多相材料的微結構設計(III)奈米鈦酸鋇多相材料

Abstract

Nickel is now used as the internal electrode for the multilayer ceramic capacitors (MLCCs). In order to increase its volume efficiency, the size of Ni particles decreases from micrometer-sized range to nanometer-sized range. In the present study, nano-sized Ni particles are mixed intimately with BaTiO3 powder. The powder compacts are then co-fired in an atmosphere with low oxygen partial pressure. The sintering behavior of the Nidoped BaTiO3 is investigated. The presence of the nanometer-sized Ni inclusions can inhibit the grain growth of BaTiO3. The solubility of Ni in BaTiO3 during co-firing is also determined. Two techniques have been applied to determine the solubility. Consistent results are obtained. The solubility of the Ni in the BaTiO3 is around 1000±100 ppm after cofiring at 1330°C for 2 h in N2.

目前金屬線已常被使用為高容值積層陶瓷電容(MLCC) 的內電極，且為了提升體積效率，金屬鎳顆粒已由微米級尺寸降至奈米級尺寸，本研究探討鈦酸鋇/鎳奈米多相材料的製備及微結構的關聯，研究結果顯示此奈米多相材料可以1330C 以上的溫度及低氧的氣分中，以無壓燒結法製備，在此條件下 1000 ± 100 ppm 的鎳可溶入鈦酸鋇中，而鎳的擴散距離可達 10 um。鎳溶質的存在可大幅減少鈦酸鋇不正常晶粒的產生，但鎳溶質及鎳顆粒皆會大幅降低緻密化及晶粒成長速率。