R-SiC and Si3N4-SiC in Al-Si Alloy Melt

silicon carbide and silicon nitride have poor wettability with molten metal. Except for magnesium, nickel, chromium alloy and stainless steel, they have no wettability to other metals. Therefore, they have outstanding corrosion resistance and are widely used in aluminum electrolysis industry.

In this paper, recrystallized silicon carbide R-SiC and silicon nitride bonded silicon carbide Si are explored from multiple latitudes.₃N₄-SiC in Thermal Cycle Al-Si Alloy Melt.

According to the experimental data of 9 thermal cycles of the two samples in the aluminum-silicon alloy melt at 495 ℃ ~ 620 ℃ for 1080h, the following analysis results are obtained.

R-SiC and Si₃N₄-SiC samples decreases with the increase of corrosion time. The corrosion rate conforms to the decay logarithm relationship. (Figure 1)

through energy spectrum analysis, R-SiC and Si₃N₄-SiC samples themselves have no aluminum-silicon element. In XRD pattern, a certain amount of aluminum-silicon peak value is aluminum-silicon alloy remaining on the surface. (Figure 2-Figure 5)

by SEM analysis, with increasing corrosion time, R-SiC and Si₃N₄-SiC sample is slightly loose, but there is no obvious damage. (Figure 6-Figure 7)

Surface Tension σ at Interface between Aluminum Liquid and Ceramic_s/l>σ_s/g, the wetting angle θ between the interface is> 90, and the interface between aluminum liquid and sheet ceramic material is not wetted.

Therefore, R-SiC and Si₃N₄-SiC has excellent corrosion resistance to aluminum-silicon melt with little difference. But Si₃N₄-SiC materials are relatively low in cost and have been successfully applied for many years.