Due to the extreme conditions experienced in gas turbine engines, especially aero-derivative type engines, internal components need to be protected against adverse effects in order to maintain component integrity and engine performance between overhauls. Among these adverse conditions are wear in the form of friction and fretting, erosion and various forms of corrosion. This paper focuses on fretting wear. To reduce coating costs, shorten the dwell time, and provide additional options for the repair of industrial gas turbine components, it presents a comprehensive study initiated by Rolls-Royce to determine the feasibility of the Sulzer Metco HVOF process as an alternative to the evaluate the D-Gun process. Based on the results of this study, it was concluded that tungsten carbide and chromium carbide sprayed with the Diamond Jet Hybrid can be used successfully as coating alternatives to the D-Gun. Paper includes a German-language abstract.

Air separation plants employ centrifugal compressors where air and electrical energy are the only raw materials used in the production process. In order to optimize compressor performance and efficiency, abradable coatings, originally developed for gas turbines, have been designed into turbocompressors. This paper describes the optimization and performance improvements achievable using aluminium silicon-boron nitride materials.

Aluminium silicon alloys have shown favourable properties when used as the matrix for abradable coatings in low pressure compressors of gas turbines [1 and 2]. This paper aims to describe the wear mechanisms found in aluminium silicon based abradables. To this end three thermally sprayed coatings are investigated. Aluminium silicon polyester, aluminium silicon-graphite and the most recently developed, aluminium silicon-hexagonal boron nitride (hBN) examined here are amongst a few of these materials. To be able to design materials to function in as wide a parameter range as possible, a test ng simulating engine mechanisms is required. Tests were conducted using titanium blades at velocities ranging from 250 - 450 m/s, temperatures of ambient to 450°C and controlled incursion rate of 5, 50 and 500 µm/s. The data obtained from these tests is best interpreted in the form of wear maps which characterise the seal performance and therefore are of use to engine and material designers.