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DE-112016002824-B4 - Cordierite-containing ceramic material, a process for its production, and its use

DE112016002824B4DE 112016002824 B4DE112016002824 B4DE 112016002824B4DE-112016002824-B4

Abstract

Cordierite-containing ceramic material with a classic porcelain appearance, comprising the following components in mass % SiO2 48 to 55.5 Al2O3 ​ 32 to 37 MgO as well as 7.5 to 11.5 K2O 1.5 to 3.0 and/or Na₂O 0.5 to 0.8 and/or Fe2O3 ​ up to 0.6 and which is a composition of 55 - 75 mass-% cordierite, 8 - 16 mass-% mullite, 10-20% corundum as well as a residue of 100% of an X-ray amorphous phase, and which is characterized by a porosity of less than 0.05%, and which is is provided with a glaze containing the following components, which are listed in mass % SiO2 52 to 63 Al2O3 ​ 16 to 30 MgO 5.6 to 12 Na₂O 0.9 to 1.9 K2O 0.7 to 1.7 B2O3 ​ 2.5 to 5.0.

Inventors

  • Rolf H. Frowein

Assignees

  • Java Enterprises Private Ltd.

Dates

Publication Date
20260513
Application Date
20160627
Priority Date
20150625

Claims (7)

  1. Cordierite-containing ceramic material with a classic porcelain appearance, comprising the following components in mass % SiO2 48 to 55.5 Al2O3 ​ 32 to 37 MgOsowie 7.5 to 11.5 K2O 1.5 to 3.0 and/or Na₂O 0.5 to 0.8 and/or Fe2O3 ​ up to 0.6 and which has a composition of 55-75 wt% cordierite, 8-16 wt% mullite, 10-20% corundum and a remainder of 100% an X-ray amorphous phase, and which is characterized by a porosity of less than 0.05%, and which is provided with a glaze containing the following components, which in wt% SiO2 52 to 63 Al2O3 ​ 16 to 30 MgO 5.6 to 12 Na₂O 0.9 to 1.9 K2O 0.7 to 1.7 B2O3 ​ 2.5 to 5.0.
  2. Cordierite-containing ceramic material according to Claim 1 , characterized in that it has a coefficient of thermal expansion at 20°C - 400°C < 2.5 · 10 -6 K -1 .
  3. Cordierite-containing ceramic material according to Claim 2 , characterized in that the glaze has the same or a smaller coefficient of thermal expansion than the material.
  4. Cordierite-containing ceramic material according to one of the preceding claims, characterized in that it has a water absorption of < 0.05 wt%.
  5. Method for producing a cordierite-containing ceramic material with a classic porcelain appearance, characterized in that - a pre-fired material with the components in mass-% Feldspar AKW 900/12 6 to 10 Calcined clay 4.5 to 10 Talc OOS 20 to 33 kaolin 30 to 55 Kaolin fireclay AK45 5 to 12 is mixed with a pre-burned additive as a nucleation for cordierite formation of 0.5 to 5 mass%, the composition of which consists of the components Kaolin 60 to 70% by mass Talc 30 to 40% by mass and contains further trace amounts of Ca, Ti, Se, P below 1 wt%, and the material thus mixed with the additive is subjected to a shaping process with the addition of water and liquefier, - and the demolded, dried and plastered material is annealed in a rapid-firing furnace at 700-1100°C The material is annealed for a period of 3 to 5 hours, - subsequently it is coated with a glaze whose composition consists of the components pre-burned material 50 to 55% by mass Borosilicate glass 20 to 25% by mass kaolin 3 to 11% by mass Calcined clay 2 to 4% by mass Talc OOS 12 to 16% by mass contains.
  6. Procedure according to Claim 5 , characterized in that an induction image is applied to the underside or inside of the cookware and is fired on by rapid firing at a maximum of 860°C and a firing time of 180 min.
  7. Use of a cordierite-containing ceramic material according to one of the Claims 1 - 4 or one according to the procedure of Claims 5 or 6 manufactured cordierite-containing ceramic material as a technical component or as tableware.

