烧结气氛对5Ni/(10NiO-NiFe2O4)金属陶瓷物相组成及力学性能的影响

摘要

5Ni/(10NiO-NiFe2O4) cermet materials were prepared by cold pressing sintering method in different atmospheres.The phase compositions were studied by XRD,microstructure was studied by SEM and mechanical properties were studied by three-point-bending strength and heat cycle.The results show that Ni/(NiO-NiFe2O4) cermet can be obtained by sintering in vacuum or atmospheres with oxygen content of 2× 10-5,2× 10-4 and 2× 10-3,respectively,but the phase composition of the ceramics varies greatly with oxygen content of the sintering atmosphere.The cermet tends to have a high content of NiO when sintered in vacuum.The content of NiFe2O4 and Ni in the cermet materials respectively increases and decreases with increasing oxygen in the sintering atmosphere.In the vacuum,cermet has an average grain size of 3.90 μm and bending strength of 138.59 MPa,which is able to withstand thermal shock tests 6.67 times in average.%在不同烧结气氛下采用冷压烧结法制备5Ni/(10NiO-NiFe2O4)金属陶瓷,通过XRD研究其物相组成,SEM研究其显微结构,并用三点抗弯测试和抗热震实验检测其力学性能.结果表明:在真空气氛及氧含量分别为2×10-5、2x10-4和2×10-3的气氛中均可获得Ni/(10NiO-NiFe2O4)金属陶瓷,但气氛中氧含量对物相含量影响较大.在真空气氛中NiO含量相对较高.材料中NiFe2O4和Ni的含量分别随着气氛中氧含量的上升而增加和减小;在真空烧结气氛中,可获得晶粒尺寸为3.90 μm的5Ni/(10NiO-NiFe2O4)金属陶瓷,其抗弯强度可达138.59 MPa,且在960℃实验条件下平均抗热震循环次数可达6.67次,具有相对较好的力学性能.