采用固相法制备了Nb2Sr2-x Y x O7陶瓷。研究了掺Y对陶瓷的晶体结构、表面形貌、铁电、介电和压电性能的影响。研究结果表明:钇掺杂Sr2Nb2O7陶瓷,Y3+取代了A位Sr2+,形成Nb2Sr2-x Y x O7固溶体,并提高了铌酸锶陶瓷铁电、介电和压电性能。在x=0.05时,Nb2Sr2-x Y x O7陶瓷的铁电性能达到最大(剩余极化强度P r=0.254μC/cm2);在x=0.1时,Nb2Sr2-x Y x O7陶瓷的介电性能达到最大(相对介电常数εr=90,介电损耗tanδ≤0.01)。
The effects of Sr and Y with different contents on the microstructure and corrosion resistance of AZ31 alloy were investigated. The results indicate that the addition of Sr can obviously reduce the grain size of AZ31 alloy and transform β-Mg 17 Al 12 phase from continuous network to scattered form. Simultaneously, Al 4 Sr phase distributed along the boundaries of grains is formed in AZ31-Sr magnesium alloys. The addition of Sr is not as effective as the simultaneous addition of Sr＋Y for the refinement of grains, and Al 2 Y and Al 3 Y phases are distributed both in intracrystalline and along grain boundaries. The corrosion resistance is improved slightly in AZ31 alloy with simultaneous addition of 0.5%Sr＋Y. Due to its smallest corrosion current density and corrosion rate, the corrosion resistance of AZ31-0.5%Sr-1.5%Y magnesium alloy is proved the best.
