The author believes that the usual method to determine the quality of the cast iron ingot mold is concentrated only for iis chemical composition. Therefore many papers already published upon the similar subject are nearly all concerned to the latter. But practical men very often experience that the molds with equal analysis do not always show the above mentioned result. consequently, it is quite important to do further investigations beyond this extent.
The author comes to the conclusion by research that the mold life chiefly depends on the following six items.
1. The design of the mold.
2. The chemical composition of the mold.
3. The grade of pig irons for the mold.
4. The casting method of the mold.
5. The annealing of the mold.
6. The using conditions of the mold.

抄録全体を表示

1. Introduction.
2. Chemical reaction between metals of the alkali and alkaline earth groups and dilute acids, water and caustic alkaline solutions involves two fundamental reactions of different types.
3. The reaction of commercial magnesium is also composed of these two different fundamental reactions.
4. The reaction of pure magnesium with water.
5. Adiscussion from the standpoint of the theory of electrochemistry.
6. Conclusions.
Metallic magnesium reacts with aqueous solutions of various chlorides so vigorously as zinc dissolves in hydrochloric acid of moderate concentration. In his previous paper, the author investigated this phenomenon in a qualitative manner, and concluded that the number of chemical species entering in the mechanism of this reaction are limited to three, namely, Mg atom, water molecule and Cl^- ion. It was also almost certain that H⁺ ion does not take part in the reaction mechanism. If so, the hydrogen gas evolved must come directly out from the water molecule decomposed by the following equation
Is such a direct reaction between Mg atom and water molecule possible? The present paper deals with this important question.
There exists, on the other hand, another fundamental chemical reaction of the electrochemical nature between Mg atom and H+ ion, such as,
Magnesium dissolves, like other metals, in dilute acid of ordinary concentration according to this (1) equation. The author tried to show the existence of these two kinds of fundamental reactions As to the alkali and alkaline earth metals, he was able to show definitely the existence of the two types of the reaction.
Direct chemical reaction between metal atom and water molecule was proved for these elements.
Commercial magnesium showed also two kinds of reaction. But, whether the direct reaction of atom with molecule (equation 2) takes place between water molecule and Mg atom itself or atoms of the alkali or alkaline earth metals contained in magnesium as impurities, he was unable to decide.
A discussi n was made from the standpoint of the theory of electrochemistry. The idea of overpotential was proved to be insufficient to understand the action of dilute acid and water on metals.

抄録全体を表示