Phase transformation and subsurface damage in 3Y-TZP after sandblasting

Area of Science:

• Materials Science
• Ceramics Engineering
• Biomaterials

Background:

• 3Y-TZP (3 mol% yttria-stabilized tetragonal zirconia polycrystal) is a widely used ceramic in dentistry.
• Surface treatments like sandblasting are common for enhancing adhesion but can affect material properties.
• Understanding sandblasting-induced changes is crucial for predicting the long-term performance of zirconia restorations.

Purpose of the Study:

• To investigate the tetragonal-to-monoclinic (t-m) phase transformation and subsurface damage in 3Y-TZP after sandblasting.
• To correlate sandblasting parameters (particle size, pressure) with the extent of transformation and damage.
• To provide critical data for optimizing sandblasting protocols in dental applications.

Main Methods:

• Sintered 3Y-TZP specimens were subjected to sandblasting with varying particle sizes (110, 250 μm) and pressures (2, 4 bar).
• Phase transformation was analyzed using X-ray diffraction (surface) and micro Raman spectroscopy (cross-section).
• Subsurface damage was evaluated using Scanning Electron Microscopy (SEM) and focused ion beam (FIB) cross-sections.

Main Results:

• Sandblasting generated a monoclinic phase fraction of 12-15% on the surface.
• A non-homogeneous t-m phase transformation gradient extended up to 12±1 μm depth.
• Subsurface damage included plastic deformation and martensitic plates, with increased severity observed for larger sandblast particles.

Conclusions:

• The study quantifies the t-m phase transformation and subsurface damage induced by different sandblasting conditions in 3Y-TZP.
• Findings highlight the significant impact of particle size on the extent of transformation and damage.
• This research is vital for understanding how sandblasting affects the mechanical integrity of zirconia used in dental crowns and frameworks.