(1. 中南大學 材料科學與工程學院，長沙 410083；
2. 中南大學 有色金屬材料科學與工程教育部重點實驗室，長沙 410083；
3. 山東大學 材料科學與工程學院，濟南 250061)
摘 要: 采用固相反應與真空燒結先后制備Y2Ti2O7粉末與Y2Ti2O7/Fe金屬陶瓷。XRD分析表明，所得Y2Ti2O7粉末為純相，Y2Ti2O7/Fe金屬陶瓷化學性質穩(wěn)定，金屬相與陶瓷相之間無界面反應產物。在10 MHz~1 GHz頻段進行測試，發(fā)現(xiàn)Y2Ti2O7/Fe金屬陶瓷的逾滲閾值處于Fe含量20%~30%(體積分數(shù))之間。當Fe含量低于逾滲閾值時，介電常數(shù)、交流導電和磁導率均隨Fe含量的增加而增加。當Fe含量超過30%時，金屬陶瓷電抗與交流電導率發(fā)生突變，在整個測試頻段都呈現(xiàn)負介電常數(shù)。Fe含量為40%的樣品的磁導率在整個測試頻段內小于1，且隨頻率增加不斷下降，應歸因于逾滲導電網(wǎng)絡導致的抗磁性。在頻率大于1 GHz時可能出現(xiàn)負磁導率，即實現(xiàn)電磁性能的雙負性。
關鍵字: Y2Ti2O7；金屬陶瓷；介電常數(shù)；磁導率
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials, Ministry of Education, Central South University, Changsha 410083, China
3. School of Materials Science and Engineering, Shan Dong University, Jinan 250061, China）
Abstract:Y2Ti2O7 powders and Y2Ti2O7/Fe cermets were fabricated by solid-state synthesis and vacuum sintering, respectively. XRD analysis suggests that the Y2Ti2O7 powders are single-phase, and the Y2Ti2O7/Fe cermets are chemically stable, with no interfacial reaction products between the ceramic phase and the metal phase. During the electromagnetic testing under the frequencies of 10 MHz-1 GHz, the percolation threshold of the Y2Ti2O7/Fe cermets is found within the iron content range of 20%-30% (volume fraction). Under the percolation threshold, the permittivity, AC conductivity, and permeability all increase with the iron content. When the iron content is beyond 30%, the reactance and the AC conductivity change greatly, leading to a negative permittivity within the entire frequency range. For the iron content at 40%, the cermet exhibits a low permeability of less than 1, which decreases consistently with the increasing frequency. This should be attributed to the percolation induced diamagnetism as the result of the formation of conducting networks inside the cermet. Negative permeability can be further expected at the frequencies beyond 1 GHz.
Key words: Y2Ti2O7; cermet; permittivity; permeability
