Theoretical Research On Physical Parameters Of Nanomaterials

Metal oxides are widely used in industry because of their good abrasion resistance, resistance to thermal shock and mechanical strength at high temperature. Nanomaterials are characterized by a typical structural size below 100nm. Due to their unique properties, great attention to nanomaterials has increased in past years. The recent progress in nanomaterials has been summarized in many papers. Microstructure of nanomaterials has important effect on physical properties. It is very important for the research on physical parameters of nanomaterials. This paper mainly discusses several physical parameters of nanomaterials, such as the lattice constant of nanomaterials and the cohesive energy of nanomaterials.Lattice constant of oxide is a major factor for synthesis and application ofmaterials. We give an equation, a0 = Aforcalculating the lattice constant of nano solid solution powders (ZrO2 system, MgO system, Bi2O3 system, ThO2 system, CeO2 system, HfO2 system, Al2O3 system). The equation is depended on the composition of the oxide solid solutions only. The computational results are corresponding to the experimental data for all nano solid solutions. The error rate is not bigger than 3.4% for all nano solid solutions. For these systems, the lattice constant closely agrees with the Vegard s law, that is, lattice constant is a function of doping concentration. The lattice constant of nano solid solutions depends on the radius of dopingmetal ions and the amount of doping concentration.At the same time, we found that the factor A in the formula is related to closely the Pauling electronegativity of metal ions and oxide ion in metal oxides.The results can be described by an equation, A . The Paulingelectronegativity of elements means the capacity of absorption for electronics. When the factor A becomes larger, the absorption between metal ion and oxide ion is stronger. So the lattice constant of nano solid solutions becomes smaller.The cohesive energy is an important physical quantity in solid-state physics. When the particle size is fairly small, the cohesive energy of nanomaterials is different from that of bulk materials. We supposed that nanosize particle is spherical and a simple equation for calculating the cohesive energy of nanosize alumina solid solutions and binary alloys (fcc, bcc, fcc-bcc) is derived. It is shown that the cohesive energy of nano alumina solid solutions and binary alloys is a function of the particle size. The equation can be described by an equation, . We have plotted size effect of cohesive energy for laves phase alloys such as NiFe3, NiFe, Ni3Fe, CuAu3, CuAu, Cu3Au, MoNb3, MoNb and Mo3Nb. At the same time, we have plotted size effect of cohesive energy for nano alumina solid solutions. When the particle size of nanomaterials is smaller than 10nm, we found that the cohesive energy of nanomaterials greatly decreases. It also is shown that the cohesive energy increases with increasing the particle size. When the particle size is larger than 100nm, the cohesive energy will approach the constant-bulk.value.We also calculated the cohesive energy of bulk materials (90 kinds laves alloys and alumina bulk solid solutions) with the equation, ) and compared the calculated results and experimental results of bulk materials; we found that the difference is small.