Ceramic heating sheet
Technical Field
The invention relates to the technical field of heatable ceramics, in particular to a ceramic heating sheet with excellent thermal shock property.
Background
Soup cooking is a traditional nutritional diet making method in China, and generally a ceramic pot is needed to cook soup. However, the ceramic pot for cooking soup has a disadvantage that if cold water is added in the middle of cooking soup, cracks may be generated in the pot body.
At present, the electric rice cooker is often used for cooking soup, but the inner pot body is made of metal products and cannot achieve the effect of ceramic soup cooking. If the ceramic pot body is used as the inner container of the electric cooker, the potential safety hazard of easy cracking exists. In addition, the heating plate is arranged at the bottom of the existing electric cooker, the heat transfer performance of the ceramic pot is far inferior to that of a metal pot, the heating efficiency is very low, and the soup cooking time can be greatly delayed.
Disclosure of Invention
In view of the above problems in the prior art, the present applicant provides a ceramic heating sheet. The ceramic heating sheet has excellent heat transfer performance, heat insulating effect, good thermal shock resistance and stable structure in the environment of sudden cooling and sudden heating.
The technical scheme of the invention is as follows:
a ceramic heating sheet is composed of the following raw materials in parts by weight:
al with particle size of 700-800 microns2O3: 40-50 parts;
SiO with particle size of 500-600 microns2: 15-20 parts of a solvent;
CaCO with particle size of 300-400 microns3: 20-25 parts;
ZrO with particle size of 100-200 microns2: 3-8 parts;
si with the particle size of 30-50 microns3N4: 4-7 parts;
y with particle size of 800-1200 nm2O3: 1-3 parts;
AlB with the particle size of 300-500 nm: 1-5 parts;
the particle size of the pretreated graphene is 80-150 nm: 1-3 parts;
the method for pretreating graphene comprises the following steps: the method comprises the steps of adding 6-9% by mass of hydroxyethyl hexahydro-s-triazine and graphene into 1-2 wt% acetone solution, carrying out ultrasonic dispersion for 40-60 minutes under the condition of stirring, and then drying into powder.
Preferably, the ceramic heating sheet is composed of the following raw materials in parts by weight:
al with particle size of 700-800 microns2O3: 45 parts of (1);
SiO with particle size of 500-600 microns2: 17 parts of (1);
CaCO with particle size of 300-400 microns3: 22 parts of (A);
ZrO with particle size of 100-200 microns2: 6 parts of (1);
si with the particle size of 30-50 microns3N4: 3 parts of a mixture;
y with particle size of 800-1200 nm2O3: 2 parts of (1);
AlB with the particle size of 300-500 nm: 3 parts of a mixture;
the particle size of the pretreated graphene is 80-150 nm: and 2 parts.
A preparation method of the ceramic heating sheet comprises the following specific steps:
(1) after all the raw materials are mixed, adding 50-60 wt% of anhydrous ethanol and 15-18 wt% of isobutyl triethoxy silane coupling agent of pretreated graphene, and placing the mixture into a planetary mill for mixing and grinding for 2-3 hours;
(2) carrying out spray granulation on a pasty product obtained after ball milling, and preparing a granulated material into a biscuit with a required shape by adopting an isostatic pressing method;
(3) sintering the biscuit at high temperature of 1450-1480 ℃ for 60-80 minutes;
(4) and then cooling to room temperature at the speed of 12-15 ℃ per minute, keeping the room temperature for 30-40 minutes, then tempering, keeping the room temperature for 30-40 minutes at 580-650 ℃, and then naturally cooling to the room temperature.
The beneficial technical effects of the invention are as follows:
the invention adopts a granularity grading method, so that the prepared ceramic heating body has a microscopic porous shape and very good thermal shock resistance. Generally, the heat transfer performance of the ceramic with the porous structure is poor, but the graphene is added in the invention, so that the influence of the thermal conductivity caused by the porous structure is compensated. Since the graphene is easy to agglomerate and not easy to disperse uniformly without treatment, the graphene is pretreated by the method, so that the graphene is not only good in dispersity, but also uniformly distributed in a ceramic biscuit, and the prepared finished product is uniform in heat transfer and cannot be locally heated.
The ceramic heating sheet prepared by the invention is made into a shape of a pot, a plurality of circles of heating wires are pasted on the outer surface of the pot body by adopting a screen printing or pasting method, and the pot body is put into a heat-preserving and high-temperature-resistant outer sleeve, so that the electric heating ceramic soup cooking pot can be made. Can also be made into a sealed pot body for cooking soup under high pressure. The pot can resist the high-low temperature alternating environment of 0-300 ℃, and is fully sufficient in daily life.
Detailed Description
The present invention will be described in detail with reference to examples.
