Controlling Surface Defects of Cold-Sprayed Parts Manufactured on Reusable Tooling

Author(s):

Tristan W. Bacha and Isaac M. Nault

Abstract:

Cold spray additive manufacturing is currently being investigated to produce rotor blade erosion caps. The erosion caps are produced by building a coating on a mandrel that then must be released. Factors influencing the presence of pit defects that occur on the release surface of the coatings are studied in this report. Substrate temperature, material type, and surface roughness are the variables of interest. Substrate (mandrel) temperature can be controlled to reduce pit defect severity and prevent premature delamination in niobium coatings that are produced on hard steel. Mandrel type and surface roughness were also identified as major variables controlling pit defect presence and premature delamination. Future studies are suggested to investigate the aging properties of mandrel materials and to determine appropriate surface pretreatments before a mandrel is used for production.