**1. Introduction**

Polycrystalline diamond compact (PDC) drill bits are critical drilling tools for most formations in oil and gas exploration and drilling, with annual market size of more than \$4.5 billion. PDC cutters are the main and critical component in PDC drill bits that cut these formations because of their excellent properties such as high hardness, thermal conductivity, impact resistance and wear resistance. PDC drill bits equipped with PDC cutters have gained widespread popularity in oil and gas drilling due to their long bit life and ability to maintain a high rate of penetration (ROP). The shearing effect caused by the fixed PDC cutter has been shown to be more effective than the crushing effect of the tooth or insert on the rollcone drill bits. Most PDC drill bits consist of a body either milled from a solid steel block or infiltrated by a metallic binder into tungsten carbide particulars. The bit body has blades, in which the actual PDC cutter is mounted in the

form of flat or shaped diamond table, as well as open areas or slots where cuttings and mud streams can escape to the annulus. **Figure 1** shows a typical 5−7/8″ diameter PDC bit. In **Figure 1**, the PDC cutters are brazed and placed on the blades. The flow pathways are used for mud and cuttings removals. However, when drilling very hard and abrasive formations, PDC drill bits on the market face very high challenges [1–3]. PDC cutters currently available on the market do not provide sufficient wear resistance, impact resistance, or thermal stability to cope with this challenging drilling environment. Low penetration rates (ROP) and short bit life have led to the use of multiple bits to drill a single interval, which is not optimal for well economy [4–6].

The main weakness in the current technology comes from the unavoidable use of a metallic catalyst (typically cobalt) during the manufacturing of the PDC cutters [4]. **Figure 2** shows a typical SEM microstructure of PDC cutter showing Co catalyst

**Figure 1.** *PDC Drill bit equipped with PDC cutters.*

**Figure 2.** *A typical SEM microstructure of conventional PDC cutters with Co.*
