Development of hard intermetallic coatings on austenitic stainless steel by hot dipping in an Al–Si alloy

Abstract

The austenitic stainless steel was coated by dipping into a molten Al-12.4%Si alloy at 765ºC. The effect of immersion times in the range of 60 to 900 s was investigated with respect to the phase nature, thickness, and microhardness. An uniform layer (~12 m) of Al 12 (Fe,Cr) 3 Si 2 intermetallic with hexagonal crystalline structure is formed, irrespectively the immersion time. Microhardness of the coating decreases with increasing dipping time, ranging between 850 and 600 HV for the shortest and longest immersion time, respectively. These hardness values are higher than that of about 200 HV for the substrate, which was not affected for the investigated periods of immersion.

Kesan Suhu Celupan ke atas Mikrostruktur dan Kekerasan Salutan Aluminium pada Keluli Karbon

“…Salutan logam Al merupakan salah satu teknik rawatan permukaan atau pengaloian yang berpotensi memberikan perlindungan kakisan yang baik bagi keluli karbon (Eggeler et al 1985). Celupan panas Al merupakan rawatan permukaan yang menghasilkan lapisan pelindung suhu tinggi aluminida pada permukaan keluli karbon untuk meningkatkan rintangan pengoksidaan keluli karbon (Cheng & Wang 2013;Frutos et al 2009). …”

“…Peningkatan suhu celupan ini telah meningkatkan nilai mikro kekerasan lapisan antara logam walaupun perubahan itu berlaku pada julat yang kecil. Peningkatan nilai kekerasan secara beransuransur ini disebabkan oleh kewujudan fasa ferit, perlite dan austenit yang lebih banyak semasa proses celupan panas (Frutos et al 2009;Kobayashi & Yakou 2002;Samsu et al 2014). Nilai kekerasan lapisan Al dan subsrat tidak menunjukkan sebarang perubahan yang ketara dengan peningkatan suhu dan tempoh celupan.…”

Effect of Sphere Properties on Microstructure and Mechanical Performance of Cast Composite Metal Foams

“…As previously reported [3,4,7,8] aluminum-steel (Al-S) CMF contains hard and brittle intermetallic from the Al-Fe-Si ternary system dispersed through the matrix of the material. The formation of intermetallics in the Al-Fe-Si system is a well-studied phenomena [9][10][11][12][13][14][15] and is due to the reciprocal diffusion of Fe and other alloying elements, like Cr and Ni, from the sphere wall into the Al-Si matrix, at the same time of diffusion of Al and Si from the matrix towards the sphere wall. Intermetallic formation in Al-S CMF influences the mechanical properties of the material and for that reason it has been widely studied [1][2][3][4][5][6][7][8].…”

Nanomechanical properties of novel intermetallic coatings developed on austenitic stainless steels by siliconisation in liquid phase

“…Interestingly, the coating/metal interface is planar, without cracks or signs of delamination during SEM examination. A more detailed microstructural analysis has been presented elsewhere [15].…”

“…Processing, microstructural characterization, and in vitro corrosion behaviour of the coated steel have been described elsewhere [15,16]. In this investigation we explore the mechanical properties of the coating, which is an important step before considering any load bearing application of the coated steel.…”