Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
M. Senthil kumar,,S. Natarajan
International Journal of Engineering Science and Technology , 2011,
Abstract: Thermal spray processes are widely used in industries to compensate the worn surfaces of different components used in automobiles. This comes as a means of savings the worn parts by reusing them afterthey have been thermally sprayed by suitable wear resistant coatings. In this study, the HVOF sprayed (WC-12%CO and Al2O3-13%TiO2) coating is applied to AISI 1040 steel substrate. The surface morphology, composition and phase structure analysis are done with the help of scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD), respectively. The high temperature pin on disc test was used to estimate the wear of the coatings at different process parameters. An orthogonal array and analysis of variance was employed to investigate the influence process parameters on the coatings.The objective is to establish a correlation between the wear of coatings and wear parameters such as load, temperature and velocity. These correlations were obtained by multiple regressions. Finally, confirmation tests were conducted to verify the experimental results foreseen from the mentioned correlations. The data were analyzed and a statistical model, explaining the effects of different parameters as well as their interaction, was obtained. Results shows that wear rate, at room temperatures, of the WC-12%Co and Al2O3–13%TiO2 are almost same. While at 600°C, the wear failure mechanism turns from plastic deformation to fracture resulting from crack propagation.
Tribological Properties of Plasma-Sprayed Coatings Under Water-Lubricated Sliding

LI Jian-Feng,HUANG Jing-Qi,ZHANG Ye-Fang,DING Chuan-Xian,

无机材料学报 , 1998,
Abstract: Tribological properties of plasma-sprayed self-mated Cr3C2-NiCr, WC-Co and Cr2O3 coatings and the Cr2O3 coating against WC Co hard alloy and toughened SiC ceramics were investigated under water-lubricated sliding. It was found that Cr2O3 coating was the most wear-resistant among the three kinds of self-mated coatings and had a wear coefficient less than 10-6mm3N-1m-1. Wear mechanisms of the coatings were explained in terms of microcracking and grain fracturing. The higher the fracture toughness, and the lower the porosity and the length of microcrack of the coating, the more wear-resistant the coating was. The friction coefficient and wear coefficient of Cr2O3 coating were obviously reduced when it was mated to WC Co hard alloy and toughened SiC ceramics, which may be related to surface condition and tribochemical reaction of material of friction pair.
Effects of WC Geometric Shape on Tribological Performance of WC Reinforced Ni-based Alloy Flame Sprayed Coatings

