Femtosecond laser texturing of crack-free zirconia composites: Texturing of pre-sintered ceramics and microcrack self-healing

Abstract

Laser surface texturing of ceramic components without inducing surface cracking and the concomitant strength degradation remains a significant challenge, limiting its application in high-strength or long-term fatigue resistance conditions. Here, a simple and convenient manufacturing methodology was explored by applying laser texturing on pre-sintered alumina toughened zirconia (ATZ) ceramics instead of fully sintered ones. Surface micro-cracks introduced by texturing were totally healed during the subsequent sintering process, giving rise to crack-free, surface-textured ATZ ceramics. Combined with the toughness improvement by triggering additional secondary phase and phase transformation toughening, the ceramics from this methodology showed a significant higher characteristic fracture strength (∼890 MPa) than their equivalents (∼700 MPa) that were laser-textured in the sintered condition, and are competitive with as-sintered (∼914 MPa) ceramics without surface texturing, which challenges the conventional cognition that laser surface-texturing invariably degrades mechanical strength. In addition, the laser textured ATZ ceramics showed a similar hydrothermal aging resistance as the polished ceramics. Our findings address key challenges in laser surface texturing of crack-sensitive ceramic materials. Achieving crack-free surface patterns is essential for ensuring the reliability of ceramics in applications such as dental implants, where laser-modified surface can enhance osseointegration, while the implants' strength must be ensured for structural support and long-term service stability.