A printable gold coating composition based on resin gold salts

Abstract

This invention relates to the field of printing coating preparation technology, and discloses a printable gold coating composition based on resin gold salt. The preparation method includes the following steps: turpentine oil and sulfur powder are stirred and mixed, refluxed at 110-130℃ for 2-4 hours, and after the reaction, the mixture is cooled and filtered to obtain sulfurized balsam, which is stored in the dark for later use; the sulfurized balsam is reacted with chloroauric acid solution to prepare sulfurized balsam gold; a composite resin acid salt additive and a portion of the solvent are ultrasonically premixed, and then the sulfurized balsam gold, a high-molecular organic carrier, and the remaining solvent are added sequentially, stirred, and degassed and aged using a planetary gravity mixer to obtain a printable gold coating composition based on resin gold salt. The obtained gold coating composition possesses good printability, conductivity, surface smoothness, and decorative properties, and is suitable for various coating methods such as screen printing and pad printing, forming a thin and continuous conductive gold film, meeting the industrial preparation requirements of ceramic-based sensor electrodes.

Description

Technical Field

[0001] This invention relates to the field of printing coating preparation technology, and specifically to a printable gold coating composition based on resin gold salt. Background Technology

[0002] Electronic pastes are key functional materials for manufacturing sensor electrodes and conductive circuits. Among them, resin-based gold salt printable gold coatings are widely used in the electrode fabrication of piezoelectric ceramic sensors due to their stable conductivity, moderate sintering temperature, and good compatibility with ceramic substrates. In practical applications, traditional gold coatings often employ a single resin carrier and a simple gold salt compound system. The synthesis process of sulfide balsam gold lacks precise control, resulting in uneven gold component distribution and poor film consistency after printing. During sintering, the concentrated thermal decomposition of the organic carrier easily leads to film shrinkage cracking and high porosity, thereby reducing conductivity and structural stability. Conventional additive systems lack thermal expansion control capabilities. The significant difference in thermal expansion coefficients between the gold film and the ceramic substrate generates significant interfacial stress during heating and cooling, causing electrode detachment and circuit breakage, affecting sensor lifespan and signal transmission stability. Traditional gold pastes typically require high sintering temperatures to achieve gold particle densification. High-temperature environments easily cause polarization degradation and performance decline in piezoelectric ceramic elements, failing to meet the low-temperature fabrication requirements of high-precision sensors. Some gold coatings are prone to problems such as poor leveling, rough edges, and low surface gloss after printing, which not only affect the decorative properties and dimensional accuracy of the electrodes, but also increase contact resistance and signal loss. Existing technologies cannot simultaneously achieve a synergistic improvement in low-temperature sintering, high-density film formation, low stress matching, and good printability, which limits the large-scale application of resin-based gold salt coatings in the field of high-end ceramic-based sensors.

[0003] Based on this, this application provides a printable gold coating composition based on resin gold salt. Summary of the Invention

[0004] Technical problems to be solved In view of the shortcomings mentioned in the background art, the present invention provides a printable gold coating composition based on resin gold salt.

[0005] Technical solution To achieve the above objectives, the present invention provides the following technical solution: A printable gold coating composition based on resin gold salt, the preparation method of which includes the following steps: S1. Mix turpentine oil and sulfur powder, reflux at 110-130℃ for 2-4 hours, cool and filter after the reaction to obtain sulfurized balsam, store in the dark for later use. In the above reaction process, the sulfur content of the sulfurized balsam product is kept between 8% and 10% by controlling the amount of sulfur added. Furthermore, in step S1, the mass ratio of turpentine oil to sulfur powder is 10:1-3.

[0006] Furthermore, in step S1, the stirring and mixing rate is 150-250 rpm.

[0007] S2. The sulfurized balsam is reacted with chloroauric acid solution to prepare sulfurized balsam gold; Furthermore, in step S2, the sulfurized balsam gold is specifically prepared by the following steps: Under the conditions of a water bath at 60-90℃ and stirring at 100-300rpm, the sulfurized balsam is added dropwise to a chloroauric acid solution over a period of 30-60 minutes. After the addition is complete, the reaction continues for 8-10 hours. The mixture is then cooled to room temperature, the supernatant is decanted, washed 2-3 times with anhydrous ethanol, centrifuged at 8000-10000rpm for 5-10 minutes, and dried under vacuum at 40℃ for 10-14 hours to obtain the sulfurized balsam gold.

[0008] Furthermore, the chloroauric acid solution is a chloroauric acid ethanol solution with a mass concentration of 10%-20%.

[0009] Furthermore, the mass ratio of chloroauric acid to sulfurized balsam is 1:1.5-2.