YAO Shun-hui,

摩擦学学报 , 2009,
Abstract: Using flame spray/fusion technique,tungsten carbide(WC 20 wt%) reinforced Ni-based alloy coatings were prepared,employing WC powders with different geometric shape.The obtained coatings then were studied for micro-structure,constitution phases,micro-hardness and friction and wear performance.The results showed that the geometric shape of WC powders was certainly an important factor that played significant effects on all kinds of applications.Considering the enhancement by WC in anti-wear resistance,the roun...
Wear Resistant Thermal Sprayed Composite Coatings Based on Iron Self-Fluxing Alloy and Recycled Cermet Powders
Materials Science , 2012, DOI: 10.5755/j01.ms.18.1.1338
Abstract: Thermal spray and WC-Co based coatings are widely used in areas subjected to abrasive wear. Commercial cermet thermal spray powders for HVOF are relatively expensive. Therefore applying these powders in cost-sensitive areas like mining and agriculture are hindered. Nowadays, the use of cheap iron based self-fluxing alloy powders for thermal spray is limited. The aim of this research was to study properties of composite powders based on self-fluxing alloys and recycled cermets and to examine the properties of thermally sprayed (HVOF) coatings from composite powders based on iron self-fluxing alloy and recycled cermet powders (Cr3C2-Ni and WC-Co). To estimate the properties of recycled cermet powders, the sieving analysis, laser granulometry and morphology were conducted. For deposition of coatings High Velocity Oxy-Fuel spray was used. The structure and composition of powders and coatings were estimated by SEM and XRD methods. Abrasive wear performance of coatings was determined and compared with wear resistance of coatings from commercial powders. The wear resistance of thermal sprayed coatings from self-fluxing alloy and recycled cermet powders at abrasion is comparable with wear resistance of coatings from commercial expensive spray powders and may be an alternative in tribological applications in cost-sensitive areas. DOI: http://dx.doi.org/10.5755/j01.ms.18.1.1338
Ceramics-Silikáty , 2011,
Abstract: Tribological properties of TiBx and WC/C coatings have been studied using the ball-on-disc method at room and elevated temperatures in air to investigate their behavior under conditions approaching high performance dry cutting. The average room temperature coefficients of friction (COF) of both nanocomposite DC magnetron sputtered TiBx coatings and PECVD WC/C coatings were in the range 0.2-0.6. The lowest value of TiBx coatings of 0.16 was achieved in case of prefferentially oriented stuctures deposited at the highest negative bias. The lowest COF of WC/C was around 0.11. The increase of testing temperature to 450°C caused the increase of COF up to approximately 0.7-0.8. The experiments at elevated temperatures suggest the existence of the oxide transfer film with higher COF than that of the sliding contact without the film. Although both coating systems have relatively high COF values at elevated temperatures, they exhibit elements of some adaptive behavior.
Influence of Wettability and Mechanical Properties on Tribological Performance of DLC Coatings under Water Lubrication  [PDF]
Chaoqun Zhang, Masahiro Fujii
Journal of Surface Engineered Materials and Advanced Technology (JSEMAT) , 2015, DOI: 10.4236/jsemat.2015.53013
Abstract: DLC coatings are currently used in a wide variety of industrial fields because of their outstanding properties such as high hardness, high wear resistance, low friction and so on under oil lubrication as well as no lubrication. In order to evaluate the tribological performance of DLC coatings under water lubrication, eight types of DLC coatings were evaluated by water-lubricated sliding tests at sliding velocities of 0.02 m/s and 0.1 m/s. The different DLC coating types comprised both hydrogenated and hydrogen-free DLC films that were deposited using different techniques: amorphous hydrogenated DLC (a-C:H), that doped with tungsten (a-C:H:W), that doped with silicon (a-C:H:Si) and hydrogen-free DLC (ta-C). DLC coatings showed low friction coefficient and excellent wear resistance. Friction coefficient and wear rate decreased with increasing sliding velocity. The effect of surface wettability and mechanical properties on tribological characteristics was investigated. Friction coefficient decreased as the contact angle increased. Hydrogen-free DLC coating with the highest hardness showed the highest friction and a larger wear rate. Furthermore, DLC coatings deposited with interlayer showed longer lifetimes.

WANG Tiegang,SONG Binghong,HUA Weigang,GONG Jun,SUN Chao State Key Laboratory of Corrosion,Protection,

金属学报 , 2011,
Abstract: Based on the orthogonal experiment, the effects of oxygen-fuel ratio and spraying distance on physical and mechanical properties of D-gun sprayed WC-Co coatings were investigated. An ideal coating with the uniform dense microstructures, high hardness and elastic modulus, and excellent wear resistance was obtained by technology optimization. The phase identifications and microstructure observation of the optimized WC-Co coating were conducted by XRD and SEM, respectively. The coating showed near-isotropic behaviors, which has been verified by the comparisons of mechanical and wear properties between cross section and surface. The mechanisms how the spraying parameters affected near--isotropic characters of the D-gun sprayed WC-Co coating were analyzed and discussed.

