Segmented crack self-healing repair method for laser remelting thermal barrier coating

Abstract

Disclosed is a segmented crack self-healing repair method for a laser remelting thermal barrier coating. The method comprises the following steps that Ni-Al / N-Al2O3 sealing particles are infiltrated into segmented cracks of the remelting coating by adopting a form of pressure and ultrasonic vibration, and by adopting Al layer oxidation reaction exotherm of the Ni-Al particles, Ni layer melts continuously to form a sealing film. The effects of nano-alumina are that the Ni-Al particles are compactly wrapped to make melted liquid not easily flow away; oxidation reaction heat dissipation is reduced, and on-going self-healing reaction is maintained; and nano-alumina is infiltrated into the sealing film to form nano-alumina reinforced composite materials, so that a nano-alumina reinforced nickelbase solid solution film is formed, the segmented cracks are sealed and plugged effectively through the nano-alumina reinforced nickel base solid solution film, and the high temperature and oxidation resistance of the remelting thermal barrier coating is improved remarkably.

Description

technical field [0001] The invention belongs to the technical field of laser processing, and in particular relates to a self-healing repair method for segmental cracks of a laser remelted thermal barrier coating. Background technique [0002] Thermal Barrier Coatings (TBCs for short) is a multi-layer structure system coated on the surface of the base metal. Safe operation, which can increase the thermal efficiency of the engine to more than 60%, thereby reducing fuel consumption and meeting the requirements of low-carbon environmental protection. At present, the biggest problem facing the preparation of thermal barrier coatings in my country is premature peeling of the coating. A large number of studies have shown that there are three main reasons for the peeling of the coating: thermally grown oxide (TGO, the main component of which is Al at the interface between the ceramic layer and the bonding layer) 2 o 3 ) formation and growth; the interface bonding strength is insuf...

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Problems solved by technology

[0004] However, laser remelting is thermal processing. Due to the characteristics of non-uniform laser heating, rapid cooling and high brittleness of ceramics, the ceramic layer after laser remelting has obvious surface network segmental cracks, and the crack depth generally runs through the entire remelting layer. Although these cracks can increase the thermal shock resistance of the coating, these cracks provide an open channel for oxygen to enter the coating, and it is easy to enter the ceramic layer / bonding layer interface through the unmelted plasma coating, resulting in excessive oxidation of the bonding layer. Make the interface crack or even fall off and fail in the early stage of the coating

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