Apple works on ways to make its myriad devices more scratch, dent resistant — Apple World Today

In this arrangement, the intermediate layer can act as a structural support that resists plastic deformation when an impact force is applied to the coating. In some embodiments, the intermediate layer is composed of a porous anodic oxide material. In some embodiments, the outer hard layer is composed of a ceramic material or a hard carbon-based material, such as diamond-like carbon.

In the patent filing, Apple notes that portable computing devices, such as mobile telephones, tablet computers, and laptop computers, come into contact with a wide range of hard and abrasive materials during normal use. What’s more, the computing devices may be dropped and subject to impacts or abrasive wear from hard counter-materials. 

If the enclosures of the computing devices are not adequately protected, the enclosures can develop scratches, gouges and other defects that detract from the cosmetic appeal of the enclosures. If the enclosures include anodized metal portions, the scratches, gouges and defects may break through the protective anodic film and allow contaminants to corrode of the underlying metal. Apple says what’s needed are improved coatings for metallic surfaces.