摘要
ZnAl_(2)O_(4) and ZnAl_(2)O_(4)-based ceramics have attracted much attention from researchers due to their good microwave dielectric,thermal and mechanical properties.In this work,the influence of 5%(in mass)CuO-TiO_(2)-Nb_(2)O_(5)(CTN)ternary composite oxide additives with different composition ratios on sintering behavior and properties of ZnAl_(2)O_(4) microwave dielectric ceramics was investigated.When the molar fraction ranges of Cu,Ti and Nb elements in 5%CTN additives are 0.625-0.875,0-0.250 and 0.125-0.625,respectively,sintering temperature of ZnAl_(2)O_(4) ceramics can be reduced from above 1400℃to below 1000℃.The sintering additives CN(Cu:Nb=1:1,molar ratio)and CTN(Cu:Ti:Nb=4:1:3,molar ratio)can reduce sintering temperature of ZnAl_(2)O_(4) ceramics to 975 and 1000℃,respectively,while maintaining good dielectric properties(dielectric constantε_(r)=11.36,quality factor Q׃=8245 GHz andε_(r)=9.52,Q׃=22249 GHz)and flexural strengths(200 and 161 MPa),which are expected to be applied in preparation of low temperature co-fired ceramic(LTCC)materials with copper electrodes.Low-temperature sintering of the ZnAl_(2)O_(4)+CTN system is characterized as activated sintering.Nanometer-level amorphous interfacial films containing Cu,Ti,and Nb elements are observed at the grain boundaries,which may provide fast diffusion pathways for mass transportation during the sintering process.Valence changes of Ti and Cu ions,along with changes of oxygen vacancies,are confirmed,which provides a potential mechanism for reduced sintering temperature of ZnAl_(2)O_(4) ceramics.In addition,a series of reactions occurring at the grain boundaries can activate these boundaries and further promote the sintering densification process.These results suggest a promising way to design a novel LTCC material with excellent properties based on the low temperature sintering of ceramics with the sintering aid of CuO-TiO_(2)-Nb_(2)O_(5) composite oxide.
ZnAl_(2)O_(4)及ZnAl_(2)O_(4)基陶瓷由于具有优良的微波介电、热学和力学性能,从而备受研究人员关注。本工作系统研究了不同组成比例的5%CuO-TiO_(2)-Nb_(2)O_(5)(CTN)三元复合氧化物烧结助剂对ZnAl_(2)O_(4)微波介电陶瓷烧结行为和性能的影响。当5%CTN烧结助剂中Cu、Ti、Nb元素的摩尔分数分别为0.625~0.875、0~0.250、0.125~0.625时,ZnAl_(2)O_(4)陶瓷的烧结温度可从1400℃以上降低至1000℃以下。烧结助剂CN(Cu:Nb=1:1,摩尔比)和CTN(Cu:Ti:Nb=4:1:3,摩尔比)可分别将ZnAl_(2)O_(4)陶瓷的烧结温度降低至975和1000℃,同时陶瓷具有优良的介电性能(介电常数ε_(r)=11.36,品质因数Q׃=8245 GHz;ε_(r)=9.52,Q׃=22249 GHz)和抗弯强度(200和161 MPa),有望用于制备铜电极低温共烧陶瓷(LTCC)材料。ZnAl_(2)O_(4)+CTN体系的低温烧结是一种活化烧结机制。晶界处存在含Cu、Ti、Nb元素的纳米级非晶态界面膜,在ZnAl_(2)O_(4)陶瓷烧结过程中为传质过程提供了快速扩散路径。Ti和Cu离子的化合价改变以及氧空位变化,降低了ZnAl_(2)O_(4)陶瓷的烧结温度。此外,晶界上发生的系列反应发挥了活化晶界的作用,进一步促进烧结致密化。本工作为设计具有优良性能、CuO-TiO_(2)-Nb_(2)O_(5)复合氧化物助烧的ZnAl_(2)O_(4)陶瓷LTCC材料提供了一种参考。
出处
《无机材料学报》
北大核心
2025年第6期711-718,I0009-I0011,共11页
Journal of Inorganic Materials
基金
National Natural Science Foundation of China (U24A2052)
Shanghai Eastern Talent Plan。
作者简介
杨燕(1994-),女,博士.E-mail:yan.yang@hongxing799.com;Corresponding author:刘志甫,研究员.E-mail:liuzf@mail.sic.ac.cn;Corresponding author:马名生,研究员.E-mail:mamingsheng@mail.sic.ac.cn。
