| 摘要 |
<p>903,135. Enamel pigments. ASSOCIATED LEAD MANUFACTURERS Ltd., and JAMIESON, H. D. March 21, 1961 [April 25, 1960], No. 14420/60. Class 56. A pigment for incorporation in glazes for ceramics consists of a calcined mixture of the following ingredients in parts by weight zircon 10 to 20; tin oxide 5 to 10; whiting 3 to 10; and potassium dichromate 0.5 to 1.0. The zircon, tin oxide and whiting in powdered form are mixed and a solution of potassium dichromate added to form a paste which is dried. The sieved mixture is calcined at 1100-1400‹ C. for an hour, washed with dilute mineral acid such as HCI, then with water, dried and recalcined at 1100-1400‹ C. for an hour. The pigment is added as a mill addition of about 6% by weight to a zinc-free glaze to give a clear red or pink colour. A suitable glaze is given, in mols.: sodium and potassium oxide together 0.3; calcium oxide 0.4; barium oxide 0.3; boric oxide 0.6; alumina 0.35 and silica 3.5.</p> |
