layer 222 was also prepared using a cubic boron nitride powder of 2 u03bcm average particle size and a binder agent of aluminum nitride nickel and titanium nitride in a volume ratio of 98 2 in accordance with traditional hpht processing the tungsten carbide disk 214 was loaded into the tantalum cup 218 and the feedstock for the intermediate layer 210 was loaded on top of the corrugated surface 214a the feedstock for the outer working layer 222 was then placed on top of the feedstock for the intermediate layer 210 finally a multilayer tantalum disc 226 was loaded on top of the feedstock for the outer working layer 222 the ends 230 of the cup 218 were then crimped to enclose the inside material the loaded cup assembly generally indicated at 234 was inserted into a typical hpht reaction cell and the cell was placed in a conventional die belt assembly with a hydraulic press the pressure was raised to about 55 kb and then the temperature was elevated to approximately 1400 u00b0 c after maintaining the temperature and pressure for approximately 30 minutes the temperature was lowered and the pressure was gradually reduced the work element 200 was 35 mm in diameter and 4 3 mm in thickness the sintered pcbn compact was ground and lapped to finish both sides and the circumferential area the pcd was then polished to examine the microstructure under the optical microscope and was subjected to edx analysis the sintered pcd showed an obvious arched intermediate layer diamond sintered form which is about 0 4 to 0 6 mm thick a normal pcbn layer was disposed on top.