Nanocrystalline bond coat development

燃气涡轮机发动机被认为是传统材料系统最恶劣的操作环境之一。对更高发动机性能、热效率和部件耐久性的日益增长的需求导致了热障涂层（TBC）系统的发展。这些系统通常用在燃气涡轮机发动机的热段部件上，例如叶片、轮叶和燃烧器，以防止高温氧化和腐蚀。TBC通常由氧化钇部分稳定的氧化锆顶涂层和MCrAlY（其中M可以是Ni和/或Co）粘结涂层组成，该粘结涂层通常通过热喷涂技术例如等离子体和/或HVOF喷涂施加在待保护的超合金基底金属上。TBC系统的全部潜力尚未达到，由于过早失效，通常发生在粘结涂层-顶涂层界面。最近的研究已经显示了获得增强的性能TBC的有希望的解决方案。特别地，已经通过HVOF生产了纳米晶粘结涂层。尽管这些粘结涂层与原始纳米晶原料粉末相比表现出部分晶粒生长，但它们表现出改善的氧化和腐蚀行为，从而增强了TBC性能。然而，这些研究表明，使用HVOF来产生粘合涂层会促进有害氧化物的形成，这是由于原料粉末的不可避免的飞行中氧化。在喷涂过程中不形成有害氧化物和晶粒生长的纳米晶粘结涂层的生产被寻求作为生产增强的TBC系统的解决方案。本研究项目的长期目标是成功地生产出增强型TBC系统，该系统将在分层/开裂方面表现出更好的性能，通过首先使用CGDS和p-CGDS技术结合使用现有研磨技术的纳米晶体粉末生产来生产非氧化纳米晶体MCrAlY粘结涂层，预期非氧化纳米晶粘结涂层将表现出关于分层/开裂的上级性能。

Gas turbine engines are considered to be amongst the most hostile operating environments for conventional material systems. Increasing demands for higher engine performance, thermal efficiency and durability of components have led to the development of thermal barrier coating (TBC) systems. These systems are typically used on the hot section components of gas turbine engines, such as blades, vanes and combustors for protection against high temperature oxidation and corrosion. TBCs typically consist of an yttria-partially-stabilized zirconia top coat and a MCrAlY (where M can be Ni and/or Co) bond coat usually applied by thermal spray techniques such as plasma and/or HVOF spraying on the superalloy base metal to be protected. The full potential of TBC systems is yet to be reached due to premature failure, usually occurring at the bond coat-top coat interface. Recent studies have shown promising solutions to obtain enhanced performance TBC. In particular, nanocrystalline bond coats have been produced by HVOF. Although these bond coats exhibited partial grain growth compared to the original nanocrystalline feedstock powder, they exhibited improved oxidation and corrosion behaviour, thus enhancing the TBC performances. However, these studies have revealed that the use of HVOF to produce the bond coat promotes the formation of detrimental oxides due to unavoidable in-flight oxidation of the feedstock powder. The production of nanocrystalline bond coat without the formation of harmful oxides and grain growth during spraying is sought as the solution to producing enhanced TBC systems. The long term objective of this research project is to successfully produce enhanced TBC systems that will exhibit better performances with respect to delamination/cracking, by first producing non-oxidized nanocrystalline MCrAlY bond coats using both CGDS and p-CGDS techniques combined with nanocrystalline powder production using existing milling techniques (shorter term objective).It is expected that non-oxidized nanocrystalline bond coats will exhibit superior performances with respect to delamination/cracking.