Study of phase transformations under hydrogen absorption and desorption in alloys of the Ti-Nb-Cr system.

• Grant number: 23/02732-0
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: August 01, 2023
• End date: January 31, 2024
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Guilherme Zepon
• Grantee: Gabriela Chimello Mayer Dias
• Supervisor: Michael Felderhoff
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Institution abroad: Max Planck Society, Mulheim, Germany
• Associated to the scholarship: 22/06719-6 - Study of hydrogen storage properties of Ti-Nb-Cr alloys, BP.MS

Abstract

The use of hydrogen as an energy carrier is a clean and sustainable alternative to meet rising energy demands without causing further environmental damage. However, hydrogen storage is another major challenge that must be overcome to allow its safe and efficient use. The storage of hydrogen in the solid state through metal hydrides is extremely promising in this scenario. Among the numerous compositions under investigation, body-centered cubic solid solutions (BCC) are highlighted. This includes the Ti-Nb-Cr system, which requires additional studies considering that few works have been dedicated to in-depth knowledge of its properties. Initial results of this project, including a PCT diagram, DSC/TGA/QMS analyses, and XRD patterns obtained after hydrogenation and dehydrogenation, showed that the equiatomic TiNbCr alloy has a two-step hydrogen absorption/desorption, with two plateau pressures in the PCI curves. In this context, this research project abroad (BEPE) aims to thoroughly investigate the phase transformations occurring during the two-step hydrogenation and dehydrogenation in the three compositions of the Ti-Nb-Cr system under study: Ti33.3-xNb33.3+xCr33.3, with x = 0, 10 and 15. In-situ X-ray diffraction and high-pressure DSC measurements will be performed on the samples, as well as cyclic performance measurements with a Sievert-type apparatus. This project will be carried out at the Max-Planck-Institut für Kohlenforschung in Mülheim an der Ruhr, Germany, under the supervision of Dr. Michael Felderhoff.