Study of corrosion mechanism of cast iron in molten aluminum

Abstract

The corrosion mechanism of three aluminum ingot mold materials used by Chinese aluminum electrolytic enterprises in molten aluminum was studied: The three materials are pearlite cast iron (PCI) contains vermicular graphite, lamellar graphite, and spherical graphite respectively. After 800°C molten aluminum corrosion for 4 h, the intermetallic compound (IMC) layers of Fe 2 Al 5 and FeAl 3 is formed at the interface. It was found that the volume of spherical graphite in IMC was reduced to 20%, and lamellar graphite aggregated in the IMC layer. The average thickness of the Fe 2 Al 5 layer in PCI1, PCI2 and PCI3 is about 180 μm, 100 μm and 101 μm, respectively. The weight loss rate of PCI1 is 2.57 (mg cm −2 )min −1 , PCI2 is 2.20 (mg cm −2 )min −1 , and PCI3 is 2.24(mg cm −2 )min −1 . There are dispersed Cr and Mo carbides in the IMC layer. Si-rich ribbon-shaped region was found at the interface between cast iron and IMC. The needle-like precipitates (Al 4 C 3 ) were observed only at the only at the boundary between cast iron and IMC in PCI1.

Towards a Better Understanding of the Interaction of Fe66Cr10Nb5B19 Metallic Glass with Aluminum: Growth of Intermetallics and Formation of Kirkendall Porosity during Sintering

“…At the same time, the aluminum atoms diffuse into the alloy and a FeAl 3 -based layer grows until the alloy is fully transformed. When cast iron corrodes in molten aluminum, a similar situation develops [33]. An Al-containing layer forms at the interface between the cast iron and the melt, while some iron dissolves into aluminum, which leads to the formation of FeAl 3 needles in the aluminum matrix at a distance from the interface.…”

Erosion mechanism of austenitic steel and martensitic steel in aluminum alloy melt

“…Therefore, scholars have explored the effect of steel microstructure on corrosion by immersion tests. [11][12][13] Zhang et al [14] suggested that duplex stainless steel could better resist corrosion than H13 steel in the aluminum melt. Besides, the intermetallics thickness of duplex stainless steel is comparatively thinner, and the interface is much flatter.…”

Review on corrosion resistance of mild steels in liquid aluminum

“…Studies [10,25,44,[72][73][74][75][76] have shown that secondary phases such as graphite, IMCs, ceramics, etc. possess extremely little solubility in liquid aluminum and hardly react with the liquid aluminum.…”

“…Balloy et al [2,10,25,76] suggested that the presence of C-rich phase (Al4C3) and J o u r n a l P r e -p r o o f 14 graphite can effectively enhance the corrosion resistance of ferrous alloys in liquid aluminum because they are able to act as an efficient barrier to the Al diffusion. Fig.…”

“…12 exhibits SEM images of graphite and black Al4C3 precipitates in cast iron for corrosion resistance to aluminum melt. Xu et al [10] and Wang et al [76] indicated that the morphology and size of graphite can play a pivotal role in corrosion resistance.…”