Preparation method and application of submicron spherical gold-platinum-palladium alloy powder for matching low-temperature co-fired ceramic

Abstract

The invention belongs to the technical field of precious metal electronic paste, and particularly relates to a preparation method and application of submicron spherical gold-platinum-palladium alloy powder used for being matched with low-temperature co-fired ceramics. The preparation method comprises the following steps: mixing a tetrachloroauric acid solution, a hexachloroplatinic acid solution and a tetrachloropalladium (II) acid solution to obtain a gold-platinum-palladium mixed solution; the gold-platinum-palladium mixed solution, the dispersing agent solution and the modified reducing agent solution are mixed for a second time, after a reduction reaction is conducted, static settlement and solid-liquid separation are conducted in sequence, obtained solids are washed and dried in sequence, and the obtained submicron spherical gold-platinum-palladium alloy powder used for being matched with the low-temperature co-fired ceramic has the advantages of being uniform in particle size, free of agglomeration, high in dispersity and the like. After low-temperature co-firing with a ceramic substrate, the substrate has the characteristics of flatness, no bubble, excellent weldability and soldering resistance, good batch stability and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of precious metal electronic pastes, and in particular relates to a preparation method and application of submicron spherical gold-platinum-palladium alloy powder for matching low-temperature co-fired ceramics. Background Art

[0002] In recent years, with the rapid development of aerospace, communication technology and artificial intelligence technology, the requirements for multifunctionality, high reliability and high integration of electronic components have been increasingly strengthened. The substrate made by low temperature co-fired ceramic (LTCC) has the functions of IC chip packaging, embedded passive components and high-density circuit assembly, and has become an important manufacturing technology for many electronic products. Gold platinum palladium paste is used as a solderable paste in LTCC due to its excellent solderability, solder resistance and reliability. Metal materials play a vital role in the welding process, and solderable gold platinum palladium paste is a welding metal material with excellent performance. The key technology lies in the preparation of the conductive phase. Considering the technical indicators of low temperature co-fired ceramics, it is necessary to prepare a conductive phase with flat powder and good welding performance to meet the technical requirements. At present, the preparation of submicron-grade irregular morphology gold, platinum and palladium powder mainly includes: Chinese patent CN117773140A discloses a method for atomizing and drying a gold, platinum and palladium mixed solution precursor, wherein precursor particles are obtained by atomizing and drying, and then heat-treated to prepare gold, platinum and palladium composite powder. The composite powder prepared by this method has a low degree of alloying, and its weldability and weld resistance are average. Chinese CN116117146A discloses the preparation of gold, platinum and palladium alloy powder by ball milling the metal mixed powder, then performing an alkali dissolution and drying treatment, and finally performing furnace annealing. The powder prepared by this method has a larger particle size, and mainly prepares spherical micron-grade gold, platinum and palladium powder, but its batch stability is poor. Summary of the invention

[0003] In view of this, the purpose of the present invention is to provide a preparation method and application of submicron spherical gold, platinum and palladium alloy powder for matching low-temperature co-fired ceramics. The submicron spherical gold, platinum and palladium alloy powder for matching low-temperature co-fired ceramics prepared by this method has the characteristics of uniform particle size and non-agglomeration. After low-temperature co-firing with a ceramic substrate, the substrate is flat and free of bubbles, and has excellent weldability and weld resistance, good batch stability, and can be used as a conductive phase in a weldable gold, platinum and palladium slurry for matching low-temperature co-fired ceramics.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] The present invention provides a method for preparing submicron spherical gold-platinum-palladium alloy powder for matching low-temperature co-fired ceramics, comprising the following steps:

[0006] first mixing a tetrachloroauric acid solution, a hexachloroplatinic acid solution and a tetrachloropalladium (II) acid solution to obtain a gold-platinum-palladium mixed solution;

[0007] The gold, platinum and palladium mixed solution, the dispersant solution and the modified reducing agent solution are mixed for a second time, and after a reduction reaction, static precipitation and solid-liquid separation are carried out in sequence. The obtained solid is washed and dried in sequence to obtain a submicron spherical gold, platinum and palladium alloy powder for matching low-temperature co-fired ceramics.

