Zhao Zaiyang, Jia Pengmin, Zhang Yuhui, Ma Lili, Sun Jingjing, Xu Yiping, Wu Yurong
Fujian Province Key Laboratory of Functional Materials and Applications, Xiamen University of Technology, Xiamen 361024, China.
School of Materials Science and Engineering, Xiamen University of Technology, Xiamen 361024, China.
Materials (Basel). 2024 Apr 15;17(8):1807. doi: 10.3390/ma17081807.
The use of metal-coated ceramic powders not only effectively enhances the wettability of the metal-ceramic interface but also promotes a more uniform microstructure in Ti(C,N)-based cermets, which is advantageous for improving their mechanical properties. In this study, ultrafine Co- and Ni-coated (Ti,W,Mo,Ta)(C,N) powders were synthesized via the spray-drying-in-situ carbothermal reduction method. Subsequently, Ti(C,N)-based cermets were effectively fabricated using the as-prepared ultrafine Co- and Ni-coated (Ti,W,Mo,Ta)(C,N) powders. The impact of reaction temperature, heating rate, and isothermal time on the phase and microstructure of prepared powders was analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Additionally, the microstructure of the as-sintered cermets was experimentally investigated. The findings reveal that the complete reduction of Co and Ni metal salts, pre-coated on the surface of (Ti,W,Mo,Ta)(C,N) particles, can be achieved through rapid heating (10 °C/min) in a specific temperature range (600-1000 °C) with an isothermal time of 3 h at a lower reduction temperature (1000 °C). The synthesized powders have only two phases: the (Ti,W,Mo,Ta)(C,N) phase and Co/Ni phase, and no other heterogeneous phases were observed with an oxygen content of 0.261 wt.%. Notably, the conventional core-rim structure was not dominant in the cermets obtained from the prepared Co- and Ni-coated (Ti,W,Mo,Ta)(C,N) powders. Moreover, the heterogeneous segregation effect of the Co/Ni coating on the ultrafine powder particles resulted in a finer microstructure than the traditional cermets with the same composition. However, the grain size is mainly in the range of 0.5-0.8 μm. The weaker residual stresses at the core and rim interfaces and the finer particle distributions could theoretically enhance the toughness of Ti(C,N)-based cermets, simultaneously.
使用金属包覆陶瓷粉末不仅能有效提高金属 - 陶瓷界面的润湿性，还能促进Ti(C,N)基金属陶瓷中更均匀的微观结构形成，这有利于改善其机械性能。在本研究中，通过喷雾干燥 - 原位碳热还原法合成了超细Co和Ni包覆的(Ti,W,Mo,Ta)(C,N)粉末。随后，使用所制备的超细Co和Ni包覆的(Ti,W,Mo,Ta)(C,N)粉末有效地制备了Ti(C,N)基金属陶瓷。利用X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)分析了反应温度、加热速率和等温时间对所制备粉末的相和微观结构的影响。此外，对烧结后的金属陶瓷的微观结构进行了实验研究。研究结果表明，预涂覆在(Ti,W,Mo,Ta)(C,N)颗粒表面的Co和Ni金属盐在特定温度范围(600 - 1000°C)内通过快速加热(10°C/min)并在较低还原温度(1000°C)下等温3 h可实现完全还原。合成的粉末只有两相：(Ti,W,Mo,Ta)(C,N)相和Co/Ni相，且未观察到其他异相，氧含量为0.261 wt.%。值得注意的是，在由所制备的Co和Ni包覆的(Ti,W,Mo,Ta)(C,N)粉末获得的金属陶瓷中，传统的核 - 壳结构并不占主导地位。此外，Co/Ni涂层在超细粉末颗粒上的异质偏析效应导致微观结构比具有相同成分的传统金属陶瓷更细。然而，晶粒尺寸主要在0.5 - 0.8μm范围内。理论上，核心和边缘界面处较弱的残余应力以及更细的颗粒分布可同时提高Ti(C,N)基金属陶瓷的韧性。
