High temperature resistant organic gold paste and use for infrared reflective gold coating

Abstract

The application discloses a kind of high-temperature-resistant organic gold slurry, including resin acid gold, resin, organic solvent and organic metal additive, resin acid gold 20-30wt%, resin 10-20wt%, organic metal additive 1.5-3wt%, the mass ratio of organic chromium, organic bismuth, organic copper and organic yttrium in organic metal additive is 1.1:1.3:0.3:0.3;Organic yttrium prepared gold slurry has excellent high-temperature resistance and reduces cost.The method for preparing gold coating based on organic gold slurry can withstand higher annealing temperature, reduce the defects of gold coating, and maintain the stability of gold coating.The prepared gold coating has good adhesion and infrared reflection performance on the surface of quartz.The gold coating prepared based on organic yttrium can achieve the same high-temperature resistance as organic rhodium.The reflectivity of the obtained gold coating in the near-infrared region can reach 96%, which prolongs the service life of the coating while maintaining the optical performance.

Description

Technical Field

[0001] The invention belongs to the technical field of coating slurries, and in particular relates to a high-temperature resistant organic gold slurry and a gold coating for infrared reflection. Background Art

[0002] Gold has good chemical stability, high conductivity and excellent ductility, and is widely used in many fields such as electronics, optics, semiconductor epitaxial growth equipment, construction engineering and aerospace engineering. In these applications, gold usually exists in the form of thin films. The methods for preparing gold thin films mainly include physical and chemical methods, such as physical vapor deposition methods such as thermal evaporation, electron beam deposition, magnetron sputtering, and electrochemical deposition. Although these methods can produce high-quality gold films, the cost of physical vapor deposition is high and it is difficult to apply to complex structure surfaces, while the electrochemical deposition method requires the substrate to be conductive, which limits the application areas of gold thin films.

[0003] An organic gold paste formulated with organic gold is applied to the surface by brushing or spraying, followed by annealing to create a gold coating. This method is applicable to complex surfaces and allows for customized color control, effectively addressing issues with physical vapor deposition and electrochemical deposition.

[0004] Although the invention of organic gold coatings has a history of more than 100 years, its main components have changed little. The main components are organic gold molecules (including resin gold, thiol gold, etc.), and also include metal additives such as chromium (Cr), bismuth (Bi), indium (In), and tin (Sn) to enhance the adhesion of the gold coating, which are used to prevent gold particles from agglomerating; palladium (Pd) and rhodium (Rh) to maintain film uniformity; iron (Fe), zinc (Zn), and titanium (Ti) to control the color of the film. For example, the invention application with publication number CN113921165A discloses an organic gold paste, which contains trifunctional thiol resin acid gold, resin acid rhodium, resin acid palladium, an organic metal compound additive, and an organic carrier. The rhodium element is conducive to obtaining a dense, bright, crack-free, and highly conductive film after sintering. The reason is that metal rhodium (Rh) exists in the form of oxide at the grain boundaries of gold particles, which can effectively prevent the fusion of adjacent gold particles at high temperatures and maintain the stability of the film structure, thereby enabling the gold coating to withstand higher annealing temperatures, reducing gold coating defects, ensuring the optical properties of the gold coating, and improving adhesion to the substrate surface.

[0005] In the process of converting organic gold coating into gold coating, different organic substances can decompose in different temperature intervals. The decomposition temperature of rhodium resinate is higher than that of other organic metals, but lower than the resin in the coating. Under certain temperature conditions, rhodium oxide can be formed and coated on the surface of gold particles, which can effectively prevent the fusion of adjacent gold particles under high temperature. Although the addition amount of rhodium is less, its price is higher, which has increased the cost of coating to a certain extent. Therefore, it is necessary to develop other organic metal additives to replace rhodium and reduce the cost of organic gold slurry. For example, the invention application of publication number CN114639501A discloses a low-cost organic gold slurry, and the coating is mainly composed of gold resinate, tin resinate, erbium resinate, bismuth resinate, chromium resinate, iron resinate and manganese resinate. Wherein the composite action of tin resinate and erbium resinate can make the film withstand high temperature without cracks, replacing rhodium resinate, and maintaining the stability of film structure.

