Effects of powder size and preset thickness on the microstructure and properties of Ni35 thin coating prepared by laser cladding.

ABSTRACT

Ni35 thin coatings were prepared on 40Cr steel by preset powder laser cladding technology. The effects of powder size and preset thickness on the dilution rate, microstructure, and properties of the coating were systematically studied. The results showed that the coating with smaller powder size and larger preset thickness had smaller grain size, denser microstructure, a flatter bottom of the molten pool, and lower dilution rate. The micro-hardness of the coating with large powder size and preset thickness was higher. The friction coefficient of the coating with small powder size and small preset thickness was smaller, but the latter had larger curve fluctuation and wear volume loss. The corrosion rate of the coating was high during the first 24 h, then relatively stable after 68 h, and the corrosion rate and loss of the coating with small powder size and large preset thickness were smaller.