Preparation method of conductive material for ruthenium resistance paste

Abstract

The invention discloses a preparation method of a conductive material for ruthenium resistance paste. The method comprises the following steps: 1, adding a lead salt solution into a ruthenium salt solution at a constant temperature, and then adding ammonium chloride to obtain a mixed solution; 2, carrying out spray drying treatment on the mixed solution, and calcining and decomposing to obtain precursor powder; 3, mixing the precursor powder with zirconium oxide balls, adding deionized water and a dispersing agent, carrying out ball milling, washing, filtering and drying to obtain dispersed powder; and 4, calcining and decomposing the dispersed powder again, mixing the obtained powder with zirconium oxide balls, and carrying out ball milling to obtain lead ruthenate powder. According to the method, mixing and dispersing of ruthenium and lead on the nanoscale are achieved through atomization drying treatment, the dispersed sphere-like powder morphology is obtained, powder agglomeration in the calcination decomposition process is reduced, the dispersity and particle size distribution uniformity of the lead ruthenate powder are improved, the method is suitable for preparation of the resistance paste, the technology is simple, the yield is high, and the method is suitable for industrial production. The industrial production is easy.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic paste powder preparation, and in particular relates to a method for preparing a conductive material for ruthenium-based resistor paste. Background Art

[0002] In the electronics industry, resistor paste is a key material for manufacturing electronic components such as resistors and capacitors. Ruthenium-based resistor pastes with ruthenium dioxide and its ruthenate series as functional phases have been rapidly developed due to their good process repeatability, wide resistance range, and high resistance stability. They have become the most widely used thick film resistor paste on the market today and are widely used in electronic devices, thermistors, and other fields. Among them, lead ruthenate is a cubic pyrochlore compound that is resistant to strong acids, has good chemical stability and thermal stability, and has a relatively large positive resistance temperature coefficient. It plays an important role in the production of high resistance thick film resistor pastes.

[0003] At present, there are two methods for preparing lead ruthenate powder: solid phase synthesis and liquid phase synthesis. The solid phase synthesis method generally prepares lead ruthenate powder by directly calcining a mixed powder of ruthenium oxide powder and lead oxide powder. The preparation process requires strict control of the atmosphere and temperature, and it is difficult to achieve uniform mixing of different elements in the calcined powder, and the powder agglomerates seriously. The liquid phase synthesis method can obtain lead ruthenate powder of various particle sizes by adjusting preparation parameters such as feed rate, reaction concentration, reaction temperature, dispersant type and concentration. The process is simple, but there are problems such as difficulty in solid-liquid separation and uneven particle size. In addition, there are many influencing factors after amplification, it is difficult to control, the batch is unstable, and it is difficult to mass produce. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a conductive material for ruthenium-based resistor paste in view of the shortcomings of the above-mentioned prior art. The method adopts atomization drying treatment to achieve mixing and dispersion of ruthenium and lead at the nanometer level, thereby obtaining a dispersed spherical powder morphology, reducing the agglomeration of the powder during the subsequent calcination and decomposition process, improving the dispersibility and particle size distribution uniformity of the lead ruthenate powder, being suitable for the preparation of resistor paste, and solving the problems of serious agglomeration, uneven particle size and difficult process control of the powder prepared by the prior method.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing a conductive material for ruthenium-based resistor paste, characterized in that the method comprises the following steps:

[0006] Step 1: under constant temperature conditions, add a lead salt solution to a ruthenium salt solution, then add ammonium chloride and stir to obtain a mixed solution;

[0007] Step 2: The mixed solution obtained in step 1 is subjected to atomization drying treatment by atomization drying equipment, and then placed in a high-temperature tube furnace for calcination and decomposition to obtain a precursor powder;

[0008] Step 3: Mix the precursor powder obtained in step 2 with zirconium oxide balls, then add deionized water and a dispersant for ball milling, and obtain dispersed powder after washing, filtering and drying;

[0009] Step 4: The dispersed powder obtained in step 3 is placed in a high-temperature tube furnace again for calcination and decomposition. The obtained powder is mixed with zirconium oxide balls and then ball-milled. The lead ruthenate powder, i.e., the conductive material for ruthenium-based resistor slurry, is obtained by sieving.

