Influence of boron nitride (BN) addition in commercially pure titanium (Cp-Ti) was characterized for their microstructural variation, hardness, and oxidation kinetics. Feedstock powders, Cp-Ti with 3 wt% BN (3BN) and 6 wt% BN (6BN), were prepared by roller mill followed by additive manufacturing using laser engineered net shaping (LENS™). Rate of oxidation was measured from thermogravimetric analysis (TGA) at 1000 °C for 50 h. Average instantaneous parabolic constants (kp) for Cp-Ti, 3BN, and 6BN were 41.2 ± 12.0, 28.6 ± 2.8, and 18.2 ± 9.2 mg2/(cm4 h), respectively. Cp-Ti displayed acicular α-Ti microstructure. After TGA, large equiaxed grains along with TiO2 formation at the grain boundaries were observed, which increased the hardness. With BN addition, plate-like TiN and needle-like TiB secondary phases were also observed. Hardness for Cp-Ti, 3BN, and 6BN were 256.9 ± 7.7, 424.0 ± 33.6, and 548.3 ± 49.7 HV0.2, respectively. Overall, a small addition of BN was effective in improving the oxidation resistance of Cp-Ti.

CoCrMo alloy was deposited on a metallic substrate using laser engineered net shaping (LENS™) – a laser-based additive manufacturing technique. Several samples with five layers of deposit were fabricated at different combinations of laser power, powder feed rate, and scan velocity to study their influence using L4 Orthogonal array. The deposits were evaluated for their microstructure, hardness, wear resistance, and electrochemical performance. Grey relational grade analysis and analysis of variance were applied to identify optimum process parameters. The x-ray diffraction and microstructural analysis of the deposits showed uniform and fine microstructural features. Our experimental results revealed that the coatings fabricated using high laser power (350 W), low powder feed rate (5 g/min), and high scan velocity (20 mm/s) provide the highest hardness (446 ± 2.87 Hv) and wear resistance (1.80 ± 0.0007 mm3/Nm). However, the corrosion resistance was observed to be high for the deposits fabricated using low laser power (200 W), low powder feed rate (5 g/min), and low scan velocity (10 mm/s).