I bashed off a bunch of pain chips from my red painted steel wheelbarrow and waved a butane flame over them. Result = iron microspheres Here's a scale comparison with the Harrit microspheres (left) and mine (right). Of note, in both their photos and mine the red layer appears undamaged. Curious, since that's supposed to be the one that's nanothermite. What seems to have happened is the iron oxide layer has "burnt" (perhaps with some of the paint, of some intermediate layer), and created some iron microspheres.