Effect of CaO on the densification and mechanical properties of 17Ni/(10NiO-NiFe_2O_4) cermets

17Ni/(10NiO-NiFe2O4) cermets added with CaO were fabricated by cold pressing-sintering.The effects of CaO content and sintering temperature on the phase composition,relative density and mechanical properties of 17Ni/(10NiO-NiFe2O4) cermets were studied.The results show that the cermets consist of Ni,NiO and NiFe2O4.Introduction of CaO can accelerate the densification of 10NiO-NiFe2O4 composites.As the sintering temperature is limited at 1250 ℃,the relative density will achieve the maximum value of 98.75% for the sample doped 1.0 wt%CaO,and then decrease with increasing the CaO content sequentially.With the temperature increasing from 1250 ℃ to 1350 ℃,the relative densities reveal the increase for the samples containing CaO with the content less than 0.5 wt% and the decrease for the samples containing more than 0.5 wt% CaO.Both increasing sintering temperature and adding CaO cause grow-up of the ceramic grain.An optimal bending strength value of 150.66 MPa of the sample sintered at 1250 ℃,is achieved at the CaO content of 1.0%.