Structure and Performance of Chemical Duplex Plating Ti Metal Layer on Diamond Surface by Hydrothermal Method

Abstract

As a surface of diamond has a higher interfacial energy and worse binding force, the diamond shed from matrix easily. For solving this, the microstructures and properties of the metallic coating on diamond surface were studied. The different temperatures, such as 110, 120, and 130 °C for 6 h, were used for coating diamond in the high-pressure reactor respectively. The structure and performance of the metallic coating on diamond surface were tested by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and diamond compressive strength instrument. The results showed that a continuous and compact coating of Ni, W and Ti on the diamond surface is obtained by the hydrothermal coating technology (chemical duplex plating) at 120 °C. After heat treatment at 850 °C for 1 h, the better layer coatings form for protecting diamonds and reducing the trend of oxidize. Because the carbides of W and Ti present at the boundries between the coating and diamond surface, the combination of chemistry and metallurgy is gotten. The compress strength of diamonds after hydrothermal and heat treatment is higher than that of uncoated particles (those are 54.40% and 85.48%, respectively).