[0010] The above-mentioned method for preparing a conductive material for ruthenium-based resistor paste is characterized in that the ruthenium salt solution in step 1 is prepared by dissolving ruthenium chloride in deionized water, and the concentration of the ruthenium salt solution is 1wt% to 5wt%.

[0011] The above-mentioned method for preparing a conductive material for ruthenium-based resistor paste is characterized in that the lead salt solution in step 1 is prepared by dissolving at least one of lead chloride, lead acetate and lead acetate in deionized water, and the concentration of the lead salt solution is 1wt% to 5wt%.

[0012] The above-mentioned method for preparing a conductive material for ruthenium-based resistor paste is characterized in that the temperature of the constant temperature condition in step one is 60°C to 90°C, the volume ratio of the ruthenium salt solution to the lead salt solution is 1:1, and the ratio of the mass of ammonium chloride to the total mass of lead ions and ruthenium ions is 1:1 to 1:3.

[0013] The above-mentioned method for preparing a conductive material for ruthenium-based resistor paste is characterized in that the temperature of the calcination and decomposition in step 2 is 400° C. to 500° C., and the insulation time is 0.5 h to 1 h.

[0014] The above-mentioned method for preparing a conductive material for ruthenium-based resistor slurry is characterized in that the dispersant in step three is at least one of oleic acid, lecithin, lauric acid, triethanolamine, and Tween-80, and the concentration of the dispersant in deionized water is 0.5wt% to 5wt%.

[0015] The above-mentioned method for preparing a conductive material for ruthenium-based resistor paste is characterized in that the temperature of the calcination and decomposition in step 4 is 600° C. to 800° C., and the insulation time is 2 h to 4 h.

[0016] The above-mentioned method for preparing a conductive material for ruthenium-based resistor paste is characterized in that the lead ruthenate powder in step 4 is spherical and has a particle size of 0.2 μm to 1 μm. The lead ruthenate powder with the above-mentioned properties obtained by the present invention has suitable viscosity and good fluidity after being prepared into resistor paste, and is easy to use.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The present invention subjects the mixed solution of ruthenium and lead to atomization drying treatment, thereby achieving the mixing and dispersion of the two different elements of ruthenium and lead at the nanometer level, ensuring that the precursor powder obtained by calcination and decomposition has a dispersed spherical powder morphology, and realizing instantaneous drying of the solution in a high-temperature drying chamber, thereby avoiding the disadvantage that the traditional drying method causes the powder to be easily agglomerated, thereby greatly reducing the hydrogen bonding force between the grains of the subsequent dispersed powder during dehydration during the calcination and decomposition process, effectively reducing the agglomeration of the powder, obtaining a powder without obvious agglomeration, and improving the dispersibility and particle size distribution uniformity of the lead ruthenate powder.

[0019] 2. Compared with directly calcining in one step to obtain the target product, the present invention adopts the process of calcination-ball milling-recalcination-ball milling, which effectively reduces the residual intermediates and is conducive to further optimization of the crystal structure and physical properties of lead ruthenate powder.

[0020] 3. In the ball milling process of the present invention, by adding a dispersant, the dispersibility of the ball milling product is effectively improved, and the adhesion between particles is effectively prevented during the calcination and decomposition process. It will be oxidatively decomposed at the high temperature of calcination and decomposition without residue, and has no effect on the components of the calcination and decomposition product.

[0021] 4. The preparation method of the present invention has simple process, high yield, and is easy for industrial production. The prepared lead ruthenate powder has good dispersibility and uniform particle size distribution, and can be used for the preparation of resistor slurry.

[0022] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a flow chart of the method for preparing the conductive material for the ruthenium-based resistor paste.

[0024] Figure 2 This is the XRD pattern of the lead ruthenate powder prepared in Example 1 of the present invention.