[0006] Based on the decomposition process of organic gold, more high-temperature resistant metal additives are developed to form a high-temperature resistant diffusion barrier layer on the surface of gold particles to maintain the stability of the gold film structure, thereby improving the flexibility of organic gold coating formulation and reducing costs. This is an urgent problem that needs to be solved in the current gold coating field. Summary of the Invention

[0007] The purpose of the present invention is to provide a high-temperature resistant organic gold slurry and an infrared reflective gold coating, which can be used to develop more high-temperature resistant metal additives, maintain the structural stability of the gold coating film, and improve the flexibility of the organic gold coating formulation.

[0008] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0009] The present invention provides a high-temperature resistant organic gold slurry, comprising resinate gold, resin, an organic solvent and an organic metal additive, wherein the organic metal additive comprises organic chromium, organic bismuth, organic copper and organic yttrium, wherein the mass percentage of the organic metal additive is 1.5%-3%, and the mass ratio of the organic chromium, organic bismuth, organic copper and organic yttrium in the organic metal additive is 1.1:1.3:0.3:0.3.

[0010] Preferably, the mass percentage of the resin acid gold in the high temperature resistant organic gold paste is 20%-30%; the mass percentage of the resin is 10%-20%.

[0011] Preferably, the gold resinate is obtained by reacting sulfide balsam with gold chlorate. For the specific preparation method, reference may be made to the invention patents with publication numbers CN117316491A and CN112735631A.

[0012] Preferably, the resin includes one or more of terpene resin, epoxy resin, acrylic resin, alkyd resin and rosin resin.

[0013] Resin has good adhesion and high temperature resistance and is widely used in the adhesive field to enhance the hardness and wear resistance of the coating. In addition, resin has good mechanical properties and is widely used in packaging materials, optical materials and other electronic components.

[0014] Preferably, the organic solvent is one or more of terpineol, linalool, camphor oil, turpentine, ethylene glycol monobutyl ether, dibutyl phthalate and trichloroethane.

[0015] As a volatile component, the organic solvent can provide polar groups and prevent the slurry from coagulating and deteriorating during long-term storage. It is used to mix the organic metal additives and other solid powders to form a paste slurry.

[0016] Preferably, the organic yttrium is selected from one or both of yttrium isooctanoate and yttrium neodecanoate;

[0017] Preferably, the organic bismuth is selected from one or both of bismuth isooctanoate and bismuth neodecanoate.

[0018] Bismuth isooctanoate or bismuth neodecanoate has good stability in high temperature and acidic environment, is not easy to decompose, and can improve the chemical resistance and high temperature resistance of the material.

[0019] Preferably, the organic chromium is selected from one or both of chromium isooctanoate and chromium neodecanoate.

[0020] Chromium 2-ethylhexanoate and chromium neodecanoate can be used as rust inhibitors on metal surfaces to enhance oxidation resistance and corrosion resistance, and improve processing quality and efficiency.

[0021] Preferably, the organic copper is selected from one or both of copper octoate and copper neodecanoate.

[0022] Copper 2-ethylhexanoate and copper neodecanoate can be used as paint additives to improve the conductivity of the paint.

[0023] The present invention also proposes a method for preparing an infrared reflective gold coating, which uses the high-temperature resistant organic gold slurry; the method for preparing an infrared reflective gold coating comprises: applying the high-temperature resistant organic gold slurry on the surface of a high-temperature resistant substrate by brushing or spraying, leveling it, and then annealing it to obtain a gold coating.

[0024] Brushing or spraying is suitable for high-solids, high-viscosity coatings and can be used to coat complex shapes with great flexibility.

[0025] Preferably, the leveling is carried out at room temperature for 10-30 minutes.

