工艺参数对SHS-铸造钢基表面TiC-Fe梯度复合涂层结构的影响

将自蔓延高温合成(SHS)技术与铸造工艺结合起来，制备了铸造钢基表面TiC—Fe梯度复合材料，研究了钢液的浇注温度、TiC—Fe预制块的组成及其相对密实度等工艺参数对梯度复合涂层结构的影响。结果表明：在保证预制块能被浇注的钢液直接点燃的条件下，适当提高钢液的浇注温度、降低预制块的密实度均有利于梯度复合涂层的形成；而且在预制块中掺加适量的低熔点金属稀释剂不仅可降低合成TiC颗粒的尺寸，而且也有利于梯度复合涂层的形成。梯度复合涂层的形成与钢液向预制块中的渗透、预制块中Fe和低熔点稀释剂的熔化以及合成的TiC颗粒向钢液中的扩散等作用有关。

Effects of technological parameters on microstructure of TiC-Fe cermet graded composite coating on cast steel substrate by SHS-casting route

A TiC-Fe cermet graded composite coating on a cast s te el substrate was successfully fabricated by an SHS-casting route. The effects o f technological parameters, such as pouring temperature of liquid steel, composi tion of Ti-C-Fe preform and its relative green density, on the microstructure of the coating were emphatically studied. The results show that, under the condi tion of ensuring the preform to be ignited, properly increasing the pouring temp erature of liquid steel and decreasing the green density of the preform are favo rable to the formation of the graded composite coating. Furthermore, adding a ki nd of metal diluents with lower melting point into the preform not only can decr ease the size of the synthesized TiC particles, but also is more advantageous fo r the formation of the graded composite coating. It is considered by analysis th at the formation of the graded composite coating is related to the combined effe cts of the infiltration of the melt into the preform, the fusion of Fe powders a nd the diluents in the preform, and the converse diffusion of the synthesized Ti C particles into the poured melt.