Separable threaded connection with asymmetric coating

A screw joint comprising a tubular element having a female thread and a tubular element having a male thread,

• said male thread and said female thread having first contact surfaces that cooperate with each other,
• the tubular elements having second contact surfaces that cooperate with each other and are different than said male and female threads and said first contact surfaces, wherein said second contact surfaces are adjacent to said female thread or said male thread that cooperate with each other,
• said first contact surfaces and said second contact surfaces having a coating which has at least a first and a second layer,
• wherein said first layer is formed as a conversion layer in each case,
• wherein one of said first contact surfaces that cooperate with each other and one of said second contact surfaces that cooperate with each other has an outermost second a layer as a ceramic layer comprised of ceramic material with a friction reducing effect, wherein said ceramic layer has a thickness of less than 1 μm, and wherein said ceramic layer comprises a titanium, zirconium, niobium, tantalum, molybdenum, chromium, silicon, vanadium, tungsten, or germanium oxide or combinations thereof, and
• wherein the other of the first contact surfaces that cooperate with each other and the other of the second contact surfaces that cooperate with each other have a different outermost second layer, said different outermost second layer comprised of a varnish layer with a binding agent comprised of an organic polymer, throughout which solid lubricant particles are distributed.