Ye Pan,

金属学报 , 2008,
Abstract: FeS/SiC composite coatings have been successfully produced by plasma spray technique. SiC particles with nano-scale are uniformly distributed in FeS matrix. There is a good bond between the coatings and 40Cr steel substrate. The tribological properties of FeS coating and FeS/SiC composite coatings have been investigated. The results show that FeS/SiC composite coatings have good antifriction and wear resistance properties. The friction coefficients of the composite coatings, mixed with nano SiC particles in weight fraction 0.2 and 0.3, are almost same as that of FeS coating under dry sliding, but the wear volume of them is remarkably decreased over the range of an order of magnitude. In oil lubrication, the friction coefficient of FeS/SiC composite coatings is smaller than that of FeS coating. So the composite coatings have superior antifriction property in the case.
Wettability, Thermal and Sliding Behavior of Thermally Sprayed Fly Ash Premixed Red Mud Coatings on Mild Steel  [PDF]
Harekrushna Sutar, Birupakshya Mishra, Rabiranjan Murmu, Sangram Patra, Sarat Chandra Patra, Subash Chandra Mishra, Debashis Roy
Materials Sciences and Applications (MSA) , 2020, DOI: 10.4236/msa.2020.111002
Abstract: The present experimental work reveals the surface characteristics like wettability, thermal and sliding wear behaviour of plasma-sprayed red mud (RM) coatings premixed with fly ash (FA). Varying weight % of FA (10, 20, 30 and 40)—RM composite powder is used as precursor for coating. Atmospheric plasma-sprayed coatings are developed at different operating power like 5 kW, 10 kW, 15 kW and 20 kW separately on mild steel substrate. Tribological behaviour viz. sliding wear properties are studied at distinct operating load (10N, 15N, 20N, 25N), speed (40 rpm, 50 rpm, 60 rpm, 70 rpm) and track diameter of 100 mm using a pin on disc tribometer for duration of 30 minutes with 3 minute gap period for each experiment. The DSC and TGA experiments of the coatings are performed to understand the high temperature application areas. The contact angle result signifies the wettability of the prepared coatings is principally a function of composition. The reaction of surface roughness and spraying power is in-significant on water contact angle (WCA). In conclusion, the sliding wear experiments are optimized by Taguchi method to ascertain the influencing parameter on wear.
Comportamiento a desgaste de recubrimientos de WC proyectados por plasma a partir de polvos micro y nanoestructurados  [cached]
Salvador, M. D.,Candel, J. J.,Bonache, V.,Segovia, F.
Revista de Metalurgia , 2008,
Abstract: The aim of the present work is the study of wear behaviour of different WC coatings deposited on stainless steel substrate by means of atmospheric plasma spraying (APS). Two types of WC commercial powders, with different metal binder (12% Cobalt and 10% Nickel) have been deposited in order to analyse the influence of the metal matrix and thickness of the coating in tribological properties.The microstructure of the depositions was characterized using scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). On the other hand, tribology characterization of the coatings was made by pin-on-disk wear tests against alumina (2400HV) and silicon nitride (1600HV) ceramic balls, without lubrication. Wear rates and friction coefficient evolution have been calculated. Finally, wear tracks and wear debris have been analysed with the help of SEM.The results of each pair of tested materials show different mechanisms of wear related to the nature of the ball that has been used, obtaining higher wear rates with silicone nitride ball..In a second phase of the study, in order to examine the influence of the initial particle size on the wear properties of the coatings, cobalt based coatings have been analysed with different initial particle size (micrometric and nanometric particles).Results show that nanostructured coatings have higher wear resistance than microstrutured ones for high loads. However for low loads, behaviour is similar in spite of the microstructural differences appreciated. El objetivo de este trabajo es estudiar el comportamiento a desgaste de distintos recubrimientos de WC sobre acero inoxidable mediante proyección por plasma atmosférico. Se proyectan dos tipos de polvos comerciales con base cobalto (12 %) y níquel (10 %), con el objeto de analizar la influencia de la matriz e incluso del espesor del recubrimiento. Los recubrimientos obtenidos se caracterizan microestructuralmente por microscopía electrónica de barrido y difracción de rayos X. La caracterización tribológica de los recubrimientos se realiza mediante ensayos pin-on-disc contra bolas cerámicas de alúmina (2.400 HV) y nitruro de silicio (1.600 HV), sin lubricación, obteniéndose las tasas de desgaste y la evolución del coeficiente de rozamiento. Las pistas de desgaste y los residuos generados se caracterizaron mediante Microscopía Electrónica de Barrido, MEB. Los resultados muestran diferentes mecanismos de desgaste en cada par de material ensayado en función de la matriz y de la naturaleza de la bola empleada en el ensayo, encontrándose mayores tasas de desgaste con bola de n
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.