Laser cladding in-situ NbC particle reinforced Fe-based composite coatings with rare earth oxide addition

• Published in: Surface & coatings technology Vol. 239; pp. 102 - 107
• Main Authors: Li, Qingtang, Lei, Yongping, Fu, Hanguang
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 25.01.2014; Elsevier
• Subjects: Applied sciences; Composite coating; Cross-disciplinary physics: materials science; rheology; Dispersion hardening metals; Exact sciences and technology; In situ; Laser cladding; Materials science; Metallic coatings; Metals. Metallurgy; Niobium carbide; Physics; Powder metallurgy. Composite materials; Production techniques; Rare earth oxide; Surface treatment; Surface treatments; Rare earth oxide; Niobium carbide; Laser cladding; Composite coating; In situ; Surface treatments; Dispersion strengthened metal; Niobium; Metal coating; Composite materials; Rare earths; Lasers; Plating; Rare earth additions
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2013.11.026

Over the past decade, researchers have demonstrated much interest in laser cladded metal matrix composite coatings for its good wear resistance, corrosion resistance and high temperature properties. The effects of RE on the microstructure and properties of laser coatings have also got more and more attention. In this paper, in situ Fe-NbC composite coatings with different CeO2 addition were produced on die steel by laser cladding. The formation mechanism of NbC particles was analyzed. The effects of RE on microstructure and micro-hardness of coatings were investigated. It was revealed that larger NbC particles with hard edges formed around Nb particles, and smaller flocculent NbC particles formed by the chemical reaction of Nb and solid graphite in the molten pool. CeO2 plays important roles in reducing micro-porosities, refining grains, and improving the precipitation of NbC. Therefore, the average micro-hardness and its smoothness from the top to the bottom of the coating were improved after adding CeO2. •The formation of NbC particles with large size around Nb particles was observed.•NbCp with small size forms by the reaction of Nb, C dissolve in the molten pool.•CeO2 can reduce porosities, refine grains and improve the precipitation of NbC.•CeO2 improves the solid solubilities of solutes in Fe matrix of the coating.•CeO2 enhances the micro-hardness and diminishs its fluctuation in the coating.