[0008] Preferably, the mass ratio of gold, platinum and palladium in the gold-platinum-palladium mixed solution is 1:0.6-0.7:0.1-0.3.

[0009] Preferably, the dispersant includes one or more of polyethylene glycol, polyvinyl pyrrolidone, polypropylene alcohol, dodecyl acetic acid, sodium dodecylbenzene sulfonate, sodium octanoate, ethyl cellulose and gum arabic.

[0010] Preferably, the method for preparing the modified reducing agent solution comprises: adding a stabilizer solution to a reducing agent solution under stirring, and continuing stirring to perform modification to obtain a modified reducing agent solution.

[0011] Preferably, the stabilizer includes one or more of p-methoxyphenol, sodium chloride, zinc chloride, zinc ricinoleate, alanine and histidine.

[0012] Preferably, the reducing agent includes one or more of catechol, sodium borohydride, potassium borohydride, hydroxyethyl mercaptan, ferrous sulfate, sodium sulfite, ascorbic acid and sodium citrate.

[0013] Preferably, the second mixing is: under stirring, first adding the dispersant solution to the gold, platinum and palladium mixed solution, adjusting the pH value of the resulting reaction solution to 2-2.5 and controlling the temperature of the resulting reaction solution to 30±0.5°C, and then dripping the modified reducing agent solution into the resulting reaction solution.

[0014] Preferably, the ratio of the mass of the dispersant to the total mass of gold, platinum and palladium in the gold-platinum-palladium mixed solution is 1 to 10:100.

[0015] Preferably, the temperature of the reduction reaction is 30±0.5°C; and the time of the reduction reaction is 60 to 360 minutes.

[0016] The present invention also provides the use of submicron spherical gold-platinum-palladium alloy powder prepared by the preparation method described in the above technical solution as a conductive phase in a weldable gold-platinum-palladium slurry for matching low-temperature co-fired ceramics.

[0017] The invention provides a preparation method of submicron spherical gold-platinum-palladium alloy powder for matching low-temperature co-fired ceramics. The method comprises the following steps: firstly mixing a tetrachloroauric acid solution, a hexachloroplatinic acid solution and a tetrachloropalladium (II) acid solution to obtain a gold-platinum-palladium mixed solution; secondly mixing the gold-platinum-palladium mixed solution, a dispersant solution and a modified reducing agent solution, performing a reduction reaction, sequentially performing static precipitation and solid-liquid separation, and sequentially washing and drying the obtained solid to obtain the submicron spherical gold-platinum-palladium alloy powder for matching low-temperature co-fired ceramics.

[0018] The present invention has the following characteristics:

[0019] 1. The present invention increases the surface activity of the gold-platinum-palladium alloy powder during the reduction process by adding a dispersant, so that the gold-platinum-palladium alloy powder can be evenly dispersed in the solution, which can effectively prevent its precipitation and aggregation in the solution, and also improves the slurryability and stability of the gold-platinum-palladium alloy powder in the process of preparing the slurry.

[0020] 2. The present invention can restrict the reaction rate of gold ions, platinum ions and palladium ions by adding a stabilizer, avoid the direct formation of a single crystal nucleus, and obtain alloyed powder by a step-by-step layered reaction, thereby improving the degree of gold-platinum-palladium alloying, while also improving the welding performance of the gold-platinum-palladium alloy powder and controlling the stability of the morphology.

[0021] 3. The submicron spherical gold-platinum-palladium alloy powder prepared by the present invention for matching low-temperature co-fired ceramics has the characteristics of uniform particle size and no agglomeration, and the particle size ranges from 100 to 800 nm.

[0022] 4. The gold-platinum-palladium alloy powder prepared by the above method of the present invention has good dispersibility in organic reagents, excellent slurry formation in the powder slurry making process, can match a variety of domestic raw porcelain materials, the substrate is flat and free of bubbles after sintering, has excellent weldability and weld resistance, good batch stability, and can be applied to low-temperature co-fired ceramic systems.

