Enamels titania-based

In the traditional enamelling methods, the adhesion is aided by the ground coat enamel and by adhesive oxides which arc responsible for galvanic corrosion of the metal and thus for coarsening the surface. More recent advances in technology allow direct application of the cover coat enamel onto the metal surface. This method is possible in the case of titania enamels and requires steel of special composition, either alloyed with titanium or carbon-free. Another possibility is based on the deposition of Ni on the metal surface. It is also necessary to adjust the slip composition and the coating thickness suitably the fired enamel thickness is only 0.1 —0.2 mm, compared with the usual 0.4 mm. 

Semi-opaque acid-resistant titania enamels and alkali-resistant frit generally have good detergent resistance whereas non-acid-resistant sign enamels and AI2O3/B2O3/P2O,-based finishes have poor resistance. 

Titanium Oxides. The common oxide is Ti02 m.p. approx. 1850 C. Used as an opacifier, particularly in vitreous enamels, and as a constituent of some ceramic colours. Titania and titanate electroceramics, for use in the radiofrequency field, are based on this oxide and its compounds. Titania occurs in three crystalline forms anatase, BROOKiTE and rutile (see under each mineral name). Ti20, TiO, Ti203 and Ti305 also exist. 

Since the development of titania white enamels, the importance of antimony or sodium antimonate as a P/E opacifier for sheet steel has been greatly reduced. Nevertheless, there are still numerous applications where antimony-based white enamels cannot be replaced by titania enamels. 

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