ZrO_2基陶瓷压痕断裂韧性的测定

Evaluation of fracture toughness of zirconia-based ceramic by the indentation method

采用压痕裂纹(IM)法测定了无压烧结ZrO_2基陶瓷的断裂韧性(K_(1C)),并引入相对偏差概念表征K_(1C)值的精确度.结果表明,由ZrO_2基陶瓷的压痕裂纹具有巴氏裂纹特征,因而只能选择Niihara(P)方程(P表示巴氏裂纹)、Shetty方程、Laugier方程或Marshall方程等来计算K_(1C).其中,用Niihara(P)压痕方程计算的K_(1C)值最符合实际,且具有最小的相对偏差.因此,正确判断压痕裂纹类型、选择合适的压症方程及科学处理实验数据等,都将有利于提高压痕断裂韧性的测定精度.

Frature toughnesses of the pressureless sinterad ZrO_2-based ceramics were evaluated by the indenta-tion methed. Relative error of K_(1C) value was proposed to characterize the accuracy of the evaluation val-ues. The results show that because indentation microcrack of ZrO_2-based ceramic are palmqvist crack, ei-ther of Niihare (P) equation, Shetty equation, Laugier equation or Marshall equation can be selected tocalculate K_(1C) value. However, only Niihara (P) equation results in the most corrective K_(1C) value and thelowest relative error. The conclusion can be drawn that it is very good for increasing the accuracy of eval-uation of identation fracture toughness to judge correctly indentation crack, to select a suitabe indentationequation, and to analyze scientifically experimental data, et al.