Standardized Test Methodologies for Specialty Coatings Durability
Abstract
Current accelerated test methods for multilayer coating systems do not accurately simulate damage modes that are relevant to field failures and do not generate data that can be used to accurately predict coating performance in service, which has led to the selection of coating systems that need to be replaced prematurely, generating a significant amount of environmentally hazardous materials. The new combined effects test method introduces relevant environmental stressors of cyclic temperature and humidity and, with the application of vibratory or dynamic strain, produces coating cracking with features similar to that observed in service over structural discontinuities. Testing indicates that crack initiation begins below the surface, and propagates to and through the topcoat as cracks grow and coalesce. The ability of this test method to detect subsurface cracking in underlying layers, as well as the observation that the impedance of even a cracked conductive coating decreases when applied strain is reduced and the coating is allowed to come back into contact, has important implications for multilayer coating system selection, maintenance, and repair.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 14, 2019
- Accession Number
- AD1154603
Entities
People
- Karen Schultz
Organizations
- Boeing
- North Dakota State University