Hot embossing of anodic aluminium oxide on high-density polyethylene: A deeper understanding based on hard surface coating

A thick anodic aluminium oxide (AAO) was used as a laminated hard coating film on high-density polyethylene (HDPE) without a binder. This thick alumina surface has a large number of polymeric nanofibers rooting inside which makes it a composite between polymer fibre and alumina. The AAO-coated film was crystalline gamma-Al₂O₃ and its Vickers hardness was higher than super alloy and martensitic stainless steel which has a durable and wear resistance surface despite the substrate is still a lightweight polymer. The film surface was firmly adhered to the polymer substrate. Therefore, it can be applied in many applications which require an extreme hard coating such as a transparent hard film or a special made polymer knife in which the sharpness is hardly worn out.