[0010] S3. Prepare composite resin acid salt additives by using sulfurized balsam and composite metal chloride; Furthermore, the composite resin acid salt additive is specifically prepared by the following steps: Weigh out the complex metal chloride, dissolve it in anhydrous ethanol, and prepare a precursor solution with a total metal ion concentration of 20-30 g / L; dissolve the sulfurized balsam in anhydrous ethanol to prepare a sulfurized balsam solution with a mass fraction of 12%-18%, and add NaOH solid to it according to the mass of the sulfurized balsam, the amount of which is 1.5%-2.0% of the mass of the sulfurized balsam, to obtain a sodium salt ethanol solution of sulfurized balsam; under the conditions of a water bath at 40-50℃ and stirring at 180-220 rpm, the precursor solution... Add the sodium sulfide balsam salt ethanol solution dropwise at a rate of 4-6 mL / min; after the addition is complete, raise the temperature to 70℃ and react for 4.5-5.5 h; add 0.4-0.6 wt% oleic acid (relative to total solids), stir for 25-35 min; centrifuge at 7000-9000 rpm for 8-12 min, wash 2-4 times with anhydrous ethanol, then wash 2-3 times with deionized water, and finally wash once with anhydrous ethanol; dry under vacuum at 40℃ for 10-14 h to obtain the composite resin acid salt additive.

[0011] Furthermore, in the composite metal chloride, the molar ratio of bismuth, copper, chromium, and rhodium is 10:(0.1-0.3):(0.7-0.9):(0.1-0.3).

[0012] Furthermore, the mass ratio of sulfurized balm to complex metal chloride is 2:1.

[0013] S4. Organic compounds with different thermal decomposition temperatures are mixed with a solvent to obtain a high molecular weight organic carrier. Furthermore, in step S4, the polymeric organic carrier is specifically prepared by the following steps: Organic compounds with different decomposition temperatures are added to a solvent and dissolved in a water bath at 85-95℃ and stirred at 280-320 rpm for 1.5-2.5 hours. The temperature is then lowered to 55-65℃, and KH550 and polyethylene glycol-400 are added and stirred for 25-35 minutes. Hydrogenated castor oil wax paste is then added, and the mixture is cooled to room temperature to obtain a high molecular weight organic carrier.

[0014] Furthermore, the total mass of organic matter at different decomposition temperatures accounts for 15% of the total mass of the solvent.

[0015] Further, in step S4, the solvent is obtained by mixing terpineol, dibutyl phthalate and ethylene glycol butyl ether acetate in a mass ratio of 6:2:2.

[0016] Further, in step S4, the organic compounds with different decomposition temperatures are obtained by mixing ethyl cellulose, rosin resin and PMMA in a mass ratio of (9-11):(28-35):(9-11).

[0017] Furthermore, based on the total mass of organic matter at different decomposition temperatures, the amount of KH550 used is 1.5-2.5 wt%.

[0018] Furthermore, based on the total mass of organic matter at different decomposition temperatures, the amount of polyethylene glycol-400 used is 0.8-1.2 wt%.

[0019] Furthermore, based on the total mass of organic matter at different decomposition temperatures, the amount of hydrogenated castor oil wax paste used is 0.2-0.4 wt%.

[0020] In the above steps, a multi-stage thermal decomposition carrier system is designed to reduce concentrated shrinkage; at the same time, active functional groups are introduced to crosslink with additives to enhance adhesion and buffer stress.

[0021] S5. Premix the composite resin acid salt additive with part of the solvent by ultrasonication for 1-3 minutes, then add the sulfurized balsam gold, high molecular organic carrier and the remaining solvent in sequence, stir at 600-1000 rpm for 20-60 minutes, degas using a planetary gravity mixer for 5-15 minutes, and age for 6-48 hours to obtain a printable gold coating composition based on resin gold salt.

[0022] Furthermore, the mass ratio of the composite resin acid salt additive, solvent, sulfurized balsam gold, and high molecular organic carrier is (0.1-2):(15-35):(20-50):(10-30), where the solvent refers to the sum of the premixed solvent and the remaining solvent.

[0023] Furthermore, the solvent is obtained by mixing terpineol and ethylene glycol butyl ether acetate in a 1:1 mass ratio.

[0024] Furthermore, the method of using the coating composition is as follows: The resin-based gold salt printable gold coating composition is coated onto a sensor ceramic substrate, leveled, pre-dried at 80-120℃ for 10-30 minutes, and then sintered in a sintering furnace to obtain a resin-based gold salt printable gold coating composition.

[0025] Furthermore, the sintering process consists of five steps, as follows: Step 1: Increase the temperature from room temperature to 120-130℃ at a rate of 1-5℃ / min, and hold for 20-30 minutes; Step 2: Increase the temperature of the system to 240-250℃ at a rate of 1-2℃ / min, and hold at that temperature for 30-40 minutes; Step 3: Increase the temperature of the system to 370-380℃ at a rate of 0.5-1℃ / min, and hold at that temperature for 40-60min; Step 4: Increase the temperature of the system to 510-520℃ at a rate of 1-3℃ / min, and hold for 45-55min; Step 5: Cool the system to 300°C at a rate of 1-2°C / min, and then cool it to room temperature in the furnace.

