阅读说明：本技术 一种电加热电阻浆料及其制备方法和应用 (Electrical heating resistance paste and preparation method and application thereof ) 是由 杜兆富 袁礼新 曹迪 叶书群 于 2020-11-30 设计创作，主要内容包括：本发明公开了一种电加热电阻浆料及其使用方法和应用。所述电阻浆料按质量百分比计,其组成包括：微米量级的电阻粉体、银粉、玻璃粉、有机载体和助剂。所述电加热电阻浆料通过丝网印刷到多孔莫来石(氧化铝)基板上,在950℃-1100℃高温烧结,形成电加热电阻膜层,电阻膜层根据需要设计成不同的电阻图形。通电后,电阻膜层迅速发热并将热量传递给基板,从而将穿过基板为液体升温。本电阻浆料适用于厚膜电阻器,加热温度在500℃以下的热水壶或其它需要给液体加热的领域。本发明提供的电加热电阻浆料与多孔莫来石(氧化铝)基板具有良好的附着力、耐热振冲击、不含重金属,具有成本低,无环境污染,制备工艺简单等优点。(The invention discloses an electric heating resistance paste and a using method and application thereof. The resistance paste comprises the following components in percentage by mass: micron-level resistance powder, silver powder, glass powder, an organic carrier and an auxiliary agent. The electric heating resistance paste is printed on a porous mullite (alumina) substrate through screen printing, and is sintered at the high temperature of 950-1100 ℃ to form an electric heating resistance film layer, and the resistance film layer is designed into different resistance patterns according to the requirement. After power is applied, the resistive film layer rapidly heats and transfers heat to the substrate, thereby heating the liquid passing through the substrate. The resistance paste is suitable for thick film resistors, hot water kettles with the heating temperature below 500 ℃ or other fields needing to heat liquid. The electric heating resistance slurry and the porous mullite (alumina) substrate have the advantages of good adhesive force, heat shock resistance, no heavy metal, low cost, no environmental pollution, simple preparation process and the like.)

1. An electrically heated resistor paste, characterized in that it comprises, in mass percent:

70-82% of resistance powder;

0-8% of silver powder;

0.5 to 5 percent of glass powder;

8-18% of organic carrier;

0-2% of auxiliary agent.

2. The electrically heated resistor paste of claim 1 wherein the resistor powder is selected from one or more of nichrome powder, nichrome-manganese-silicon alloy powder, and kovar powder;

preferably, the particle size of the resistance powder is 0.1-5 microns.

3. The electrically heated resistor paste according to claim 1, wherein said silver powder is flake-shaped;

preferably, the thickness of the silver powder is 100-500 nm.

4. An electrically heated resistive paste according to claim 1, wherein said glass frit is a calborosilicate series glass frit having a difference in coefficient of thermal expansion from kovar alloy in the range of 5% to 10%;

preferably, the particle size of the glass powder is 1-15 microns.

5. An electrically heated resistive paste according to claim 1, wherein the organic carrier is selected from at least three of terpineol, butyl carbitol acetate, ethylene glycol ethyl ether acetate, cetyl alcohol, ethyl cellulose, castor oil and methyl ethyl ketone.

6. The electrically heated resistive paste of claim 1, wherein the additive is selected from one or more of a silane coupling agent, tributyl phosphate, lecithin, and fish oil.

7. A method for preparing an electrically heated resistive paste according to any one of claims 1 to 6, comprising the steps of:

weighing the components in proportion, mixing uniformly and grinding to obtain the composition;

alternatively, the first and second electrodes may be,

weighing the components in proportion; respectively mixing glass powder and part of organic carriers uniformly to prepare slurry 1; uniformly mixing the resistance powder with part of the organic carrier to prepare slurry 2; uniformly mixing silver powder, an auxiliary agent and the rest of organic carriers to prepare slurry 3; then, the electrically heated resistive paste was composed of paste 1, paste 2, and paste 3.

8. Use of an electrically heated resistive paste according to any of claims 1 to 6 for the preparation of a resistive film layer.

9. Use according to claim 8, characterized in that it comprises the following steps:

weighing the components in proportion, uniformly mixing and grinding to obtain electric heating resistance paste, then printing the electric heating resistance paste on a porous mullite substrate through a screen printing process, and sintering to obtain the mullite ceramic substrate.

