Utilizing carbon nanotubes in ceramic particle reinforced MMC coatings deposited by laser cladding with Inconel 625 wire

Abstract

Three types of novel composite coatings were fabricated to simultaneously achieve excellent mechanical properties and high-precision surface appearance by hybridizing carbon nanotubes (CNTs) into reinforcement powder. Results showed a uniformly dispersed morphology of ceramic powders in Inconel 625 composite coatings because CNTs weakened the van der Waals force between adjacent reinforcement powders. The composite coatings presented a sound metallurgical bonding with 316L substrate due to the absence of powder agglomeration. In contrast to Ti(C, N), the decarburization of WC caused the formation of intermetallic compounds dominated by W2C. However, due to the presence of considerable CNTs accompanied by sufficient carbon, more Laves phase and NbC were observed in the clad coatings. In addition, the resultant mechanical properties of these powder mixture reinforced coatings were progressively improved due to the homogeneous microstructures refined by reinforcement particles. The present study offered a reference to simultaneously eliminate the agglomeration of reinforcement powder on a micro-scale and promote the mechanical properties of clad protective coatings.

Keywords

• Laser cladding
• Ceramic powder
• Carbon nanotubes
• Powder mixture
• Metal matrix composite