Development and Characterization of Al₂O₃-ZrO₂ Composites Using ZrO₂(Y₂O₃)-Recycled as Raw Material

Abstract

The objective of this work was the development of Al2O3-ZrO2 ceramic composites using recycled-source of ZrO2(Y2O3). Al2O3 powder was mixed with different proportions of ZrO2(Y2O3) arising from pre-sintered blocks used in dental prostheses manufacturing. The mixtures containing 3wt% to 15wt% ZrO2(Y2O3) were uniaxially pressed at 80MPa and sintered at 1600°C-2h. Raw materials and sintered samples were characterized by X-ray diffraction, scanning electron microscopy (SEM), relative density, hardness and fracture toughness. The results of X-ray diffraction showed α-Al2O3 and tetragonal-ZrO2 as crystalline phases after sintering. Furthermore, the relative density in all compositions was higher than 95%. The samples presented Vickers hardness and fracture toughness higher than 1300HV and 3.5MPa. m1/2, respectively.

Current prospect of dental zirconia recycling: A scoping review

“…Recycled zirconia powders exhibit an irregular shape as a result of milling during the CAD/CAM process [4,6,32]. This shape irregularity poses a significant challenge to the rearrangement of the powders during pressing [32].…”

“…Recycled zirconia powders exhibit an irregular shape as a result of milling during the CAD/CAM process [4,6,32]. This shape irregularity poses a significant challenge to the rearrangement of the powders during pressing [32]. Cold isostatic pressing was investigated as a method to enhance the density and uniformity of recycled zirconia green bodies [11,13].…”

“…3). The predominant zirconia material used for recycling is 3 mol% Y-TZP (3Y-TZP) [4][5][6][11][12][13][25][26][27][28][29][30][31][32][33]. Among the included studies, one was published in Chinese [6], while the others were published in English.…”

“…Four studies reported the recycling of zirconia residue blocks using the CAD/CAM Milling process [5,6,28,32]. The residue blocks are generally pulverized into powder and pressed into green zirconia bodies, which are then sintered [5,6,28].…”

“…The residue blocks are generally pulverized into powder and pressed into green zirconia bodies, which are then sintered [5,6,28]. Cossu et al [32] prepared an alumina/zirconia composite by mixing recycled zirconia powder derived from residual dental zirconia blocks with alumina powder. The resulting composite exhibited a relative density of over 95%, a Vickers hardness value of >1,300 HV, and a fracture toughness value of >3.5 MPa•m 1/2 .…”