[0026] In the above sintering process, the free solvent is removed in step one, forming microchannels to prevent bubbling in the final product. Step two decomposes ethyl cellulose and polyethylene glycol-400, simultaneously promoting the bonding of the silane coupling agent to the matrix. In step three, at 370-380℃, the organic sulfur in the rosin resin and sulfurized balsam decomposes, and the resin acid salt additives reduce to bismuth, copper, and other nano-metallic phases. Combined with the process in step four, the gold particles sinter and rearrange, forming bismuth-gold eutectic, solid solution, and other components, promoting coating densification while regulating the coating's thermal expansion adaptability. Finally, step five involves slow cooling before 300℃ to prevent cracking caused by the shrinkage difference between the gold film and the ceramic (most substrates are made of ceramic materials).

[0027] Beneficial technical effects In the technical solution of this invention, by adjusting the synthesis parameters of sulfurized balsam and the preparation process of sulfurized balsam gold, the composition and morphology of the gold precursor can be stabilized and controlled, the uniformity and printability of the gold paste system can be improved, and the coating film quality and the continuity of the conductive path can be guaranteed.

[0028] In the technical solution of this invention, a bismuth-copper-chromium-rhodium multi-component resin acid salt additive is used to form a low-melting-point eutectic phase and a thermal expansion-regulating phase that matches the ceramic substrate during the sintering process. This promotes the densification and sintering of gold particles, reduces the internal porosity and interfacial stress of the coating, and improves the bonding strength and structural stability between the coating and the substrate.

[0029] In the technical solution of this invention, a multi-stage thermal decomposition polymer organic carrier system is constructed, which enables the organic components to decompose step by step in different temperature zones, avoiding the sudden shrinkage of volume and film defects caused by concentrated decomposition. At the same time, a chemical bond is established between the organic carrier and the ceramic substrate through a silane coupling agent, thereby enhancing the interfacial adhesion.

[0030] In the technical solution of this invention, a segmented low-temperature sintering process is designed to achieve the step-by-step completion of solvent removal, organic decomposition, metal reduction and gold film densification, suppressing bubbling, pinholes and cracking, and completing film formation at a lower sintering temperature to avoid performance damage to the piezoelectric ceramic element of the sensor caused by high temperature. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a sample image from Embodiment 1 of the present invention.

[0033] Figure 2 This is a sample image from Embodiment 2 of the present invention.

[0034] Figure 3 This is a sample image from Embodiment 3 of the present invention.

[0035] Figure 4 This is a sample image from Comparative Example 1 of the present invention.

[0036] Figure 5 This is a sample image from Comparative Example 2 of the present invention.

[0037] Figure 6 This is a sample image from Comparative Example 3 of the present invention.

[0038] Figure 7 This is a sample image from Comparative Example 4 of the present invention.

[0039] Figure 8 This is a sample image from Comparative Example 5 of the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] The raw materials used in the embodiments of this invention are shown below, and all reagents used are analytical grade. Additionally: Chloroauric acid: Aladdin, model number A100309, purity 99.9%.

[0042] Ethyl cellulose: Dow Chemical, model number Ethocel Standard 10.

[0043] Hydrogenated castor oil wax paste: Elementis, a thixotropic agent for electronic pastes, Casting Powder 146.

[0044] Rosin resin: Disproportionated rosin DK-100.