[0025] Figure 3 This is a SEM image of the lead ruthenate powder prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0026] Example 1

[0027] like Figure 1 As shown, this embodiment includes the following steps:

[0028] Step 1, weighing ruthenium chloride and lead chloride and adding them to deionized water respectively to prepare a ruthenium salt solution with a concentration of 3wt% and a lead salt solution with a concentration of 3wt%, then adding the lead salt solution to the ruthenium salt solution at a volume ratio of 1:1 under a constant temperature condition of 90°C, and then adding ammonium chloride at a ratio of the mass of ammonium chloride to the total mass of lead ions and ruthenium ions of 1:1 and stirring and mixing to obtain a mixed solution;

[0029] Step 2: The mixed solution obtained in step 1 is subjected to atomization drying treatment by atomization drying equipment, and then placed in a high-temperature tube furnace for calcination and decomposition at a temperature of 400° C. for a holding time of 0.5 h to obtain a precursor powder;

[0030] Step 3: Mix the precursor powder obtained in step 2 with zirconium oxide balls, then add deionized water and dispersant oleic acid for ball milling for 30 minutes, and the concentration of the dispersant is 4wt%, and then wash, filter and dry to obtain dispersed powder;

[0031] Step 4: Place the dispersed powder obtained in step 3 in a high-temperature tube furnace again for calcination and decomposition at a temperature of 750°C for 2 hours. The obtained powder is mixed with zirconium oxide balls and ball-milled for 30 minutes. Lead ruthenate powder, i.e., conductive material for ruthenium-based resistor slurry, is obtained by sieving.

[0032] The particle size (D50) of the lead ruthenate powder prepared in this embodiment is 0.26 μm, and the specific surface area is 14.7 m 2 / g, the shape is spherical.

[0033] Figure 2 The XRD pattern of the lead ruthenate powder prepared in this example is as follows: Figure 2 It can be seen that the characteristic peak is between RuO2 and PbO, which matches well with the standard card, indicating that lead ruthenate crystalline powder is generated.

[0034] Figure 3 This is the SEM image of the lead ruthenate powder prepared in this example. Figure 3 It can be seen that the lead ruthenate powder has a spherical microstructure and good dispersibility.

[0035] The lead salt in this embodiment can also be at least one of lead chloride, lead acetate, and lead acetate other than lead chloride; the dispersant can also be at least one of oleic acid, lecithin, lauric acid, triethanolamine, and Tween-80 other than oleic acid.

[0036] Example 2

[0037] like Figure 1 As shown, this embodiment includes the following steps:

[0038] Step 1, weighing ruthenium chloride and lead acetate and adding them to deionized water respectively to prepare a ruthenium salt solution with a concentration of 5wt% and a lead salt solution with a concentration of 5wt%, then adding the lead salt solution to the ruthenium salt solution at a volume ratio of 1:1 at a constant temperature of 90°C, then adding ammonium chloride at a ratio of the mass of ammonium chloride to the total mass of lead ions and ruthenium ions of 1:2 and stirring and mixing, then adding 10g of ammonium chloride and stirring and mixing to obtain a mixed solution;

[0039] Step 2: The mixed solution obtained in step 1 is subjected to atomization drying treatment by atomization drying equipment, and then placed in a high-temperature tube furnace for calcination and decomposition at a temperature of 400° C. for a holding time of 1 h to obtain a precursor powder;

[0040] Step 3: Mix the precursor powder obtained in step 2 with zirconium oxide balls, then add deionized water and dispersant lauric acid for ball milling for 30 minutes, and the concentration of the dispersant is 4wt%, and then wash, filter and dry to obtain dispersed powder;

[0041] Step 4: Place the dispersed powder obtained in step 3 in a high-temperature tube furnace again for calcination and decomposition at a temperature of 750°C for 2 hours. The obtained powder is mixed with zirconium oxide balls and ball-milled for 30 minutes. Lead ruthenate powder, i.e., conductive material for ruthenium-based resistor slurry, is obtained by sieving.

