Abstract
For the purpose of approaching to the dispersion strengthened steel, an investigation was undertaken to study in detail the relation between the distribution of oxides, which were sprayed into molten steel by force, and interfacial factors.
The main results obtained are summarized as follows:
1) The distribution of oxides depends on both the contact angle of molten steel on various oxides and the interfacial tension. The oxides particle size in steel increases with the contact angle and the interfacial tension.
2) The effect of carbon in steel on the distribution of oxides is not remarkable. This result may indicate that carbon is less surface-active.
3) Addition of alloying elements which have a large standard free energy of oxide formation (-ΔG°) is very effective in lowering the oxide particle size. This can be attributed to the selective adsorption of the alloying element in steel at the interface and the interfacial reaction of its element with sprayed oxide.
4) The oxide particle size shows a sharp decrease on additions of niobium, which is the most effective element in lowering the oxide particle size, but changes only slightly above 0.7 at% niobium.
