烧结工艺对NiFe_2O_4-10NiO双相陶瓷烧结行为及微观结构的影响

Effect of sintering process on densification procedure and microstructures of NiFe_2O_4-10NiO dual-phase ceramic

采用粉末冶金法制备NiFe2O4-10NiO双相陶瓷,对该陶瓷在不同烧结气氛、不同烧结温度和保温时间等条件下的烧结行为进行研究,探讨烧结气氛、烧结温度和保温时间等对NiFe2O4-10NiO双相陶瓷烧结致密化进程及显微结构演变规律的影响。结果表明:N2气氛下NiFe2O4-10NiO双相陶瓷的致密化速率及晶粒长大速率均较空气气氛中快,1 300℃下样品致密化速率及晶粒长大速率为空气气氛下的1.1倍和23.8倍,烧结工艺为1 300℃/120 min时,N2气氛下样品的烧结密度和晶粒尺寸比空气气氛下的烧结密度和晶粒尺寸分别高约36.1%和426.5%;另外,N2气氛下烧结的NiFe2O4-10NiO陶瓷中析出金属相Ni-Fe及尖晶石相,其形成与Fe2O3、NiO相离解及两相间发生扩散型固态相变密切相关。

NiFe2O4-10NiO dual-phase ceramic was prepared by traditional powder metallurgy method and sintered in different atmosphere,temperature and time.The influences of sintering conditions on densification procedure and microstructure were studied.The results show that the densification rate and coarsening velocity of grains of NiFe2O4-10NiO dual-phase ceramic sintered in N2 are higher than that in air.When the sintering temperature is 1 300 ℃,the densification rate and coarsening velocity of grains in N2 are 1.1 and 23.8 times of that in air respectively.When sintering process is 1 300 ℃/120 min,the density and grain size of the samples sintered in N2 are 36.1% and 426.5% higher than that of in air atmosphere,respectively.Moreover,the Ni-Fe and spinell phases only separate out from NiFe2O4-10NiO when singtering in N2,it is considered that the forming process is due to dissociation of Fe2O3 and NiO,as well as diffuse type solid-state phase changes between them.