[0045] Example 1 A printable gold coating composition based on resin gold salt, the preparation method of which specifically includes the following steps: S1. Mix turpentine oil and sulfur powder at a mass ratio of 10:2, stirring at a speed of 200 rpm, and reflux at 120°C for 3 hours. After the reaction is complete, cool down to 30°C, filter, and obtain sulfurized balsam. Store in the dark for later use. S2. Prepare a 15% (w / w) chloroauric acid ethanol solution. Under the conditions of a 75℃ water bath and stirring at 200 rpm, add the sulfurized balsam dropwise to the chloroauric acid solution. The mass ratio of chloroauric acid to sulfurized balsam is 1:1.8, and the addition time is 45 min. After the addition is complete, continue the reaction for 9 h. Cool to room temperature, decant the supernatant, wash 3 times with anhydrous ethanol, centrifuge at 9000 rpm for 8 min, and vacuum dry at 40℃ for 12 h to obtain sulfurized balsam gold. S3. Weigh 10g of the composite metal chloride according to the molar ratio of bismuth, copper, chromium, and rhodium of 10:0.2:0.8:0.2, dissolve it in anhydrous ethanol, and prepare a precursor solution with a total metal ion concentration of 25g / L; dissolve the sulfurized balm in anhydrous ethanol to prepare a sulfurized balm solution with a mass fraction of 15%, add 1.5% NaOH solid by mass of the sulfurized balm to obtain a sodium salt ethanol solution of sulfurized balm; the mass ratio of sulfurized balm to composite metal chloride is 2:1; under the conditions of a 45℃ water bath and 200rpm stirring, add the precursor solution dropwise to the sodium salt ethanol solution of sulfurized balm at a rate of 5mL / min; after the addition is complete, raise the temperature to 70℃ and react for 5h; add 0.5wt% oleic acid (relative to total solids), stir for 30min; centrifuge at 8000rpm for 10min, wash 3 times with anhydrous ethanol, wash 3 times with deionized water, and finally wash once with anhydrous ethanol; vacuum dry at 40℃ for 12h to obtain the composite resin acid salt additive. S4. Ethyl cellulose, rosin resin, and PMMA were mixed in a mass ratio of 10:30:10 to obtain organic compounds with different decomposition temperatures. These organic compounds were then added to a solvent composed of terpineol, dibutyl phthalate, and ethylene glycol butyl ether acetate in a mass ratio of 6:2:2, with the total mass of the organic compounds accounting for 15% of the total solvent mass. The mixture was dissolved in a 90°C water bath at 300 rpm for 2 hours. The temperature was then lowered to 60°C, and 2 wt% KH550 and 1 wt% polyethylene glycol-400 (based on the total mass of the organic compounds) were added. The mixture was stirred for 30 minutes. Finally, 0.3 wt% hydrogenated castor oil wax paste (based on the total mass of the organic compounds) was added, and the thixotropic index was adjusted to 3.0. The mixture was then cooled. The mixture is cooled to room temperature to obtain a high molecular weight organic carrier. S5. According to the mass ratio, take 1 part of composite resin acid salt additive, 35 parts of sulfurized balsam gold, 20 parts of high molecular weight organic carrier, and 25 parts of total solvent (terpineol and ethylene glycol butyl ether acetate are mixed in a 1:1 mass ratio). The composite resin acid salt additive and 30% of the total solvent are ultrasonically premixed at 40 kHz and 100 W for 2 min. Then, sulfurized balsam gold, high molecular weight organic carrier, and the remaining 70% of the solvent are added sequentially. The mixture is stirred at 800 rpm for 40 min, degassed using a planetary gravity mixer for 10 min, and aged for 24 h to obtain a printable gold coating composition based on resin gold salt.

[0046] A printable gold coating composition based on resin gold salt was applied to a sensor ceramic substrate, leveled, pre-dried at 100°C for 20 min, and then sintered in a sintering furnace. The sintering procedure was as follows: Step 1: Heat from room temperature to 125°C at a rate of 3°C / min and hold for 25 min; Step 2: Heat to 245°C at a rate of 1.5°C / min and hold for 35 min; Step 3: Heat to 375°C at a rate of 0.8°C / min and hold for 50 min; Step 4: Heat to 515°C at a rate of 2°C / min and hold for 50 min; Step 5: Cool to 300°C at a rate of 1.5°C / min, and then cool to room temperature in the furnace to complete the coating curing.

[0047] See sample images Figure 1 .