[0026] The room temperature leveling method can help the paint form a flat, smooth and uniform coating film during the drying process, thereby improving the decorative and protective functions of the paint.

[0027] Preferably, the annealing process includes two heating steps, the first step is a heating temperature of 80-100°C and a heating time of 10 minutes; the second step is a heating temperature of 750-850°C and a heating time of 10 minutes; the heating rate during the annealing process is 10°C / min. After the heating is completed, the temperature is naturally cooled. When the temperature drops below 100°C, the sample is taken out to obtain a gold coating for infrared reflection.

[0028] The purpose of the first annealing treatment is to keep the slurry fixed after leveling, which is beneficial for the subsequent second step treatment.

[0029] More preferably, the first step heating temperature is 80° C., and the heating time is 10 min; the second step heating temperature is 850° C., and the heating time is 10 min.

[0030] The invention also proposes a gold coating for infrared reflection prepared based on the method.

[0031] The invention also proposes the application of the infrared reflective gold coating in a coating reactor.

[0032] The beneficial effects of the present invention are:

[0033] The present invention provides a high-temperature resistant organic gold paste, which uses organic yttrium as a high-temperature resistant organic metal additive to prepare the organic gold paste. The obtained organic gold paste has excellent high-temperature resistance and effectively reduces the cost of the organic gold paste.

[0034] The method for preparing an infrared reflective gold coating provided by the present invention uses a high-temperature resistant organic gold slurry that can withstand high annealing temperatures, reduces defects in the gold coating, and maintains the stability of the gold coating. The prepared gold coating has good adhesion to the quartz surface and excellent infrared reflective performance. Organic yttrium is used as a high-temperature resistant organic metal additive to achieve good high-temperature resistance. The reflectivity of the obtained gold coating in the near-infrared region can reach 96%, effectively reducing the cost of the organic gold coating while maintaining the optical properties of the gold coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is an optical picture of the gold coating, where Figure 1 A in the figure is an optical image of gold coatings prepared with different high-temperature resistant agents; Figure 1 Figure B is an optical image of the gold coating prepared on the cylindrical quartz surface using yttrium-containing gold slurry.

[0036] Figure 2Microstructural characterization of the gold coatings prepared from the organic gold paste prepared in Example 1 at different annealing temperatures.

[0037] Figure 3 Near-infrared reflectivity of gold coatings prepared for different high-temperature agents.

[0038] Figure 4 Near-infrared reflection properties of gold coatings prepared at different annealing temperatures.

[0039] Figure 5 To characterize the adhesion of gold coating prepared by yttrium-gold slurry on quartz surface, Figure 5 A in the figure is the adhesion strength curve of the gold coating prepared on the quartz surface by using yttrium-gold slurry; Figure 5 Figure B is an optical microscope image of the scratch of the gold coating prepared with yttrium-gold slurry.

[0040] Figure 6 The gold coating photos of the organic gold pastes prepared in Comparative Examples 3 and 4 are shown in FIG. Figure 6 A is a gold coating prepared from a yttrium-containing gold slurry with 0.1 wt%; Figure 6 B is a gold coating prepared without organic metal additives. DETAILED DESCRIPTION

[0041] Example 1

[0042] The preparation method of yttrium-containing organic gold paste is as follows:

[0043] Gold resinate (YDAUP002, Industrial Technology Research Institute) was added to a mixed solution of terpineol and linalool, wherein the mass ratio of terpineol to linalool was 1:1, and a stable solution was obtained by magnetic stirring, namely the gold resinate solution.

[0044] Add terpene resin to terpineol solution and use ultrasonic dispersion to form a uniform and stable solution, which is the resin solution.

[0045] The resin solution is added to the resinate gold solution, and organic metal additives such as chromium isooctanoate, bismuth isooctanoate, copper isooctanoate and yttrium isooctanoate are added and fully mixed to prepare an organic gold coating containing 30wt% of resinate gold, 20wt% of terpene resin, 1.1wt% of chromium isooctanoate, 1.3wt% of bismuth isooctanoate, 0.3wt% of copper isooctanoate and 0.3wt% of yttrium isooctanoate.

