Effect of metallic phase content on mechanical properties of (85Cu-15Ni)/(10NiO-NiFe 2O 4) cermet inert anode for aluminum electrolysis

• Published in: Transactions of Nonferrous Metals Society of China 2007-10, Vol.17 (5), p.1063-1068
• Main Authors: ZHANG, Gang, LI, Jie, LAI, Yan-qing, TIAN, Zhong-liang
• Format: Article
• Language: English
• Subjects: aluminum electrolysis; cermet inert anode; fracture toughness; metallic phase; NiFe 2O 4; thermal shock resistance
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(07)60226-X

(85Cu-15Ni)/(10NiO-NiFe 2O 4) cermets were prepared with Cu-Ni mixed powders as toughening metallic phase and 10NiO-NiFe 2O 4 as ceramic matrix. The phase composition, microstructure of composite and the effect of metallic phase content on bending strength, hardness, fracture toughness and thermal shock resistance were studied. X-ray diffraction analysis indicates the coexistence of (Cu-Ni), NiO and NiFe 2O 4 phases in the cermets. Within the content range of metallic phase from 0% to 20% (mass fraction), the maximal bending strength (176.4 MPa) and the minimal porosity (3.9%) of composite appear at the metallic phase content of 5%. The fracture toughness increases and Vickers' hardness decreases with increasing metal content. When the thermal shock temperature difference (Δ t) is below 200 °C, the loss rate of residual strength for 10NiO-NiFe 2O 4 ceramic is only 8%, but about 40% for (85Cu-15Ni)/(10NiO-NiFe 2O 4) cermets. As Δ t is above 200 °C, the residual strength sharply decreases for sample CNO and falls slowly for samples CN5–CN20.