Corrosion and Wear Resistance of Dual-Reinforced Al-7075 Cold Sprayed Coatings
Abstract
Cold spray coatings using nano- and micro-sized reinforcements have been recognized for their improvement of mechanical properties such as adhesion strength and hardness. Unknown at this time are the effects that reinforced coatings have on the wear and corrosion resistance of aircraft-grade aluminum. In this study, aluminum 7075 powders were reinforced with a combination of graphene-nanoplatelets (GNP) and micro-boron carbide (micro-B4C) at 2 and 4 vol. percent. The composite powders were then cold-sprayed onto Al-7075 substrates. Optical and scanning electron microscopy were used to characterize splat structure, coating thickness, porosity, and corrosion modes. Wear testing was conducted on as-sprayed specimens from which depth, coefficient of friction (COF), and mass loss measurements were recorded. Results indicate a negative trend of vol. percent reinforcement to wear resistance. The 2 vol. percent micro-B4C sample showed the closest wear resistance to the control, improving mass loss by 3 percent and COF by 4 percent. For corrosion testing, coated samples were placed in a salt fog chamber, simulating an aggressive marine environment for up to 2000 hours. Pitting corrosion was found in all samples starting as soon as 1000 hours. The 2 vol. percent micro-B4C sample had the least average weight gain and delamination of coating upon completion of the tests.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2023
- Accession Number
- AD1213564
Entities
People
- Nathan E Mathes
Organizations
- Naval Postgraduate School