Preparation and Corrosion of Mullite Thin Film on ß-SiAlON Ceramics

2008 ◽  
Vol 403 ◽  
pp. 135-138 ◽  
Author(s):  
Yasunobu Noritake ◽  
Hajime Kiyono ◽  
Shiro Shimada
Keyword(s):  
Thin Film ◽  
Corrosion Resistance ◽  
Dip Coating ◽  
Coated Sample ◽  
Coating Process ◽  
Al2o3 Film ◽  
High Temperature Water ◽  
Water Vapor Corrosion ◽  
Al2o3 Films ◽  
Temperature Water

Mullite film was formed on ß-SiAlON (Si6-zAlzOzN8-z, z = 3) ceramics by reaction of Al2O3 films with silica formed on oxidation to improve a high temperature water vapor corrosion resistance. Sintered ß-SiAlON was fabricated by hot pressing of ß-sialon (z = 3) powder without additive at 1900°C and at 24 MPa for 4 h in N2. The Al2O3 film was deposited on polished ß-SiAlON ceramics by a dip coating process of Al2O3 precursor sols prepared from the alkoxide solution and aluminum sol. The Al2O3 coated sample was heated in Ar/O2 (95/5 vol.%) at 1300°C for 2 h, resulting in the formation of mullite by reaction with silica produced from sialon. The resulting mullite-coated sample was corroded in H2O/Ar/O2 (90/8/2 vol.%) at 1200°C for 2 ~ 100 h. The corroded samples were characterized by XRD and SEM-EDS for the evaluation of the corrosion resistance of mullite-coated sialon.

Effect of Al2O3 Thin Film on Corrosion Resistance of Pure Mg and Its Anodic Coating

2005 ◽  
Vol 488-489 ◽  
pp. 865-868 ◽  
Author(s):  
Da Yong Shan ◽  
Rong Fa Zhang ◽  
En Hou Han
Keyword(s):  
Thin Film ◽  
Corrosion Resistance ◽  
Base Metal ◽  
Sol Gel ◽  
Al2o3 Film ◽  
Anodic Coating ◽  
Polarization Test ◽  
Al2o3 Films ◽  
Better Than ◽  
Al2o3 Thin Film

Al2O3 thin film was formed on pure magnesium and its anodic coating by sol-gel method. SEM observation and EDX analysis showed that Al2O3 film could not totally cover the surface of base metal, but they blocked small pores when they were formed on anodic coating. Potentiodynamic polarization test indicated that Al2O3 films improved corrosion resistance of both anodizing coating and base metal, and the effect on anodizing coating was better than on base metal.

The Behavior of Galvanized Steel Coated with a Double and Triple Layer of Hybrid Films

2012 ◽  
Vol 727-728 ◽  
pp. 1604-1609
Author(s):  
Sandra Raquel Kunst ◽  
Rogério Freitas dos Santos ◽  
Cláudia Trindade Oliveira ◽  
Elen Leal da Silva ◽  
Iduvirges Lourdes Müller ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Protection ◽  
Morphological Analysis ◽  
Hybrid Film ◽  
Dip Coating ◽  
Galvanized Steel ◽  
Coating Process ◽  
Barrier Effect ◽  
Hybrid Films ◽  
Triple Layer

The aim of this work is to characterize by electrochemical, physicochemical and morphological analysis the hybrid films applied on galvanized steel by dip-coating process. Preliminaries studies showed that a monolayer of silane is not enough to increase the corrosion resistance protection of the substrate. In this context, the galvanized steel was coated with a double and triple layer of hybrid film obtained from a sol constituted by silane precursors 3 - (trimetoxisililpropil) methacrylate (TMSPMA) and tetraethoxysilane (TEOS) with addition of cerium nitrate at a concentration of 0.01M. The hybrid films were cured for 20 minutes at 60°C in each application of the film. The results showed that a double and triple layer of hybrid film increase the barrier effect contributing to corrosion protection of galvanized steel.

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