Abstract
• The effect of B 3+ on atomic cluster distribution, oxygen distribution and atomic diffusion capacity were determined by a molecular dynamics simulation. • B-O was preferentially involved in the Al-O network structure rather than by separate B-O network. B 3+ tended to enter the Al-centered atomic cluster Q 4 . • The formation of B Ⅲ -O-Al Ⅳ structure prevented the extension of the complex Al-O three-dimensional network resulting in the increase of bridge oxygen while the atomic cluster Q n in the high polymerization state decreased overall. CaO-Al 2 O 3 -based mold flux has been a good candidate for high aluminum steel casting. However, the high melting temperature, great viscosity and complexed crystallization of CaO-Al 2 O 3 slags had affected the controlling of heat transfer and lubrication between mold flux and steel. B 2 O 3 as a good additive, can effectively adjust the properties of slag. Therefore, the effect of B 2 O 3 on the structure of CaO-Al 2 O 3 -B 2 O 3 system were investigated by molecular dynamics simulation. The results showed that Al 3+ was dominated by [AlO 4 ] tetrahedra (about 80%), with [AlO 5 ] and [AlO 6 ] as the rest. B 3+ mainly formed two-dimensional layered [BO 3 ] and [BO 4 ] tetrahedral. As the increase of B 2 O 3 , B 3+ tended to form more [BO 3 ] and combined with [AlO 4 ] to form the B Ⅲ -O-Al Ⅳ linkage, which prevented the extension of the Al-O three-dimensional network, and reduced the degree of network polymerization, and resulting in the decrease of viscosity. This work would be helpful to optimize the design of CaO-Al 2 O 3 mold flux.
Published Version
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