The Use of Thermal Spraying to Enhance the Bonding Characteristics of a Urethane Coated Propeller
Abstract
In order to reduce the cost and machining time of producing propeller blades, the Naval Surface Warfare Center, NSWC, has developed an alternative production method for propeller blades. The alternative production method consisted of a Nickel-Aluminum-Bronze (NAB) blade, covered by two coats of paint and a urethane coating. After exposure to seawater and impressed current cathodic protection, the bond between the paint and the NAB substrate failed to meet NSWC's minimum required bond strength of 80 lbs./ linear inch. This project attempted to improve the bond between the paint and NAB by developing a surface treatment technique that would produce a strong, lasting bond. The surface treatment technique chosen was thermal spraying, specifically arc wire spraying, which created a rough, porous surface. This type of surface promoted mechanical bonding, as well as enhanced chemical bonding, of the paint to the substrate. In order to produce various surfaces, the thermal spray distance was varied at six inch intervals from six inches to two feet. A 90-degree peel test, SEM analysis with x-ray micro-analysis, and optical metallography were all used to evaluate the characteristics of each coating. After testing, it was determined that flame sprayed coatings created a surface that produced a mechanical bond, increased chemical bonding, and reduced the effects of cathodic protection.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 03, 1999
- Accession Number
- ADA376187
Entities
People
- Corey A. Poorman
Organizations
- United States Naval Academy