CVD Diamond Coated Carbide Pretreatment—Transition Applied (2/2)

The first part mainly describes the concept and the function of transition layer, this part we introduce some experiments about it. Related researchers certain related technology by using titanium (Ti) and nitrogen (N) ion and the substrate to produce a large number gradually decreased reaction TiCN N ions, so that transition layer containing C, N decrement amount to the surface direction, until the final surface titanium This is to the surface at the time of planting, diamond crystals partially reacted with a titanium Ti titanium carbide TiC, as part of the process of diamond film deposition seed, in order to improve the bonding strength between the diamond film and the buffer layer and the diamond nucleation density; some studies have found that uses TiN and TiCN deposition as the transition layer, it will make diamond film with high purity, but the speed of nucleation is slow. Therefore, they attempt to directly deposited on the surface layer of aluminum carbide substrate, or discontinuous deposit a certain amount of diamond grains, thereby improving the imbalance in thermal expansion coefficient between the TiN / TiC and diamond, making the diamond and speed and adhesion have been significantly improved.

Relevant foreign scholars have used plasma pulsed laser melting method in cemented carbide substrate surface layer of boron nitride (BN) film, which not only eliminates the adverse effects of cobalt Co brought, and significantly improve the binding force between diamond coating layer and tungsten carbide matrix. In addition, Chinese scholars are based on chromium carbide buffer layer deposition CVD diamond coating, and spectral analysis by SEM showed that the deposition process have a more significant impact on the diamond's shape and composition, and ultimately to the complete crystalline, less non-diamond ingredients with carbide substrate binding tightly CVD diamond coating.

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