EBSD INVESTIGATIONS APPLIED TO CHARACTERISE THE CRYSTALLOGRAPHIC RELATIONSHIPS AT THE INTERFACES OF BIOCOMPOSITE MOLLUSK SHELLS

摘要

A shell consists of 1 - 5 % of organic matrix, reinforced by 95 - 99 % of inorganic phase [1]. The organic part is composed of proteins, lipids and acidic glycoproteins rich in aspartic acid and plays a key role in biomineralisation process. Moreover, it controls nucleation, orientation and growth of the calcium carbonate crystals [2]. The inorganic phase occurs in two polymorphic variants: calcite and aragonite [3]. This layer can occur in a different form: globular, prismatic or crossed-lamellar depending on the environment in which the animal lives. Shells represents unique properties, including strength (especially compressive strength), toughness and hardness [4]. Detailed microstructural characterization of such materials could give an explanation for their unusual mechanical behaviour. The structure of shells interior and the dependence between each component, forming a material, is crucial.