Effect of sintering atmosphere on corrosion resistance of Ni/(NiFe_2O_4-10NiO) cermet inert anode for aluminum electrolysis

烧结气氛对铝电解Ni/(NiFe_2O_4-10NiO)金属陶瓷惰性阳极耐腐蚀性能的影响（英文）

A comparative study on the corrosion resistance of 17Ni/（NiFe2O4-10NiO） cermet inert anode prepared in differentsintering atmospheres was conducted in Na3AlF6-Al2O3 melt. The results indicate that the corrosion rates of NiFe2O4-based cermetanodes prepared in the vacuum and the atmosphere with oxygen content of 2×10^-3 （volume fraction） are 6.46 and 2.71 cm/a,respectively. Though there is a transition layer with lots of holes or pores, a densified layer is formed on the surface of anode due tosome reactions producing aluminates. For the anode prepared in the atmosphere with oxygen content of 2×10^-3, the thickness of thedensification layer （about 50 μm） is thicker than that （about 30 μm） formed on the surface of anode prepared in the vacuum. Thecontents of NiO and Fe（II） in NiFe2xO4-y-z increase with the decrease of oxygen content in sintering atmosphere, which reduces thecorrosion resistance of the material.

对比研究了不同烧结气氛条件下制备的17Ni/(NiFe_2O_4-10NiO)金属陶瓷惰性阳极在Na_3Al F_6-Al_2O3_熔体中的耐腐蚀性能。研究结果表明,在真空和氧含量为2×10^(-3)(体积分数)气氛下制备的NiFe_2O_4基金属陶瓷阳极电解腐蚀率分别为6.46和2.71 cm/a。尽管电解后阳极过渡层中出现了许多孔洞,但在反应新生成的铝酸盐作用下,阳极表面形成了一层致密层。对于氧含量为2×10^(-3)气氛下制备的阳极,其表面电解后生成的致密层厚度(约为50μm)大于真空条件下阳极表面所生成的致密层厚度(约为30μm)。随着烧结气氛中氧含量的降低,所获材料中NiO和NiFe_(2x)O_(4-y-z)中Fe(II)的含量均增加,材料的抗腐蚀能力降低。