Mechanical properties of highly textured porous Ni–YSZ and Co–YSZ cermets produced from directionally solidified eutectics

Abstract

It is well known that several ceramic materials develop an usual; and sometimes unique; combination of properties as a result of mixing different phases with similar expansion coefficients. Sometimes they are elastically stiff, have relatively low thermal expansion coefficients, good thermal and electrical conductivities, and are resistant to chemical attack.As this paper will show, their mechanical properties are also enhanced. Nanoindentation technique is used to measure the mechanical properties for each phase of NiO-YSZ and CoO-YSZ eutectics produced by the laser floating zone technique, and also the analogues Ni-YSZ and Co-YSZ cermets produced by reduction from the eutectics precursors.The different tests have been performed at a constant indentation depth of 100nm, in order to obtain a residual imprint lower than the size of the secondary phase and extract the hardness and Young's modulus using the Oliver and Pharr approach. Moreover, several tests have been 2 performed at 2000nm of indentation range to obtain the general response of each material. In this case, only hardness and Young's modulus of the composite can be determined. Finally, the different residual imprints have been visualized by Atomic Force Microscopy to correlate each mechanical property with each phase.

Modeling of elastic modulus and hardness determination by indentation of porous yttria stabilized zirconia coatings

“…This value is slightly higher than the value previously obtained from the raw indentation data. For comparison, the elastic modulus of a dense yttria stabilized zirconia is around 200 GPa and the hardness ranging between 10 and 15 GPa [54][55][56][57][58]. For example, Roa et al [55] found the highest value for the hardness by nanoindentation limiting the indentation depth to 100 nm.…”

“…For comparison, the elastic modulus of a dense yttria stabilized zirconia is around 200 GPa and the hardness ranging between 10 and 15 GPa [54][55][56][57][58]. For example, Roa et al [55] found the highest value for the hardness by nanoindentation limiting the indentation depth to 100 nm. Jang and Matsubara [56] and Lugscheider et al [58] have found similar values on YSZ coatings obtained by EB-PVD technique.…”

Increase Corrosion Resistance of Alkyd Paint With Nio-zro2y Coating on Hot-rolled Steel

“…Employing zirconia as an anticorrosive would be an alternative for improving metal-alkyd coating adhesion. It is known that ZrO 2 is characterized by its excellent properties of resistance to corrosion and that it can be synthesized by means of various methods [17][18][19][20]. Zirconia deposited as a thin lm on various types of steel has been shown to increase the corrosion resistance of the substrate [21][22][23], and as a buffer layer, it increases the corrosion resistance of epoxy paints [11].…”

High temperature mechanical behavior of porous ceria and ceria‐based solid‐oxide fuel cells

“…The vulnerability of SOFCs to mechanical failure is a well‐known issue. However, much of the research into this phenomenon has focused on yttrium stabilized zirconia (YSZ) based devices . This material has been the standard for the field and has desirable mechanical properties but requires high temperatures to function well.…”

“…However, much of the research into this phenomenon has focused on yttrium stabilized zirconia (YSZ) based devices. [2][3][4] This material has been the standard for the field and has desirable mechanical properties but requires high temperatures to function well. As efforts are made to lower SOFC operating temperatures, a shift to ceria-based electrolytes has occurred.…”