In gas turbine technology, the use of running-in layer systems has been state of the art since the early 1970s to achieve optimal operating results through defined leakage gap management. The material systems used are usually applied by atmospheric plasma spraying and essentially comprise systems based on AlSi-polyester, AlSi-graphite, Ni-graphite, and defined, porous-sprayed Ni-base alloys. AlSi graphite systems have proven to be excellent with regard to the requirements placed on them, but in particular, corrosive loads and associated material damage can cause efficiency losses and increasing aircraft turbine operating costs. This article describes the development and successful application of AlSi/hBN-based running-in layer systems for various Rolls Royce turbines. In addition, work and results are presented on the basis of which a comparative evaluation of the properties of AlSi graphite and AlSi/hBN systems is carried out. Paper includes a German-language abstract.