Radiation-selective absorber coating and absorber tube with said radiation-selective absorber coating

An absorber tube (13), in particular for parabolic trough collectors, said absorber tube (13) comprising a steel tube (1), on an outer side of which is applied a radiation-selective absorber coating (20), and wherein said radiation-selective absorber coating (20) comprises

• at least two barrier layers (24a, 24b);
• an infrared reflective layer (21) that reflects infrared radiation, said infrared reflective layer (21) being applied on said at least two barrier layers (24a, 24bb);
• at least one absorption layer (22) arranged above the infrared reflective layer (21);
• and
• an antireflection layer (23) arranged above the at least one absorption layer (22);
• wherein the at least two barrier layers (24a, 24b) comprise a first barrier layer (24a) and a second barrier layer (24b) arranged above the first barrier layer, said first barrier layer consisting of a thermally produced oxide;
• wherein said second barrier layer (24b) consists of a cermet material composed of aluminum oxide and molybdenum;
• and
• wherein said second barrier layer (24b) comprises 20 to 70% by volume of said molybdenum.