[0023] 5. The preparation method of the present invention is simple, the operation process is highly controllable, the product reliability is excellent, and mass production can be carried out. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a scanning electron microscope photograph of the submicron spherical gold-platinum-palladium alloy powder prepared in Example 1 for matching low-temperature co-fired ceramics;

[0025] Figure 2 This is a scanning electron microscope photograph of the submicron spherical gold-platinum-palladium alloy powder prepared in Example 2 for matching low-temperature co-fired ceramics;

[0026] Figure 3This is a scanning electron microscope photograph of the submicron spherical gold-platinum-palladium alloy powder prepared in Example 3 for matching low-temperature co-fired ceramics;

[0027] Figure 4 This is a scanning electron microscope photograph of the submicron spherical gold-platinum-palladium alloy powder prepared in Example 4 for matching low-temperature co-fired ceramics;

[0028] Figure 5 This is a scanning electron microscope photograph of the submicron spherical gold-platinum-palladium alloy powder prepared in Example 5 for matching low-temperature co-fired ceramics;

[0029] Figure 6 This is a scanning electron microscope photograph of the gold-platinum-palladium alloy powder prepared in Comparative Example 1;

[0030] Figure 7 This is a scanning electron microscope photograph of the gold-platinum-palladium alloy powder prepared in Comparative Example 2;

[0031] Figure 8 This is a scanning electron microscope photograph of the gold-platinum-palladium alloy powder prepared in Comparative Example 3;

[0032] Fig. 9 This is a test diagram of the weldability of the gold-platinum-palladium slurry used in Example 1 for preparing weldable gold-platinum-palladium slurry and matching the ceramic substrate after low-temperature co-firing;

[0033] Fig.10 This is a test diagram of the weldability of comparative example 1 after preparing weldable gold-platinum-palladium slurry and matching it with a ceramic substrate after low-temperature co-firing. DETAILED DESCRIPTION

[0034] The present invention provides a method for preparing submicron spherical gold-platinum-palladium alloy powder for matching low-temperature co-fired ceramics, comprising the following steps:

[0035] first mixing a tetrachloroauric acid solution, a hexachloroplatinic acid solution and a tetrachloropalladium (II) acid solution to obtain a gold-platinum-palladium mixed solution;

[0036] The gold, platinum and palladium mixed solution, the dispersant solution and the modified reducing agent solution are mixed for a second time, and after a reduction reaction, static precipitation and solid-liquid separation are carried out in sequence. The obtained solid is washed and dried in sequence to obtain a submicron spherical gold, platinum and palladium alloy powder for matching low-temperature co-fired ceramics.

[0037] Unless otherwise specified, the present invention has no special requirements on the sources of the raw materials used in the preparation, and commercially available products known to those skilled in the art can be used.

[0038] The invention first mixes a tetrachloroauric acid solution, a hexachloroplatinic acid solution and a tetrachloropalladium (II) acid solution to obtain a gold-platinum-palladium mixed solution.

[0039] In the present invention, the concentration of the tetrachloroauric acid (HAuCl4) solution is preferably 0.8-1.5 mol / L, more preferably 1 mol / L; the preparation method of the tetrachloroauric acid solution preferably includes: dissolving gold powder with aqua regia, removing nitric acid and excess hydrochloric acid in the resulting solution, and then adding deionized water to adjust the concentration of the solution; the purity of the gold powder is preferably 99.99%.

[0040] In the present invention, the concentration of the hexachloroplatinic acid (H2PtCl6) solution is preferably 0.6-1.2 mol / L, more preferably 1 mol / L; the preparation method of the hexachloroplatinic acid solution preferably comprises: dissolving platinum powder with aqua regia, removing nitric acid and excess hydrochloric acid in the resulting solution, and then adding deionized water to adjust the concentration of the solution; the purity of the platinum powder is preferably 99.99%.

