Effects of Al Addition on Microstructure and Wear Resistance of High-Velocity-Oxygen-Fuel-Sprayed FeCoNiCrMn High Entropy Alloy Coating

2019 ◽  
Vol 11 (5) ◽  
pp. 685-693 ◽  
Author(s):  
Zhidan Zhou ◽  
Xiubing Liang ◽  
Yongxiong Chen ◽  
Baolong Shen ◽  
Junchao Shang ◽  
...  
2018 ◽  
Vol 929 ◽  
pp. 142-149 ◽  
Author(s):  
Myrna Ariati Mochtar ◽  
Wahyuaji Narottama Putra ◽  
Raditya Perdana Rachmansyah

Tube boiler operating condition initiates common problems that can occur as a problem in the wear resistance material. It leads to a decreased function of the material so that it is necessary to repair or replacement. High Velocity Oxygen Fuel (HVOF) is regarded as one of the effective methods to increase the wear resistance of the material. In this study, the materials were ASTM SA213-T91 as a material commonly used for boiler tube and JIS G 3132 SPHT-2 as an alternative material. In the early stages, both of specimens were given initial surface heating with temperature variations 0, 50, 100 and 150oC. The materials were then coated with Stellite-1 using HVOF method. The material were then characterized for the microstructure, porosity, hardness distribution, and wear resistant. The results showed that the coating Stellite-1 as a top coat with HVOF method can improve the performance of the material. Microhardness increases from 220 HV to 770 HV on ASTM SA213-T91, while on the substrate JIS G 3132 SPHT-2 the microhardness increased from 120 HV to 750 HV. Better wear resistance was achieved with increasing preheating [1]. Wear resistance of the materials increased from the range 3.69x10-7at 0°C preheating up to 0.89x10-7on a specimen with initial surface heating 150oC. Porosity also decreases with the increasing preheating temperature.


2019 ◽  
Vol 813 ◽  
pp. 159-164
Author(s):  
Carlos Alberto Souto ◽  
Gustavo Faria Melo da Silva ◽  
Laura Angelica Ardila Rodriguez ◽  
Aline C. de Oliveira ◽  
Kátia Regina Cardoso

Coatings with high entropy alloys of the AlCoCrFeNiV system were obtained by selective laser melting on low carbon steel substrates. The effect of the variation of the Fe and V contents as well as the laser processing parameters in the development of the coating were evaluated. The coatings were obtained from the simple powder mixtures of the high purity elemental components in a planetary ball mill. The coatings were obtained by using CO2 laser with a power of 100 W, diameter of 0.16 mm, and scan speed varying from 3 to 12 mm/s. Phase constituents, microstructure and hardness were investigated by XRD, SEM, and microhardness tester, respectively. Wear resistance measurements were carried out by the micro-abrasion method using ball-cratering tests. The coatings presented good adhesion to the substrate and high hardness, of the order of 480 to 650 HV. Most homogeneous coating with nominal composition was obtained by using the higher scan speed, 12 mm/s. Vanadium addition increased hardness and gave rise to a high entropy alloy coating composed by BCC solid solutions. Ball cratering tests conducted on HEA layer showing improvement of material wear resistance, when compared to base substrate, decreasing up to 88% its wear rate, from 1.91x10-6 mm3/Nmm to 0.23x10-6 mm3/Nmm.


Author(s):  
Zhetcho Doinov Kalitchin ◽  
Mara Krumova Kandeva ◽  
Yana Petrova Stoyanova

This research work studies the characteristics of wear and wear resistance of composite powder coatings, deposited by high-velocity oxygen fuel, which contain composite mixtures Ni-Cr-B-Si having different chromium concentrations – 9.9%; 13.2%; 14%; 16% and 20% , at one and the same size of the particles and the same content of the remaining elements. The coating of 20% Cr does not contain B and Si. Out of each powder, composite coatings have been prepared without any preliminary thermal treatment of the substrate and with preliminary thermal treatment of the substrate up to 650оС. The coatings have been tested under identical conditions of dry friction over a surface of solid firmly attached abrasive particles using the tribological testing device „Pin-on-disk“. Results have been obtained and the dependences of the hardness, mass wear, intensity of the wearing process, absolute and relative wear resistance on the Cr concentration under identical conditions of friction. It has been found out that for all the coatings the preliminary thermal treatment of the substrate leads to a decrease in the wear intensity. Upon increasing Cr concentration the wear intensity diminishes and it reaches minimal values at 16% Cr. In the case of coatings having 20% Cr concentration, the wear intensity is increased, which is due to the absence of the components B and Si in the composite mixture, whereupon no inter-metallic structures are formed having high hardness and wear resistance. The obtained results have no analogues in the current literature and they have not been published by the authors.


2012 ◽  
Vol 518-523 ◽  
pp. 3984-3988
Author(s):  
Bai Lin Zha ◽  
Xiao Jing Yuan ◽  
De Wen Wang

Environmental protection and worker safety measures against the extensively used hard chrome plating (EHC) is becoming more stringent, which leads to the development and application of alternative technology. As one of the most promising replacement technology of EHC, WC/Co coatings deposited by High Velocity Oxygen Fuel (HVOF) have well performances in corrosion and wear resistance. The paper analyzed technical characteristics, property and cost of EHC and HVOF deposited WC-Co coatings, while results show that performance of HVOF sprayed WC-Co coatings is superior or equal to EHC with much higher expense, so current replacement of EHC by HVOF centers airplane and military arm field which have relatively higher profit.


Entropy ◽  
2018 ◽  
Vol 20 (12) ◽  
pp. 915 ◽  
Author(s):  
Kaijin Huang ◽  
Lin Chen ◽  
Xin Lin ◽  
Haisong Huang ◽  
Shihao Tang ◽  
...  

In order to improve the wear and corrosion resistance of an AZ91D magnesium alloy substrate, an Al0.5CoCrCuFeNi high-entropy alloy coating was successfully prepared on an AZ91D magnesium alloy surface by laser cladding using mixed elemental powders. Optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction were used to characterize the microstructure of the coating. The wear resistance and corrosion resistance of the coating were evaluated by dry sliding wear and potentiodynamic polarization curve test methods, respectively. The results show that the coating was composed of a simple FCC solid solution phase with a microhardness about 3.7 times higher than that of the AZ91D matrix and even higher than that of the same high-entropy alloy prepared by an arc melting method. The coating had better wear resistance than the AZ91D matrix, and the wear rate was about 2.5 times lower than that of the AZ91D matrix. Moreover, the main wear mechanisms of the coating and the AZ91D matrix were different. The former was abrasive wear and the latter was adhesive wear. The corrosion resistance of the coating was also better than that of the AZ91D matrix because the corrosion potential of the former was more positive and the corrosion current was smaller.


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