Example 1
A ceramic heating sheet is composed of the following raw materials in parts by weight: al with particle size of 700-800 microns2O3: 40 portions of(ii) a SiO with particle size of 500-600 microns2: 15 parts of (1); CaCO with particle size of 300-400 microns3: 20 parts of (1); ZrO with particle size of 100-200 microns2: 3 parts of a mixture; si with the particle size of 30-50 microns3N4: 4 parts of a mixture; y with particle size of 800-1200 nm2O3: 1 part; AlB with the particle size of 300-500 nm: 1 part; the particle size of the pretreated graphene is 80-150 nm: 1 part;
the method for pretreating graphene comprises the following steps: hydroxyethyl hexahydro-s-triazine with the mass of 6% of graphene and graphene are added into an acetone solution with the concentration of 1 wt%, and ultrasonic dispersion is carried out for 40 minutes under the condition of stirring, and then the powder is dried. The preparation method of the ceramic heating sheet comprises the following specific steps:
(1) after all the raw materials are mixed, adding anhydrous ethanol with the weight of 50% of the raw materials and isobutyl triethoxy silane coupling agent with the weight of 15% of the pretreated graphene, and putting the mixture into a planetary mill for mixing and grinding for 2 hours;
(2) carrying out spray granulation on a pasty product obtained after ball milling, and preparing a granulated material into a biscuit with a required shape by adopting an isostatic pressing method;
(3) sintering the biscuit at high temperature of 1450 ℃ for 80 minutes;
(4) then cooling to room temperature at a rate of 12 deg.C per minute, tempering after 30 minutes at room temperature, holding at 580 deg.C for 40 minutes, and then naturally cooling to room temperature.
Example 2
A ceramic heating sheet is composed of the following raw materials in parts by weight: al with particle size of 700-800 microns2O3: 45 parts of (1); SiO with particle size of 500-600 microns2: 17 parts of (1); CaCO with particle size of 300-400 microns3: 22 parts of (A); ZrO with particle size of 100-200 microns2: 6 parts of (1); si with the particle size of 30-50 microns3N4: 3 parts of a mixture; y with particle size of 800-1200 nm2O3: 2 parts of (1); AlB with the particle size of 300-500 nm: 3 parts of a mixture; pretreated stone with particle size of 80-150 nmGraphene: and 2 parts.
The method for pretreating graphene comprises the following steps: hydroxyethyl hexahydro-s-triazine with the mass of 8% of graphene is added into an acetone solution with the concentration of 1.5 wt% together with the graphene, ultrasonically dispersed for 50 minutes under the condition of stirring, and then dried into powder. The preparation method of the ceramic heating sheet comprises the following specific steps:
(1) mixing all the raw materials, adding anhydrous ethanol with the weight of 55% of the raw materials and isobutyl triethoxy silane coupling agent with the weight of 17% of the pretreated graphene, and placing the mixture into a planetary mill for mixing and grinding for 2.5 hours;
(2) carrying out spray granulation on a pasty product obtained after ball milling, and preparing a granulated material into a biscuit with a required shape by adopting an isostatic pressing method;
(3) sintering the biscuit at 1460 deg.C for 70 min;
(4) then cooling to room temperature at a rate of 14 ℃ per minute, tempering after holding at room temperature for 35 minutes, holding at 600 ℃ for 35 minutes, and then naturally cooling to room temperature.
Example 3
A ceramic heating sheet is composed of the following raw materials in parts by weight: al with particle size of 700-800 microns2O3: 50 parts of a mixture; SiO with particle size of 500-600 microns2: 20 parts of (1); CaCO with particle size of 300-400 microns3: 25 parts of (1); ZrO with particle size of 100-200 microns2: 8 parts of a mixture; si with the particle size of 30-50 microns3N4: 7 parts; y with particle size of 800-1200 nm2O3: 3 parts of a mixture; AlB with the particle size of 300-500 nm: 5 parts of a mixture; the particle size of the pretreated graphene is 80-150 nm: 3 parts of a mixture;
the method for pretreating graphene comprises the following steps: hydroxyethyl hexahydro-s-triazine with the mass of 9% of graphene and graphene are added into an acetone solution with the concentration of 2 wt%, and ultrasonic dispersion is carried out for 60 minutes under the condition of stirring, and then the powder is dried. The preparation method of the ceramic heating sheet comprises the following specific steps:
(1) after all the raw materials are mixed, adding anhydrous ethanol with the weight of 60% of the raw materials and isobutyl triethoxy silane coupling agent with the weight of 18% of the pretreated graphene, and putting the mixture into a planetary mill for mixing and grinding for 3 hours;
(2) carrying out spray granulation on a pasty product obtained after ball milling, and preparing a granulated material into a biscuit with a required shape by adopting an isostatic pressing method;
(3) sintering the biscuit at high temperature of 1480 ℃ for 60 minutes;
(4) then cooling to room temperature at a rate of 15 ℃ per minute, tempering after holding at room temperature for 40 minutes, holding at 650 ℃ for 30 minutes, and then naturally cooling to room temperature.
Test example:
the ceramic bodies prepared in examples 1 to 3 were subjected to performance tests, and the test results are shown in table 1.
TABLE 1
Performance of
|
Example 1
|
Example 2
|
Example 3
|
Coefficient of thermal conductivity (W.m)-1·K-1)
|
11.5
|
12.9
|
12.1
|
Thermal shock resistance
|
26 cracks
|
32 time cracking
|
29 times of cracking
|
Bending strength (MPa)
|
438
|
465
|
447
|
Fracture toughness (MPa. m)1/2)
|
7.3
|
8.1
|
7.5 |
Remarking: in table 1, the thermal conductivity was measured at 25 ℃; the thermal shock resistance is tested alternately at-10 deg.C to 500 deg.C.