[0041] In the present invention, the concentration of the tetrachloropalladium (II) acid (H2PdCl4) solution is preferably 1-2 mol / L, more preferably 1 mol / L; the preparation method of the tetrachloropalladium (II) acid solution preferably comprises: dissolving palladium powder with aqua regia, removing nitric acid and excess hydrochloric acid in the obtained solution, and then adding deionized water to adjust the concentration of the solution; the purity of the palladium powder is preferably 99.99%.

[0042] In the present invention, the mass ratio of gold, platinum and palladium in the gold-platinum-palladium mixed solution is preferably 1:0.6-0.7:0.1-0.3, and more preferably 1:0.7:0.15.

[0043] After obtaining the gold-platinum-palladium mixed solution, the present invention preferably secondly mixes the gold-platinum-palladium mixed solution, the dispersant solution and the modified reducing agent solution to perform a reduction reaction.

[0044] In the present invention, the dispersant preferably includes one or more of polyethylene glycol, polyvinyl pyrrolidone, polypropylene alcohol, dodecyl acetic acid, sodium dodecylbenzene sulfonate, sodium octanoate, ethyl cellulose and gum arabic, and is more preferably polyvinyl pyrrolidone or polyethylene glycol; the preparation method of the solution of the dispersant preferably includes: dissolving the dispersant in deionized water; the ratio of the mass of the dispersant to the total mass of gold element, platinum element and palladium element in the gold-platinum-palladium mixed solution is preferably 1 to 10:100, and more preferably 2 to 5:100.

[0045] In the present invention, the method for preparing the modified reducing agent solution preferably comprises: adding the solution of the stabilizer to the solution of the reducing agent under stirring, continuing to stir for modification, and obtaining the modified reducing agent solution. In the present invention, the stabilizer preferably comprises one or more of p-methoxyphenol, sodium chloride, zinc chloride, zinc ricinoleate, alanine and histidine, more preferably sodium chloride or alanine; the method for preparing the solution of the stabilizer preferably comprises: dissolving the stabilizer in deionized water. In the present invention, the reducing agent preferably comprises one or more of catechol, sodium borohydride, potassium borohydride, hydroxyethyl mercaptan, ferrous sulfate, sodium sulfite, ascorbic acid and sodium citrate, more preferably ascorbic acid or sodium sulfite; the method for preparing the solution of the reducing agent preferably comprises: dissolving the reducing agent in deionized water; the concentration of the reducing agent solution is preferably 0.8 to 2 mol / L, more preferably 1 mol / L. In the present invention, the stirring rate is preferably 50-200 r / min, more preferably 100-150 r / min; the modification time is preferably 10-30 min, more preferably 15 min; the modification temperature is preferably 40-60°C, more preferably 50±0.5°C; the ratio of the mass of the stabilizer in the raw materials for preparing the modified reducing agent solution to the total mass of gold, platinum and palladium in the gold-platinum-palladium mixed solution is preferably 5-10:100, more preferably 10:100; the total molar ratio of the reducing agent in the raw materials for preparing the modified reducing agent solution and the gold, platinum and palladium in the gold-platinum-palladium mixed solution is preferably 1-2:1, more preferably 1.5:1.

[0046] In the present invention, the second mixing is preferably: under stirring, first adding the dispersant solution to the gold, platinum and palladium mixed solution, adjusting the pH value of the resulting reaction solution to 2-2.5 and controlling the temperature of the resulting reaction solution to 30°C, and then dripping the modified reducing agent solution into the resulting reaction solution; the stirring rate is preferably 50-100r / min, more preferably 100r / min; the reagent used to adjust the pH value of the resulting reaction solution is preferably hydrochloric acid solution or sodium hydroxide solution; the concentration of the hydrochloric acid solution is preferably 0.1-1mol / L, more preferably 0.1-0.5mol / L; the concentration of the sodium hydroxide solution is preferably 0.1-1mol / L, more preferably 0.1-0.5mol / L; the temperature of the resulting reaction solution is preferably controlled by a low-temperature water bath; the dripping rate is preferably 0.5-2mL / s, more preferably 1-1.5mL / s.

