CVD diamond

CVD diamond is a diamond material of high wear resistance of pure, non-binding agent, which is at low pressure (<0.1MPa) prepared under. CVD diamond films are coated

CVD (CD) and CVD thick (TFD) forms.
CD is a CVD (chemical vapor deposition) process, the carbide substrate (K type alloy used) is deposited to a thickness of about 10 ~ 30μm, composed of a

polycrystalline diamond film is made. Matrix is ​​made easy due to complex shapes, it applies to the complex geometry of the knife

Tools, such as taps, drills, end mills and band chipbreakers indexable inserts and so on. International instruments the market have a CD tool products, such as the

Swedish Sandvik's CD1810 and the United States Kennametal's KCD25, mainly for non-ferrous metals and non-metallic materials with high

Speed ​​precision machining, tool life than uncoated carbide increased nearly tenfold or even several times. However, the tool is not suitable for processing of metal a

CD-based composite materials, composite materials because of hard particles in a very short period of time will be worn tool surface layer of coating, the

Although the price of the tool with CD PCD cutting tool to be lower than similar, but due to the diamond film and the adhesion between the matrix material is small, so

limiting its widespread application.
TFD is deposited to a thickness of 1mm or more even a few mm (De Beers company deposition thickness up to 5mm) thick non-diamond substrate, according to need and then

cut to the shape of thick pieces, then welded carbide formed composite blades or knives. TFD good

The overall performance, it is not natural diamond anisotropy shortcomings, because no metal binding agent, low impurity content, purity close to 100%, the hardness

and thermal conductivity higher than that PCD (see Table 1), the friction factor is smaller, better chemical stability, can be compared

PCD cutting tool is higher, but the toughness is slightly less than the PCD, because of the non-conductive, it can not be used for electrical discharge machining (EDM)

technology. TFD has been trimmed in wood processing tools and the tool has been widely used. TFD existing foreign products (such as De

Beers company DIAFILM brand). Although TFD tools more expensive, but with the improvement of the manufacturing process, the future is expected to replace expensive

natural TFD Diamond blade and part of the PCD tool. Table 2 shows the PCD, TFD and synthetic diamond single crystal diamond three

Performance comparison.