In ultra-precision machining, in addition to high-precision machine tools and ultra-stable processing environments, high-quality cutting tools are also a crucial factor in ensuring the quality of the machined surface. Natural diamonds possess high hardness, excellent wear resistance, high strength, good thermal conductivity, low friction coefficient with non-ferrous metals, good anti-adhesion properties, as well as excellent corrosion and chemical stability. They can be ground into sharp edges, making them an ideal material for ultra-precision cutting tools and holding a significant position and wide application in the field of mechanical processing, particularly in ultra-precision machining.

Diamond is a crystalline form of pure carbon, with its crystal structure belonging to the cubic face-centered cubic system (a system with high atomic density). Due to the sp3 hybridized covalent bonds between carbon atoms in diamond, it possesses strong bonding, stability, and directional properties. Its microhardness can reach up to 10,000 HV, with other physical characteristics listed below.

Explanation of Diamond's Physical Properties

Physical Properties - Numerical

Hardness: 60,000 to 100,000 MPa, depending on crystal orientation and temperature.

Flexural Strength - 210～490 MPa

Compressive Strength - 1,500 to 2,500 MPa

Elastic Modulus: (9 to 10.5) × 10^12 MPa

Thermal Conductivity: 8.4～16.7 J/cm·s·℃

Quality Heat Capacity - 0.156 J/(g·℃) (Room Temperature)

Initial Oxidation Temperature: -900 to 1000K

The start of graphitization temperature is -1800K (in an inert gas).

Friction coefficient between aluminum alloy and brass: -0.05 to -0.07 (at room temperature)