Method 4.7.19 is a coating workmanship test applicable to coated carbon-based conductive fibers only. A metallurgical cross-section of coated conductors is examined to demonstrate that the individual fibers are coated 360 degrees with metal.
This examination is performed using magnification of at least 400X. The test verifies the quality and completeness of the metallic coating applied to individual carbon fibers.
Proper 360-degree coverage is essential for maintaining consistent electrical conductivity and protection of the carbon fiber substrate, particularly in applications where the coating provides corrosion resistance or improved electrical contact.