Spark Deposition And Alloying

In this investigation, by utilizing a new electro-spark deposition equipment .some samples are surface deposited by WC position electrode. In addition,the forming mechanism and the characters of the deposit layer are systemically researched as well as the layer' s construction and element distribution are studied. In order to improve the deposit productiveness and the layer' quality,the layer' s hardness, wearing resistance ,coarse degree and deposit depth are inspected under different deposit parameters such as the power,the voltage, the frequency and the deposit time, and an optimum technology is put forward.According to the analyses of the x-ray diffraction and line scan, the depositing layer is consisted of carbides, the elements of positive electrodes and specimen' s. The electro-spark deposition is not only a process of the position electrodes' overlaying on the matrix materials,but also a complicate alloying and metallurgy process of the elements coming from the positive electrodes and specimen.The metallograph analysis of the layer' s surface and section appearance demonstrates that the deposit period is the key factor to forming a successive, well-distributed layer with a certain depth. If the deposit period is too short, the layer will be too thin and has less effect. On the other hand, if the deposit period is too long, the layer will break and come of f, and the surface quality as well as the deposit productiveness will decreases.Tests show that the hardness and wearing resistance of the deposit layer are much higher than that of the matrix materials. The hardness is very high in the white-bright area. If the specimen is hardened by a stiff and highly wearing resistant positive electrode for a appropriate hardening period, its surface hardness and wearing resistance will be greatly improved.The optimum technology of electro-spark deposition is that: to meet the requirement of a certain layer depth and improve the deposit productiveness, a large deposit parameter should be adopted first, and then a smaller deposit parameter is selected to improve the layer' s smoothing and compactness.