Microstructure and Tribocorrosion Behavior of Al 2 O 3 /Al Composite Coatings: Role of Al 2 O 3 Addition

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Microstructure and Tribocorrosion Behavior of Al2O3/Al Composite Coatings: Role of Al2O3 Addition Jiangbo Cheng1 • Yunyun Ge1 • Bishi Wang1 • Lianhua Zhang2 • Xianlong Hu3 Shen Hong1 • Xiubing Liang4 • Xiancheng Zhang5



Submitted: 2 April 2020 / in revised form: 1 June 2020 Ó ASM International 2020

Abstract Pure Al coating and Al2O3 particles reinforced Al composite coatings were prepared by arc-spraying. The feedstocks were pure Al wires and Al-based cored wires containing 10, 20, 30 vol.% Al2O3, respectively. The evolutions of microstructure, porosity and microhardness of the coatings with different Al2O3 contents were investigated. Microstructural analysis shows that the addition of Al2O3 particles improves density and decreases the porosity of the coating. The average hardness of the composite coatings varies from 39 to 416.5 HV0.1 as Al2O3 content increases from 0 to 30 vol.%. However, the microhardness of the Al matrix in the coatings increases first and then decreases as a function of Al2O3 contents. The tribocorrosion tests were performed under potentiodynamic polarization conditions in 3.5 wt.% NaCl solution. The cathodic shift of open circuit potential and the increase in current density are induced by sliding wear. Compared with pure Al coating, the Al2O3 particles reinforced composite coatings display a lower wear rate and & Jiangbo Cheng [email protected] 1

College of Mechanics and Materials, Hohai University, No. 8 Focheng West Road, Nanjing 211100, People’s Republic of China

2

Jiangsu Huawei Machinery Manufacturing Co., Ltd., Yancheng 224799, People’s Republic of China

3

Baosteel Roll Science & Technology Co., Ltd., Changzhou 213019, People’s Republic of China

4

National Institute of Defense Technology Innovation, Academy of Military Sciences PLA China, Beijing 100010, People’s Republic of China

5

Key Laboratory of Pressure Systems and Safety, Ministry of Education, East China University of Science and Technology, Shanghai 200237, People’s Republic of China

coefficient of friction. The Al-20 vol.%Al2O3 composite coating shows superior resistance to tribocorrosion. The tribocorrosion mechanism of the composite coatings is delamination coupling of corrosion wear. Keywords arc-spray  coatings  Tribocorrosion

Introduction The harsh marine environments involving corrosion and wear simultaneously will accelerate the degradation of offshore equipment and the reduction in life span of components used for critical operations (Ref 1-3). To improve the reliability and service life of these infrastructures or components, the surface coating is an available method to protect structural materials in such aggressive working atmosphere (Ref 4-6). The aluminum coating prepared by thermal spraying process has been widely employed because of cathodic protection (Ref 7, 8). However, the low hardness and poor wear resistance are the main defects for the as-sprayed pure Al coating (Ref 9, 10). Once the Al coating is partially damaged, it will be produced the further dissolution by ga

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