Metastability of the Martensitic Transformation in a 12 mol% Ceria‐Zirconia Alloy: II, Grinding Studies

Abstract

Observations of the grinding-induced transformation in singlephase Ce-TZP materials, referred to in an earlier paper, are presented. Two techniques were used to grind the surface: by hand in a slurry of abrasive particles and with a high-speed diamond-impregnated wheel. Significant differences in X-ray diffraction profiles between the two grinding methods was observed. Limited monoclinic Zr02 was detected on the machineground surface, along with the reversal of the tetragonal ZrOz (200) peak intensities. On the hand-ground surface, considerable monoclinic phase was observed. The disappearance of the monoclinic phase with heating was followed by X-ray diffraction, and the A, was found to exceed 700"C, while the reversal in tetragonal (200) peak symmetry and intensity remained unaltered up to at least 1000°C. Transmission electron microscope studies at various depths below the ground surface were undertaken to identify the differences between these surfaces and fractured surfaces. A simple explanation is proposed for the reversal of the tetragonal peak intensities. This reversal has previously led to the notion of a ferroelastic toughening mechanism in similar TZP materials. [

Effect of Air-Abrasion Regimens and Fine Diamond Bur Grinding on Flexural Strength, Weibull Modulus and Phase Transformation of Zirconium Dioxide

“…The lower flexural strength values, compared to those reported by the manufacturers of Y-TZP, may be due the fact that specimens were only sintered, rather than sintered and polished as recommended by the ANSI/ADA specification for dental ceramics (23). Furthermore, Swain and Hannink (18) reported that hand ground Ce-TZP surface contained almost five times more monoclinic zirconia than severely machine ground surface of the same material.…”

“…Wet hand-grinding with a fine-grit diamond rotary cutting instrument is another surface modification described in the literature, with a favourable effect on the strength of zirconia (11,17). Previous investigators advocated fine grinding as an alternative method for roughening zirconia reconstructions in the absence of air-abrasion armamentarium (10,12,18).…”

Digital dentistry: an overview of recent developments for CAD/CAM generated restorations

“…The addition of three molecules of Y 2 O 3 results in a stabilising tetragonal phase at room temperature, which, as a result of a transition to a monoclinic phase can prevent the pro gression of cracks in the ceramic (Trans formation strengthening). [24][25][26][27] Examples of Zirconium oxide blocks: Lava Frame (3M ESPE), Cercon Smart Ceramics (DeguDent), Everest ZS und ZH (KaVo), inCoris Zr (Sirona), In-Ceram YZ (Vita), zerion (etkon) and Zeno Zr (Wieland-Imes)…”

Influence of handling and heating cycle on the morphology and flexural strength of glass-infiltrated alumina bars

“…It was shown that grinding and sandblasting promote a severe damage on dental prosthesis mainly during excess glass removal. Despite the use of a water coolant, Swain and Hannink [17] dealing with zirconia, observed that an excessive heat generated during grinding could promote changes in its microstructure. In this case, this heating could promote crack healing which did not occurred during sandblasting.…”