Thermisch gespritzte Quasikristall-Verbundschichten für Anwendungen in der Gleitlagertechnik

Quasicrystalline phases, when alloyed from the same components, exhibit exceptional properties, including high thermal stability, unique thermal and electrical conductivity, and excellent tribological performance. However, their high hardness often leads to brittleness, which is a disadvantage for applications such as anti-adhesive, friction-reduced surfaces. To mitigate brittleness, quasicrystalline phases can be embedded in a more ductile material, forming a metal-matrix composite that retains some quasicrystalline characteristics. Various methods, including blended, agglomerated, chemically encased, or attrition-milled powders, as well as cored wires, were used for thermal spraying to create these composite coatings. The study involved spray trials with materials prepared through these techniques, utilizing different compositions. Techniques employed included Arc-Wire-Spraying, High-Velocity-Oxy-Fuel-Spraying, Atmospheric Plasma-Spraying, and Wire-Flame-Spraying. Structural and metallurgical analyses were conducted to confirm the presence of quasicrystal contents and assess the adherence and embedding behavior of the matrix phase. Mechanical property analysis via Vickers indentation was performed to evaluate ductility improvements resulting from the composite structure, while friction tests focused on the sliding wear behavior in relation to the quasicrystalline phase content.