In-situ alloying of Ti-xPt using laser powder bed fusion to produce novel alloys

¹ Mechanical and Mechatronic Engineering Department, Faculty of Engineering, Stellenbosch University, Stellenbosch, South Africa
² Centre for Rapid Prototyping and Manufacturing, Central University of Technology, Bloemfontein, South Africa

^* Corresponding author: gterhaar@sun.ac.za

Abstract

This study investigates the in-situ alloying of Ti-xPt (x = 5, 10 wt%) using laser powder bed fusion (L-PBF) to produce novel alloys with enhanced electrochemical properties. Two different powder mixtures and process parameter sets were employed to evaluate the influence of composition and processing conditions on microstructure development and electrochemical performance. The samples with 5 wt% Pt achieved full density, while the ones with 10 wt% Pt exhibited approximately 91% relative density due to incomplete fusion at Ti-Pt interfaces. Microstructural analysis revealed the formation of Ti3Pt and Ti2Pt intermetallic compounds at the partially alloyed interfaces, with significant Pt diffusion evidenced by increased hardness values compared to cp-Ti. Electrochemical testing demonstrated superior corrosion resistance in all samples of Ti-xPt, with corrosion potentials shifting positively from -304.5 mV for cp-Ti to between -10.9 and -23.3 mV. Notably, the hydrogen evolution reaction performance of the Ti-xPt alloys matched or exceeded that of pure platinum, with most samples requiring lower over-potentials at 10 mA/cm². These findings demonstrate that L-PBF-processed Ti-Pt alloys with minimal platinum content can achieve excellent electrochemical properties, presenting significant cost advantages for biomedical and energy conversion applications where platinum’s catalytic properties are essential.