Effects of Cobalt Content on the Microstructure, Mechanical Properties and Cavitation Erosion Resistance of HVOF Sprayed Coatings
Cobalt-based alloy coatings and WC-Co-based ceramic−metal (cermet) coatings have been widely used because of their desirable mechanical properties and corrosion resistance. In this work, the influence of Co content on the microstructure, mechanical properties and cavitation erosion (CE) re...
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doaj-7a442f56bbd046b18934556f4f0217ce2020-11-25T02:00:09ZengMDPI AGCoatings2079-64122019-08-019953410.3390/coatings9090534coatings9090534Effects of Cobalt Content on the Microstructure, Mechanical Properties and Cavitation Erosion Resistance of HVOF Sprayed CoatingsJi Liu0Xiuqin Bai1Tongzhou Chen2Chengqing Yuan3Reliability Engineering Institute, National Engineering Research Center for Water Transport Safety, Wuhan University of Technology, Wuhan 430063, ChinaReliability Engineering Institute, National Engineering Research Center for Water Transport Safety, Wuhan University of Technology, Wuhan 430063, ChinaState Key Laboratory of Special Surface Protection Materials and Application Technology, Wuhan Research Institute of Materials Protection, Wuhan 430030, ChinaReliability Engineering Institute, National Engineering Research Center for Water Transport Safety, Wuhan University of Technology, Wuhan 430063, ChinaCobalt-based alloy coatings and WC-Co-based ceramic−metal (cermet) coatings have been widely used because of their desirable mechanical properties and corrosion resistance. In this work, the influence of Co content on the microstructure, mechanical properties and cavitation erosion (CE) resistance were investigated. A cobalt-based alloy coating, a WC-12Co coating, and a WC-17Co cermet coating were deposited by high-velocity oxygen fuel (HVOF) spraying on 1Cr18Ni9Ti substrates. Results indicate that the cobalt-based alloy coating had the largest surface roughness because surface-bonded particles of lower plastic deformation were flattened. The existence of WC particles had led to an increase in hardness and improved the fracture toughness due to inhibit crack propagation. The pore appeared at the interface between WC particles, and the matrix phase had introduced an increase in porosity. With the increase in Co content, the cohesion between matrix friction and WC particles increased and then decreased the porosity (from 0.99% to 0.84%) and surface roughness (<i>R</i><sub>a</sub> from 4.49 to 2.47 μm). It can be concluded that the hardness had decreased (from 1181 to 1120 HV<sub>0.3</sub>) with a decrease in WC hard phase content. On the contrary, the fracture toughness increased (from 4.57 to 4.64 MPa∙m<sup>1/2</sup>) due to higher energy absorption in the matrix phase. The WC-12Co and WC-17Co coatings with higher hardness and fracture toughness exhibited better CE resistance than the cobalt-based alloy coating, increasing more than 20% and 16%, respectively. Especially, the WC-12Co coating possessed the best CE resistance and is expected to be applicable in the hydraulic machineries.https://www.mdpi.com/2079-6412/9/9/534cobalt-based alloyWC-Cocobalt contentHVOFmechanical propertiescavitation erosion |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Ji Liu Xiuqin Bai Tongzhou Chen Chengqing Yuan |
spellingShingle |
Ji Liu Xiuqin Bai Tongzhou Chen Chengqing Yuan Effects of Cobalt Content on the Microstructure, Mechanical Properties and Cavitation Erosion Resistance of HVOF Sprayed Coatings Coatings cobalt-based alloy WC-Co cobalt content HVOF mechanical properties cavitation erosion |
author_facet |
Ji Liu Xiuqin Bai Tongzhou Chen Chengqing Yuan |
author_sort |
Ji Liu |
title |
Effects of Cobalt Content on the Microstructure, Mechanical Properties and Cavitation Erosion Resistance of HVOF Sprayed Coatings |
title_short |
Effects of Cobalt Content on the Microstructure, Mechanical Properties and Cavitation Erosion Resistance of HVOF Sprayed Coatings |
title_full |
Effects of Cobalt Content on the Microstructure, Mechanical Properties and Cavitation Erosion Resistance of HVOF Sprayed Coatings |
title_fullStr |
Effects of Cobalt Content on the Microstructure, Mechanical Properties and Cavitation Erosion Resistance of HVOF Sprayed Coatings |
title_full_unstemmed |
Effects of Cobalt Content on the Microstructure, Mechanical Properties and Cavitation Erosion Resistance of HVOF Sprayed Coatings |
title_sort |
effects of cobalt content on the microstructure, mechanical properties and cavitation erosion resistance of hvof sprayed coatings |
publisher |
MDPI AG |
series |
Coatings |
issn |
2079-6412 |
publishDate |
2019-08-01 |
description |
Cobalt-based alloy coatings and WC-Co-based ceramic−metal (cermet) coatings have been widely used because of their desirable mechanical properties and corrosion resistance. In this work, the influence of Co content on the microstructure, mechanical properties and cavitation erosion (CE) resistance were investigated. A cobalt-based alloy coating, a WC-12Co coating, and a WC-17Co cermet coating were deposited by high-velocity oxygen fuel (HVOF) spraying on 1Cr18Ni9Ti substrates. Results indicate that the cobalt-based alloy coating had the largest surface roughness because surface-bonded particles of lower plastic deformation were flattened. The existence of WC particles had led to an increase in hardness and improved the fracture toughness due to inhibit crack propagation. The pore appeared at the interface between WC particles, and the matrix phase had introduced an increase in porosity. With the increase in Co content, the cohesion between matrix friction and WC particles increased and then decreased the porosity (from 0.99% to 0.84%) and surface roughness (<i>R</i><sub>a</sub> from 4.49 to 2.47 μm). It can be concluded that the hardness had decreased (from 1181 to 1120 HV<sub>0.3</sub>) with a decrease in WC hard phase content. On the contrary, the fracture toughness increased (from 4.57 to 4.64 MPa∙m<sup>1/2</sup>) due to higher energy absorption in the matrix phase. The WC-12Co and WC-17Co coatings with higher hardness and fracture toughness exhibited better CE resistance than the cobalt-based alloy coating, increasing more than 20% and 16%, respectively. Especially, the WC-12Co coating possessed the best CE resistance and is expected to be applicable in the hydraulic machineries. |
topic |
cobalt-based alloy WC-Co cobalt content HVOF mechanical properties cavitation erosion |
url |
https://www.mdpi.com/2079-6412/9/9/534 |
work_keys_str_mv |
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1724962218900979712 |