Fabrication and Corrosion Resistance of Copper Electroforming Layers on Tube Electrodes in EDM Processes for Turbine Blade Cooling Holes

Abstract

Abstract: In order to reduce EDM electrode wear rate of turbine blade cooling holes of high temperature nickel base alloy, based on precision electroforming processes, the process parameters of fundamental electroforming solution were optimized, and some pure copper electroforming samples of copper tube electrode were prepared with different nano La₂O₃ addition quantities. These samples were used to compare with the copper electroforming samples prepared without La₂O₃. Blade cooling hole of Inconel 718 nickel base alloy was processed, and copper tube electrode was researched comparatively to verify the performance of electrical corrosion resistance. Experimental results show that copper electroforming layers with smallest grain size 15.9μm, microhardness 98.2HV, and roughness 0.140μm may be obtained with 1.2g/L La₂O₃. Its electrode wear rate decreases 13.29% and 7.26% than pure copper and copper electroforming layer without nano La₂O₃ addition respectively.

Key words: electroforming, nano La₂O₃, electrical erosion resistance, electrode wear rate, electrical discharge machining(EDM)

摘要： 以降低高温镍基合金涡轮叶片冷却孔电火花加工电极损耗率为目标，基于精密电铸工艺，优化了铸液工艺参数，在添加纳米La₂O₃条件下制备了铜管电极的铜电铸层，并将其与未添加La₂O₃所制备的铜电铸层进行了材料性能对比分析。以Inconel 718镍基合金叶片冷却孔为加工对象，利用所制备的带有纯铜电铸层的管电极进行了抗电蚀性能对比研究。试验结果表明：铸液中La₂O₃的添加量为1.2g/L时，铜电铸层晶粒最细，晶粒平均直径为15.9μm，表面粗糙度降至0.140μm，显微硬度可达98.2HV；用其制成的铜管电极损耗率较普通紫铜管电极和未添加纳米La₂O₃的铜管电极损耗率分别降低了13.29%和7.26%。

关键词: 电铸；纳米La₂O₃；抗电蚀性；电极损耗率, 电火花加工

CLC Number:

TG661

LI Zhiyong, LI Li, ZHENG Guangming. Fabrication and Corrosion Resistance of Copper Electroforming Layers on Tube Electrodes in EDM Processes for Turbine Blade Cooling Holes[J]. China Mechanical Engineering.

李志永, 李丽, 郑光明. 涡轮叶片冷却孔电火花加工管电极的铜电铸层制备及其抗电蚀性[J]. 中国机械工程.

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