Ferro Corporation

Clifford G Ruderer

Robert C Stroup

Gordon J Roberts

George C Korn

Hasan B Emlemdi

This invention relates to a lead-free glass coating made by firing a lead-free glass enamel composition comprising a glass frit having by weight from about 20% to about 40% zinc oxide, from about 20% to about 32% boron oxide, and from about 10% to about 30% silicon dioxide, from about 0% to about 12% titanium dioxide, from about 4% to about 12% sodium oxide, from about 0% to about 10% potassium oxide, from about 0% to about 12% zirconia, up to about 4% alumina, up to about 5% lithium and up to about 5% fluorine. The lead-free glass coating exhibits excellent adhesion and improved acid resistance.

Lead-free glass coatings

The present invention provides a method of producing an enamel finish on formed section of glass. The enamel composition partially crystallizes upon heating, thereby helping to prevent the forming and handling equipment from sticking and/or adhering to the composition during the forming operation. The enamel composition includes a crystallizable glass frit portion and a seed powder. The crystallized glass frit portion includes precursors from which Zn.sub.2 SiO.sub.4 can be crystallized upon firing of the enamel composition. The seed powder causes at least a portion of the precursors to crystallize upon firing such that during firing at least a part of the crystallizable glass frit yields crystallized Zn.sub.2 SiO.sub.4 formed by the precursors. Preferably, the precursors comprise ZnO and SiO.sub.2, and the seed powder comprises crystalline Zn.sub.2 SiO.sub.4. The enamel composition also preferably includes bismuth oxide (Bi.sub.2 O.sub.3) in order to help further ensure that no sticking and/or adhering problems develop during the forming operation.

Method of forming glass having a Zn.sub.z SiO.sub.4 enamel layer thereon

The present invention provides a new and useful enamel composition and method of using the same for producing an enamel finish on a formed section of glass. The enamel composition partially crystallizes upon heating, thereby helping to prevent the forming and handling equipment from sticking and/or adhering to the composition during the forming operation. The enamel composition includes a crystallizable glass frit portion and a seed powder. The crystallized glass frit portion includes precursors from which Zn.sub.2 SiO.sub.4 can be crystallized upon firing of the enamel composition. The seed powder causes at least a portion of the precursors to crystallize upon firing such that during firing at least a part of the crystallizable glass frit yields crystallized Zn.sub.2 SiO.sub.4. The enamel composition also preferably includes bismuth oxide (Bi.sub.2 O.sub.3) in order to help further ensure that no sticking and/or adhering problems develop during the forming operation.

Crystallizing enamel composition and method of making and using the same

The present invention provides a new and useful composition and method of using the same for producing an enamel finish on a formed section of glass. The composition partially crystallizes upon heating, thereby helping to prevent the forming and handling equipment from sticking and/or adhering to the composition during the forming operation. The composition includes a crystallizable glass frit and seed powder. The crystallized glass frit includes precursors from which Zn.sub.2 SiO.sub.4 can be crystallized upon firing of the composition. The seed powder causes at least a portion of the precursors to crystallize upon firing such that during firing at least a portion of the crystallizable glass frit yields crystallized Zn.sub.2 SiO.sub.4 formed by the precursors. Preferably, the precursors contain 30-75 wt %/5-20 wt % SiO.sub.2, and the seed powder contains crystalline Zn.sub.2 SiO.sub.4.

Partially crystallizing enamel containing Zn.sub.2 SiO.sub.4 to be used

A process is disclosed for preparing an iron workpiece containing at least 0.03% by weight carbon for a direct-on, one-fire ceramic or enamel coat. A substantially continuous layer of substantially pure iron is pressure-bonded onto a surface of the carbon-rich iron workpiece. Thereafter, the workpiece and bonded iron layer are placed in an electroconducting liquid medium and, while using the workpiece as an anode, some of the deposited iron is electrolytically removed to produce an exposed, fissured, textured surface in the pure iron layer. When a ceramic coat is conventionally applied over the fissured surface, it adheres well, even though the iron workpiece may contain appreciable amounts of carbon which normally prevent such adherence for a direct-on ceramic coat. Optionally, the pressure-bonded layer may be followed by an electrodeposit of a porous, substantially pure iron layer prior to applying a ceramic coat.

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Pittsburgh, PA, United States of America

Clifford G Ruderer