Transformation of intermetallic layer due to oxidation heat treatment on hot-dipped aluminum coated steel

Abstract

ABSTRACT

Heat treatment was introduced onto the aluminum coated low carbon steel to promote the formation of thin layer of oxide for enhancement of oxidation protection of steel. This process has transformed the existing intermetallic layer formed during hot dip aluminizing process. Experiment was conducted on the low carbon steel substrates with 10mm x 10mm x 2mm dimension. Hot dip aluminizing of low carbon steel was carried out at 750 ºC dipping temperature in a molten pure aluminum for 5 minutes. Aluminized samples were heat treated at 600 ºC, 700 ºC, 800 ºC, and 900 ºC for 1 hour. X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and EDAX were used in investigation. From the observation, it showed the intermetallic thickness increased with the increase in temperature. The result of EDAX analysis revealed the existence of oxide phase and the intermetallics. The XRD identified the intermetallics as Fe₂Al₅ and FeAl₃.

ABSTRAk

Rawatan haba diperkenalkan ke keluli karbon rendah bersalut aluminium untuk mempromosikan pembentukan lapisan nipis oksida untuk meningkatkan perlindungan pengoksidaan keluli. Proses ini telah mengubah lapisan intermetallic sedia ada yang terbentuk semasa proses aluminizing panas. Eksperimen dilakukan pada substrat keluli karbon rendah dengan dimensi 10mm x 10mm x 2mm. Mematapkan aluminizing keluli karbon rendah dilakukan pada 750 ºC suhu mencelupkan dalam aluminium tulen cair selama 5 minit. Sampel aluminized adalah haba yang dirawat pada 600 ºC, 700 ºC, 800 ºC, dan 900 ºC selama 1 jam. Difraksi sinar-X (XRD), Mikroskop elektron imbasan (SEM) dan EDAX digunakan dalam penyiasatan. Dari pemerhatian, ia menunjukkan ketebalan intermetallic meningkat dengan peningkatan suhu. Hasil analisis EDAX menunjukkan kewujudan fasa oksida dan intermetallik. XRD mengenalpasti intermetalkics sebagai Fe₂Al₅ dan FeAl₃.