旋转电弧加热在环状工件内壁沉积金刚石涂层

为实现在大口径环状工件内壁沉积金刚石涂层，研制一种能够产生旋转电弧的分体式等离子炬。利用活动阳极形成的伞状电弧帽，改变平行于轴且向下吹的工作气体旋转电离的方向，使其垂直吹向环状工件内壁。测试不同阳极直径下电弧的工作参数，并用相机拍摄相应的电弧形貌。进行金刚石涂层沉积试验，在内径为180?mm的硬质合金拉拔模具和内径为100?mm的石墨内表面沉积出高质量的金刚石涂层。利用拉曼光谱仪和扫描电镜对涂层的成分、表面形貌等进行测试分析。已沉积金刚石涂层的硬质合金模具成功应用于超高压电缆铝护套的拉拔设备中。 

Diamond coating deposited on the inner wall of annular workpiece by rotating arc heating

A plasma torch with split anode and rotating arc was developed. The diamond was coated on the inner wall of large diameter annular workpiece by the torch. The umbrella-like arc formed by the movable anode makes the axial working gas blow vertically to the inner wall of the annular workpiece. The parameters of arc under different anode diameters were tested, and the arc shap was taken by camera. High quality diamond coatings were successfully deposited on the inner surface of cemented carbide drawing die with inner diameter of 180 mm and graphite with inner diameter of 100 mm. The composition and surface morphologies of the coating were analyzed by Raman spectroscopy and scanning electron microscopy. The diamond coating cemented carbide die has been successfully applied in the drawing equipment of aluminum sheath of extra-high voltage cable.