Graphite
Graphite is the most widely utilized of all solid lubricants. This is very soapy to touch, non-inflammable and not oxidised in air below 375oC. In the absence of air, it may be utilized up to much higher temperatures. Graphite is utilized either in powdered form or as suspension. Suspension of graphite in oil or water is brought around with the help of an emulsifying agent like tannin. While graphite is dispersed in oil, it is known as "oildog" and while it is dispersed in water, it is known as "aquadog". Oildog is found specifically useful in IC engines because it forms a film among the piston rings and the cylinder and gives a tight fit contact thereby increasing compression. Conversely aquadog is useful where a lubricant free from oil is required (e.g. foodstuffs).
Uses
As lubricant in air compressors, lathes.