Abstract
The optimum conditions for preparation of vapor phase rust-inhibiting papers, powders, tablets, and oils for aluminum were investigated by using hexamethylenetetramine (HMT) and various subcomponents; and the vapor transfer mechanism of rust-inhibitors was discussed together. The results obtained were as follows: (1) Among water-soluble binders for the vapor phase rust-inhibiting papers, polyvinyl alcohol, milk casein, and gum arabic showed the most remarkable effects at the contents of 5-7, 8-10, and 9-10%, respectively. As for an oil soluble binder, 4-7% of shellac solution gave good effects. (2) As for extenders for the vapor phase rust inhibiting powders, white pigments such as titanium white, talc, and kaolin showed good effects. (3) In the case of vapor phase rustinhibiting tablets, the extenders did not show direct contact effects as on the powders. However, the pigments effective for vapor phase rust-inhibiting powders were also effective for the tablets, and the addition of 20% or more of HMT in general showed good rust-inhibiting effects. (4) In the case of vapor phase rust-inhibiting oils, the addition of 0.5% or more of HMT showed good effects. (5) The discussion on the vapor phase transfer mechanism of HMT led to the following presumption on its rust-inhibition. Since HMT is hygroscopic, it reduces corrosion of aluminum by removing environment moisture; in addition, the decomposition products due to moisture absorption such as ammonia and formaldehyde give space effects such as prevention of aluminum surface from oxide formation, which will bring the rust-inhibiting effects.
