ZTA颗粒增强高铬铸铁基复合材料界面研究

Interfacial Bonding Behavior of High Chromium Cast Iron Composites Reinforced with ZTA Ceramic Particles

以自制Fe-Ti金属粘结剂和ZTA(氧化锆增韧氧化铝)陶瓷颗粒为原料,采用粉末冶金工艺制备多孔陶瓷预制体,并浇注高铬铸铁制备ZTA颗粒增强高铬铸铁基复合材料。使用OM、SEM、XRD等分析手段研究预制体和复合材料的复合界面行为。结果表明,Ti含量15%的粘结剂/ZTA复合界面结合优于Ti含量10%的粘结剂/ZTA复合界面。烧结过程中Ti、O、Zr元素扩散到复合界面微区反应形成致密、连续的Ti O_x过渡层,实现ZTA活化包覆。粘结剂与ZTA结合机制为机械结合与反应冶金结合。Ti含量15%的粘结剂制备的预制体具有一定强度和抗热冲击性能,在高铬铸铁液铸渗情况下能保持结构和尺寸,基体与ZTA结合界面致密,无空隙、孔洞缺陷,Ti O_x过渡层分布于界面处起到活化、改善界面结合的作用。

Porous network ceramic prefabrications were prepared by sintering the mixture of self-made Fe-Ti metallic binder and ZTA （ZrO2 toughened Al2O3） ceramic particles. High chromium cast iron composites reinforced with ZTA ceramic particles were then prepared by cast-penetrating the ceramic prefabrications with liquid melt. Interfacial bonding behavior of ceramic prefabrications and iron matrix was investigated by OM （optical microscope）, SEM （scanning electron microscopy） and XRD （X-ray diffraction）. The results show that the interracial bonding of binder/ZTA with 15% Ti is stronger than that of binder/ZTA with 10% Ti. A consecutive transitional TiO~ layer is coated on the ZTA particles connecting the ceramic and metal matrix. The inter-diffusion ofTi, O and Zr at the interface leads to the formation of the TiOx layer during sintering. Interfacial bonding mechanism of binder and ZTA includes mechanical bonding and metallurgical bonding. Prefabrications made of binder with 15% Ti could maintain their original structure and size under the cast-penetrated condition by the high chromium cast iron liquid. The composites have certain strength and thermal shock resistance. The interface of high chromium cast iron and ZTA is found compact, without cracks or voids. The TiOx transitional layer in the interface helps to activate and improve the interfacial bonding.