Observations of intermetallic compound formation of hot dip aluminized steel

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Authors

  • KeeHyun Park
  • Van Daele Benny
  • Van Tendeloo Gustaaf
  • Jong Kyu Yoon

Colleges, School and Institutes

External organisations

  • Material Science and Engineering
  • Seoul National University
  • University of Antwerp

Abstract

A hot dip aluminizing process to simulate the continuous galvanizing line (CGL) was carried out in three successive steps by a hot dip simulator: the pre-treatment for removing scales on the 200 × 250 mm2 and 1mm in thickness cold rolled steel sheet, the dipping in 660°C Al-Si melt for 3s and the cooling. In a pre-treatment, the steel specimen was partly coated by Au to confirm the mechanism of intermetallic compound (IMC) formation. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) analyses were followed to observe the cross-section and the distribution of the elements. The specimen was analyzed in the boundary of the dipped-undipped part to see the formation mechanism of the aluminized steel. An intermetallic compound (IMC) is rapidly developed and grown in the steel-liquid interface. It has been usually reported that the IMC was formed by the dissolution of iron in the steel substrate toward the melt and the diffusion of aluminum in an opposite direction. The specimen is covered with aluminum-10 wt.% silicon, forms the IMC in the part that was not Au coated. However, IMC is not formed in the Au-coated part. The interface of the dipped-undipped is also analyzed by EDX. At the interface of the steel-IMC, it is clearly shown that the IMC is only formed in the dipped part and exists in the steel substrate as well, and contributes by iron, aluminum and silicon. The result clearly shows that only aluminum diffuses into the steel substrate without the dissolution of iron and forms the IMC between the steel substrate and the melt. Au coating and the short dipping time prevent the iron from dissolving into the aluminum melt. By TEM combined with focused ion beam (FIB) sample preparation, the IMC is confirmed as Fe2SiAlg, a hexagonal structure with space group P63/mmc.

Details

Original languageEnglish
Title of host publicationAluminium Alloys 2006
Subtitle of host publicationResearch Through Innovation and Technology - Proceedings of the 10th International Conference on Aluminium Alloys
Publication statusPublished - 2006
Event10th International Conference on Aluminium Alloys, (ICAA-10) - Vancouver, Canada
Duration: 9 Jul 200613 Jul 2006

Publication series

NameMaterials Science Forum
NumberPART 2
Volume519-521
ISSN (Print)0255-5476
ISSN (Electronic)1662-9752

Conference

Conference10th International Conference on Aluminium Alloys, (ICAA-10)
CountryCanada
CityVancouver
Period9/07/0613/07/06

Keywords

  • Diffusion, Dissolution, Hot dip aluminizing process, Interface, Intermetallic compound