Nov_Dec_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | N O V E M B E R / D E C E M B E R 2 0 1 7 4 2 iTSSe TSS iTSSe TSS JTST HIGHLIGHTS 12 Fig. 5 — BSE images of metallographic cross sections showing 2-mm-thick freestanding CoNiCrAlY coatings after 1100°C exposure in synthetic air for 72 hours: LPPS coating. parameters used for bondcoat deposi- tion. The well-established LPPS process competes nowadays with alternative technologies such as HVOF and APS. In addition, new technologies have been developed for bondcoat manufacturing such as high-velocity APS or a combi- nation of HVOF and APS for application of a flashcoat. Future developments of bondcoat systems will likely include op- timization of thermal spray methods for obtaining complex bondcoat roughness profiles required for extended APS-TBC lifetimes. Introduction of the newest generation of single crystal superalloys possessing low Cr and high Al and refrac- tory metals (Re, Ru) contents will require definition of new bondcoat compositions and/or multilayered bondcoats to mini- mize interdiffusion issues. The develop- ments of new bondcoat compositions may be substantially facilitated using thermodynamic-kinetic modeling, the vast potential of which has been demon- strated in recent years (Fig. 5).