Fabrication of Zirconia Ceramic Using Titanium SinteringAid via SPS Method and Characterization of its Properties

This research investigates the influence of ZrO₂ particle size on the structural and mechanical propertiesof ZrO₂-Ti composites. Micro-ZrO₂-Ti and nano-ZrO₂-Ti composites were fabricated employing theSpark Plasma Sintering (SPS) method under the following conditions: a temperature of ۱۳۰۰°C, aholding time of ۵ minutes and an applied pressure of ۳۰ MPa. Subsequently, the sintered samplesunderwent X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and hardness testing forcharacterization. Phase identification patterns revealed that the volume fraction of m-ZrO₂ in the micro-ZrO₂-Ti composite was ۴۹.۵۹%, while in the nano-ZrO₂-Ti composite, this fraction increased to ۸۴.۱۹%.Additionally, titanium (Ti) reacted with oxygen (O) to form Ti₂O within the structure during thesintering process. The lattice parameter in the nano-ZrO₂-Ti composite was significantly smaller thanthat in the micro-ZrO₂-Ti composite, reducing crystallite size. However, due to the shorter atomicdistance in the unit cell, lattice strain in the nano-ZrO₂-Ti composite was higher than in the micro-ZrO₂-Ti composite. Vickers hardness testing was employed to evaluate the impact of particle size on thecomposites' hardness. The results indicated that the average hardness of the micro-ZrO₂-Ti compositewas ۲۷۱ HV, whereas, in the sample fabricated with ZrO₂ nanoparticles, this value increased to ۲۹۵ HV,demonstrating an approximate ۸% growth. The fracture toughness of the micro-ZrO₂-Ti and nano-ZrO₂-Ti composites was determined to be ۳.۵ MPa·m (-۱/۲) and ۴.۶ MPa·m (-۱/۲), respectively, revealing thatthe fracture toughness of the nano-ZrO₂-Ti composite is approximately ۱ MPa·m (-۱/۲) higher than thatof the micro-ZrO₂-Ti composite. Furthermore, microstructural investigations showed that crackdeflection and branching are the predominant toughening mechanisms in micro-ZrO₂-Ti and nano-ZrO₂-Ti composites.