Ba_(1-x)Sr_xTiO_3材料具有强的介电非线性特性,在可调微波器件方面有广阔的应用前景。电子陶瓷器件的小型化、集成化的发展要求Ba_(1-x)Sr_xTiO_3材料能够实现低温烧结。采用柠檬酸盐法制备名义组成为Ba_(0.6)Sr_(0.4)TiO_3+0.5wt.%Li_...Ba_(1-x)Sr_xTiO_3材料具有强的介电非线性特性,在可调微波器件方面有广阔的应用前景。电子陶瓷器件的小型化、集成化的发展要求Ba_(1-x)Sr_xTiO_3材料能够实现低温烧结。采用柠檬酸盐法制备名义组成为Ba_(0.6)Sr_(0.4)TiO_3+0.5wt.%Li_2O(简称BSTL)的陶瓷样品,研究了在烧结温度为900℃下,保温时间对BSTL陶瓷的结构与介电性能的影响。研究结果表明,Li_2O的添加有效地降低了Ba_(0.6)Sr_(0.4)TiO_3(简称BST)材料的烧结致密化温度。保温时间的增加,促进了Li+固溶进入BST晶格,加快烧结过程中的传质,提高了样品的致密度。烧结温度为900℃、保温时间为8 h的陶瓷样品介电性能最佳:在频率10 k Hz下,介电常数为2 246,介电损耗为0.3%;偏置电场为30 k V/cm和频率为10 k Hz条件下,可调性为29.6%,优值系数(FOM)为96.2。展开更多
The traditional low-pressure sintering was optimized for the preparation of Ti(C_(0.5)N_(0.5))-WC-Mo_2 C-TaC-Co-Ni cermets. Nitrogen was introduced into sintering system during different stages and with different pres...The traditional low-pressure sintering was optimized for the preparation of Ti(C_(0.5)N_(0.5))-WC-Mo_2 C-TaC-Co-Ni cermets. Nitrogen was introduced into sintering system during different stages and with different pressures. The morphology and mechanical properties of cermets were investigated by scanning electron microscopy(SEM), X-ray diffraction(XRD), and measurements of transverse rupture strength(TRS), Vickers-hardness(HV) and fracture toughness(K_(IC)). The degree of denitrification is directly related to the amount of η phase. When nitrogen is introduced into the sintering system, the amount of observed η phase decreases. When nitrogen is introduced during solid-state sintering with appropriate pressure, the core-rim structure is well developed. And TRS and hardness get enhanced while toughness tends to be deteriorated with the nitrogen pressure increasing. When nitrogen is introduced after the sintering temperature reaches 1 350 ℃ or at higher pressures, the volume fraction of η phase increases. Sintered with a nitrogen pressure of 1.0 kPa during 1 200-1 350 ℃, the bulk materials possess enhanced mechanical properties, in which the TRS, HV, and K_(IC) are 1 966 MPa, 1 583 MPa, and 9.08 MPa·m^(1/2), respectively.展开更多
文摘Ba_(1-x)Sr_xTiO_3材料具有强的介电非线性特性,在可调微波器件方面有广阔的应用前景。电子陶瓷器件的小型化、集成化的发展要求Ba_(1-x)Sr_xTiO_3材料能够实现低温烧结。采用柠檬酸盐法制备名义组成为Ba_(0.6)Sr_(0.4)TiO_3+0.5wt.%Li_2O(简称BSTL)的陶瓷样品,研究了在烧结温度为900℃下,保温时间对BSTL陶瓷的结构与介电性能的影响。研究结果表明,Li_2O的添加有效地降低了Ba_(0.6)Sr_(0.4)TiO_3(简称BST)材料的烧结致密化温度。保温时间的增加,促进了Li+固溶进入BST晶格,加快烧结过程中的传质,提高了样品的致密度。烧结温度为900℃、保温时间为8 h的陶瓷样品介电性能最佳:在频率10 k Hz下,介电常数为2 246,介电损耗为0.3%;偏置电场为30 k V/cm和频率为10 k Hz条件下,可调性为29.6%,优值系数(FOM)为96.2。
基金Funded by the National Key Research and Development Plan of China(No.2017YFB0305900)the National Natural Science Foundation of China(No.51634006)the Sichuan Provincial Science Research Program of China(No.1640STC30132/01)
文摘The traditional low-pressure sintering was optimized for the preparation of Ti(C_(0.5)N_(0.5))-WC-Mo_2 C-TaC-Co-Ni cermets. Nitrogen was introduced into sintering system during different stages and with different pressures. The morphology and mechanical properties of cermets were investigated by scanning electron microscopy(SEM), X-ray diffraction(XRD), and measurements of transverse rupture strength(TRS), Vickers-hardness(HV) and fracture toughness(K_(IC)). The degree of denitrification is directly related to the amount of η phase. When nitrogen is introduced into the sintering system, the amount of observed η phase decreases. When nitrogen is introduced during solid-state sintering with appropriate pressure, the core-rim structure is well developed. And TRS and hardness get enhanced while toughness tends to be deteriorated with the nitrogen pressure increasing. When nitrogen is introduced after the sintering temperature reaches 1 350 ℃ or at higher pressures, the volume fraction of η phase increases. Sintered with a nitrogen pressure of 1.0 kPa during 1 200-1 350 ℃, the bulk materials possess enhanced mechanical properties, in which the TRS, HV, and K_(IC) are 1 966 MPa, 1 583 MPa, and 9.08 MPa·m^(1/2), respectively.