[0042] The particle size (D50) of the lead ruthenate powder prepared in this embodiment is 0.32 μm, and the specific surface area is 12.5 m 2 / g, the shape is spherical.

[0043] Example 3

[0044] like Figure 1 As shown, this embodiment includes the following steps:

[0045] Step 1, weighing ruthenium chloride and lead acetate and adding them to deionized water respectively to prepare a ruthenium salt solution with a concentration of 5wt% and a lead salt solution with a concentration of 5wt%, then adding the lead salt solution to the ruthenium salt solution at a volume ratio of 1:1 at a constant temperature of 80°C, and then adding ammonium chloride at a ratio of the mass of ammonium chloride to the total mass of lead ions and ruthenium ions of 1:3 and stirring and mixing to obtain a mixed solution;

[0046] Step 2: The mixed solution obtained in step 1 is subjected to atomization drying treatment by atomization drying equipment, and then placed in a high-temperature tube furnace for calcination and decomposition at a temperature of 500° C. for a holding time of 1 h to obtain a precursor powder;

[0047] Step 3: Mix the precursor powder obtained in step 2 with zirconium oxide balls, then add deionized water and dispersant Tween-80 for ball milling for 30 minutes, and the concentration of the dispersant is 5wt%, and then wash, filter and dry to obtain dispersed powder;

[0048] Step 4: Place the dispersed powder obtained in step 3 in a high-temperature tube furnace again for calcination and decomposition at a temperature of 800°C for 4 hours. The obtained powder is mixed with zirconium oxide balls and ball-milled for 30 minutes. After screening, lead ruthenate powder is obtained, i.e., conductive material for ruthenium-based resistor slurry.

[0049] The particle size (D50) of the lead ruthenate powder prepared in this embodiment is 0.43 μm, and the specific surface area is 10.6 m 2 / g, the shape is spherical.

[0050] Example 4

[0051] like Figure 1 As shown, this embodiment includes the following steps:

[0052] Step 1, weighing ruthenium chloride and lead acetate and adding them to deionized water respectively to prepare a ruthenium salt solution with a concentration of 1wt% and a lead salt solution with a concentration of 1wt%, then adding the lead salt solution to the ruthenium salt solution at a volume ratio of 1:1 at a constant temperature of 60°C, and then adding ammonium chloride at a ratio of the mass of ammonium chloride to the total mass of lead ions and ruthenium ions of 1:1.5 and stirring to obtain a mixed solution;

[0053] Step 2: The mixed solution obtained in step 1 is subjected to atomization drying treatment by atomization drying equipment, and then placed in a high-temperature tube furnace for calcination and decomposition at a temperature of 500° C. for a holding time of 1 h to obtain a precursor powder;

[0054] Step 3: Mix the precursor powder obtained in step 2 with zirconium oxide balls, then add deionized water and dispersant oleic acid lecithin for ball milling for 30 minutes, and the concentration of the dispersant is 0.5wt%, and then wash, filter and dry to obtain dispersed powder;

[0055] Step 4: Place the dispersed powder obtained in step 3 in a high-temperature tube furnace again for calcination and decomposition at a temperature of 600°C for 4 hours. The obtained powder is mixed with zirconium oxide balls and ball-milled for 30 minutes. Lead ruthenate powder, i.e., conductive material for ruthenium-based resistor slurry, is obtained by sieving.

[0056] The particle size (D50) of the lead ruthenate powder prepared in this embodiment is 0.17 μm, and the specific surface area is 16.2 m 2 / g, the shape is spherical.

