Gradation Process by Imbibition in WC-Co for Mining Tools Application

Abstract

Continuous composition gradients of several millimetres were generated in commercial WC-Co cutters to improve their shock resistance. This important gradation was obtained in one-step by using the imbibition process. The effects of this thermal processing were analysed in terms of microhardness, cobalt concentration and WC grain size. A gradient of a 300 HV amplitude is measured in the 8 mm-height sample treated by the imbibition process in association with a boron-rich coating. This gradient was preserved after the HPHT (high pressure – high temperature) step used for the diamond table deposition on the WC-Co cutter. To our knowledge, such gradients have never before been reported and should certainly increase cutter service life.

Quality and wear behavior of graded polycrystalline diamond compact cutters

“…This study focuses on PDC cutters made by the imbibition process first introduced by Lisovsky [10]. As presented by Lefort-Sorlier et al [11], this process consists on a gradual enrichment of cobalt in the WC-Co substrate. These authors associated to the imbibition process a boron nitride reactive coating on the substrates forming borides WCoB at the PDC/WC-Co interface [12,13].…”