Yuan Shidan, Ma Ye, Li Xingyi, Ma Zhen, Yang Hui, Mu Liting
School of Materials Science and Engineering, Jiamusi University, Jiamusi 154007, China.
School of Pharmacy, Jiamusi University, Jiamusi 154007, China.
Materials (Basel). 2020 Sep 7;13(18):3948. doi: 10.3390/ma13183948.
Nanometer hydroxyapatite (n-HA) powders were synthesized by the chemical precipitation method, and a novel ZnO/HA composite, which consisted of second-phase particles with different sizes and distributions, was successfully fabricated. ZnO/HA composites were prepared by using powder sintering with different Zn contents and a prefabrication pressure of 150 MPa. Microstructure and local chemical composition were analyzed by a scanning electron microscope (SEM) and energy-dispersive spectrometer (EDS), respectively. The phase composition and distribution of the composite were determined with electron back-scattered diffraction (EBSD) and an X-ray diffractometer (XRD), respectively. The experimental results of the XRD showed that the chemical precipitation method was a simple and efficient method to obtain high-purity n-HA powders. When the sintering temperature was lower than 1250 °C, the thermal stability of HA was not affected by the Zn in the sintering process. Due to sintering in an air atmosphere, the oxidation reaction of Zn took place in three stages, and ZnO as the second phase had two different sizes and distributions in the composites. The compressive strength of ZnO/HA composites, of which the highest was up to 332 MPa when the Zn content was 20%, was significantly improved compared with pure HA. The improvement in mechanical properties was mainly due to the distribution of fine ZnO particles among HA grains, which hindered the HA grain boundary migration and refinement of HA grains. As grain refinement increased the area of the grain boundary inside the material, both the grain boundary and second phase hindered crack development in different ways.
采用化学沉淀法合成了纳米羟基磷灰石（n-HA）粉末，并成功制备了一种新型的ZnO/HA复合材料，该复合材料由具有不同尺寸和分布的第二相颗粒组成。通过粉末烧结法，在不同锌含量和150MPa的预制压力下制备了ZnO/HA复合材料。分别用扫描电子显微镜（SEM）和能谱仪（EDS）分析了复合材料的微观结构和局部化学成分。分别用电子背散射衍射（EBSD）和X射线衍射仪（XRD）测定了复合材料的相组成和分布。XRD实验结果表明，化学沉淀法是获得高纯度n-HA粉末的一种简单有效的方法。当烧结温度低于1250℃时，HA的热稳定性在烧结过程中不受锌的影响。由于在空气气氛中烧结，锌的氧化反应分三个阶段进行，复合材料中作为第二相的ZnO具有两种不同的尺寸和分布。ZnO/HA复合材料的抗压强度在锌含量为20%时最高可达332MPa，与纯HA相比有显著提高。力学性能的提高主要归因于细小的ZnO颗粒分布在HA晶粒之间，阻碍了HA晶粒边界的迁移和HA晶粒的细化。随着晶粒细化增加了材料内部晶界的面积，晶界和第二相以不同方式阻碍了裂纹的发展。
