Al对反应火焰喷涂TiC-TiB_2复相陶瓷涂层的影响

Influence of Al on Reactive Flame Sprayed TiC-TiB_2 Multiphased Ceramic Coatings

通过静态燃烧合成试验,确定以Ti-B4C-C+5wt％Al为喷涂反应体系,利用反应火焰喷涂技术在金属表面制备Ti(C0.7,No．3)-TiB2-Al2O3复相陶瓷涂层．研究发现,涂层为复相非均质层状亚稳结构,由TiC0.7N0．3、TiB2、Al2O3和钛的氧化物相及气孔组成．涂层组织可分为三类: TiB2尺度在微-纳米级呈团簇状分布的Ti(C0.7, No．3)-TiB2共晶体组织; Ti(C0．7,No．3)呈块状颗粒、尺寸1-2μm、其间分布着针状或长条状TiB2的组织;黑色不规则气孔．三类组织的形成原因与不加Al时基本相同,但Al的加入使喷涂体系的反应速率提高,并使涂层陶瓷相增多,组织细化,气孔率下降,显微硬度提高．

By static combustion synthesis tests, Ti-B4C-C＋5wt%Al was chosen as the reactive system to prepare the Ti（C0.7, N0.3）-TiB2-Al2O3 multiphased ceramic coatings on the metal substrate with a reactive flame spray technology. It is found that the coatings have the multiphased heterogeneous metastable structure, which consists of TiC0.7N0.3, TiB2, Al2O3, titanium oxide and some pores. The structure of the coatings can be divided into three kinds： the Ti（C0.7, N0.3）＋TiB2 eutectic structure with the cluster-shaped TiB2 in micron-nanometer size, the structure with mass-shaped 1 2μm Ti（C0.7, N0.3） particle surrounded by the needle-shaped or strip-shaped TiB2 and the black phase of anomalous pores. The forming causes of the three kinds of structure are the same as those of the coatings with no additive Al. However the additive A1 raises the reaction velocity, so the amount of ceramic phase increases, the structure becomes fine, the pores reduce and the micro-hardness of the coatings is increased.