Abstract
This work describes the synthesis and characterization of nanostructured coatings produced by low pressure plasma spraying (LPPS) of cryomilled NiTi powder. Ni and Ti powders (60 and 40 wt %, respectively) were cryomilled together and LPPS sprayed onto stainless steel substrates. The elemental powders reacted and alloyed during cryomilling forming a nanocrystalline grain structure with nanodispersed oxide and nitride phases. These nanodispersoids are formed due to contamination by the milling media (liquid nitrogen). After spray deposition, the coatings presented a nanostructured microstructure with enhanced mechanical properties when compared with conventional NiTi coatings sprayed under the same conditions. High hardness and toughness values together with intrinsic corrosion resistance of the NiTi alloy lead to the formation of an attractive coating material for applications where corrosion and wear resistance are required. The ability to synthesize the NiTi from elemental Ni and Ti powders and the refinement of the microstructure achieved during milling makes the cryomilling process together with thermal spray of the nanostructured NiTi coatings a unique process and coating to be used in engineering applications. Abstract only; no full-text paper available.
