What is the difference between diamond single crystal, polycrystalline and polycrystalline?

What is single crystal diamond?

Single crystals can be further classified into cubes, octahedrons, rhombic dodecahedrons. The crystal form of synthetic diamond, of which the hexahedral form is the most common. Synthetic diamond single crystal is flat, with obvious crystal edges and apex angles.

The characteristics of single crystal diamond are hardness and wear resistance. Diamond is a crystal combined by covalent bonds with saturation and directionality, so it has extremely high hardness and wear resistance, and is the hardest known in nature. substance.

What is polycrystalline diamond?

Polycrystalline diamond (PCD) (micropowder) is made from graphite by a unique directional blasting method. The shock wave of the high-explosive explosive directional blasting accelerates the flying of the metal flyer and hits the graphite sheet, thereby causing the graphite to be converted into polycrystalline diamond. Its structure is very similar to that of natural diamond, which is formed by unsaturated bonds and has good toughness.

What is polycrystalline diamond?

The structure of polycrystalline diamond is very similar to that of natural Carbonado, which is composed of spherical crystallites with a size of only 3-10 nm. Excellent grinding performance: high removal rate and toughness, with self-sharpening Compared with single crystal diamond, it is less prone to surface scratches and more suitable for grinding workpieces with different hardness materials

Application: As a precision abrasive, it is used for ultra-precision grinding and polishing of sapphire, magnetic head, hard disk, hard glass and crystal, ceramic and cemented carbide, such as thinning of LED sapphire.

As a coating additive, it is used in the coating of metal molds, tools, parts, etc., which can greatly improve the surface wear resistance, surface hardness and prolong the service life.

So what's the difference between them?

1. From the production method:

Single crystal diamond is synthesized by graphite by six-sided top press; polycrystalline diamond is synthesized by explosion method; polycrystalline diamond is just a diamond polymer formed by sintering single crystal diamond and binder under high temperature and high pressure.

2. From the perspective of microstructure:

Polycrystalline diamond has more crystal edges and grinding surfaces than single crystal diamond. During the polishing process, each crystal edge has a grinding force, and the coarse particles will be broken into smaller particles during the grinding process. It can maintain continuous grinding force and is not easy to cause scratches.

3. The structural advantages of polycrystalline diamond make it widely used in grinding and polishing of sapphire substrates, optical crystals, and electronic industries.

Testing method:

The morphology can be seen under the scanning electron microscope. The single crystal has only one crystal morphology, such as 100 or 111 faces, and the polycrystalline contains two or more crystal forms. It is the nature of the crystal itself! It can also be detected by xrd

Synthetic diamond polycrystalline is a kind of diamond polymer made by sintering diamond and binder under high temperature and high pressure. It has extremely high heat resistance and high thermal stability. Widely used in the manufacture of petroleum, geological drill bits, diamond processing and machining tools, etc.