On March 1, 2026, relevant research in the coating process field pointed out that the common industry idea of thickening the primer layer or changing materials to solve coating peeling has cognitive misunderstandings. The primer layer can only improve part of the adhesion problems and is not a panacea. Adhesion failure is essentially divided into two categories: insufficient interface bonding and structural imbalance. The primer layer is only effective for the former, which can make up for interface pollution by forming a diffusion mixed layer and providing structural transition. However, the primer layer cannot fundamentally solve structural imbalance problems such as excessive internal stress in the film layer, thermal expansion mismatch, and overly thick main coating. It can only transfer rather than eliminate stress, and even its excessive thickness will introduce new stress and become an inducement of failure. The instantaneous strength from adhesion tests also cannot reflect long-term stress evolution. A mature process needs to control the main layer stress and match thermal expansion first, then design the transition layer to achieve stress balance in the coating system, rather than simply relying on the primer layer.
For more information, please click: https://www.tiktok.com/@mia_iota/video/7597717976720149782