Range of low lead release onglaze purple colours

Citation

(1999), "Range of low lead release onglaze purple colours", Pigment & Resin Technology, Vol. 28 No. 3. https://doi.org/10.1108/prt.1999.12928cad.011

Range of low lead release onglaze purple colours

Range of low lead release onglaze purple colours

Keywords Colour, Glazes, Heraeus

Heraeus has enlarged the purple range of low lead release onglaze colours of the series H64. The range includes two new base blue types, three different cobalt blue shades as well as two blue violet colour mixes. All colours of the purple range are said to be especially colour intensive and easy to past and print, because of the small grain size distribution. Fired decorations are distinguished by their brilliance as well as by a high mechanical and chemical durability. Their lead release values are stated to lie well under the limits of DIN 51032.

Colours of the series H64 are produced for a firing range of 780 (1,436) up to 880°C (1616°F) and are suitable for the decoration of porcelain, bone china, earthenware and tiles. The small and even grinding of the onglaze purple colours secure a small grain size distribution from batch to batch. Besides the excellent pasting- and printing characteristics, it contributes to a high colour intensity of all colours in the range.

According to Heraeus, special attention deserves to be given to the new intensive blue shades, royal blue H64195 and cobalt blue H64196. Even a double printing with a 325 mesh steel screen, makes cobalt decorations possible. H64014 and H64115 are two base blue types, for mixes with the purple colours or black H64888. With them, colour shades from cobalt blue to violet are mixable.

It is reported that in tests of Heraeus the new blue shades showed a good acetic acid durability and withstood 1,000 washing cycles in a household dishwasher without visible attack, as with all colours of the series H64. Therefore all colours deserve the predicate, dishwasher resistant.

Heraeus states that the determined lead release values of test decorations, fired at 850°C (1562°F), lay under 0,1 mg/dm², the cadmium release values under 0,0002mg/dm². These results fall well under the limits set by DIN 51032.

For firing temperatures of 780 (1436) up to 880°C (1616°F), colours of the series H64 are especially suitable for modern fast firing. A short firing cycle at high temperatures, influences the mechanical and chemical durability positively and minimizes the heavy metal release.

Further details from W.C. Heraeus GmbH, Ceramic Colours Department. Tel: +49 (0) 6181 35 5337; Fax: +49 (0) 6181 35 9603; E-mail: klaus.abt@europe.heraues.com