CaO对17Ni/(10NiO-NiFe2O4)金属陶瓷的致密化及力学性能的影响

采用冷压-烧结技术制备了CaO掺杂的17Ni/(10NiO-NiFe₂O₄)金属陶瓷惰性阳极。研究了CaO的添加量和烧结温度对17Ni/(10NiO-NiFe₂O₄)金属陶瓷的物相组成、 致密度和力学性能的影响。结果表明, CaO含量在小于5.0wt%范围内, 烧结样品由Ni、 NiO和NiFe₂O₄组成。CaO掺杂对17Ni/(10NiO-NiFe₂O₄)金属陶瓷具有明显的助烧作用。当烧结温度为1250℃时, CaO掺杂量为1.0wt%的样品致密度达到最大值97.87%, 继续增加CaO掺杂量将导致材料致密度的下降。当烧结温度从1250℃提高到1350℃时, 当CaO掺杂量小于0.5wt%时, 样品的致密度随烧结温度的提高而增加; 当CaO掺杂量大于或等于0.5wt%时, 样品的致密度随烧结温度的提高而降低。提高烧结温度和添加CaO均能促进陶瓷相晶粒长大。样品在1250℃烧结时, 其抗弯强度在CaO掺杂量为1.0wt%时达到极大值为150.66MPa。

Effect of CaO on the densification and mechanical properties of 17Ni/(10NiO-NiFe2O4) 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%.