Naturally Biological Materials and Their Tribology:A Review

Because of the natural selections and evolution of the respective biological systems through millions of years, naturally biological materials have unique structures and some extraordinary properties. The structures and surface morphologies of naturally biological materials have widely been researched in order to develop biomimetic structure, biomimetic materials and biomimetic tribological surfaces. Thus the characteristics of some naturally biological materials and their tribological behavior are reviewed. Focus has been placed on the structures and properties of biological composite materials and keratin materials, the surface morphologies of soil animals' cuticle and plant leaves, the friction and wear behavior of naturally biological materials such as bamboo and pangolin scales, the anti adhesion of soil animals, and the biological lubrication of animal joints. Then the concept of biomimetics in tribology is put forward.