Improvement of Mechanical Properties of Artificial Bone Material Composed of Hydroxyapatite and Zirconia

迄今为止，已经使用羟基磷灰石（HAP）和部分稳定的氧化锆（PSZ）的粉末混合物进行了一些研究，以开发对骨组织具有亲和力并表现出高机械强度和断裂韧性的人工骨材料，但结果不太令人满意。在这项研究中，通过干冲击共混法进行了相对大尺寸的球形细HAP颗粒（Dm= 9.32 μ m）与小尺寸细PSZ颗粒（Dm= 0.12 μ m）的表面包覆。使用NHS-0型杂交系统（奈良机械公司）将球形细HAP颗粒与细PSZ颗粒混合。球形HAP微粒的表面被PSZ微粒完全包覆。由100%HAP组成的烧结体的断裂韧性为1.1MPam-1<0.5>，而HAP/PSZ重量比为10/2和10/5以及10/10的烧结体的断裂韧性分别为1.8和2.8MPam-1<0.5>。2.8MPam ^的断裂韧性值<0.5>接近<0.5>人造骨所需的3.0MPam ^。通过电子显微镜观察，发现很少观察到彼此直接连接的细HAP颗粒。该复合细颗粒的烧结体包括PSZ的三维连续网状相，其中分散有球形细HAP颗粒。由此可见，PSZ的断裂韧性仍保留在复合微粒的烧结体中。X射线衍射分析结果表明，HAP/PSZ比为10/2、10/5和10/10的烧结体由HAP和PSZ单独组成，表明HAP没有转化为磷酸三钙。

Several studies have been made using powder mixture of hydroxyapatite (HAP) and partially stabilized zirconia (PSZ) so far to develop an artificial bone material with affinity to bone tissue and exhibiting high mechanical strength and fracture toughness, but with less satisfactory results. In this study surface coating of relatively large-sized spherical fine HAP particles (Dm=9.32mum) with small-sized fine PSZ particles (Dm=0.12mum) by the dry impact blending method conducted. The spherical fine HAP particles were mixed with fine PSZ particles using an NHS-0 Type Hybridization System (Nara Machinery Co.). The surface of the spherical fine HAP particles were completely coated with the fine PSZ paricles. The fracture toughness of the sintered body consisting of 100% HAP was 1.1MPam^<0.5>, while those with the HAP/PSZ weight ratios of 10/2 and 10/5, and 10/10 are 1.8 and 2.8 MPam^<0.5>, respectively. Fracture toughness values of 2.8 MPam^<0.5> is close to the 3.0 MPam^<0.5> required for the artificial bone. By electron microscopic observation, it was revealed that fine HAP particles directly connected to each other are seldom observed. The sintered body of the composite fine particles comprises a three-dimensional, continuously reticulate phase of PSZ in which spherical fine HAP particles are scattered. It could be understand from this observation fracture toughness of PSZ still remains in the sintered body of the composite fine particles. The result of the X-ray diffractometry indicates that the sintered bodies with the HAP/PSZ ratios of 10/2,10/5 and 10/10 consist of HAP and PSZ alone, showing that HAP is not transformed to tricalcium phosphate.