• Senderowski, Cezary
• Panas, Andrzej J.
• Fikus, Bartosz

Abstract

<p>Intermetallics are known for their unique mechanical and thermal properties, and thus they are used as structural materials to be applied in multilayer protective coatings. A special protective barrier feature can be achieved with the gas detonation spraying (GDS) process. The resultant structure contains both intermetallic phases and oxide ceramics. Both the thermal and mechanical properties of the GDS coating differ from the properties of the intermetallic powder substrate material. However, as was proven in a study of a complex thermophysical property of a certain Fe-40 at.% Al GDS coating, these properties change when the coating material is exposed to temperature exceeding a threshold level. In order to characterize these temperature induced changes, the Fe-40 at.% Al GDS coating is hereby subjected to systematic dilatometric studies. The measurements were carried out from room temperature up to 1180 °C at repeated cycles. The measurements performed on the coating material specimens are compared to results of dilatometric measurements up to around 1000 °C done on a sintered Fe-40 at.% Al GDS substrate powder. The investigations revealed both non-reversible changes and reversible 2-nd order magnetic phase transition in the coating material. The findings contribute to a better understanding of the GDS process phenomena.</p>

Topics

• impedance spectroscopy
• phase
• phase transition
• intermetallic
• oxide ceramic