A study on mechanical and tribological properties of eco-friendly synthesized ZrO₂-doped borosilicate glasses

The research article aims to investigate the mechanical and tribological characteristics of bioactive glass specimens comprising 31B₂O₃-20SiO₂-24.5Na₂O-(24.5-x) CaO and xZrO₂ (mol%). This glass system was partially derived from bio-waste, with varying concentrations of Zirconia (ZrO₂) represented x (x = 0, 1, 3, and 5). The specimens were fabricated using the traditional melt-quench method. Mechanical studies like hardness and compressive strength were measured using Vickers hardness tester and universal tensile machine respectively, while a pin-on-disk tribometer was used to analyze the tribological characteristics. All the specimens were soaked in SBF for a week to assess in-vitro bioactivity. The research findings indicate that Zirconia inclusion resulted in a significant reduction in the intensity of hydroxyapatite peaks of FTIR and XRD spectra, suggesting a decrease in bioactivity. However, it concurrently resulted in increased glass hardness, with the highest value (∼7.55 GPa) observed in the BSG-5 glass sample. Similarly, compressive strength results demonstrated maximum strength in BSG-5 glass specimen, with a value of approximately ∼132 MPa. Moreover, the tribological properties of the glass system were enhanced, evident from the reduced coefficient of friction and specific wear rate. Notably, the BSG-5 glass specimen exhibited the least wear coefficient of 0.018 mm³/N-m at a track radius of 40 mm and a load of 15N. These findings were further supported by SEM images of the worn-out ZrO₂-Doped Borosilicate Glass surface. Overall, the results suggest that the addition of Zirconia to borosilicate glass holds promise for improving its mechanical and tribological characteristics. However, this enhancement comes at the expense of its bioactivity. Consequently, the modified glass system presents a cost effective viable option for various applications, particularly in load-bearing and dental applications.