[0047] The present invention increases the surface activity of the gold-platinum-palladium alloy powder by adding a dispersant, so that the gold-platinum-palladium alloy powder can be evenly dispersed in a solution, which can effectively prevent the gold-platinum-palladium alloy powder from precipitating and aggregating in the solution, and also improves the slurry-forming property and stability in the process of preparing a slurry using the gold-platinum-palladium alloy powder.

[0048] The present invention maintains the pH value in the reaction process by adding a stabilizer, thereby promoting the reduction reaction to proceed stably, and improving the product effect and reliability of the gold-platinum-palladium alloy powder while controlling the generation of the gold-platinum-palladium alloy powder morphology.

[0049] In the present invention, the temperature of the reduction reaction is preferably 25-35°C, more preferably 30±0.5°C; the time of the reduction reaction is preferably 60-360min, more preferably 180-240min; the reduction reaction is preferably carried out under stirring; the stirring rate is preferably 200-400r / min, more preferably 200-300r / min.

[0050] After the reduction reaction is completed, the present invention sequentially subjects the product obtained from the reduction reaction to static precipitation and solid-liquid separation, and sequentially washes and dries the obtained solid to obtain a submicron spherical gold-platinum-palladium alloy powder for matching low-temperature co-fired ceramics.

[0051] In the present invention, the static precipitation time is preferably 6 to 24 hours, more preferably 12 to 24 hours; the washing is preferably washing with deionized water and washing with anhydrous ethanol in sequence; the number of washings with deionized water is preferably 3 to 7 times, more preferably 5 times; the number of washings with anhydrous ethanol is preferably 2 to 4 times, more preferably 2 times; the drying temperature is preferably 60 to 75°C, more preferably 75°C; the drying time is preferably 18 to 24 hours, more preferably 24 hours.

[0052] The present invention washes the powder with anhydrous ethanol to remove organic impurities and fat-soluble substances on the precipitate, thereby achieving the purpose of purification.

[0053] The present invention prevents the produced gold-platinum-palladium alloy powder from agglomerating through drying treatment, which helps to improve the dispersibility of the gold-platinum-palladium alloy powder in slurry making.

[0054] In the present invention, the particle size of the submicron spherical gold-platinum-palladium alloy powder used to match the low-temperature co-fired ceramic is preferably 100-800 nm, more preferably 300-500 nm.

[0055] The submicron spherical gold-platinum-palladium alloy powder for matching low-temperature co-fired ceramics prepared by the present invention has the characteristics of uniform particle size and no agglomeration. After low-temperature sintering with ceramics, the substrate is flat and free of bubbles, and it has excellent weldability and weld resistance, and good batch stability. It can be used as a conductive phase of a weldable gold-platinum-palladium slurry for matching low-temperature co-fired ceramics.

[0056] The present invention also provides the use of the submicron spherical gold-platinum-palladium alloy powder prepared by the preparation method described in the above technical solution as a conductive phase in a weldable gold-platinum-palladium slurry for matching low-temperature co-fired ceramics.

[0057] The present invention has no special limitation on the application of the submicron spherical gold-platinum-palladium alloy powder as a conductive phase in a weldable gold-platinum-palladium slurry for matching low-temperature co-fired ceramics, and any application method known in the art may be used.

[0058] The technical solutions of the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention, but they should not be construed as limiting the protection scope of the present invention.

[0059] The deionized water and other chemical reagents used in the following examples of the present invention were of analytical grade.

