First-principles study on growth mechanism of TiN on MgO (1 0 0) and (1 1 0) surfaces

Abstract

Substrate nucleation is one of the important modes of heterogeneous nucleation. The substrate nucleation occurs with the absorbed atoms transforming atomic layers phase of the nucleated phase on the substrate in the actual production process. For example, TiN grows layer by layer on MgO substrate during solidification of steel, which is an important way for MgO inclusions to play the role of oxide metallurgy to induce inclusions or precipitated phase. In this work, the first-principles calculation is employed to study the growth mechanism of TiN on MgO (100) and (110) surfaces. Study on atomic binding energy and charge density difference have shown that the effecting of MgO substrate template effect can be divided into two parts: coherent epitaxial layer and transition layer. For MgO(100)/TiN(100) and MgO(110)/TiN(110) systems, the critical size includes four and five atomic layers(TiN), respectively. The interfacial energy and work of adhesion of MgO(100)/TiN(100) system are both smaller than those of MgO(110)/TiN(110) system in the evolution process of TiN nucleation layer by layer on MgO substrate. The interfacial and surface properties of MgO/TiN systems are both related to MgO substrate, especially at the beginning of nucleation. The relation between electron work function or outermost atoms adsorption energy and charge distribution is also discussed simply.