Microstructure, Hardness, Wear, and Magnetic Properties of (Tantalum, Niobium) Carbide-Nickel–Sintered Composites Fabricated from Blended and Coated Particles

Abstract

Abstract (Tantalum, niobium) carbide-nickel composites were prepared by the powder metallurgy technique. Microsize (tantalum, niobium) carbide particles were reinforced in the nickel matrix. Different nickel contents were added to (tantalum, niobium) carbide powders by two different methods, namely, blending and electroless coating. The results of the microstructure show a good distribution of the (tantalum, niobium) carbide particles in the nickel matrix. The produced (tantalum, niobium) carbide-nickel composite powders were cold compacted at 400 MPa and sintered under vacuum at 1,450°C for 90 min. The density of the (tantalum, niobium) carbide-nickel–sintered materials was measured by the Archimedes method. The mechanical properties of the obtained sintered materials were evaluated by measuring the Vickers hardness and the wear rate using a pin-on-ring wear test machine. The microstructure of the sintered (tantalum, niobium) carbide-nickel as well as the microstructure of worn samples were investigated by a scanning electron microscope. The results revealed that the (tantalum, niobium) carbide-nickel–sintered materials, which were prepared by the electroless nickel coating of (tantalum, niobium) carbide particles, have a homogeneous microstructure and exhibit higher relative density, hardness, and low specific wear rate than the samples of the (tantalum, niobium) carbide/nickel–sintered materials prepared by blending of nickel with the (tantalum, niobium) carbide powders. The magnetic properties of the obtained blended and coated (tantalum, niobium) carbide particles as well as the sintered one have been studied. It was observed that the saturation magnetization is increased by increasing the nickel content.