Authors : R. Louahdi , V. Hays , R. Le Gall and S. Abdeslam
Abstract: Boron was deposited on stainless steel by Chemical Vapor Deposition (CVD) from a gaseous mixture of B2H6 (diborane) with a mixture of argon and hydrogen. The SEM and EDX studies showed that an amorphous uniform layer of boron was obtained Thickness measurements were carried out using a Dektak profilometer. A minimum thickness of 2200 Å was obtained.The boron enriched steel was annealed at 1050°C and then quenched in water in order to avoid any precipitation (especially that of BN). Isothermal anneals were then carried out and Auger Electron Spectroscopy (AES) was used to study surface precipitation. The studies on the material isothermally annealed at 750°C indicated that precipitation of hexagonal Boron Nitride (hBN) took place on the surface of the stainless steel. This precipitation is not observed if the annealing temperature is greater or equal to 800°C. From the obtained data, a three-stage mechanism of BN precipitation on the surface of stainless steel was put forward. A precursion stage during which nitrogen and chromium atoms co-segregate to the steel surface. Then, superficial nitrogen atoms react with those of boron which migrate by diffusion, to form hBN. Finally, the hBN compound thus formed grows layer by layer starting from the interface.
R. Louahdi , V. Hays , R. Le Gall and S. Abdeslam , 2007. The Formation of Hexagonal Boron Nitride on the Surface of Stainless Steel by Chemical Vapour Deposition . Journal of Engineering and Applied Sciences, 2: 1090-1096.