Nanoengineered Polycrystalline Diamond Composites with Advanced Wear Resistance and Thermal Stability

Abstract

Fluorinated grains of micrometer size diamonds overcoated with nanodiamond particles were used as a feedstock for high-pressure, high-temperature synthesis of new polycrystalline diamond composites (PDCs). Such a nanoengineering approach for exploring the interfacial chemistry of diamonds has been implemented in two methods: (i) infiltration of Co from the WC-Co layer into a fluorinated diamond layer with added Al and (ii) sintering of fluorinated micro- and nanosize diamond homogeneous mixtures with added Al and Co. We found that unlike commercial PDCs made with a metallic Co binder for drilling tools, the binding phase in new composites comprises only intermetallic compound AlCo or ternary carbide AlCo3C. As a result, composites made from homogeneous mixtures showed greater promise for improving the thermal stability, while the two-layer experimental composites during granite turning tests have demonstrated >2 times higher wear resistance than leached commercial PDCs.

Diamond Composites Produced from Fluorinated Mixtures of Micron-Sized and Nanodiamonds by Metal Infiltration

“…It has also been shown that the FDM-3Al mixture layer can be sintered with a hard alloy WC-Co substrate. In this case, cobalt penetrates into the FDM-3Al layer and increases its wear resistance to a level significantly higher than that of the corresponding homogeneous mixture [ 14 ]. The cobalt melt during infiltration promotes the mutual rearrangement of diamond grains, promotes their dense packing, and promotes the formation of strong interfacial contacts between them.…”

“…The FDM mixture with 3 wt.% aluminum was designated as FDM-3Al, and the FDM mixture with 2 wt.% aluminum and 6 wt.% cobalt was designated FDM-2Al-6Co. The process of preparation and analysis of such mixtures is described in more detail in [ 14 ].…”

“…The thermal stability of such PDCs has been improved due to the formation of binder phases of the AlCo intermetallic compound and AlCo 3 C ternary carbide [ 13 ]. The wear resistance of a PDC diamond layer containing such binder phases was found to be several times higher than that of commercial premium composites [ 14 ].…”

Lightweight diamond/Cu interface tuning for outstanding heat conduction

“…11 To improve the bonding of the diamond-Cu interface, an interfacial bonding layer can be introduced at the interface through metallization of the diamond surface 10 and metal matrix alloying. 12 Commonly used transition layer metals include Chromium (Cr), [12][13][14] Titanium (Ti), 5 Zirconium (Zr), 8,15 Boron (B), [16][17][18] and Tungsten (W). 10,19,20 For instance, adding 1.5 wt% Ti to Cu metal was reported to improve the interface bonding between the copper matrix and diamond, in which the thermal conductivity of the Cu-diamond (55 vol%) composite prepared by hot forging can reach up to 410 W m −1 K −1 .…”

“…The thermal conductivity of W-coated diamond particle-reinforced copper matrix composites can theoretically reach more than 900 W m −1 K −1 . 10 At present, the main methods for preparing diamond/ Cu composites include vacuum hot pressing, 20 discharge plasma sintering, 19 gas infiltration, high-temperature and high-pressure sintering, 8,17 and so forth. It is widely known that magnetron sputtering technology and hightemperature and high-pressure technology have been applied in many industrial fields, and the use of these technologies will enable surface modification of diamond particles and further preparation of composite heat dissipation materials that are more conducive to industrial application.…”