Skip to Main content Skip to Navigation
Theses

Réalisation et caractérisation des revêtements à base magnésium élaborés par projection à froid

Abstract : Cold spraying has shown unique advantages in preparing coatings of metal, composite and ceramic. However, the deposition mechanism of magnesium and magnesium-based composite coatings fabricated using cold spraying was not researched although magnesium and metallic matrix composites based magnesium have drawn more and more attention due to their excellent specific strength. Therefore, the deposition mechanism of magnesium and magnesium-based composite coating has been studied in this study. The research carried out in this study involves several fields:Effect of the particle velocity of magnesium particles on the deposition efficiency, microstructure, microhardness and bonding strength of coatings; Effect of the particle size of magnesium particles on the deposition efficiency and microstructure of coatings;Effect of the substrate preheating on the microstructure, microhardness and bonding strength of coatings;Effect of the particle velocity of magnesium alloy (AZ91D) particles on the deposition efficiency, microstructure, and frictional behavior of coatings;Effect of the particle size of strengthening phrase (SiC) on the microstructure, bonding strength and frictional behavior of coatings;Effect of the particle content (15 vol.% - 60 vol.%) of strengthening phrase (SiC) on the microstructure, bonding strength and frictional behavior of coatings.The results show that cold spraying can be used to fabricate magnesium and magnesium-based coatings without any oxidation or phase transformation. The critical velocity of magnesium particles is 653 m•s-1- 677 m•s-1. Magnesium particles with a size too large or too small are not suitable to the deposition. The maximum of deposition efficiency of magnesium particles are obtained using the powder with a size range of 22-64 μm. The maximum of bonding strength between magnesium coatings and substrates is 11.6 ± 0.5 MPa as the substrate is preheated at 200oC. The deposition of AZ91D coatings is due to the effect of mechanical interlocking. And the friction type of AZ91D coatings is adhesive wear. The friction type of AZ91D – SiC composite coatings turn to be abrasive wear. The SiC content in composite coatings decreases as the SiC particle size decreases due to the effect of bow shock. The deposition efficiency of AZ91D and SiC mixed powder increases as the SiC content increases from 15 vol.% to 30 vol.%, and then decreases as the SiC content increases from 30 vol% to 60 vol.%.
Document type :
Theses
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-00864186
Contributor : Abes Star :  Contact
Submitted on : Friday, September 20, 2013 - 2:57:40 PM
Last modification on : Tuesday, October 1, 2019 - 3:43:39 PM
Long-term archiving on: : Saturday, December 21, 2013 - 4:30:35 AM

File

These_SUO_-_Xinkun_UTBM.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-00864186, version 1

Collections

Citation

Xinkun Suo. Réalisation et caractérisation des revêtements à base magnésium élaborés par projection à froid. Autre. Université de Technologie de Belfort-Montbeliard, 2012. Français. ⟨NNT : 2012BELF0190⟩. ⟨tel-00864186⟩

Share

Metrics

Record views

879

Files downloads

5771