Mechanical properties of stabilized zirconia nanocrystalline EB-PVD coating evaluated by micro and nano indentation

Abstract

Yttria-stabilized zirconia (YSZ) thin nanocrystalline coatings at different substrate preheating temperatures were deposited via electron beam-physical vapour deposition (EB-PVD). Nanocrystalline ZrO 2 -Y 2 O 3 was deposited on the bond coat in order to compensate for the coefficient of thermal expansion (CTE), which can be functionalized as a thermal barrier coating (TBC). The aim of this study was to evaluate mechanical properties with respect to adhesion of zirconia nanocrystalline's top ceramic layer to the interfacial bond coat by utilizing micro and nano indentation tests. In the present paper, the structural studies were carried out using X-ray diffraction (XRD) analysis of coating content (8 mol% of Y 2 O 3 ). The tetragonal phase of stabilized zirconia was observed. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) were employed to characterize the coatings' morphology and microstructure. The mechanical behavior of ZrO 2 -Y 2 O 3 thin films under point loading conditions was studied by nanoindentation using a Berkovich indenter with 130 nm tip radius. Therefore, adhesion of top coat to the interfacial underlying metallic bond coat known as MCrAlY (M = Ni, Co) was estimated according to the highest peak load tests; for a 120 mN peak load, the film manifested tolerable adhesion properties. Moreover, nanoindentation of ZrO 2 -Y 2 O 3 nanostructure deposited at 1050 ℃ substrate preheating temperature produced the highest hardness value of about 21.7 GPa. Vickers micro hardness was utilized with the aid of the Tabor equation in order to achieve deeper insight into the correlation between adhesion and deposition process parameters.

Acid etching of glass-infiltrated zirconia and its biological response

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Optimizing thickness of ceramic coatings on plastic components for orthopedic applications: A finite element analysis

“…For this reason, an elasto-plastic curve with kinematic hardening for the deposited zirconia was considered. A yield stress of 3464.2 MPa was obtained by implementing the transformation of the measured hardness in Vickers units (Hv [kgf/mm 2 ] = 0.0945 H it [MPa] according to EN ISO 14577-1 F3) and by applying the Tabor's rule (σy = Hv/2.9, as indicated in [29]). The slope corresponding to the plastic region was obtained by reverse analysis, i.e.…”

Evaluating high temperature elastic modulus of ceramic coatings by relative method

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