TiC-TiB2 复相陶瓷涂层的反应火焰喷涂制备

基于SHS 反应火焰喷涂技术, 采用Ti-B₄C-C 喷涂体系, 在钢基表面制备了TiC- TiB₂ 复相陶瓷涂层。通过对SHS 火焰喷涂陶瓷涂层的电子显微观察和X射线衍射及能谱分析, 探讨了SHS 反应火焰喷涂TiC- TiB₂复相陶瓷涂层的组织结构及成因。研究发现, 涂层是一种复相非均质、传统热喷涂层状涂层特征不明显的亚稳结构。涂层由占主体的TiC_0.7N_0.3 、TiC_0.2N_0.8 、TiB₂ 相和少量TiO₂ 、Ti₂O、Ti₃O₅ 相及气孔组成。涂层中有三类特征各异的组织, 即尺度在微2纳米级呈团簇状分布的组织, 尺寸在1～3μm 之间呈等轴状颗粒分布的组织和呈深黑色的不规则气孔。三类组织是由在喷涂粒子与基材接触之前, 喷涂团聚粉粒经飞行燃烧和反应合成形成的熔融陶瓷液滴(又分为实心和空心两类) 和不规则陶瓷颗粒(其形状与原喷涂团聚颗粒一样, 但组织结构已发生转变,基本成为陶瓷相) 与基材碰撞变形、冷却凝固、快速结晶形成的。

TiC-TiB2 multiphase ceramic coatings prepared by reactive flame spray

Based on the reactive fame spray technique , TiC- TiB2 multiphase coatings were prepared on the steelsubst rate with Ti-B4C-C reactant s. By elect ronic microcosmic observation , X-ray diff raction and energy spect rumanalysis , the st ructure and it s forming causes of TiC- TiB2 multiphase coatings were discussed. The result s showthat the coatings have the multiphase heterogeneous metastable st ructure , which have no conspicuous layer-shapedst ructure that the t raditional flame spray coatings have. The coatings are composed of the major phases TiC0.7N0.3 ,TiC0.2N0.8 , TiB2 , a little of TiO2 , Ti2O , Ti3O5 and some pores. There are three kinds of st ructures with differentcharacteristics in the coatings the cluster-shaped st ructure in micron-nanometer size , the 1～3μm st ructure takingon equiaxed particles dist ribution , and the deep black pores. Before meeting the subst rate the spray particles combust , react , and form molten ceramic beads (in solid and hollow two kinds) or abnormal ceramic granules (having thesame figure as the spray particles) . Af ter colliding with the subst rate , they distort , cool , quickly crystallize andform the three kinds of st ructures.