[0048] Example 2 A printable gold coating composition based on resin gold salt, the preparation method of which specifically includes the following steps: S1. Mix turpentine oil and sulfur powder at a mass ratio of 10:1, stirring at a speed of 150 rpm, and reflux at 110°C for 4 hours. After the reaction is complete, cool down to 25°C, filter, and obtain sulfurized balsam. Store in the dark for later use. S2. Prepare a 10% (w / w) chloroauric acid ethanol solution. Under the conditions of a 60℃ water bath and stirring at 100 rpm, add the sulfurized balsam dropwise to the chloroauric acid solution. The mass ratio of chloroauric acid to sulfurized balsam is 1:1.5, and the addition time is 30 min. After the addition is complete, continue the reaction for 8 h. Cool to room temperature, decant the supernatant, wash twice with anhydrous ethanol, centrifuge at 8000 rpm for 5 min, and vacuum dry at 40℃ for 10 h to obtain sulfurized balsam gold. S3. Weigh 8g of the composite metal chloride according to the molar ratio of bismuth, copper, chromium, and rhodium of 10:0.2:0.8:0.2, dissolve it in anhydrous ethanol to prepare a precursor solution with a total metal ion concentration of 20g / L; dissolve the sulfurized balm in anhydrous ethanol to prepare a sulfurized balm solution with a mass fraction of 12%, add 1.5% NaOH solid by mass of the sulfurized balm to obtain a sodium salt ethanol solution of sulfurized balm; the mass ratio of sulfurized balm to composite metal chloride is 2:1; under the conditions of a 40℃ water bath and 180rpm stirring, add the precursor solution dropwise to the sodium salt ethanol solution of sulfurized balm at a rate of 4mL / min; after the addition is complete, raise the temperature to 70℃ and react for 4.5h; add 0.4wt% oleic acid (relative to total solids), stir for 25min; centrifuge at 7000rpm for 8min, wash twice with anhydrous ethanol, wash three times with deionized water, and finally wash once with anhydrous ethanol; vacuum dry at 40℃ for 12h to obtain the composite resin acid salt additive. S4. Ethyl cellulose, rosin resin, and PMMA were mixed in a mass ratio of 9:28:9 to obtain organic compounds with different decomposition temperatures. These organic compounds were then added to a solvent composed of terpineol, dibutyl phthalate, and ethylene glycol butyl ether acetate in a mass ratio of 6:2:2, with the total mass of the organic compounds accounting for 15% of the total solvent mass. The mixture was dissolved in an 85°C water bath at 280 rpm for 1.5 h with stirring. The temperature was then lowered to 55°C, and 1.5 wt% KH550 and 0.8 wt% polyethylene glycol-400 (based on the total mass of the organic compounds) were added, followed by stirring for 25 min. Finally, 0.2 wt% hydrogenated castor oil wax paste (based on the total mass of the organic compounds) was added, and the thixotropic index was adjusted to 2.8. After cooling to room temperature, a polymeric organic carrier is obtained; S5, according to the mass fraction, take 0.1 parts of composite resin acid salt additive, 20 parts of sulfurized balsam gold, 10 parts of polymeric organic carrier, and 15 parts of total solvent (terpineol and ethylene glycol butyl ether acetate are mixed in a 1:1 mass ratio). The composite resin acid salt additive and a portion of the solvent accounting for 30% of the total solvent are ultrasonically premixed for 2 minutes at 40 kHz and 100 W. The sulfurized balsam gold, polymeric organic carrier, and the remaining 70% of the solvent are added sequentially. The mixture is stirred at 600 rpm for 20 minutes, degassed using a planetary gravity mixer for 10 minutes, and aged for 6 hours to obtain a printable gold coating composition based on resin gold salt.

[0049] A printable gold coating composition based on resin gold salt was applied to a sensor ceramic substrate, leveled, pre-dried at 80°C for 30 min, and then sintered in a sintering furnace. The sintering procedure was as follows: Step 1: Heat from room temperature to 120°C at a rate of 1°C / min and hold for 30 min; Step 2: Heat to 240°C at a rate of 1°C / min and hold for 40 min; Step 3: Heat to 370°C at a rate of 0.5°C / min and hold for 60 min; Step 4: Heat to 510°C at a rate of 1°C / min and hold for 55 min; Step 5: Cool to 300°C at a rate of 1°C / min, and then cool to room temperature in the furnace to complete the coating curing.

[0050] See sample images Figure 2 .

[0051] Example 3 A printable gold coating composition based on resin gold salt, the preparation method of which specifically includes the following steps: S1. Mix turpentine oil and sulfur powder at a mass ratio of 10:3, stirring at a speed of 250 rpm, and reflux at 130°C for 2 hours. After the reaction is complete, cool down to 35°C, filter, and obtain sulfurized balsam. Store in the dark for later use. S2. Prepare a 20% (w / w) chloroauric acid ethanol solution. Under the conditions of a 90℃ water bath and stirring at 300 rpm, add the sulfurized balsam dropwise to the chloroauric acid solution. The mass ratio of chloroauric acid to sulfurized balsam is 1:2, and the addition time is 60 min. After the addition is complete, continue the reaction for 10 h. Cool to room temperature, decant the supernatant, wash 3 times with anhydrous ethanol, centrifuge at 10000 rpm for 10 min, and vacuum dry at 40℃ for 14 h to obtain sulfurized balsam gold. S3. Weigh 12g of the composite metal chloride according to the molar ratio of bismuth, copper, chromium, and rhodium of 10:0.2:0.8:0.2, dissolve it in anhydrous ethanol, and prepare a precursor solution with a total metal ion concentration of 30g / L; dissolve the sulfurized balm in anhydrous ethanol to prepare a sulfurized balm solution with a mass fraction of 18%, add 1.5% NaOH solid by mass of the sulfurized balm to obtain a sodium salt ethanol solution of sulfurized balm; the mass ratio of sulfurized balm to composite metal chloride is 2:1; under the conditions of a 50℃ water bath and 220rpm stirring, add the precursor solution dropwise to the sodium salt ethanol solution of sulfurized balm at a rate of 6mL / min; after the addition is complete, raise the temperature to 70℃ and react for 5.5h; add 0.6wt% oleic acid (relative to total solids), stir for 35min; centrifuge at 9000rpm for 12min, wash 4 times with anhydrous ethanol, wash 3 times with deionized water, and finally wash once with anhydrous ethanol; vacuum dry at 40℃ for 12h to obtain the composite resin acid salt additive. S4. Ethyl cellulose, rosin resin, and PMMA were mixed in a mass ratio of 11:35:11 to obtain organic compounds with different decomposition temperatures. These organic compounds were then added to a solvent composed of terpineol, dibutyl phthalate, and ethylene glycol butyl ether acetate in a mass ratio of 6:2:2, with the total mass of the organic compounds accounting for 15% of the total solvent mass. The mixture was dissolved in a 95°C water bath at 320 rpm for 2.5 h with stirring. The temperature was then lowered to 65°C, and 2.5 wt% KH550 and 1.2 wt% polyethylene glycol-400 were added, followed by stirring for 35 min. Finally, 0.4 wt% hydrogenated castor oil wax paste was added, and the thixotropic index was adjusted to 3.2. The mixture was then cooled to room temperature to obtain the high-molecular-weight organic carrier. S5. According to the mass ratio, take 2 parts of composite resin acid salt additive, 50 parts of sulfurized balsam gold, 30 parts of high molecular weight organic carrier, and 35 parts of total solvent (terpineol and ethylene glycol butyl ether acetate are mixed in a 1:1 mass ratio). Premix the composite resin acid salt additive with 30% of the total solvent using ultrasonication at 40 kHz and 100 W for 2 minutes. Then add the sulfurized balsam gold, high molecular weight organic carrier, and the remaining 70% of the solvent sequentially. Stir at 1000 rpm for 60 minutes, degas using a planetary gravity mixer for 10 minutes, and age for 48 hours to obtain a printable gold coating composition based on resin gold salt. The printable gold coating composition of gold salt was coated onto the sensor ceramic substrate, leveled, pre-dried at 120°C for 10 min, and then sintered in a sintering furnace. The sintering procedure was as follows: Step 1: Heat from room temperature to 130°C at a rate of 5°C / min and hold for 20 min; Step 2: Heat to 250°C at a rate of 2°C / min and hold for 30 min; Step 3: Heat to 380°C at a rate of 1°C / min and hold for 40 min; Step 4: Heat to 520°C at a rate of 3°C / min and hold for 45 min; Step 5: Cool to 300°C at a rate of 2°C / min, and then cool to room temperature in the furnace to complete the coating curing.

