铁触媒表面的氧化铁包覆层对金刚石成核的影响

INFLUENCE OF IRON OXIDE COATING OF IRON CATALYST SURFACE ON DIAMOND NUCLEATION

在国产SPD 6×1200型六面顶压机上,研究了高温高压条件下铁触媒表面的氧化铁包覆层对金刚石成核的影响。研究发现,在5.7GPa和1600℃的条件下,铁触媒表面的氧化铁包覆层与石墨碳源发生氧化还原反应而生成了F e3O4和F eO,同时包覆层内部的铁熔融渗出,并与石墨碳源接触,促使了金刚石的成核生长。与纯铁触媒相比,氧化铁包覆层对金刚石成核具有明显的抑制作用,而且随着包覆层厚度的增加,抑制作用更明显。文中同时还借助穆斯堡尔谱、X-ray衍射和扫描电镜测试手段,对上述实验机理进行了深入的探讨。

The influence of iron oxide coat on surface of iron catalyst on diamond nucleation was studied on domestic made SPD 6 × 1200 type cubic hinge press. It is found by the research that Fe3O4 and FeO were formed by oxidation and reduction between iron oxide coating on iron catalyst surface and carbon source of graphite at 5. 7GPa and 1600℃, with some iron melted and exuded out, its contact with carbon source of graphite caused diamond nucleation and growth. Compared with pure iron catalyst, the iron oxide coating obviously restrained diamond nucleation and with the increasing of the thickness of the coating the restraining became more obvious. Mosshauer spectrum, X ray diffraction and electronic scanning were also used to do the further research on the above experiment mechanism.