Nano-engineered encapsulated particles for the creation of self-lubricating coatings and alloys

Deposition of nickel coated hexagonal boron nitride (hBN) via high velocity particle consolidation (Cold spray) has been investigated as a possible self-lubricating coating for surfaces prone to fretting in high performance machines. Although hBN is a solid lubricant, which has a low coefficient of friction and is able to retain its lubricious properties in high temperatures and at high pressures, its brittle nature makes it a poor candidate for Cold Spray processes. Encapsulation of hBN particles within a ductile medium, such as nickel, allows for particle deformation needed to create Cold Spray coatings. Electroless nickel coatings have successfully been deposited onto hBN powder. The fabricated powder has effectively been used in creating a self lubricating coating through a Cold Spray procedure. Incorporation of hBN within a nickel matrix proved to reduce the coefficient of friction and increase microhardness [1].