Purkitus

Purkitus refers to a phenomenon observed in certain types of metal alloys, particularly those used in high-temperature applications like turbine blades. It is characterized by the formation of a brittle, intermetallic layer at the interface between the base alloy and a protective coating. This layer, often composed of aluminum or other alloying elements, grows over time through diffusion processes.

The primary consequence of purkitus is a degradation of the mechanical properties of the component. The intermetallic layer is significantly less ductile than the surrounding material, leading to a reduction in fracture toughness and an increased susceptibility to cracking, especially under thermal cycling conditions. This can compromise the structural integrity and service life of the component.

The formation of purkitus is influenced by several factors, including the composition of the alloy and coating, the operating temperature, and the duration of exposure. Understanding and mitigating purkitus is crucial for ensuring the reliability and longevity of components in demanding environments. Research often focuses on developing new coating systems or modifying alloy compositions to inhibit or slow down the diffusion processes responsible for its development.