Post-Graduate Program in Oral Science, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul State, Marechal Floriano Peixoto Street 1184, 97015-372, Brazil.
Post-Graduate Program in Chemical Engineering, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul State, Roraima Avenue 1000, 97015-900, Brazil.
J Mech Behav Biomed Mater. 2019 Oct;98:11-19. doi: 10.1016/j.jmbbm.2019.05.032. Epub 2019 May 22.
This study assessed the fatigue performance (biaxial flexure fatigue strength), surface characteristics (topography and roughness) and structural stability (t-m phase transformation) of a Y-TZP ceramic subjected to air-abrasion using new powders (7% and 20% silica-coated aluminum oxide particles) in comparison to commercially available powders. Disc-shaped specimens were manufactured (ISO 6872-2015) and randomly allocated into four groups considering the air-abrasion materials: SiC: commercially available silica-coated aluminum oxide; AlOx: commercially available aluminum oxide; 7%Si and 20%Si: experimentally produced materials consisting of 7% and 20% silica-coated AlOx, respectively. Air-abrasion was executed by a blinded researcher (1 cm distance from the tip to the specimen surface, under 2.8 bar pressure for 10 s). The fatigue tests (n = 15) were performed by the staircase method under a piston-on-three-balls assembly. Topography and roughness assessments (n = 30) of abraded samples and fractography of failed discs were performed. The highest fatigue strength (MPa) was observed for 7%Si (887.20 ± 50.54) and SiC (878.16 ± 29.81), while the lowest fatigue strength for 20%Si (773.89 ± 46.44) and AlOx (796.70 ± 46.48). Topography analysis depicted similar surface morphology for all conditions. However, roughness (μm) was only statistically different between 7%Si (Ra = 0.30 ± 0.09; Rz = 2.31 ± 0.63) and SiC (Ra = 0.26 ± 0.04; Rz = 1.99 ± 0.34). Monoclinic phase grains appeared on Y-TZP surface in a similar content (≈11-12%) for the protocols. Fractography showed all failures starting on air-abraded surface/sub-surface defects from the tensile side. In terms of roughness, phase transformation and fatigue, the new 7% silica-coated aluminum oxide presented similar behavior to the commercially available powder. Increasing silica-coating concentration to 20% did not lead to a gentle air-abrasion protocol.
本研究评估了 Y-TZP 陶瓷的疲劳性能（双轴弯曲疲劳强度）、表面特性（形貌和粗糙度）和结构稳定性（t-m 相转变），该陶瓷经空气喷砂处理后使用新型粉末（7%和 20%二氧化硅包覆氧化铝颗粒），与市售粉末相比。根据空气喷砂材料，将圆盘状试件（ISO 6872-2015）制成并随机分为四组：SiC：市售二氧化硅包覆氧化铝；AlOx：市售氧化铝；7%Si 和 20%Si：分别由 7%和 20%二氧化硅包覆 AlOx 组成的实验材料。由一名盲研人员（距试件表面 1cm 距离，2.8bar 压力下 10s）进行空气喷砂处理。疲劳试验（n=15）通过活塞-三球组件以阶梯法进行。对喷砂后的样品进行形貌和粗糙度评估（n=30），并对失效盘的断口进行分析。观察到最高疲劳强度（MPa）的为 7%Si（887.20±50.54）和 SiC（878.16±29.81），而最低疲劳强度的为 20%Si（773.89±46.44）和 AlOx（796.70±46.48）。形貌分析显示所有条件下的表面形貌相似。然而，粗糙度（μm）仅在 7%Si（Ra=0.30±0.09；Rz=2.31±0.63）和 SiC（Ra=0.26±0.04；Rz=1.99±0.34）之间存在统计学差异。在所有方案中，四方相晶粒在 Y-TZP 表面的出现量相似（约 11-12%）。断口分析显示所有失效均从拉伸侧的空气喷砂表面/亚表面缺陷开始。就粗糙度、相转变和疲劳而言，新型 7%二氧化硅包覆氧化铝的表现与市售粉末相似。将二氧化硅包覆浓度增加到 20%并没有导致温和的空气喷砂方案。
