This invention is related to the production of glazes and enamels for decorating glass, glass-ceramic, and ceramic articles. The glass frits suitable therefor exhibit good glass stability, coefficients of thermal expansion (20.degree.-300.degree. C.) between about 65-75.times.10.sup.-7 /.degree.C., demonstrate excellent resistance to attack by acids and bases, and, being essentially free from toxic heavy metals such as lead, are eminently useful in food preparation and service applications. The frit compositions are encompassed within the system Li.sub.2 O--BaO--TiO.sub.2 --ZrO.sub.2 --B.sub.2 O.sub.3 --SiO.sub.2, wherein at least one member of the group consisting of MgO, CaO, ZnO, and Bi.sub.2 O.sub.3, is optionally present. Operable frits are encompassed within the ranges, expressed in weight percent, of:
The present invention refers to glass-ceramics consisting of the mixtures (I): ZrO.sub.2 --SiO.sub.2 --Me.sup.II O, or (II) SiO.sub.2 --Me.sup.III O.sub.2 --Me.sup.II O, wherein: Me.sup.II is chosen in the group consisting of: Ca, Ba, Mg, Zn or mixture thereof; Me.sup.III is chosen in the group consisting of Al, B or mixtures thereof; each of the above said constituents being present in determined quantities; the invention refers also to a process for preparing the glass-ceramics above defined; porcelain stonewares and glazes containing them and their use for preparing ceramic items.
This invention relates to the production of frits especially suitable for use in contact with foods. The frits are essentially free from cadmium and lead and consist essentially, in weight percent on the oxide basis, of: Li.sub.2 O: 3-4 Na.sub.2 O: 0.75-3 BaO: 3.5-9.5 B.sub.2 O.sub.3 : 14-17.5 Al.sub.2 0.sub.3 : 6.75-8.75 SiO.sub.2 : 48-55 ZrO.sub.2 : 6.75-10.5 F: 3-4.
The present invention relates to the production of lead-free glasses exhibiting densities of at least 2.9 g/cm.sup.3 and refractive indices of at least 1.545 which consist essentially, in weight percent, of
Glass frits containing lithium are used in thick film palladium-silver compositions which after firing result in conductors or resistors that exhibit very low resistivity and TCR.
A lead-free frit suitable for use on aluminum, consisting essentially of: The frit has a fusion temperature below about 1050.degree. F. and displays good qualities of gloss, acid resistance, and adhesion.
