WC、ZrO2 、Cr2O3 和Al2O3 陶瓷颗粒/ 镍合金复合涂层微观组织结构的分形

采用等离子喷涂工艺, 制备了WC、ZrO₂ 、Cr₂O₃ 和Al₂O₃ 陶瓷颗粒/ 镍合金复合涂层。用X 射线衍射研究了陶瓷颗粒复合涂层相的分布; 用里氏硬度计测量陶瓷颗粒/ 镍合金复合涂层的硬度; 用CSS-1110 电子万能试验机研究陶瓷颗粒复合涂层的弯曲断裂性能。对涂层金相组织结构进行二值化处理, 利用Sandbox 法对陶瓷颗粒在金属基体中的分布进行研究, 得到了不同体积分数下陶瓷颗粒复合材料涂层的分维数。结果表明,陶瓷颗粒/ 镍合金复合涂层分维数随陶瓷颗粒含量的增加而增加, 与陶瓷颗粒种类无关; 陶瓷颗粒/ 镍合金复合涂层硬度和分维数随陶瓷颗粒直径减小而增加。随着分维数的增加, 复合涂层弯曲断裂角下降。 

FRACTAL CHARACTERISTIC OF MICROSTRUCTURE OF WC, ZrO2, Cr2O3AND Al2O3 CERAMIC PARTICLES/ NICKEL ALLOY COMPOSITE COATINGS

Four kinds of WC, ZrO_2, Cr_2O_3 and Al_2O_3 ceramic particles/nickel alloy composite coatings were prepared with the plasma spraying method. The X-ray diffraction analysis was used to investigate the phase constituent of ceramic particles in composite coatings. The hardness of the ceramic particles/nickel alloy composite coating was measured by the Leeb hardness tester. The properties of bend breaking of composite coatings were measured using CSS-1110 electric all-purpose test meter. The micro-structures of composite coatings were treated as a binarization after morphological processing. The fractal dimensions of the ceramic particles/nickel alloy composite coatings with different volume fractions of particles were obtained by means of the Sandbox method. Experimental results indicate that the distributions of ceramic particles in metal matrix have a fractal characteristic. The fractal dimensions increase with the increase of particle volume fractions. The dimensions are irrelative with the kinds of ceramic particles. The hardness and dimension of composite coatings increase with the decrease of diameter of ceramic particles. The bending fracture angles decrease with the increase of dimensions of ceramic particles/nickel alloy composite coatings.