ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
A hot dip aluminizing process to simulate the continuous galvanizing line (CGL) wascarried out in three successive steps by a hot dip simulator: the pre-treatment for removing scales onthe 200 × 250 mm2 and 1mm in thickness cold rolled steel sheet, the dipping in 660°C Al-Si melt for3s and the cooling. In a pre-treatment, the steel specimen was partly coated by Au to confirm themechanism of intermetallic compound (IMC) formation. Scanning electron microscopy (SEM),energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) analyseswere followed to observe the cross-section and the distribution of the elements. The specimen wasanalyzed in the boundary of the dipped-undipped part to see the formation mechanism of thealuminized steel. An intermetallic compound (IMC) is rapidly developed and grown in thesteel-liquid interface. It has been usually reported that the IMC was formed by the dissolution of ironin the steel substrate toward the melt and the diffusion of aluminum in an opposite direction. Thespecimen is covered with aluminum-10 wt.% silicon, forms the IMC in the part that was not Aucoated. However, IMC is not formed in the Au-coated part. The interface of the dipped-undipped isalso analyzed by EDX. At the interface of the steel-IMC, it is clearly shown that the IMC is onlyformed in the dipped part and exists in the steel substrate as well, and contributes by iron, aluminumand silicon. The result clearly shows that only aluminum diffuses into the steel substrate without thedissolution of iron and forms the IMC between the steel substrate and the melt. Au coating and theshort dipping time prevent the iron from dissolving into the aluminum melt. By TEM combined withfocused ion beam (FIB) sample preparation, the IMC is confirmed as Fe2SiAl8, a hexagonal structurewith space group P63/mmc
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/13/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.519-521.1871.pdf
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