1Cr18Ni9Ti与TiC-TiB_2熔化连接及其陶瓷涂层制备研究

Fusion Bonding of TiC-TiB_2 Ceramic Coating to 1Cr18Ni9Ti Substrate and the Preparation of the Ceramic Coating

采用超重力场燃烧合成技术,通过液态陶瓷与1Cr18Ni9Ti之间的熔化连接,在1Cr18Ni9Ti基底上制备出具有成分扩散特征的TiC-TiB2陶瓷涂层。XRD、FESEM及EDS分析表明陶瓷涂层由大量细小的TiB2片晶、TiC不规则晶体及少量的Cr基合金相构成,并且陶瓷涂层相对密度、显微硬度及断裂韧性分别达到98.2%、24.6GPa与(14.5±3.5)MPa·m0.5。在1Cr18Ni9Ti基底与陶瓷涂层之间因出现Ti、Cr与C原子向不锈钢基底的单程扩散,使得陶瓷与不锈钢之间存在着富(Fe,Ti)合金碳化物颗粒呈梯度分布的中间过渡层,同时受超重力所限,中间过渡层存在粗大的氧化物夹杂与氧化物夹杂层,致使陶瓷涂层与不锈钢之间的剪切强度仅达到(125±35)MPa。

Based on fusion bonding of liquid TiC-TiB2 ceramic film to stainless steel substrate of 1Cr18Ni9Ti, the ceramic coating on stainless steel substrate characterized by composition diffusion was achieved by combusion synthesis in high-gravity field. XRD, FESEM and EDS results show the ceramic coating is composed of a large amount of fine TiB 2 platelets, irregular TiC grains and a few of Cr metallic binder and the inclusions of Al2O3 partilces. The relative density, microhardness and fracture toughness of the ceramic coating are 98.2%, 24.6 GPa and 14.5 ± 3.5 MPa·m 0.5 , respectively. In the presence of limited unidirectional diffusion of Ti, Cr and C atoms to the molten substrate of stainless steel from liquid ceramic film, matrix Ti-Fe enriched carbides are distributed in graded composition at the intermediate of Fe-Cr-Ni-Ti metallic matrix between the ceramic coating and the stainless steel substrate; meanwhile, there are some coarsened α-Al2O3 inclusions nearby the ceramic coating and the barrier layers of Al2O3 between the ceramic and the intermediate due to limited high gravity supplied by the centrifugal machine, so moderate shear strength of 125 ± 35 MPa is presented between the ceramic coating and the stainless steel substrate.