Shift of lines in phase diagrams for nanograined materials

摘要: If one adds the atoms of a second component B to one-component polycrystal A, they distribute between bulk and grain boundaries (GBs) form solid solution (A). amount exceeds solubility limit in (A), particles phase appear start grow, concentration (A) remains constant equal limit. However, equilibrium GBs is usually much higher than bulk. Therefore, overall would be single-crystal Thus, lines diagrams should shift with decreasing size. We measured Mn Co zinc oxide size about 20 nm compared that ZnO single-crystals. At 500°C, increases from 2 33 at.% 28 Mn. Temperature dependences for 20, 100 1,000 were calculated using published data papers devoted investigations ferromagnetism doped ZnO. The quantitative estimation leads conclusion that, close limit, thickness Co- Mn-enriched layer several monolayers at least two free surfaces.