title: Microstructure and corrosion resistance of Ni-based alloy laser coatings with nanosize CeO2addition.
abstract: Micron-size Ni-base alloy (NBA) powders were mixed with both 1.5 wt.% (hereinafter %) micron-size CeO2(m-CeO2) and also 1.5% and 3.0% nano-size CeO2(n- CeO2) powders. These mixtures were coated on low-carbon steel (Q235) by 2.0 kW CO2laser cladding. The effects on the microstructures, phases and electrochemical corrosion of the coatings upon the addition ofm- andn- CeO2powders to NBA (m- andn- CeO2/NBA) have been investigated. The results showed that a smooth coating was prepared under suitable processing parameters (P= 2.0 kW,V= 180 mm min- 1) by adding 1.5%n- CeO2. In addition to the primary phases of γ-Ni, Cr23C6and Ni3B in the Ni-base alloy coating, CeNi3was formed in Ni-base alloy coatings with bothn- CeO2andm-CeO2particles, and CeNi5appeared in the coating upon decreasing the size of CeO2particles. Well-developed dendrites were observed in the Ni-base alloy coating; directional dendrites grew at the interface in the coating upon the addition ofm-CeO2, whereas fine and multioriented dendrites grew upon decreasing the size of CeO2particles to the nanoscale. Actinomorphic dendrites and compact equiaxed dendrites grew from the interface to near the surface upon increasing the content ofn- CeO2from 1.5 to 3.0%. In strongly acidic HNO3solution, the severe corrosion of dendrites occurred and there were many corrosion pits in the Ni-base alloy coating; intercrystalline corrosion also has a dominant role upon the addition ofm-CeO2, whereas uniform corrosion occurs in the coating as the size of CeO2particles is decreased to nanoscale.
authors.affiliation: School of Materials Science and Engineering, Anhui University of Technology, Maanshan City, Anhui Province, 243002, People's Republic of China; School of Nano and Advanced Materials Engineering, Changwon National University, 9, Sarim-Dong, Changwon, Gyeongnam, 641-773, South Korea.
authors.forename: Shi
authors.initials: S
authors.lastname: Hong Zhang
authors.affiliation: School of Materials Science and Engineering, Anhui University of Technology, Maanshan City, Anhui Province, 243002, People's Republic of China.
authors.forename: Ming
authors.initials: M
authors.lastname: Xi Li
authors.affiliation: School of Nano and Advanced Materials Engineering, Changwon National University, 9, Sarim-Dong, Changwon, Gyeongnam, 641-773, South Korea.
authors.forename: Jae
authors.initials: J
authors.lastname: Hong Yoon
authors.affiliation: School of Nano and Advanced Materials Engineering, Changwon National University, 9, Sarim-Dong, Changwon, Gyeongnam, 641-773, South Korea.
authors.forename: Tong
authors.initials: T
authors.lastname: Yul Cho
authors.affiliation: School of Materials Science and Engineering, Anhui University of Technology, Maanshan City, Anhui Province, 243002, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhu He
authors.affiliation: School of Nano and Advanced Materials Engineering, Changwon National University, 9, Sarim-Dong, Changwon, Gyeongnam, 641-773, South Korea.
authors.forename: Chan
authors.initials: C
authors.lastname: Gyu Lee
keywords: corrosion resistance; laser cladding; microstructure; n-CeO2/Ni-based alloy