10. Use according to claim 8, characterized in that it comprises the following steps:

weighing the components in proportion; respectively mixing glass powder and part of organic carriers uniformly to prepare slurry 1; uniformly mixing the resistance powder with part of the organic carrier to prepare slurry 2; uniformly mixing silver powder, an auxiliary agent and the rest of organic carriers to prepare slurry 3; then printing the slurry 1 on a porous mullite substrate through a screen printing process to form a glass layer with a required pattern; after drying and sintering, printing the slurry 2 on a glass layer through a screen printing process to form a resistance layer; after drying, printing the slurry 3 on a resistance layer through a screen printing process to form a silver layer, and drying and sintering to obtain the silver-coated printed circuit board;

preferably, the line width of the glass layer is greater than the line width of the resistance layer;

preferably, the thickness of the silver layer is less than 1/5 times the thickness of the resistive layer;

preferably, the mass percentage of the silver powder and the auxiliary agent in the slurry 3 is 78-85%.

Technical Field

The invention relates to the field of resistance paste, in particular to electric heating resistance paste and a preparation method and application thereof.

Background

The electronic paste is a composite material formed by combining conductor particles, inorganic non-metal particles, organic carrier liquid and related dispersing agents, coating agents, auxiliary agents and the like. Aiming at different application scenes and specific requirements, various subdivided varieties are developed, such as conductor slurry, resistance slurry, high-temperature sintering, medium-temperature sintering and low-temperature sintering slurry. The method is widely applied to electronic components such as thick film integrated circuits, piezoresistors, thin film switches, sensitive components and the like. The development of solar cells and the field of electronic information drives the development of the electronic paste industry. The electric heating resistance paste is mainly used for the aspects of heat management of resistors, water heaters, chemical industry, various products and the like. At present, the research on the domestic resistance paste used in the civil field is relatively few. The application of the resistance paste is especially lacking in the fields of consumer-grade household appliances and large-scale chemical industry, where a large amount of liquid needs to be uniformly heated. Reasons include many aspects, such as the high cost of raw materials such as silver, ruthenium oxide, etc.; the resistor is not well combined with the substrate and is easy to fall off; the resistor contains elements such as lead which are harmful to human bodies or pollute the environment. Therefore, it has become an important problem to be solved to manufacture a low-cost paste for domestic electric heating resistors, which does not contain lead and has good performance.

Disclosure of Invention

A first object of the present invention is to provide an electrically heated resistor paste.

The second purpose of the invention is to provide a preparation method of the electric heating resistance paste

A third object of the invention is to provide a use of the electrically heated resistive paste.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides an electrically heated resistor paste, which comprises, by mass:

70-82% of resistance powder;

0-8% of silver powder;

0.5 to 5 percent of glass powder;

8-18% of organic carrier;

0-2% of auxiliary agent.

Further, the resistance powder is selected from one or more of nichrome powder, nichrome manganese silicon alloy powder or Kovar alloy (Kovar alloy) powder; the grain diameter of the resistance powder is 0.1-5 microns.

The silver powder is flake-shaped, according to the specific embodiment of the invention, the thickness of the flake-shaped silver powder is 100-500 nm,

the average diameter of the flake silver powder is 1-5 microns.

The glass powder is calcium borosilicate series glass powder with the difference of the thermal expansion coefficient of the kovar alloy between 5 and 10 percent. According to a particular embodiment of the invention, the glass frit has a particle size of 1 to 15 microns.

The organic carrier is selected from at least three of terpineol, butyl carbitol acetate, ethylene glycol ethyl ether acetate, cetyl alcohol, ethyl cellulose, castor oil and butanone. According to a specific embodiment of the invention, the organic carrier is prepared from the following components in percentage by mass: 15-25% of terpineol, 17-27% of butyl carbitol, 13-23% of butyl carbitol acetate, 1-5% of ethylene glycol ethyl ether acetate, 2-8% of cetyl alcohol, 2-8% of ethyl cellulose, 5-15% of castor oil and 2-8% of butanone.

The auxiliary agent is selected from one or more of silane coupling agent, tributyl phosphate, lecithin and fish oil.

The electric heating resistance paste provided by the invention adopts the specific resistance powder and reasonably mixes the components, so that the use amount of the silver powder is less than 10%, even the silver can be omitted, the production cost is greatly saved, the oxidation resistance of the resistor is effectively improved, the migration of silver ions in a matrix is slowed down, and the service life of the resistor is prolonged.

In a second aspect, the present invention provides a method for preparing an electrically heated resistor paste, comprising the steps of:

weighing the components in proportion, mixing uniformly and grinding to obtain the composition;

alternatively, the first and second electrodes may be,

weighing the components in proportion; respectively mixing glass powder and part of organic carriers uniformly to prepare slurry 1; uniformly mixing the resistance powder with part of the organic carrier to prepare slurry 2; uniformly mixing silver powder, an auxiliary agent and the rest of organic carriers to prepare slurry 3; then, the electrically heated resistive paste was composed of paste 1, paste 2, and paste 3.

In a third aspect, the invention provides an application of an electrically heated resistor paste in preparing a resistor film layer.

