Abstract
The vitreous enamelling of aluminium is a relatively new application and there are still many problems to be solved.
This is to report on the various conditions applied to the enamelling of aluminium with a lead-base enamel coating.
In this experiment, aluminium alloy sheets, which had been directly white-cover-coated and fired at 530°C, were used.
Findings are as follows:
(1) 2S and 3S alloy sheets require only cleaning prior to the enamelling. But in case of using old slips, the sheets should be prefired after cleaning, or pre-treated so as to prevent from formation of bubbles or pin-holes on the surface of enamel coating.
(2) From the view point of anti-exfoliation, 52S alloy sheet should inevitably be cleaned and pretreated before enamelled.
The oxide film formed on 52S alloy sheet by anodizing with water glass solution gives the sheet high resistance against the accelerated exfoliation test and makes its color effect better.
(3) To give the nice whiteness to the white-cover-coat in practice, it is recommended to add titanium oxide as muuch as 15 parts against 100 parts of frit.
(4) In case the objects are fired for unnecessarily long time, their whiteness is spoiled and the enamel gets easily exfoliated. The firing should, therefore, be made for the shortest necessary time to obtain the desirable luster.
