Carbides are truly marvelous materials that exhibit some fantastic properties, which makes them incredibly useful for countless applications across a range of industries. Carbides are compounds; combinations of elements fused together to create materials with improved features or characteristics. Carbides are compounds formed with carbon as the main element. As carbon has an unbelievable high melting point, carbides are created with the use of great pressures and temperatures. As such, the resultant carbide also usually enjoys a very high melting point, along with high conductivity of heat and electricity.
There are three major types of carbide:
Ionic
Ionic carbides like calcium carbide, also sometimes referred to as “salt-like” or “saline” carbides, are crafted from highly electropositive elements like alkali metals, the ions of which are highly attracted to one another through a powerful electrostatic force. These ions project a magnet-like force upon one another due to differences in their charge, creating a solid bond between the atoms.
Covalent
Covalent bonds are created not from ions being attracted to one another, but from atoms sharing electrons. As a result of similar electronegativity between the atoms, they can share electrons, effectively fusing the two atoms together though the shared pair of electrons existing inside both shells. In chemistry atoms in this arrangement are known as a bonded pair.
Interstitial
These interesting carbides are bonded together through a complicated arrangement. In an interstitial carbide, the large metallic atoms are able to form a lattice in which the smaller carbon atoms sit. These structures can create carbides of fantastic strength and very high points. Two interstitial carbides, titanium carbide and tungsten carbide, are invaluable in the tooling industry for creating ultra-strong milling cutters, like carbide end mills. Tungsten carbide is particularly revered in the tooling industry for its amazing properties. Tungsten is the heavy metal with the highest melting point on the periodic table, at 3414°C, and carbon has the highest overall at 3550°C. Interestingly, tungsten carbide’s melting point is a little lower than either of its ingredients, at 2870°C, but the compound is also far less brittle and able to withstand much higher pressures due to the bonds between the elements.