Grinding performance of electroplated diamond tools strengthened with Cr-C deposit using D-150 diamond particles

Electroplated diamond tools with single-layered high density diamond particles in an average size of 150 μm were prepared through a three-step electroplating process, including Ni-undercoating, Ni-diamond co-electrodeposition, and Cr-C strengthening electroplating. Martensitic stainless steel (AISI 440C) rods with a diameter of 3 mm were used as substrates for tool fabrications. To evaluate tool grinding performances, linear slot grinding tests on the Al₂O₃ plates were conducted. The grinding performance of an electroplated diamond tool was determined through its maximum ground length upon tool failure. Experimental results show that an electroplated diamond tool with high density of diamond particles can be prepared by using Ni-diamond co-electrodeposition. After annealing at 500 °C for 30 min, the hardness of Cr-C deposit was significantly increased from 597 to 1636 Hv. The anneal-hardened Cr-C deposit is a suitable strengthening layer for fabricating electroplated diamond tools. The grinding performance of an electroplated diamond tool was strongly affected by the Ni-undercoating thickness. The highest maximum ground length of 2231 mm can be achieved by the electroplated diamond tool with a Ni-undercoating thickness of 90 μm. When the Cr-C strengthening deposit wore out, extruded diamond particles on the tool surface could be easily embedded into the Ni-undercoating, leading to fatigue fracture of the AISI 440C substrate.