[0052] See sample images Figure 3 .

[0053] Comparative Example 1 The difference between this comparative example and Example 2 is that in step S3, only bismuth resin salts are prepared, without introducing Cu, Cr, or Rh. Specifically, step S3 of this comparative example is as follows: 8g of bismuth trichloride is dissolved in anhydrous ethanol to prepare a precursor solution with a total metal ion concentration of 25g / L. Sulfurized balsam is dissolved in anhydrous ethanol to prepare a 15% (w / w) sulfurized balsam solution. 1.5% (w / w) of NaOH solid is added to obtain a sodium salt ethanol solution of sulfurized balsam; the mass ratio of sulfurized balsam to BiCl3 is 2:1 (i.e., 16g of sulfurized balsam to 8g of BiCl3). Under a 45°C water bath and stirring at 200rpm, the precursor solution is added dropwise to the sodium salt ethanol solution of sulfurized balsam at a rate of 5mL / min. After the addition is complete, the temperature is raised to 70°C and the reaction is carried out for 5 hours. 0.5wt% oleic acid (relative to total solids) is added and stirred for 30 minutes. Centrifuge at 8000 rpm for 10 min, wash three times with anhydrous ethanol, then wash three times with deionized water, and finally wash once with anhydrous ethanol. Dry under vacuum at 40°C for 12 h to obtain a single bismuth resin acid salt additive. In step S5, take 0.1 part of this additive, and the remaining components and mixing, printing, and sintering procedures are exactly the same as in Example 2.

[0054] See sample images Figure 4 .

[0055] Comparative Example 2 The difference between this comparative example and Example 2 is that only BiCl3 and CuCl2 are used in the composite resin acid salt additive, with a molar ratio of Bi:Cu of 10:0.2. See sample image below. Figure 5 .

[0056] Comparative Example 3 The difference between this comparative example and Example 2 is that only a single resin is used in step S4; specifically, rosin resin is used instead of organic compounds with different decomposition temperatures, and ethyl cellulose and PMMA are not added. See sample images below. Figure 6 .

[0057] Comparative Example 4 The difference between this comparative example and Example 2 is that the final sintering procedure was changed to a single-stage heating process: the temperature was directly increased from room temperature to 520°C at a rate of 5°C / min, held for 60 minutes, then decreased to 300°C at a rate of 5°C / min, and then cooled in the furnace without an intermediate holding period. See sample images below. Figure 7 .

[0058] Comparative Example 5 The difference between this comparative example and Example 2 is that, in preparing the polymeric organic carrier, after dissolving the resin at 90°C, the temperature was lowered to 60°C, and only 0.8 wt% polyethylene glycol-400 was added, without adding KH550. See sample images below. Figure 8 .

