The composition according to the present embodiment is a composition for forming a lubricant coating layer on a threaded connection for pipes or tubes, and contains Cr.sub.2O.sub.3, a metal soap, a wax and a basic metal salt of an aromatic organic acid. The threaded connection for pipes or tubes according to the present embodiment includes a pin and a box. The pin and the box each include a contact surface including a threaded portion. The threaded connection for pipes or tubes includes, as an outermost layer, a lubricant coating layer formed from the aforementioned composition on at least one of the contact surfaces of the pin and the box.

The composition according to the present embodiment is a composition for forming a lubricant coating layer on a threaded connection for pipes or tubes, and contains Cr.sub.2O.sub.3, a metal soap, a wax and a basic metal salt of an aromatic organic acid. The threaded connection for pipes or tubes according to the present embodiment includes a pin and a box. The pin and the box each include a contact surface including a threaded portion. The threaded connection for pipes or tubes includes, as an outermost layer, a lubricant coating layer formed from the aforementioned composition on at least one of the contact surfaces of the pin and the box.

A sliding system includes a pair of sliding members having opposing sliding surfaces adapted to move relative to each other, and a lubricating oil interposed between the opposing sliding surfaces. Here, at least one of the sliding surfaces is a covered surface covered with a specific chromium nitride film. The lubricating oil contains an oil-soluble molybdenum compound formed of a molybdenum dialkyldithiocarbamate. In the chromium nitride film, when an amount of atoms constituting the entire chromium nitride film is set as 100 atom %, there is 32 atom % to 47 atom % of N, the balance is Cr, and a relative area which is an area ratio of the (111) plane with respect to the (200) plane obtained when the chromium nitride film is analyzed by X-ray diffraction is 20% to 30%.

The present invention relates to a method for coating AI-Cr-0 coatings with the help of a PVD-coating process. The PVD-coating process is performed with the help of Al and Cr comprising targets which are doped with Si. The doping of Si prevents the forming of oxide islands on the target during the reactive coating process.