The β to α phase transition of tantalum coatings deposited by modulated pulsed power magnetron sputtering

► We deposited thick tantalum coatings by modulated pulsed power magnetron sputtering. ► We deposited α-Ta coatings without substrate heating or annealing. ► The β → α-Ta phase change is an abrupt transition, not a complete phase transformation. ► There is an abrupt β → α phase transition once the coating is 5-7 μm. ► Thermocouple measurements show that β-Ta is no longer stable above 365-375 °C.