[0059] The products prepared in the examples and comparative examples are now subjected to performance testing. The specific testing methods are as follows: 1. Conductivity test: The sheet resistance of samples from different groups was tested using an HPS2523 coated sheet resistance meter. After powering on, the instrument was preheated for 15 minutes to stabilize the internal circuitry. The four-probe sensor was placed on the standard calibration plate, and the "Calibrate" button was pressed. The calibration error should be ≤ ±0.5%. The sintered gold film sample was placed in the center of the test stage, film side up. The film surface was gently wiped with a lint-free cloth dampened with alcohol to remove dust, and then allowed to air dry. The four-probe sensor was then pressed vertically and gently onto the film surface, ensuring good contact between the four probes and the film surface. Measurements were then taken at five different locations (center and perimeter) for each sample, and the arithmetic mean was taken as the sheet resistance of that sample.

[0060] 2. Adhesion test Referring to the test method in GB / T9286-2021, a crisscross tool with a 1mm tooth pitch was used to crisscross the gold film surface obtained in different groups, creating 10×10 1mm×1mm grids, penetrating the film layer to the substrate. Debris was removed with a soft brush, and then 3M 600 tape was applied to the grid area, pressing it flat with a finger to ensure no air bubbles. The tape was then quickly peeled off perpendicular to the film surface, and the area of ​​peeling off the grid area was observed. Ratings were given as follows: 5B (no peeling), 4B (<5% peeling), 3B (5%-15%), 2B (15%) to evaluate the adhesion of the samples.

[0061] The specific test results are shown in Table 1 below.

[0062] Table 1

[0063] As shown in Table 1, the conductivity and adhesion of the embodiments are significantly better than those of the comparative examples, proving that the components and process parameters of the present invention have a synergistic effect. Comparative Example 1 uses only a single bismuth resin acid salt additive, lacking the synergistic regulation of copper, chromium, and rhodium, making it difficult to form an effective eutectic phase and thermal expansion-adaptive structure. The gold particles are not fully sintered, the continuity of the conductive pathway is poor, and the interfacial bonding force is reduced, resulting in decreased adhesion. Comparative Example 2 uses a bismuth-copper binary additive, lacking the thermal expansion regulation effect of chromium and rhodium. The internal stress of the coating cannot be released, the film layer is not dense enough, and the conductivity and adhesion are weaker than those of the embodiments. Comparative Example 3 uses a single rosin resin carrier. The concentrated decomposition of organic components leads to uneven film shrinkage, an increase in internal defects, obstruction of conductive pathways, and a decrease in interfacial bonding strength. Comparative Example 4 uses single-stage rapid heating sintering. The solvent and organic components rapidly volatilize and decompose, generating a large number of pores and defects, destroying the integrity of the conductive network. At the same time, thermal stress accumulates rapidly, resulting in a significant decrease in adhesion. Comparative Example 5, without the addition of silane coupling agent, lacks chemical bonding between the coating and the substrate, resulting in weak interfacial forces, significantly reduced adhesion, and consequently affecting conductivity stability.

[0064] The surface quality of the samples from Examples 1-3 and Comparative Examples 1-5 is now evaluated using the following methods: 1. Surface smoothness test: Gently wipe the surface of the sintered gold film sample with a lint-free cloth dampened with alcohol to remove dust, and allow it to air dry. Place the sample on the stage with the film side facing upwards. Select a 100x objective lens and scan an area of ​​500μm × 500μm. Calculate the arithmetic mean roughness and maximum peak-valley height within the measurement area using software. Randomly select three different areas for each sample and record the average value.

[0065] 2. Gloss test: A 60° gloss meter (BYK4563) was used to test different samples. Three different positions were measured for each sample, and the average value was recorded.

[0066] The specific test results are shown in Table 2 below.

[0067] Table 2

[0068] As shown in Table 2, the surface roughness and gloss of the embodiments are superior to those of the comparative examples, demonstrating the optimization effect of the present invention system on surface morphology. Comparative Example 1, lacking chromium-rhodium nanophase regulation, exhibited poor sintering uniformity of the gold film, large surface undulations, high roughness, and low gloss. Comparative Example 2 had an incomplete additive system, resulting in insufficient particle regularity during sintering, numerous surface defects, and both roughness and gloss were inferior to the embodiments. Comparative Example 3 used a single resin carrier, and the violent decomposition process led to an uneven film surface, increased roughness, and decreased gloss. Comparative Example 4's single-stage heating caused rapid release of organic components and solvents, forming numerous pinholes and uneven structures, significantly increasing surface roughness and drastically reducing gloss. Comparative Example 5 lacked the interfacial modification effect of a coupling agent, resulting in uneven bonding between the film and substrate, localized undulations, increased roughness, and slightly lower gloss than the embodiments.

[0069] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0070] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0071] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments.