[0060] Example 1

[0061] Use aqua regia to dissolve 55g of gold powder with a purity of 99.99%, add hydrochloric acid to boiling chloroauric acid to remove nitric acid, then add deionized water to dilute the hydrochloric acid under heating conditions to remove nitric acid and excess hydrochloric acid in the resulting solution, and use deionized water to adjust the solution concentration to prepare a 1 mol / L tetrachloroauric acid (HAuCl4) solution;

[0062] Use aqua regia to dissolve 35g of platinum powder with a purity of 99.99%, remove nitric acid and excess hydrochloric acid in the resulting solution, and the operation is consistent with the above content. Use deionized water to adjust the solution concentration to prepare a 1mol / L hexachloroplatinic acid (H2PtCl6) solution;

[0063] Use aqua regia to dissolve 10g of palladium powder with a purity of 99.99%, remove nitric acid and excess hydrochloric acid in the resulting solution, and the operation is consistent with the above content. Use deionized water to adjust the solution concentration to prepare a 1mol / L tetrachloropalladium (II) acid ((H2PdCl4) solution;

[0064] The tetrachloroauric acid (HAuCl4) solution, the hexachloroplatinic acid (H2PtCl6) solution and the tetrachloropalladium (II) acid ((H2PdCl4) solution) are mixed to obtain a gold-platinum-palladium mixed solution, wherein the mass ratio of gold, platinum and palladium metals is 1:0.636:0.182;

[0065] Dissolve 5 g of polyethylene glycol in 1000 mL of deionized water to obtain a polyvinyl alcohol solution;

[0066] Dissolve 10 g of alanine in 150 mL of deionized water to obtain an alanine solution;

[0067] 230 g of ferrous sulfate heptahydrate was dissolved in 1000 mL of deionized water to obtain a reducing agent solution; under stirring at 100 rpm, the alanine solution was added to the reducing agent solution, and stirring was continued for 15 minutes to perform modification, thereby obtaining a modified reducing agent solution;

[0068] Under the condition of stirring at 100 rpm, the above polyethylene glycol solution was added to the gold, platinum and palladium mixed solution, the pH value of the reaction solution was adjusted to 2.0 with 0.1 mol / L hydrochloric acid solution, and the temperature of the reaction solution was controlled to 30°C by a low-temperature water bath, and then the modified reducing agent solution was added dropwise at a rate of 1 mL / s to the obtained reaction solution, and the stirring was continued for 3 h until the reaction was complete, and the solution was allowed to stand for 24 h. After solid-liquid separation, the supernatant was poured out, and the obtained solid was repeatedly washed with deionized water for 5 times, and then washed with anhydrous water. The mixture was washed with ethanol twice, and finally dried in an oven at 75°C for 24 hours, wherein the ratio of the mass of polyethylene glycol to the total mass of gold, platinum and palladium in the gold-platinum-palladium mixed solution was 1:20, the ratio of the mass of alanine to the total mass of gold, platinum and palladium in the gold-platinum-palladium mixed solution was 1:10, and the total molar ratio of ferrous sulfate heptahydrate to gold, platinum and palladium in the gold-platinum-palladium mixed solution was 1.5:1, thereby obtaining a submicron spherical gold-platinum-palladium alloy powder (particle size of 300 nm) for matching low-temperature co-fired ceramics.

[0069] Example 2

[0070] 55 g of gold powder with a purity of 99.99% was dissolved in aqua regia, and nitric acid and excess hydrochloric acid in the resulting solution were removed. The operation was consistent with Example 1, and the concentration of the solution was adjusted with deionized water to prepare a 1 mol / L tetrachloroauric acid (HAuCl4) solution;

[0071] 35 g of platinum powder with a purity of 99.99% was dissolved in aqua regia, and nitric acid and excess hydrochloric acid in the resulting solution were removed. The operation was the same as in Example 1, and the concentration of the solution was adjusted with deionized water to prepare a 1 mol / L hexachloroplatinic acid (H2PtCl6) solution;

[0072] 10 g of palladium powder with a purity of 99.99% was dissolved in aqua regia, and nitric acid and excess hydrochloric acid in the resulting solution were removed. The operation was consistent with Example 1, and the concentration of the solution was adjusted with deionized water to prepare a 1 mol / L tetrachloropalladium (II) acid ((H2PdCl4) solution;

