Abstract:In order to study the corrosion behavior of AlSi-PHB sealing coatings in marine environment and the effect of corrosion on coating properties, the AlSi-PHB sealing coating was prepared on TC4 matrix by plasma spraying technology. The 192 h acid salt spray test, hardness test and bond strength test were carried out. Using scanning electron microscopy (SEM), X-ray diffraction (XRD) and other testing methods to study the corrosion morphology, corrosion mechanism, coating bond strength and hardness changes before and after corrosion. The results show that after 192 h acid salt spray test, the surface structure of the coating is completely destroyed, and large transverse cracks and corrosion areas appear inside the coating, and the main corrosion product is Al(OH)3. The existence of pores inside the coating provides a place for corrosion. The corrosive medium Cl- invades into the interior of the coating through the pores, and more intense corrosion occurs in the deep layer of the coating under the action of "blocked battery". Before and after corrosion, the average hardness of the coating drops from (65.2±10.7) HR15Y to (59.6±8.5) HR15Y, and the average bonding strength drops from (11.3±1.1) MPa to (1.7±0.6) MPa, which could not meet the service requirements.