Nitride protective coatings on aerospace components and methods for making the same

Embodiments of the present disclosure generally relate to protective coatings on various substrates including aerospace components and methods for depositing the protective coatings. In one or more embodiments, a method of forming a protective coating on an aerospace component includes forming an aluminum oxide layer on a surface of the aerospace component and depositing a boron nitride layer on or over the aluminum oxide layer during a vapor deposition process. In some examples, the method includes depositing a metal-containing catalytic layer on the aluminum oxide layer before depositing the boron nitride layer. The boron nitride layer can include hexagonal boron nitride (hBN).