Principle Of Diamond Surface Metallization

Since ancient times, diamonds have been regarded as an extremely valuable ornament. However, with the development of modern industrial technology, the unique mechanical, thermal and electrical properties of diamond have been gradually excavated, turning it from a simple process to an important industrial raw material.

 

But no matter how excellent the diamond itself is, it will be hard to sound alone --- because the particle size of synthetic diamond is so small that almost all applications require crystal bonding or implantation into the substrate. However, diamond has high interfacial energy with most metals, ceramics, etc., so the bonding force between diamond and matrix is poor and diamond is easy to fall off at early stage.

 

Diamond surface metallization is the use of surface treatment technology to coat metal on the surface of diamond particles, so that its surface has the properties of metal or metal-like. The metallized surface consists of three layers of materials, from the outside to the inside, as follows:

The first layer is the metal layer, which can endow the diamond surface with many new characteristics, such as excellent thermal conductivity;
The second layer is the alloying layer, which is composed of carbide and metal structures;
The third layer is the carbide layer, which is generally hundreds to thousands of angstroms thick and can be firmly attached to the surface of diamond particles. It is the key to the surface metallization of diamond particles. It is generally composed of metals with good wettability with diamond, such as Ti, W, Cr, V, etc. These elements can react with diamond at high temperature to generate stable carbide. It can not only have a good chemical combination with diamond, but also isolate its direct contact with oxygen to prevent it from being oxidized at high temperature.