The German term "Schmieren" comes from the Middle High German word "smer". So our ancestors designated raw animal fat with which they greased the bearings of their wagons and carts to reduce friction and thus the exertion of force required for humans and animals, while minimizing the wear of vehicles within limits.
Man's search for effective lubricants is varied and as old as the history of mankind. The Chinese made use of the lubricating effect of water already around 3500 B.C., and the Egyptians used animal fat or olive oil mixed with lime powder for their chariots around 1400 B.C.; Around 780 B.C. the Chinese discovered the friction-reducing characteristic of a blend of vegetable oils and lead, and more than 100 years ago, it was first time to point out that air has an aptitude as a lubricant.
The modern definition of the term "lubricants" initially includes products that are used for the lubrication of sliding and rolling elements. However, these related products, that are similar in composition, production and properties, are also called "lubricants", such as power transfer, heat conduction and cooling, serving as insulating oils, as corrosion inhibitors or under the name "process oils" as a tool for industrial processes.
The proportion of lubricants of the total mineral oil consumption reaches about 0.8 percent on average worldwide, around 1 percent in highly industrialized countries. The economic significance of lubricants is however far greater than their relatively small proportion suggested on the oil market. By friction 30 percent of the energy produced in the world would be consumed, and by wear billions of losses would be caused year after year.
Designers now know that the lubricant is not only a necessary fuel, but a design element. From the point of view of lubricating technology, sophisticated designs and proper lubrication help save energy, reduce downtime losses and the cost of spare parts and repair, as well as maintain the value of the machinery and equipment. The lubricants are thus constantly being developed through intensive research.
In line with the quantity, the main lubricants are oils, which are derived from petroleum. Additionally, there are the lubricants for specific applications. Lubricants are classified according to varieties.