Abstract: A glaze composition for refractory materials includes 30 to 80% by weight of at least one lead-free and barium-free borosilicate, borophosphate or phosphate glass frit having a dilatometric softening point of below 600.degree. C.; 2 to 30% by weight of aluminium powder or an aluminium alloy powder; 2 to 30% by weight of silicon powder or silicon alloy powder, up to 10% by weight of an inhibitor; and optionally a refractory filler, a clay or other additives. The glaze composition is of particular use as a glaze for carbon containing refractory materials such as submerged entry nozzles and graphite electrodes.

Abstract: A pigmentary material comprises silver in a lattice of crystalline zirconia, which material contains at least 0.4% by weight of the silver. A process for preparing a pigmentary material comprising silver in a lattice of crystalline zirconia comprises calcining a zirconium component which yields the zirconia, and a silver component which yields the silver, forming a calcination mixture of the resultant zirconium and silver moieties and cooling the mixture, the weight of fluoride compound in the total weight of the components to be calcined being less than 6%.

Abstract: A glass composition which is essentially free of lead and cadmium includes 30 to 70 wt % SiO.sub.2, 1 to 25 wt % B.sub.2 O.sub.3, 0 to 10 wt % Al.sub.2 O.sub.3, 0 to 5 wt % Bi.sub.2 O.sub.3, 0.1 to 30 wt % CoO, 0.1 to 20 wt % ZnO, 1 to 30 wt % total of at least one of Li.sub.2 O, Na.sub.2 O or K.sub.2 O, up to 10 wt % ZrO.sub.2 and other optional ingredients. The glass composition can be used as a blue colored on-glaze enamel which relies upon the presence of Co.sup.2+ in a network-forming position in the glass to produce the blue color, with oxygen donors such as ZnO.sub.2, alkaline earth oxides and alkali oxides increasing the amount of cobalt occupying network-forming positions, and ZrO.sub.2 to provide chemical durability.

Abstract: An on-glaze low expansion glass flux composition suitable for coating onto a glazed surface which is essentially free from lead and cadmium and comprises, in mole percent, SiO.sub.2 : 35 to 75%, Bi.sub.2 O.sub.3 : 4 to 12%, Al.sub.2 O.sub.3 : 2 to 12%, B.sub.2 O.sub.3 : 18 to 35%, at least one of Li.sub.2 O, Na.sub.2 O, K.sub.2 O : 0 to 12% (in total), and certain other optional ingredients with the provisos that BaO is not contained in an amount of more than 2 mole percent, the total amount of Bi.sub.2 O.sub.3 +B.sub.2 O.sub.3 +Li.sub.2 O,Na.sub.2 O and K.sub.2 O is in the range of from 25 to 45 mole percent, the total amount of Li.sub.2 O, Na.sub.2 O and K.sub.2 O is in the range of up to 10 percent by weight except when the only alkali metal oxide present is Li.sub.2 O, and the composition has a coefficient of thermal expansion in the range of from 4.0 to 7.0.times.10.sup.-6 /.degree.C.