Screening for Al2O3 failure in MCrAlY APS coatings using short-term oxidation at high temperature

Some aspects of elemental behaviour in HVOF MCrAlY coatings in high-temperature oxidation

High Temperature Oxidation Performance of Aluminide Coatings

In order to determine the potential benefits and limitations of aluminide coatings, coatings made by chemical vapor deposition (CVD) on Feand Ni-base alloy substrates are being evaluated in various hightemperature environments. Testing of coatings on representative ferritic (Fe-9Cr-1Mo) and austenitic (type 304L stainless steel) alloys has found that high frequency thermal cycling (1h cycle tim...

Development of APS MCrAlY Dense Bond Coats

The objective of this study was to mimic the microstructure of MCrAlY coatings sprayed using HVOF (High Velocity Oxy-Fuel) processes by using an Air Plasma Spray (APS) process in order to improve oxidation and spallation life of MCrAlY APS coatings. Figure 1 shows the typical microstructures obtained when spraying bond coats using the (a) HVOF process, and (b) the APS process. The microstructur...

Ultrasonic Al2O3 Ceramic Thermometry in High-Temperature Oxidation Environment

In this study, an ultrasonic temperature measurement system was designed with Al₂O₃ high-temperature ceramic as an acoustic waveguide sensor and preliminarily tested in a high-temperature oxidation environment. The test results indicated that the system can indeed work stably in high-temperature environments. The relationship between the temperature and delay time of 26 °C-1600 °C ceramic mater...

Effect of Surface Morphologies on the Isothermal Oxidation Behavior of MCrAlY Coatings Fabricated by High-velocity Oxyfuel Processes

In this study, the effect of surface morphologies on the isothermal oxidation behavior of MCrAlY coatings fabricated by high-velocity oxyfuel (HVOF) processes was investigated. To do so, free standing coatings with as-sprayed and polished surfaces were isothermally oxidized at 1050°C. The thickness of the bond coat was approximately 380μm. The Ra of the as-sprayed and polished surfaces were 6.4...