Claims

1. A printable gold coating composition based on resin gold salt, characterized in that, Its preparation method includes the following steps: S1. Mix turpentine oil and sulfur powder, reflux at 110-130℃ for 2-4 hours, cool and filter after the reaction to obtain sulfurized balsam, store in the dark for later use. S2. The sulfurized balsam is reacted with chloroauric acid solution to prepare sulfurized balsam gold; S3. Prepare composite resin acid salt additives by using sulfurized balsam and composite metal chloride; S4. Organic compounds with different thermal decomposition temperatures are mixed with a solvent to obtain a high molecular weight organic carrier. S5. The composite resin acid salt additive and part of the solvent are ultrasonically premixed, and sulfurized balsam gold, high molecular organic carrier and the remaining solvent are added in sequence. The mixture is stirred, and degassed and aged using a planetary gravity mixer to obtain a printable gold coating composition based on resin gold salt. The method of using the coating composition is as follows: The resin-based gold salt printable gold coating composition is coated onto a sensor ceramic substrate, leveled, pre-dried at 80-120℃ for 10-30 minutes, and then sintered in a sintering furnace to obtain a resin-based gold salt printable gold coating composition.

2. The printable gold coating composition based on resin gold salt according to claim 1, characterized in that, In step S1, the mass ratio of turpentine oil to sulfur powder is 10:1-3.

3. The printable gold coating composition based on resin gold salt according to claim 1, characterized in that, In step S2, the sulfurized balsam gold is specifically prepared by the following steps: Under the conditions of a water bath at 60-90℃ and stirring at 100-300rpm, the sulfurized balsam is added dropwise to a chloroauric acid solution over a period of 30-60 minutes. After the addition is complete, the reaction continues for 8-10 hours. The mixture is then cooled to room temperature, the supernatant is decanted, washed with anhydrous ethanol, centrifuged, and dried to obtain the sulfurized balsam gold.

4. The printable gold coating composition based on resin gold salt according to claim 3, characterized in that, The chloroauric acid solution is a chloroauric acid ethanol solution with a mass concentration of 10%-20%.

5. The printable gold coating composition based on resin gold salt according to claim 1, characterized in that, In step S3, the composite resin acid salt additive is specifically prepared by the following steps: Weigh out the composite metal chloride, dissolve it in anhydrous ethanol to prepare a precursor solution; dissolve the sulfurized balm in anhydrous ethanol to prepare a sulfurized balm solution, add NaOH to obtain a sodium salt ethanol solution of sulfurized balm; under the conditions of a water bath at 40-50℃ and stirring at 180-220rpm, add the precursor solution dropwise to the sodium salt ethanol solution of sulfurized balm; after the addition is complete, raise the temperature to 70℃ and react for 4.5-5.5h; add oleic acid, stir, centrifuge, wash, and dry to obtain the composite resin acid salt additive.

6. The printable gold coating composition based on resin gold salt according to claim 5, characterized in that, In the composite metal chloride, the molar ratio of bismuth, copper, chromium, and rhodium is 10:(0.1-0.3):(0.7-0.9):(0.1-0.3).

7. The printable gold coating composition based on resin gold salt according to claim 1, characterized in that, In step S4, the polymeric organic carrier is specifically prepared by the following steps: Organic compounds with different decomposition temperatures are added to a solvent and dissolved by stirring in a water bath at 85-95℃; the temperature is then lowered to 55-65℃, KH550 and polyethylene glycol-400 are added, and the mixture is stirred; hydrogenated castor oil wax paste is added, and the mixture is then cooled to room temperature to obtain a high molecular weight organic carrier.

8. The printable gold coating composition based on resin gold salt according to claim 1, characterized in that, In step S4, the organic compounds with different decomposition temperatures are obtained by mixing ethyl cellulose, rosin resin and PMMA in a mass ratio of (9-11):(28-35):(9-11).

9. The printable gold coating composition based on resin gold salt according to claim 1, characterized in that, In step S5, the mass ratio of the composite resin acid salt additive, solvent, sulfurized balsam gold, and high molecular organic carrier is (0.1-2):(15-35):(20-50):(10-30), where the solvent refers to the sum of the premixed solvent and the remaining solvent.

10. The printable gold coating composition based on resin gold salt according to claim 1, characterized in that, The sintering process consists of five steps, as follows: Step 1: Increase the temperature from room temperature to 120-130℃ at a rate of 1-5℃ / min, and hold for 20-30 minutes; Step 2: Increase the temperature of the system to 240-250℃ at a rate of 1-2℃ / min, and hold at that temperature for 30-40 minutes; Step 3: Increase the temperature of the system to 370-380℃ at a rate of 0.5-1℃ / min, and hold at that temperature for 40-60min; Step 4: Increase the temperature of the system to 510-520℃ at a rate of 1-3℃ / min, and hold for 45-55min; Step 5: Cool the system to 300°C at a rate of 1-2°C / min, and then cool it to room temperature in the furnace.

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