高エネルギー密度電子ビーム溶射法の確立に関する研究

本课题的研究目的是开发一种新的高能密度电子束表面改性方法，并将其应用于常规热喷涂难以获得的致密WC-Co涂层。采用30 kW电子束焊机作为热源，材料为WC-12%Co粉末和Ni-Cr自熔合金粉末。采用高能量密度电子束对WC-Co涂层进行表面改性，并将其应用于WC-Co涂层的表面改性。研究结果表明，该方法能有效地提高WC-Co涂层的致密性，提高涂层的耐磨性和耐蚀性。采用混合粉末沉积法在低碳钢基体上获得了厚度大于800 μ m、均匀致密地分散在Ni-Cr基体中的Co涂层。对涂层进行了X射线衍射、电子探针、维氏硬度、滑动磨损和腐蚀试验。结果表明，该涂层具有足够的耐磨性和耐腐蚀性。分析了高能量密度电子束喷涂涂层的形成机理，研制了一种可在真空条件下工作的送粉装置和一种可在真空条件下连续形成涂层的电子束喷涂方法。在真空连续加料条件下，获得了与粉末固化法相似的涂层。

The purpose of this research project is to develop a new surface modification method using high energy density electron beam and to apply it to a dense WC-Co coating which is difficult to achieve with conventional thermal spraying method.A heat source used was a 30kW electron beam welder and materials used were WC-12%Co powders with Ni-Cr self fusion alloy powder.A WC-Co coating of over 800 mum in thickness which dispersed densely and homogeneously in Ni-Cr matrix on mild steel substrate was obtained using the mixed powder setting method. The coating layrs were examined by X-ray diffraction, EPMA,Vickers hardness test, sliding abrasion test and corrosion test. It was found that this coating layrs have enough abrasion and corrosion characteristics. Furthermore, the formation mechanism of coating layr by high energy density electron beam was analyzed.A powder feeder which can function under vacuum condition and electron beam spraying method which can form a coating layr continuosly in vacuum was developed. A similar coating layr as the powder setting method was obtained under a continuous feeding condition in vacuum.