The development of Nanocrystalline cBN Abrasives and Their Application to Grinding

以化学气相沉积法制备的高纯hBN为原料，采用高温高压直接转化法制备了一种新型多晶CBN磨粒。这种新型多晶CBN（CBN-U）磨粒的平均初生晶粒直径小于1 μm，其断裂强度是常规多晶CBN（CBN-55）磨粒的1.5倍左右。在磨削高速工具钢时，含CBN-U磨粒的砂轮的磨削比是含CBN-55磨粒的砂轮的7 ~ 9倍。根据加工表面的粗糙度，CBN-U砂轮的估计刀具寿命比CBN-55砂轮长得多。

A new type of polycrystalline CBN grit has been developed by direct transformation at high temperature and pressure from hBN of high purity which was produced using a chemical vapor deposition process. This new polycrystalline CBN(CBN-U) grit possesses an average primary crystal grain diameter less than 1 μm and its fracture strength is around 1.5 times higher than conventional polycrystalline CBN(CBN-55) grit. In grinding high-speed tool steel, the grinding ratio of the wheel containing CBN-U grits is 7〜9 times higher than that of the wheel containing CBN-55 grits. The estimated tool Life of the CBN-U wheel, based on the roughness of the finished surface, is much longer than that of the CBN-55 wheel.