Y2O3, La2O3, Sm2O3对氧化铝瓷烧结及力学性能的影响

研究了3种稀土氧化物对氧化铝陶瓷烧结性能和力学性能的影响.结果表明 含Y2O3,La2O3,Sm2O3的添加剂促进了氧化铝瓷的烧结,提高了氧化铝瓷的力学性能.Y2O3和Sm2O3掺量为0.50%,La2O3掺量为0.75%时氧化铝瓷在1600或1620 ℃保温2 h烧结,相对密度达98.9%以上,强度超过439 MPa,断裂韧性达5.15 MPa·m1/2以上.微观结构分析表明,Y2O3,La2O3,Sm2O3抑止氧化铝晶粒生长,细化晶粒,使晶粒尺寸较均匀形成致密化结构.     

Elec tronic St rue tu res and Thermoelec trie Properties of ZnSb Doped with Cd and In from First Principles Calculations

Thermoelectric properties of pure,Cd-and In-doped ZnSb are studied by first principles calculations of electronic structures and the semi-classical Boltzmann transport theory.The doping of Cd or In at the Zn lattice site slightly increases the lattice parameters due to the larger atomic radii of Cd and In compared with that of Zn.Cd or In doping also apparently increases the interatomic distances between the dopant atoms and the surrounding atoms.The power factor of n-type ZnSb is much larger than that of p-type ZnSb,indicating that n-type ZnSb has better thermoelectric performance than p-type ZnSb.After the doping of Cd or In,the power factor reduces mainly due to the decrease of the electrical conductivity.The temperature dependences of the Seebeck coefficient and the power factor of pure,Cd-and In-doped ZnSb are related to carrier concentrations.