Origin and Evolution of High-Mg Carbonatitic and Low-Mg Carbonatitic to Silicic High-Density Fluids in Coated Diamonds from Udachnaya Kimberlite Pipe

Microinclusions of high-density fluids (HDFs) were studied in coated diamonds from the Udachnaya kimberlite pipe (Siberian craton, Russia). The presence of C-centers in the coats testifies to their formation shortly before kimberlite eruption, whereas the cores have much longer mantle residence in chemically different mantle substrates, i.e., peridotite-type (P-type) and eclogite-type (E-type). The carbon isotope composition indicates an isotopically homogeneous carbon source for coats and a heterogeneous source for cores. Microinclusions in the coats belong to two groups: high-Mg carbonatitic and low-Mg carbonatitic to silicic. A relationship was found between high-Mg carbonatitic HDFs and peridotitic host rocks and between low-Mg carbonatitic to silicic and eclogites. The composition of high-Mg carbonatitic HDFs with a “planed” trace-element pattern can evolve to low-Mg carbonatitic to silicic during percolation through different mantle rocks. The compositional variations of microinclusions in the coats reflect this evolution.

Manufacturing and Microstructure of Cu Coated Diamonds/SnAgCu Composite Solder Bumps

Diamonds/SnAgCu composite solder bumps were prepared on Cu pad by mechanically incorporating diamond particles into Sn3.0Ag0.5Cu (SAC) solder paste and then reflowed at 260°C for 60s. Chemical copper plating method was proved to be an efficient way to achieve high addition amount of diamond particles (> 1 wt.%, which is much better than former studies) in solder, and to get solder bumps with better morphology. The spreading rate of this novel solder was turned out to be acceptable in operating range. Shear strength and microstructure of composite solder bumps were studied, showing that they could be influenced by the changes in morphology of the Ag3Sn net work caused by the various additions of Cu coated diamond particles.

Influence of a TiС Coating on the Wear Resistance of Fe-Diamonds Composites

Some diamond tools use iron in their composition, and it is known that iron is a strong catalyst for the graphitization of diamonds. This graphitization occurs mainly during the processing of composite materials - conventional sintering or hot pressing, and during cutting operations. This work studies the influence of the behavior of the wear and adhesion, of iron-diamond composites, by considering the use of TiC coated diamonds. Samples were prepared by mixing powders of Fe (40 μm) and diamond (425 μm), and subsequent hot pressing at 35MPa/900°C, for a time of 3 minutes. It was evaluated the mechanism of wear, and the behavior of the samples during diametral compression test. It was used the cumulative times of 2, 6, 12 and 20 minutes during the testing of abrasion.