[0073] The tetrachloroauric acid (HAuCl4) solution, the hexachloroplatinic acid (H2PtCl6) solution and the tetrachloropalladium (II) acid ((H2PdCl4)) solution are mixed to obtain a gold-platinum-palladium mixed solution, wherein the mass ratio of gold, platinum and palladium metals is 1:0.636:0.182;

[0074] Dissolve 2 g of polyvinyl pyrrolidone in 1000 mL of deionized water to obtain a polyvinyl pyrrolidone solution;

[0075] Dissolve 10 g of sodium chloride in 150 mL of deionized water to obtain a sodium chloride solution;

[0076] 90 g of catechol was dissolved in 1000 mL of deionized water to obtain a reducing agent solution; under a stirring condition of 100 rpm, the sodium chloride solution was added to the reducing agent solution, and stirring was continued for 15 minutes to perform modification, thereby obtaining a modified reducing agent solution;

[0077] Under the condition of stirring at 100 rpm, the polyvinyl pyrrolidone solution was added to the gold, platinum and palladium mixed solution, the pH value of the reaction solution was adjusted to 2.0 with 0.1 mol / L hydrochloric acid solution and the temperature of the reaction solution was controlled to 30°C by a low-temperature water bath, and then the modified reducing agent solution was added dropwise at a rate of 1 mL / s to the obtained reaction solution, and the stirring was continued for 3 h until the reaction was complete, and the solution was allowed to stand for 24 h. After solid-liquid separation, the supernatant was poured out, and the obtained solid was repeatedly washed with deionized water for 5 times, and then used The mixture was washed twice with anhydrous ethanol, and finally dried in an oven at 75°C for 24 hours, wherein the ratio of the mass of polyvinyl pyrrolidone to the total mass of gold, platinum and palladium in the gold-platinum-palladium mixed solution was 1:50, the ratio of the mass of sodium chloride to the total mass of gold, platinum and palladium in the gold-platinum-palladium mixed solution was 1:10, and the total molar ratio of catechol to the gold, platinum and palladium in the gold-platinum-palladium mixed solution was 1:1, thereby obtaining a submicron spherical gold-platinum-palladium alloy powder (particle size of 500 nm) for matching low-temperature co-fired ceramics.

[0078] Example 3

[0079] The difference from Example 1 is that the reducing agent is replaced by 150 g of ascorbic acid instead of 230 g of ferrous sulfate heptahydrate, and the rest of the contents are the same as those in Example 1.

[0080] Example 4

[0081] The difference from Example 1 is that the reducing agent is replaced by 35 g of sodium borohydride instead of 230 g of ferrous sulfate heptahydrate, and the rest of the contents are the same as those in Example 1.

[0082] Example 5

[0083] The difference from Example 1 is that the reducing agent is replaced by 210 g of sodium citrate instead of 230 g of ferrous sulfate heptahydrate, and the rest of the contents are consistent with Example 1.

[0084] Comparative Example 1

[0085] The difference from Example 1 is that the dispersant polyethylene glycol is removed, and the rest of the contents are consistent with Example 1.

[0086] Comparative Example 2

[0087] The difference from Example 1 is that the stabilizer alanine is removed, and the rest of the contents are consistent with Example 1.

[0088] Comparative Example 3

[0089] The difference from Example 1 is that the modified reducing agent solvent is not first prepared using the stabilizer alanine and the reducing agent ferrous sulfate heptahydrate and then used, but the gold platinum palladium mixed solution, the dispersant solution, the stabilizer solution and the reducing agent solution are directly mixed in sequence, and the rest of the contents are consistent with Example 1.

[0090] Performance Testing

[0091] Figures 1 to 8 The scanning electron microscope photographs are respectively of the submicron spherical gold-platinum-palladium alloy powder for matching low-temperature co-fired ceramics prepared in Examples 1 to 5 and the gold-platinum-palladium alloy powder prepared in Comparative Examples 1 to 3.

[0092] pass Figure 1 and Figure 6 It can be seen that the dispersant effectively increases the surface activity of particles and powders, and effectively prevents them from precipitation and aggregation in the solution during the reduction reaction.

