New potential for preparation of performing h-BN coatings via polymer pyrolysis in RTA furnace

An innovative IR irradiation annealing process is used to increase the crystallization ratio of hexagonal boron nitride (h-BN) coatings on pure titanium pellets. Since the polymer pyrolysis route requires heating the green polymer at high temperature to convert it into a ceramic, the use of IR radiation furnace (compared to a resistive furnace) allows achievement of better crystallized h-BN while the substrate remains at relatively low temperature (<1000 °C). Annealing treatments have been performed under argon or nitrogen using either a halogen lamp or a Rapid Thermal Annealing (RTA) furnace. Advanced structural and chemical characterizations have shown a good chemical stability of the coatings. In addition, it has been revealed that samples annealed under Ar present a micro-composite structure at the interphase composed of a μ-layer of TiB2/TiB/Ti(N)x between the coating and the substrate, whereas samples annealed under nitrogen display a simpler structure at the interphase, with only TiN.