Formation of an Environmental Barrier Coating Using DC–RF Hybrid Plasma

Abstract

The characteristics of an Al2O3 coating on a Nb or Mo substrate using a direct current‐radio frequency induction (DC‐RF) thermal plasma of Ar‐H2 were studied. A porous and crystallographically stable coating with highly preferred orientation of {110} planes of α‐Al2O3 crystals was obtained. The preferred orientation was strongly dependent on the diameter of the introduced Al2O3 powder. The formation mechanism of the preferred orientation of the coating is explained by accumulation of charged clusters on the substrate. The coating prepared by this procedure revealed the superior capability of protecting the substrate against high‐temperature oxidation.

Thermal spray coatings in environmental barrier coatings

“…For example, cold gas dynamic spraying has been used recently to fabricate metal-based coatings to act as environmental barriers (Bala et al, 2010). The use of smaller particles has been shown to produce denser coatings since they are easier to melt and accelerate in the plasma jet (Otsuka and Yamamoto, 2003;Mawdsley et al, 2001). The use of smaller particles has been shown to produce denser coatings since they are easier to melt and accelerate in the plasma jet (Otsuka and Yamamoto, 2003;Mawdsley et al, 2001).…”

Temperature Dependence of Thermal Reflection Behavior of Al2O3–TiO2 Multilayer Thermal Energy Window Coating

“…To protect ceramics from a high‐temperature environment, the so‐called environmental barrier coatings (EBCs) have recently been developed 1,2 . EBCs have multifunctional properties, mostly to protect the surface of ceramics in a service environment, such as oxidation and/or water vapor, and so on.…”

“…To protect ceramics from a high-temperature environment, the so-called environmental barrier coatings (EBCs) have recently been developed. 1,2 EBCs have multifunctional properties, mostly to protect the surface of ceramics in a service environment, such as oxidation and/or water vapor, and so on. Other applications of structural ceramics are to reduce problems in the flow of thermal energy from the environment to ceramics because of difficulty in using aircooling systems, which are popular in superalloy com-ponents.…”