Surface defects refer to imperfections found on the outer layer of materials, such as metals, plastics, or ceramics. These defects can include scratches, dents, pits, or discoloration, which may affect the material's appearance and performance. Identifying and addressing surface defects is crucial in manufacturing and quality control processes to ensure product reliability. Common causes of surface defects include improper handling, manufacturing errors, or environmental factors. Techniques like visual inspection, non-destructive testing, and surface treatment can help detect and mitigate these issues. Addressing surface defects is essential for maintaining the integrity and longevity of products in various industries.