A comparative transmission electron microscopy, energy dispersive x-ray spectroscopy and spatially resolved micropillar compression study of the yttria partially stabilised zirconia - porcelain interface in dental prosthesis

Lunt, Alexander J.G.; Mohanty, Gaurav; Ying, Siqi; Dluhoš, Jiří; Sui, Tan; Neo, Tee K.; Michler, Johann; Korsunsky, Alexander M.

doi:10.1016/j.tsf.2015.07.070

Cited by 10 publications

(26 citation statements)

References 61 publications

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“…Failure was found to be more likely within the near-interface porcelain at a distance of between 1 − 2 μm from the interface. This length scale correlates well with the position of nanoscale voiding observed in porcelain by Lunt et al [11] (0.4 − 1.5 μm from the interface) suggesting that there may be an underlying structural weakness in the porcelain at this location. The random nature of void type features may also explain the large scatter observed in the fracture toughness of the near-interface porcelain pillars.…”

Section: Micropillar Indentation Splittingsupporting

confidence: 86%

“…At present the exact origin of this increased toughness is not clear. One explanation may be high elemental composition sensitivity of YPSZ fracture toughness [18,36] and the variations in the concentration of Si, K, Na and Al known to be present within the first 5 μm of the interface [11]. Perhaps more likely, given the scatter in the fracture toughness values obtained, is the grain size dependence of YPSZ fracture toughness [37].…”

Section: Micropillar Indentation Splittingmentioning

confidence: 99%

“…In order to aid in aligning the indenter on the center of each pillar, a 25 nm deep target cross was milled into the surface, as shown in Figure 1b. High resolution imaging was performed on each pillar in using SEM stage tilt angles of 0° and 35° in order to measure the radius ( ) and height of each pillar using the technique previously outlined by Lunt et al [11]. Precise measurement of the distance from the interface to the center of each pillar was also performed during this process.…”

Section: Micropillar Fib Machiningmentioning

confidence: 99%

“…Microanalysis and compositional mapping of the YPSZ-porcelain interface has been performed using a broad range of experimental techniques including Scanning Electron Microscopy (SEM) [10,11], Energy Dispersive Spectroscopy (EDS) [11,12], Transmission Electron Microscopy (TEM) [11,13] and micro-focus X-ray diffraction [10,14]. These studies have demonstrated that the microstructural variation at the YPSZ-porcelain interface is limited to within the first few hundred microns of the interface, and that the behavior is influenced by both nano-voiding and nano-grain features.…”

Section: Introductionmentioning

confidence: 99%

“…However, these studies do not provide insight into the mechanical properties of most significance for prosthesis integrity: stiffness, hardness (yield strength) and toughness. Recently, microscale spatially resolved studies of Young's modulus and yield strength variation across the YPSZ-porcelain interface region have recently been published [11,15,16]. The analysis of toughness variation at very short length scales has remained an insurmountable challenge, despite the fact that material resistance to crack initiation and propagation, is critical for understanding the origins of the brittle failure observed at the YPSZ-porcelain interface.…”

Section: Introductionmentioning

confidence: 99%

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Microscale resolution fracture toughness profiling at the zirconia-porcelain interface in dental prostheses

et al. 2015

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The high failure rate of the Yttria Partially Stabilized Zirconia (YPSZ)-porcelain interface in dental prostheses is influenced by the micro-scale mechanical property variation in this region. To improve the understanding of this behavior, micro-scale fracture toughness profiling by nanoindentation micropillar splitting is reported for the first time. Sixty 5 μm diameter micropillars were machined within the first 100 μm of the interface. Berkovich nanoindentation provided estimates of the bulk fracture toughness of YPSZ and porcelain that matched the literature values closely. However, the large included tip angle prevented precise alignment of indenter with the pillar center. Cube corner indentation was performed on the remainder of the pillars and calibration between nanoindentation using different tip shapes was used to determine the associated conversion factors. YPSZ micropillars failed by gradual crack propagation and bulk values persisted to within 15 μm from the interface, beyond which scatter increased and a 10% increase in fracture toughness was observed that may be associated with grain size variation at this location. Micropillars straddling the interface displayed preferential fracture within porcelain parallel to the interface at a location where nano-voiding has previously been observed and reported. Pure porcelain micropillars exhibited highly brittle failure and a large reduction of fracture toughness (by up to ~90%) within the first 50 μm of the interface. These new insights constitute a major advance in understanding the structure-property relationship of this important bi-material interface at the micro-scale, and will improve micromechanical modelling needed to optimize current manufacturing routes and reduce failure.

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Section: Micropillar Indentation Splittingsupporting

confidence: 86%