A heavy-duty wear test was performed on two identical PDC teeth (the surface of the diamond layer of one of the teeth was decobalted). After cutting 5000 m of granite stone, the wear 

rate of PDC cutter insert without cobalt removal began to increase sharply. Relatively speaking, the de-cobalt PDC maintained a relatively stable cutting speed during the cutting of about

15,000 m of rock.

In the high-pressure sintering process of PDC, cobalt acts as a catalyst to promote the direct combination of diamond and diamond and integrates the diamond layer with the tungsten 

carbide matrix. As a result, it has both high toughness and excellent wear resistance. PDC cutting teeth suitable for oilfield geological drilling.

The heat resistance of diamond is very limited. At atmospheric pressure, the diamond surface will be converted to graphite at 900 ° C or higher. During use, the traditional PDC will 

undergo enthalpy change at around 750 °C, while the PDC will easily reach this temperature due to frictional heat when drilling in a hard and abrasive rock formation, while the 

instantaneous temperature (ie, microscopy) The localized temperature of the layer) will be higher than the melting temperature of cobalt (1495 ° C).

Compared to pure diamond, diamond is converted to graphite at lower temperatures due to the presence of cobalt. As a result, the wear of the diamond is caused by the graphitization

that occurs due to the influence of local frictional heat. In addition, the coefficient of thermal expansion of cobalt is much larger than that of diamond, and the bonding between diamond

grains is destroyed by the expansion of cobalt during heating.

The so-called "de-cobalt" is formed into a PDC in a conventional manner, and the surface of the diamond layer is immersed in a strong acid to remove the cobalt phase by an acid etching

process. The depth of cobalt removal can be as high as about 200 microns.

LINKUT could supply the high quality PDC cutter inserts with or without cobalt removal based on your actual requirements.