Preparation of quaternary spherical TiO2-B4C-C-Cu composite powder for laser cladding

Abstract

Powder preparation is the key step in producing laser cladding coatings with desired properties. In this paper, quaternary TiO2-B4C-C-Cu composite powder with high sphericity and good densification has been successfully prepared by a powder fabrication process combining spray granulation with densification sintering. The effects of slurry characteristics, spray granulation process parameters, and densification sintering temperature on particle morphology and performance were studied. The formation mechanism of quaternary spherical TiO2-B4C-C-Cu composite powder was revealed by analyzing the process of heat transfer and water transfer in the droplets, and the optimization direction of the powder preparation was indicated. The optimized process parameters for the quaternary spherical TiO2-B4C-C-Cu composite powder are: slurry solid content of 52 wt%, dispersant content of 1.25 wt%, binder content of 2 wt%, inlet temperature of 180 °C, the airflow rate of 310 L/h, slurry feed rate of 4.5 ml/min, and the two-stage temperatures of densification sintering are 500 ℃ and 900 ℃ for 1 h, in turn. Under the optimized process, the fluidity of the powder reaches 112 s/50 g, the apparent density reaches 1.2 g/ml, and more than 70% of the particles are between 15–53 µm. The powder has been verified by laser cladding to prepare in-situ synthesized TiB2-TiC-Cu composite coatings, which could have a better prospect for potential application.