The first method, preparing a resistance film layer, comprises the following steps:

weighing the components in proportion, uniformly mixing and grinding to obtain electric heating resistance paste, then printing the electric heating resistance paste on a porous mullite substrate through a screen printing process, and sintering to obtain the mullite ceramic substrate.

Preferably, the sintering temperature is 950-1100 ℃. The sintering temperature referred to herein is only the temperature at the high temperature stage of the sintering process, since the binder removal temperature, the glass melting temperature, etc. also need to be considered in a particular sintering process.

The other method for preparing the resistance film layer comprises the following steps:

uniformly mixing the resistance powder with part of the organic carrier to prepare slurry 2; uniformly mixing silver powder, an auxiliary agent and the rest of organic carriers to prepare slurry 3; then printing the slurry 1 on a porous mullite substrate through a screen printing process to form a glass layer with a required pattern; after drying and sintering, printing the slurry 2 on a glass layer through a screen printing process to form a resistance layer; and after drying, printing the slurry 3 on a resistance layer through a screen printing process to form a silver layer, and drying and sintering to obtain the silver-coated printed circuit board.

Further, in the above method, in the resistance film layer, the line width of the glass layer is greater than the line width of the resistance layer.

The thickness of the silver layer is less than 1/5 of the thickness of the resistive layer.

The particle size of the glass powder in the slurry 1 is 5-15 microns.

The mass percentage of the silver powder and the auxiliary agent in the paste 3 is 78-85%, namely the sum of the silver powder and the auxiliary agent accounts for 78-85% of the mass percentage of the paste 3.

The sintering conditions include, but are not limited to, sintering in vacuum or hydrogen blanket.

The first method is that the electric heating resistance paste is mixed evenly and is printed on a porous mullite (alumina) substrate through a screen printing process, and then the porous mullite (alumina) substrate is sintered to obtain the electric heating resistance paste, in the whole process, glass powder can naturally sink due to melting and gravity action, and finally a resistor is formed on the upper layer, and the structure of glass on the lower layer is formed, namely the resistance film layer of the thick film resistor is actually a layered structure; the second method is that the slurry 1 containing glass powder is printed on a porous mullite (alumina) substrate to obtain a glass layer, the slurry 2 containing resistance powder is printed on the glass layer, and finally the slurry 3 containing silver powder is printed on a resistance layer, wherein the silver layer can prevent the resistance layer from being oxidized.

The invention has the following beneficial effects:

the electric heating resistance paste provided by the invention is printed on a porous mullite (alumina) substrate through screen printing, and after high-temperature sintering, an electric heating resistance film layer is formed, and the resistance film layer is designed into different resistance patterns according to requirements.

The resistance paste provided by the invention is suitable for thick film resistors and is used for a hot water kettle with the heating temperature below 500 ℃ or other fields needing to heat liquid.

The electric heating resistance slurry provided by the invention has good adhesive force and heat shock resistance with a porous mullite (alumina) substrate, so that an electric heater element for uniformly heating liquid, which is suitable for household appliances or chemical industry, is prepared. The electric heating resistance slurry has the advantages of low cost, no harmful elements, no environmental pollution, good matching effect with porous mullite, long service life and simple preparation process.

The consumption of silver in the electric heating resistance paste is less than 10%, so that the production cost is saved to a great extent, the electric conductivity of the film layer can be increased, and the migration of silver ions is effectively slowed down.

The electric heating resistance paste provided by the invention has the advantages that the resistance value of the paste resistance is adjusted by changing the content of the silver powder and the type of the resistance powder, and the use is more flexible.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 shows a physical diagram of a resistance pattern printed on porous mullite by the electrically heated resistance paste of example 1 of the present invention.

Fig. 2 is a schematic view showing the operation of the electrically heated resistive paste of example 5 of the present invention for use in the preparation of a resistive film layer; (a) a schematic diagram showing slurry 1 printing a glass layer on a porous mullite substrate; (b) a schematic diagram of the paste 3 printing a resistor pattern on a resistor layer is shown.

Detailed Description

In order to make the technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Example 1

Firstly, preparing electric heating resistance slurry by adopting the components and the weight percentages of the components shown in the table 1

1. Preparation of organic Carrier liquid

Putting all organic matters into a reaction kettle according to the mass percentage shown in the table 2, uniformly stirring, heating to 80 ℃, continuously stirring for 2 hours to form uniform transparent liquid, and then cooling to room temperature.

2. Resistance paste homogenate

Adding the auxiliary agent into the organic carrier liquid according to the mass percentage shown in the table 1, stirring for 0.5 hour, then weighing the organic carrier liquid, the resistance powder, the calcium-boron-silicon glass powder and the flake silver powder, placing the organic carrier liquid, the resistance powder, the calcium-boron-silicon glass powder and the flake silver powder into a stirring container for homogenizing, keeping the mixture at 900r/min for 30s, keeping the mixture at 1500r/min for 30s, and keeping the mixture at 1200r/min for 20.