[0057] Example 5

[0058] like Figure 1 As shown, this embodiment includes the following steps:

[0059] Step 1, weighing ruthenium chloride and lead acetate and adding them to deionized water to prepare a ruthenium salt solution with a concentration of 2wt% and a lead salt solution with a concentration of 2wt%, then adding the lead salt solution to the ruthenium salt solution at a volume ratio of 1:1 at a constant temperature of 70°C, and then adding ammonium chloride at a ratio of the mass of ammonium chloride to the total mass of lead ions and ruthenium ions of 1:2 and stirring to obtain a mixed solution;

[0060] Step 2: The mixed solution obtained in step 1 is subjected to atomization drying treatment by atomization drying equipment, and then placed in a high-temperature tube furnace for calcination and decomposition at a temperature of 450° C. for a holding time of 0.5 h to obtain a precursor powder;

[0061] Step 3: Mix the precursor powder obtained in step 2 with zirconium oxide balls, then add deionized water and dispersant triethanolamine for ball milling for 30 minutes, and the concentration of the dispersant is 3wt%, and then wash, filter and dry to obtain dispersed powder;

[0062] Step 4: Place the dispersed powder obtained in step 3 in a high-temperature tube furnace again for calcination and decomposition at a temperature of 650°C for 3 hours. The obtained powder is mixed with zirconium oxide balls and ball-milled for 30 minutes. Lead ruthenate powder, i.e., conductive material for ruthenium-based resistor slurry, is obtained by sieving.

[0063] The particle size (D50) of the lead ruthenate powder prepared in this embodiment is 0.19 μm, and the specific surface area is 15.8 m 2 / g, the shape is spherical.

[0064] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a conductive material for ruthenium-based resistor paste, characterized in that: The method comprises the following steps: Step 1: under constant temperature conditions, add a lead salt solution to a ruthenium salt solution, then add ammonium chloride and stir to obtain a mixed solution; Step 2: The mixed solution obtained in step 1 is subjected to atomization drying treatment by atomization drying equipment, and then placed in a high-temperature tube furnace for calcination and decomposition to obtain a precursor powder; Step 3: Mix the precursor powder obtained in step 2 with zirconium oxide balls, then add deionized water and a dispersant for ball milling, and obtain dispersed powder after washing, filtering and drying; Step 4: The dispersed powder obtained in step 3 is placed in a high-temperature tube furnace again for calcination and decomposition. The obtained powder is mixed with zirconium oxide balls and then ball-milled. The lead ruthenate powder, i.e., the conductive material for ruthenium-based resistor slurry, is obtained by sieving.

2. The method for preparing a conductive material for ruthenium-based resistor paste according to claim 1, characterized in that: The ruthenium salt solution in step 1 is prepared by dissolving ruthenium chloride in deionized water, and the concentration of the ruthenium salt solution is 1wt% to 5wt%.

3. The method for preparing a conductive material for ruthenium-based resistor paste according to claim 1, characterized in that: The lead salt solution in step 1 is prepared by dissolving at least one of lead chloride, lead acetate and lead acetate in deionized water, and the concentration of the lead salt solution is 1wt% to 5wt%.

4. The method for preparing a conductive material for ruthenium-based resistor paste according to claim 1, characterized in that: The temperature of the constant temperature condition in step 1 is 60° C. to 90° C., the volume ratio of the ruthenium salt solution to the lead salt solution is 1:1, and the ratio of the mass of the ammonium chloride to the total mass of the lead ions and the ruthenium ions is 1:1 to 1:

3.

5. The method for preparing a conductive material for ruthenium-based resistor paste according to claim 1, characterized in that: The calcination and decomposition temperature in step 2 is 400° C. to 500° C., and the insulation time is 0.5 h to 1 h.

6. The method for preparing a conductive material for ruthenium-based resistor paste according to claim 1, characterized in that: The dispersant in step three is at least one of oleic acid, lecithin, lauric acid, triethanolamine, and Tween-80, and the concentration of the dispersant in deionized water is 0.5wt% to 5wt%.

7. The method for preparing a conductive material for ruthenium-based resistor paste according to claim 1, characterized in that: The calcination and decomposition temperature in step 4 is 600° C. to 800° C., and the insulation time is 2 h to 4 h.

8. The method for preparing a conductive material for ruthenium-based resistor paste according to claim 1, characterized in that: The lead ruthenate powder in step 4 is spherical and has a particle size of 0.2 μm to 1 μm.

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