| Faults found with various types of chrome greens
and the methods of obviating them. |
K. N. MADHAVA PANICKER, B. A.,
Pages : 76-78
DOI : 10.1080/0371750X.1946.10877798 |
| Abstract |
| The stable oxide which imparts the various Rreen
shades iq pottery colours and g-lazes is chromium
oxide, Cr20 8 • Potassium dichromate is also used in
green colour recipes. It gives a better mixing beingsoluble,
and in the process of manufacturing- the g-reen
colours the soluble potassium salts are removed by
washing-. Although Cr203 gives its characteristic
gret!n colours of various shades, the green colour can
be completely altered or spoiled by other ing-redients
present in the colour or tbe glaze, and also by the
indiscriminate process of firing these colours. Chromium
oxide gives a bright g-reen with lime but if barium
oxide is present in the colour, it changes to yellow
brown. Coppec oxide with Cr.Oa gives blue green,
all these substances forming the respP.ctive chromates.
But these chromates are ·not stable above easy glost
temperature and so some of them can only be used
in on-glaze colours. Chromium oxide itself when
calcined is extremely inert and refractory. |
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