Many companies and industries experience losses when their machines break down because of wearing. One of the causes of this problem is friction. That is why it is important to use lubricants, which may be liquid lubricants, solid lubricants, or high temperature lubricants, so that friction is reduced.
Engines and other power equipments experience a lot of friction happening between the surfaces inside them. People usually do not notice this because the effects are not visible until the machines start showing it by not working properly.
Lubricants are available in grease form, powder form, Teflon tape and many more. Graphite, tungsten disulfide and molybdenum disulfide are examples of dry lubricants that work just fine even if exposed at temperatures as high as 350 degrees Celsius.
Why should we use lubricants? Lubricants perform a lot of functions that would make industries save a lot of money. Like what I mentioned earlier, they reduce the friction between two surfaces and make sure that parts that are supposed to move are kept moving. They transfer heat and eliminate debris and contaminants. They also transmit power. They provide protection against wear and tear and corrosion too. They remove the risk of producing fire or forming smoke in objects.
High-temperature lubricants are probably a good example to demonstrate how lubricants can stop fire and other dangerous stuff from happening. This particular type of lubricant is used in jet turbines, which are operated at high levels of temperature. It is able to overcome the difficulty of doing its job even at above normal temperature and keeping the pumpability temp to a minimum.
Lubricants can be classified into solid lubricants, gas lubricants and liquid lubricants (which include suspensions and emulsions).
Solid lubricants are also considered as dry lubricants. They are categorized into three, namely PTFE or Teflon, metal or alloy, and non-metals. Teflon is used in many cooking utensils because of its ability to make a surface non-stick. It operates at temperatures not greater than 350 degrees Celsius. Non-metal lubricants like molybdenum disulfide, graphite, tungsten disulfide and hexagonal boron nitride are used in operations that require hot temperature. However, they have poor oxidation resistance. Metals and alloys like zinc, tin, gold, cadmium, bronze and lead are used plating and as slide bearings.
Gaseous lubricants have high compressibility and low viscosity in comparison to liquid lubricants. Some examples are technical gases, liquid-metal and steam vapors. Liquid lubricants are often oil-based like lanolin, synthetic oils and mineral oils.