[0093] pass Figure 1 and Figure 7 It can be seen that by adding stabilizers, the reaction rates of gold ions, platinum ions and palladium ions can be constrained to avoid the direct formation of a single crystal nucleus, thereby increasing the degree of gold-platinum-palladium alloying. At the same time, it also improves the welding performance of the gold-platinum-palladium alloy powder and controls the stability of the morphology.

[0094] pass Figure 1 and Figure 8 It can be seen that the quality and stability of the preparation are improved by modifying the reducing agent, making the operation process highly controllable and the batch stability good. The prepared submicron-level spherical gold, platinum and palladium powder with regular morphology has the characteristics of uniform particle size and no agglomeration.

[0095] Fig. 9 and Fig.10 They are respectively the weldability test diagrams of Example 1 and Comparative Example 1 used to prepare weldable gold-platinum-palladium slurry and then matched with ceramic substrate after low-temperature co-firing. By comparison, it can be seen that: submicron gold-platinum-palladium powder is prepared by adding a dispersant, and its tinning effect is better, and its weldability and solder resistance are excellent. Choosing a suitable dispersant helps to improve the uniform dispersion ability of the particles, thereby affecting the overall welding performance.

[0096] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention rather than all the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing submicron spherical gold-platinum-palladium alloy powder for matching low-temperature co-fired ceramics, characterized in that: The following steps are involved: first mixing a tetrachloroauric acid solution, a hexachloroplatinic acid solution and a tetrachloropalladium (II) acid solution to obtain a gold-platinum-palladium mixed solution; The gold, platinum and palladium mixed solution, the dispersant solution and the modified reducing agent solution are mixed for a second time, and after a reduction reaction, static precipitation and solid-liquid separation are carried out in sequence. The obtained solid is washed and dried in sequence to obtain a submicron spherical gold, platinum and palladium alloy powder for matching low-temperature co-fired ceramics.

2. The preparation method according to claim 1, characterized in that: The mass ratio of gold, platinum and palladium in the gold-platinum-palladium mixed solution is 1:0.6-0.7:0.1-0.

3.

3. The preparation method according to claim 1, characterized in that: The dispersant includes one or more of polyethylene glycol, polyvinyl pyrrolidone, polypropylene alcohol, dodecyl acetic acid, sodium dodecyl benzene sulfonate, sodium octanoate, ethyl cellulose and gum arabic.

4. The preparation method according to claim 1, characterized in that: The preparation method of the modified reducing agent solution comprises: adding a stabilizer solution into a reducing agent solution under stirring, and continuing stirring to perform modification to obtain the modified reducing agent solution.

5. The preparation method according to claim 4, characterized in that: The stabilizer includes one or more of p-methoxyphenol, sodium chloride, zinc chloride, zinc ricinoleate, alanine and histidine.

6. The preparation method according to claim 4, characterized in that: The reducing agent includes one or more of catechol, sodium borohydride, potassium borohydride, hydroxyethyl mercaptan, ferrous sulfate, sodium sulfite, ascorbic acid and sodium citrate.

7. The preparation method according to claim 1, characterized in that: The second mixing is: under stirring, first adding the dispersant solution to the gold, platinum and palladium mixed solution, adjusting the pH value of the resulting reaction solution to 2-2.5 and controlling the temperature of the resulting reaction solution to 30±0.5°C, and then dripping the modified reducing agent solution into the resulting reaction solution.

8. The preparation method according to claim 1, characterized in that: The ratio of the mass of the dispersant to the total mass of gold, platinum and palladium in the gold-platinum-palladium mixed solution is 1 to 10:

100.

9. The preparation method according to claim 1, characterized in that: The temperature of the reduction reaction is 30±0.5°C; the time of the reduction reaction is 60 to 360 minutes.

10. Use of the submicron spherical gold-platinum-palladium alloy powder prepared by the preparation method according to any one of claims 1 to 9 as a conductive phase in a weldable gold-platinum-palladium slurry for matching low-temperature co-fired ceramics.

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