羟基磷灰石-氧化锆复合材料的致密化及其力学性能

Densification and mechanical properties of hydroxyapatite-zirconia composite materials

在无压条件下,采用添加CaF2法制备了羟基磷灰石氧化锆致密材料,并研究了CaF2含量对HA ZrO2材料的致密化、微观结构和力学性能的影响。结果显示:在HA ZrO2(10%～40%,质量分数,下同)复合材料中添加CaF2,使HA变成了分解温度高的氟部分取代羟基的磷灰石FHA,材料的密度和力学性能(抗弯强度和断裂韧性)明显提高;加入6%(质量分数)CaF2经1350℃烧结4h后,HA ZrO2(10%～40%)的相对密度均达到95%,抗弯强度达到100～120MPa,断裂韧性提高到1.2～1.6MPa·m1/2;随ZrO2含量的升高,HA ZrO2致密度有所下降;而当CaF2含量为6%,ZrO2含量高于40%时,HA ZrO2复合材料中形成αCa3(PO4)2、HA/ZrO2固溶体或立方氧化锆,导致复合材料的力学性能下降。

Densified HA-ZrO_2 composites were fabricated by adding CaF_2 under pressureless condition. The effects of CaF_2 content on the densification, phase compositions, microstructures and mechanical properties of HA-ZrO_2 composites were investigated. The results show that the reaction between CaF_2 and HA leads to the formation of fluorine partially substituted hydroxyapatite FHA with higher thermal stability, which enhances the densification, microstructures and mechanical properties of HA-ZrO_2 composites. When the HA(10%40%, mass fraction)-ZrO_2 composites adding 6% CaF_2 were sintered at 1350℃ for 4h, their theoretical densities can reach more than 95%. Fractural strength reaches 100200MPa and fracture toughness can enhance 1.21.6MPa·m^(1/2). The effects of zirconia on phase compositions and mechanical properties were also studied. The densities of HA- ZrO_2 composites decrease with increasing ZrO_2 contents. When the mass fraction of CaF_2 is above 6% and that of ZrO_2 is above 40%, formations of CaZrO_3, α-Ca_3(PO_4)_2, HA/ZrO_2 solid solution, and c-ZrO_2 lead to the poorer mechanical property of HA- ZrO_2 composites.