3. Resistor paste grinding

And (4) carrying out three-roll grinding on the primarily mixed slurry until the fineness of the slurry is less than 10 mu m.

Application of electric heating resistor paste in preparation of aluminum-based thick film resistor

The obtained resistance paste is directly printed with a 400-micron wide and 45-millimeter long resistance graph on a porous mullite substrate through screen printing, the temperature rise rate is increased to 800 ℃ at the speed of 5 ℃/min in the hydrogen protective atmosphere, the temperature is maintained for 30min, then the temperature is increased to 1100 ℃, the temperature is maintained for 30min, sintering is carried out, and furnace cooling is carried out. The resulting resistance pattern had a thickness of 80 μm, as shown in FIG. 1. The resistance value of the obtained electric heating resistor was 3.5 Ω.

Example 2

The technical scheme is basically the same as that of the example 1, except that the raw materials are calculated and weighed according to the corresponding proportion of the example 2 shown in the table 1-2, and other conditions and operation methods are the same as those of the example 1. The resistance value of the obtained electric heating resistor was 5.2 Ω.

Example 3

The technical scheme is basically the same as that of the example 1, except that the raw materials are calculated and weighed according to the corresponding proportion of the example 3 shown in the table 1-2, and other conditions and operation methods are the same as those of the example 1. The resistance value of the obtained electric heating resistor was 5.5 Ω.

Example 4

The technical scheme is basically the same as that of the example 1, except that the raw materials are calculated and weighed according to the corresponding proportion of the example 4 shown in the table 1-2, and other conditions and operation methods are the same as those of the example 1. The resistance value of the obtained electric heating resistor was 4.0 Ω.

As can be seen from examples 1 and 4, the resistance value of the resistance pattern can be changed by changing the content of the silver powder and the type of the resistance powder, that is, the powder ratio and the powder type of the resistance paste can be flexibly adjusted as needed.

TABLE 1 formulation parameters for each of the components of examples 1-4

TABLE 2 examples 1-4 formulation parameters for organic carrier liquids

In examples 1 to 4, the particle size distribution D50 of the nichrome powder, the nichrome-manganese-silicon alloy powder, or the Kovar alloy powder (Kovar alloy) was 0.5 to 4 μm; the particle size distribution D50 of the flake silver powder is 2-5 microns; the softening temperature of the calcium borosilicate glass powder is 700-850 ℃, the particle size distribution D50 is 1-5 microns, and the auxiliary agent is lecithin.

Example 5

Firstly, preparing electric heating resistance paste:

1. preparing an organic carrier liquid: the organic vehicle formulation and method of example 1 was used;

2. weighing the components according to the formula proportion in the embodiment 1, and uniformly mixing the glass powder and the organic carrier according to the proportion shown in the table 3 to obtain slurry 1; uniformly mixing the resistance powder and the organic carrier to obtain slurry 2; uniformly mixing silver powder, an auxiliary agent and an organic carrier to obtain slurry 3; the paste 1, the paste 2, the paste 3 and the paste 4 constitute resistance paste.

Secondly, the application of the electrical heating resistance paste in the preparation of the aluminum-based thick film resistor:

1. slurry 1 was printed on a porous mullite substrate: the width is 500 μm, the thickness is 40 μm, as shown in fig. 2(a), drying, and sintering at 830 deg.C to obtain a glass layer;

2. the paste 2 is printed with a resistance layer on the glass layer, the width is 400 μm, the thickness is 60 μm, and the glass layer is dried at 150 ℃;

3. and printing a silver layer with the width of 400 mu m and the thickness of 5 mu m on the resistance layer by using the paste 3, drying the silver layer as shown in figure 2(b), and sintering the silver layer at 1100 ℃ in a hydrogen protective atmosphere to obtain the conductive paste.

The resistance value of the resulting electric heating resistor was 3 Ω. Through the thermal vibration at 0-500 ℃, the thermal vibration resistance of the embodiment 5 is 1.5 times that of the embodiment 1, and the thermal vibration resistance is increased.

And (3) testing the adhesive force: after the product obtained in this example was subjected to temperature increase and decrease (i.e., thermal vibration) for 200 times, the resistor did not crack and did not separate from the substrate.

TABLE 3 formulation parameters for glass, nickel chromium and silver pastes

It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and it will be obvious to those skilled in the art that other variations or modifications may be made on the basis of the above description, and all embodiments may not be exhaustive, and all obvious variations or modifications may be included within the scope of the present invention.