and work-hardening lead to rapid crack propagation and eventually the fatigue fracture of Fe-28Al. Plastic deformation is the main wear mechanism of Fe-28Al-10Ti under the load of 200N, which are characterized by micro-crack and small splitting from the worn surface.


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