EP0452065A1
Expired / Lapsed
EP
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Glaze compositions
Assignee: Vesuvius Holdings Ltd
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Filing: 1991-04-08
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Granted: —
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Expires: 2011-04-08
Abstract
Abstract Glaze composition for use on bone china and fine china which is essentially free from lead and cadium comprises, by weight, SiO₂:35 to 60%, Bi₂O₃: 5 to 45%, Al₂O₃:5 to 20%, B₂O₃:1 to 15%, at least one of CaO, MgO, SrO or BaO:2 to 20%, at least one of Li₂O, Na₂O, K₂O:1 to 10%, and certain other optional ingredients, with the proviso that BaO is not contained in an amount of more than 2% by weight.
Inventors
- 👤 John Francis Of Burnhouse Clifford
- 👤 Ivan Of 7 Checkley Grove Wozniak
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 20:32
CPC Classifications
C; C03; C03C; C03C3/00; C03C3/04; C03C3/062; C03C3/064; C03C3/076; C03C3/089; C03C3/091; C03C8/00; C03C8/02
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
168 words
A glaze composition for use on bone china and fine china which is essentially free from lead and cadmium and which comprises the following components: SiO₂ 35 to 60% Bi₂O₃ 5 to 45% Al₂O₃ 5 to 20% B₂O₃ 1 to 15% at least one of CaO, MgO, SrO or BaO 2 to 20% at least one of Li₂O, Na₂O, K₂O 1 to 10% TiO₂ 0 to 10% ZrO₂ 0 to 10% SnO 0 to 10% Nb₂O₅ 0 to 5% Ta₂O₅ 0 to 5% Sb₂O₃ 0 to 5% a rare earth oxide 0 to 10% ZnO 0 to 10% P₂O₅ 0 to 10% MoO₃ and/or WO₃ 0 to 5% fluoride ions 0 to 5% all percentages being percentages by weight based on the total weight of the composition, with the proviso that BaO is not contained in an amount of more than 2% by weight, the glaze composition having a firing temperature of 1100°C ± 40°C, and having a coefficient of thermal expansion of 50 to 90 x 10⁻⁷°C⁻¹.
Claim 2
Dependent Claim
18 words
A glaze composition as claimed in claim 1 which comprises from 10 to 25% by weight of Bi₂O₃.
Claim 3
Dependent Claim
21 words
A glaze composition as claimed in claim 1 or claim 2 which comprises from 45 to 60% by weight of SiO₂.
Claim 4
Dependent Claim
22 words
A glaze composition as claimed in any one of the preceding claims which comprises from 7 to 15% by weight of Al₂O₃.
Claim 5
Dependent Claim
22 words
A glaze composition as claimed in any one of the preceding claims which comprises from 4 to 10% by weight of B₂O₃.
Claim 6
Dependent Claim
33 words
A glaze composition as claimed in any one of the preceding claims which fires at a temperature range of from 1060° to 1140°C and which has a refractive index of at least 1.45.
Claim 7
Dependent Claim
15 words
A glaze as claimed in any of the preceding claims which additionally contains a pigment.
Claim 8
Independent Claim
41 words
A method of glazing a ceramic body, which method comprises coating a ceramic body with a glaze composition as claimed in any one of the preceding claims and firing the coated ceramic body at a glazing temperature of 1100°C ± 40°C.
Claim 9
Dependent Claim
17 words
A method as claimed in claim 8 wherein the ceramic body is bone china or fine china.
Claim 10
Dependent Claim
20 words
A method as claimed in claim 8 or claim 9 wherein the ceramic body is coated by dipping or spraying.
Claim 11
Dependent Claim
20 words
Bone china or fine china whenever glazed by a method as claimed in any one of claims 8 to 10.
References Cited (Backward Citations)
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