A Survey of Modification Research of Surface of the Synthetic Diamond

The synthetic diamond grit abrasives are made into various abrasive tools, which are widely used in a great deal of the manufacturing industries, such as aerospace, automobile, ship, hydraulic, engine, bearing, optical components and so on. Because of its high thermal conductivity, good chemical inertia, good optical transparency (from ultraviolet to infrared) and corrosion resistance, diamond can be used as a field emitter in the electronic industry, as a chemical and biological sensor for DNA and protein chips, as an electrode material for electrocatalytic reaction, as a high thermal conductivity material for electronic packaging materials and so on. However, the surface of diamond is also chemically inert and difficult to combine with many substances, which limits its application.

In order to improve the surface properties of diamond and its bonding ability with other materials, researchers have modified the surface of diamond by different methods, such as metallization of diamond surface, surface coupling agent or surfactant treatment and functionalization of diamond surface, enhancing or expanding its performance and scope of use.

Conclusions and Advice

1) Metallization methods of the surface of the synthetic diamond grit include: physical vapor deposition, chemical vapor deposition, electroless plating, electroplating, vacuum micro-evaporation plating, salt bath plating, and so on. Among them, the mature industrial methods are electroless plating, electroplating and vacuum micro-evaporation plating, which is mainly used in diamond abrasives, abrasives and electronic packaging materials.

2) Synthetic diamond grits are treated with coupling agents or surfactants to improve the properties of the interface between organic system and diamond. It is used in the dispersion of diamond powder and the manufacture of resin abrasives.

3) The functional modification objects of diamond surface are diamond film and nanometer diamond. The products are mainly used in electrochemistry, biosensors and electrode materials.