Reliability during Thermal Shock Testing of NiCr Films on Mn-Ni-Co Oxide Substrates
There is an increasing reliability concern of thermal stress-induced failures in multilevel coatings in recent years. This work reports investigations of cracking of NiCr coatings due to thermal cycling. The temperature cycling in accelerated testing was performed in three temperature range of 150, 175 and 200°C. The NiCr coatings were considered to have failed when the sheet resistance changed by 30% relative to an initial value. As the cyclic repetition of thermal shock increased, the sheet resistance of NiCr coatings increased. The Coffin-Manson equation was applied to the failure mechanism of cracking of NiCr coatings and the SEM observation of cracks and delamination in NiCr coatings due to thermal cycling agreed well with the failure mechanism.
T. Ohji, T. Sekino and K. Niihara
M. S. Jeon, J. K. Song, E. J. Lee, H. S. Lee, T. H. No, D. H. Kim, I. G. Park, "Reliability during Thermal Shock Testing of NiCr Films on Mn-Ni-Co Oxide Substrates", Key Engineering Materials, Vols. 317-318, pp. 553-556, 2006