EVALUATION OF MECHANICAL CHARACTERISTICS OF BIO-CERAMIC FUNCTIONALLY GRADIENT COATING IMPLANT

研究目的是从残余应力和粘附强度的角度评价生物陶瓷梯度功能涂层种植体的力学特性。采用常压等离子喷涂工艺制备了生物陶瓷梯度功能涂层试样。随后在钛基体表面涂覆四层羟基磷灰石和钛的体积混合比逐渐变化的层。每层的厚度为20μm。将功能梯度涂层试样的力学特性与仅涂覆羟基磷灰石的试样的力学特性进行比较。(1)使用X射线衍射法测量涂层中产生的残余应力。采用Mo-Kα特征X射线。本实验选用（002）晶面的羟基磷灰石。确认了以下结果。(a)涂层中存在224 MPa的残余压应力。（B） 关于我们 测得仅涂覆羟基磷灰石的试样涂层中的残余压应力为295 MPa。(c)当使用功能梯度涂层时，生物陶瓷涂层试样的涂层中的压缩残余应力降低。(2)使用三点弯曲法评价涂层的粘附强度。以与上述相同的方式，在60×10×2mm^3的弯曲试样上涂覆羟基磷灰石和钛。三点弯曲的跨度为42 mm。对样本施加载荷，直至最大挠度达到3 mm。测量涂层的分层区域的尺寸。确认了以下结果。(a)功能梯度涂层试样和仅涂覆羟基磷灰石的试样的分层面积分别为4.6mm^2和10.9mm^2。(b)梯度功能涂层试样的涂层结合强度优于单纯羟基磷灰石涂层试样，具有上级性能。少

The purpose of research is to evaluate the mechanical characteristics of a bio-ceramic functionally gradient coating implant from a point of view of residual stress and adhesion strength. The bio-ceramic functionally gradient coating specimen was made using atmospheric plasma-spray processing. Four layers in which the volume mixture ratio of the hydroxyapatite and the titanium gradually change were subsequently coated on the surface of titanium substrate. The thickness of each layer was 20μm. The mechanical characteristics of the functionally gradient coating specimen were compared with those of the specimen coated only with hydroxyapatite.(1) The residual stress generated in the coating layer was measured using X-ray diffraction method. The characteristic X-ray of Mo-Kα was used. The (002) lattice plane of hydroxyapatite was selected in this experiment. The following results were confirmed.(a) Compressive residual stress of 224MPa existed in the functionally gradient coating layer.(b) … More Compressive residual stress of 295MPa in the coating layer of the specimen coated only with hydroxyapatite was measured.(c) The compressive residual stress in the coating layer of the bio-ceramic coating specimen decrease when using a functionally gradient coating.(2) The adhesion strength of the coating layer was evaluated using three-point bending method. The bending specimen of 60×10×2mm^3 was coated with hydroxyapatite and titanium in the same manner as state above. The span for three-point bending was 42mm. The specimen was loaded until the maximum deflection became 3mm. The size of delaminated area of coating layer was measured. The following results were confirmed.(a) The delaminated areas of the functionally gradient coating specimen and the specimen coated only with hydroxyapatite were 4.6mm^2 and 10.9mm^2, respectively.(b) The functionally gradient coating specimen is superior in the adhesion strength of coating layer in comparison with the specimen coated only with hydroxyapatite. Less