Since World War II, the use of diamond has expanded dramatically, owing to the material's unique mix of characteristics and greater availability as synthesis processes improved. The following uses are discussed in further depth further down:
Hardness, strength, low thermal expansion coefficient, low friction coefficient, and chemical resistance are among the characteristics utilized by these applications. Oil drilling bits, rock drill cutters, wire drawing dies, extrusion dies, cutting tool inserts, optical grinding tools, coatings for computer hard discs, and coatings for ball bearings are just a few of the goods available in this category. In this field, polycrystalline diamond or diamond coatings can be employed. Manufacturers must pay attention to coating adherence and ensure that the coating is homogeneous and follows the contours of the component for proper application. It is not possible to apply the coating to ferrous materials since it would react and dissipate.
Diamond is the only material that has both excellent heat conductivity and electrical insulation. Hybrid circuit packages, heat sinks for laser diodes and tiny microwave power devices, integrated circuit substrates, and printed circuit boards are all examples of applications. Diamond allows for faster working speeds since components can be packed more densely without overheating. Because the junctions in the devices will be operating at a lower temperature when mounted on diamond, further reliability improvements could be expected.
Diamond's electrical structure features a large band gap, allowing it to be used as a semiconductor. However, a number of difficulties must be addressed before diamond coatings can be widely used in this field. The development of single crystal or highly orientated films, as well as efficiently doping the material, are the main problems. Boron doped films produced on diamond substrates have been used to make active devices. The devices can operate at temperatures above 500 degrees Celsius, compared to 200 degrees Celsius for silicon and gallium arsenide devices. Very high-power transistors, high-temperature integrated circuits, and piezoelectric devices are all possible uses.
Diamond is becoming more used in optical components, especially as a protective coating for infrared optics in hostile settings. Infrared windows constructed of ZnS, ZnSe, and Ge, which are fragile and readily broken, can be protected by a thin coating of CVD diamond. Freestanding polycrystalline film may be used in future applications if optical flatness can be attained.
Diamond's outstanding characteristics offer the potential to increase performance in a wide range of applications. The most significant impediments are cost and production scale. Metal wires and fibres, for example, can be CVD coated with diamond to increase their modulus to near that of diamond, allowing for stronger and stiffer composites, ceramic armour, and projectiles. Micro components, such as micro gears with a diameter of 250 microns and a thickness of 12 microns, may also be manufactured in diamond for use in micro robots and micro mechanical devices, outperforming currently available silicon and polysilicon components.
