【摘要】 为了提高电镀金刚石工具的质量,采用脉冲电沉积纳米镍作为其胎体材料。在对其显微结构、晶粒尺寸、显微硬度及抗拉强度的测试基础上,确定了制备工具合适的电镀工艺参数。结果表明,在恒定脉冲模式下(脉冲导通时间2ms,脉冲断开时间45ms),镀层晶粒尺寸随电流密度的上升而明显下降,硬度与强度则显著上升,当电流密度超过8A/dm2时,抗拉强度开始急剧下降而硬度保持6kN/mm2的高位基本不变,当超过12A/dm2时,硬度也开始下降。同时得到最大硬度与强度时材料的晶粒尺寸大约为20nm,由其制出的工具切割使用寿命比普通Ni-Co胎体材料工具高20.2%。更多还原

【Abstract】 Nanocrystalline nickel coating was prepared and used as the matrix of electroplated diamond tool by pulse-electrodeposition so as to improve its quality and extend its service life. Thus the pulse parameters were determined based on examination of the microstructure, grain size, hardness and tensile strength of the deposits obtained at different average current densities with constant pulse-on time (ton =2 ms) and pulse-off time (toff= 45 ms). It was found that the grain size of the coating sharply decreased while the hardness and tensile strength significantly increased with increasing current density. The tensile strength of the coating dramatically decreased, whereas the hardness was as much as 600 kN/mm2 and kept almost unchanged at a current density of above 8 A/dm2. As the current density was above 12 A/dm2, the hardness of the coating decreased as well. Moreover, the coating with a grain size of about 20 nm had the highest hardness and strength, and it was able to increase the service life of the diamond tools by about 20. 2% as compared with conventional Ni-Co coating.更多还原