梯度结构烤瓷的成分优化及性能

以镍铬合金为金属基底，在白榴石为主晶相的烤瓷粉中按不同比例加入Ni、Cr、NiO、Cr₂O₃作为梯度调节物，制备具有成分梯度结构的金属烤瓷。采用材料抗弯强度测试和热膨胀系数测试的方法筛选优化梯度调节物的配比，发现质量比为m(NiO)∶m( Cr₂O₃)∶m(Ni)∶m(Cr)＝0∶50∶40∶10时能得到抗弯强度为101.217 MPa的最佳梯度层。用弹性应力模型模拟计算梯度层内的热应力曲线，研究了梯度层中富陶瓷端到富梯度调节物端热应力缓和的情况。抗弯强度、扫描电镜、XRD测试表明，减小烤瓷粉粒度可增强梯度层的性能，降低烧结温度。梯度层的抗弯强度呈现各向异性的特点。

Composition optimization and properties of porcelain fused to metal with functional gradient material structure

The porcelain-fused to metal (PFM) based on nickel-chromium alloy with the composition gradient structure was prepared by adding Ni，Cr，NiO and Cr2O3 in different proportions to the porcelain powder mainly constituted by leucite. The bending strength and thermal expansion coefficient (TEC) of the different gradient compositions were tested. SEM and XRD were also employed to characterize the as-prepared gradient samples. The thermal stress of the samples was simulated using  an elastic stress model. The results show that when m(NiO)∶m(Cr2O3)∶m(Ni)∶m(Cr)＝0∶50∶40∶10，the functional gradient material (FGM) with high bending strength（101.217 MPa）and comparatively low thermal stress is obtained. The thermal stress curves exhibit that FGM structure could relax the thermal stress of the samples in the cross-sectional direction. The study result also indicates that the smaller particle size of the porcelain powder could improve the performance of FGM and reduce the sintering temperature，and the bending strength of the gradient materials presents aeolotropism.