Description

The invention relates to a cordierite-containing ceramic material, a method for its production, and its use. Ceramics are used in many areas of technology as hard and durable components. Furthermore, porcelain ceramics are used in the home, among other things, as tableware, especially cookware and eating utensils. These include vessels, plates, pots, pans, etc., for storage, preparation, serving, and consumption, made from materials such as plastic, cardboard, metal, ceramic, glass, wood, stone, and many others. Such porcelain items consist of a wide variety of different materials. These specialized products each fulfill only specific tasks. This means that different products are required in the chain of food storage, preparation, consumption, and waste disposal. For example, it is well known that vessels made of metal or porous ceramic are not suitable for microwave heating. For cooking, steaming, and frying, metals (stainless steel, aluminum, copper, enameled iron) are preferred due to their heat resistance. But here too, attempts are being made to improve performance characteristics with various coatings made of heat-resistant organic materials (Teflon, silicone) or, more recently, with so-called white ceramic coatings. In the realm of dining, classic porcelain and related products such as bone china and vitreous china are still preferred for cultural and hygienic reasons. It is therefore evident that the transfer of food from one item to another occurs. From the DE 196 17 147 A1 It is also known to provide porcelain or ceramics with electrically conductive layers in order to heat the porcelain or ceramics using induction devices, in order to heat food or keep it warm. On the other hand, ceramic and glass-ceramic products are known for their low coefficient of thermal expansion, which allows for the preparation of food to a limited extent. Classic ceramics (including porcelain, bone china, vitreous china, stoneware, and earthenware) have a coefficient of thermal expansion of 5.0 to 7.0 × 10⁻⁶ K⁻¹ . However, their resistance to thermal shock is, at best, only sufficient for the classic oven, and even then, only with appropriate optimization, for cooking food in so-called casserole dishes up to approximately 250 °C. Ceramics with lower coefficients of thermal expansion exist based on cordierite and lithium silicates. US 4 295 892 A Disclosure reveals a ceramic cordierite composite body with a thermal expansion coefficient in the temperature range of 25 to 1000°C of not more than 2.2 · 10 -6 K -1 , consisting mainly of cordierite and 8-20 wt.% spinel, corundum and/or mullite, containing 43-51 wt.% SiO 2 , 35-41 wt.% Al 2 O 3 and 11-16 wt.% MgO. WO 00/30995 A1 Disclosure reveals a sintered ceramic object containing as a crystalline phase 65-95% cordierite and 5-35% mullite, spinel and/or sapphirine, as well as 32-51% SiO₂ , 35-49% Al₂O₃ and 7-16% MgO. The coefficient of thermal expansion in the range of 25 to 1000°C is less than approximately 1.5 × 10⁻⁶ K⁻¹ . US 2014/ 370 232 A1 Disclosing cordierite-containing ceramic composite bodies, containing an aluminum oxide component between 34.9 and 71.8 wt.%, silicon dioxide between 28.2 and 52.0 wt.% and magnesium oxide between 5.0 and 13.8 wt.%. DE 10 2011 005 817 A disclosed solar absorber module containing cordierite, wherein the cordierite contains 30 wt.% to 60 wt.% aluminium oxide, 30 wt.% to 60 wt.% silicon oxide and 1 wt.% to 10 wt.% magnesium oxide. However, the products currently available on the market are only partially suitable. Some ceramics with a relatively low coefficient of thermal expansion of 1.0 to 1.5 × 10⁻⁶ K⁻¹ are porous, have opaque glazes, and therefore do not meet the appearance and basic properties of porcelain ( DE 20 2010 014 638 U1 Various other porcelain-like products achieve average coefficients of thermal expansion of 3.1 × 10⁻⁶ K⁻¹ . Currently available products are intended only for kitchen use in cooking and baking and exhibit premature cracking in the glaze or even the body of the product under higher temperature fluctuations. The instructions for use advise particular caution. From the DE 1 621 026 B A glaze for ceramic bodies with a low linear coefficient of thermal expansion of 1.5 to 2.0 × 10⁻⁶ K⁻¹ is known. This glaze is opaque and has a matte appearance. In summary, it can be stated that no products exist on the market that universally meet all requirements for microwave, gas flame, oven tube, also with grill, ceramic hob and induction hob in the kitchen and for eating. The invention therefore aims to provide a material, in particular a porcelain-like material, that avoids the disadvantages of the prior art and is suitable for broad application both as a technical material and for household use, such as in the kitchen and tableware sector. Furthermore, it should be producible using conventional methods. The invention also aims to provide a ceramic material that is not only break-resistant but also highly resistant to tem