| 摘要 |
PURPOSE:To accomplish the sure fining effect of casting structure free from recular change by aligning the electron arrangement of a molten metal by the diffusing power of metal borides of high m.p. quickly. CONSTITUTION:Metal borides are chemically stable even at high temp., and under high temp. conditions, the borides can cause self-diffusion or electric field diffusion easily with valance electrons specific to these material and metal atoms. Such dominant diffusivity aligns the electron arrangements of molten metal quickly and fines the casting structure of various metals. Further if acetylldes or nitrodes of alkaline earth metals or peritectic reaction type inorg. elements are bound or added to the borides, the H2 dissolved in the molten metal is chemically removed efficiently. Further, the dissolved O2 is naturally reduced or released to the outside. As a result, the entire part of the molten metal is cleaned, and the fining power for the casting structure is increased, whereby the sure fining effect of the casting structure free from secular change is accomplished. |
