Silicon–Oxygen Quartz Tetrahedra and Consolidation Processes during High-Pressure Torsion

A mechanism for the consolidation (performed experimentally earlier) of brittle quartz powder particles under a strong external action (high-pressure torsion) is proposed. This mechanism is based on possible destruction of silicon–oxygen tetrahedra via breakage of the Si–O interatomic bonds. The surface layer of the ceramic powder particles is shown to contain initial tetrahedra and their “fragments,” i.e., defects of the tetrahedra (proposed for the first time by the authors together with the name). The emergence of the tetrahedra and their fragments to the surface by the faces, edges, and vertices predetermines the surface shape and, eventually, surface adhesion. The enhancement of an external action results in healing broken Si–O bonds, which predetermines the possibility of partial or complete consolidation.