... detect the thickness of non-magnetic coating (such as: zinc, aluminum, chromium, copper, rubber, paint etc.) on magnetic metal matrix iron ... measurement method, can detect the thickness of non-conductive coating (such as:rubber, paint, plastic, anodic oxide film,etc) on non- ... steel, etc.) and the thickness of non-conductive coating(such as:rubber, paint, plastic, anodic oxide film,etc) on non-magnetic ...