[0046] Example 2

[0047] The organic gold slurry is prepared in the same manner as in Example 1, except that the resin acid gold is 20 wt % to obtain the organic gold slurry.

[0048] Example 3

[0049] The organic gold paste is prepared in the same manner as in Example 1, except that the resin is 10 wt %.

[0050] Example 4

[0051] The organic gold paste is prepared in the same manner as in Example 1, except that the mass ratio of chromium isooctanoate, bismuth isooctanoate, copper isooctanoate and yttrium isooctanoate is 1.1:1.3:0.3:0.3, wherein the yttrium isooctanoate is 0.15 wt %, to obtain the organic gold paste.

[0052] Example 5

[0053] The organic gold paste is prepared in the same manner as in Example 1, except that the mass ratio of chromium isooctanoate, bismuth isooctanoate, copper isooctanoate and yttrium isooctanoate is 1.1:1.3:0.3:0.3, wherein the yttrium isooctanoate is 0.1 wt %, to prepare the organic gold paste.

[0054] Comparative Example 1

[0055] The preparation method of rhodium-containing organic gold slurry is as follows:

[0056] The organic gold slurry preparation method of Example 1 is as follows, except that yttrium isooctanoate is replaced by rhodium isooctanoate, and the components of other organic metal additives remain unchanged to prepare an organic gold coating.

[0057] Comparative Example 2

[0058] The preparation method of zirconium-containing organic gold slurry is as follows:

[0059] The organic gold slurry preparation method of Example 1 is as follows, except that yttrium isooctanoate is replaced by zirconium isooctanoate, and the components of other organic metal additives remain unchanged, to prepare an organic gold coating.

[0060] Comparative Example 3

[0061] The preparation method of organic gold paste without high temperature resistant agent is as follows:

[0062] The organic gold slurry preparation method of Example 1 is as follows, except that yttrium isooctanoate is removed and the components of other organic metal additives in the organic gold slurry remain unchanged to prepare an organic gold coating.

[0063] Test Example 1

[0064] Preparation of gold coating using organic gold paste: The organic gold pastes obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were evenly brushed on the surface of a quartz substrate, respectively, and placed at room temperature in a clean environment for 10-30 minutes. The samples were then transferred to an annealing furnace for a two-step annealing treatment.

[0065] The specific annealing process is as follows: the first step of annealing is to heat up to 80°C at a rate of 10°C / min and heat for 10 minutes; then the temperature is raised to 850°C at a rate of 10°C / min and heated for 10 minutes. After heating is completed, when the annealing furnace temperature drops below 100°C, the sample is taken out to obtain a gold coating.

[0066] Another group of gold coatings underwent a two-step annealing process. The first annealing process involved heating to 100°C at a rate of 10°C / min for 10 minutes. The temperature was then raised to 850°C at a rate of 10°C / min for 10 minutes. After heating, the annealing furnace temperature dropped below 100°C, and the samples were removed to obtain the gold coatings. The first annealing process ensures the slurry remains stable after leveling, facilitating the subsequent second step. Unless otherwise specified, the first annealing temperature is assumed to be 80°C, and the second annealing temperature is 850°C.

[0067] like Figure 1 The following are optical images of gold coatings prepared using the organic gold pastes of Example 1 and Comparative Examples 1-3, as well as an optical image of a gold coating prepared on a cylindrical quartz surface using an organic gold paste containing yttrium (Example 1). The results show that when zirconium (Comparative Example 2) is used as a heat-resistant agent, the resulting gold coating film has a reddish color. However, when yttrium and rhodium (Example 1 and Comparative Example 1) are used as heat-resistant agents, the gold coating has minimal color difference, which does not affect the coating's appearance and can replace high-cost gold coatings of the same color.

[0068] Test Example 2

[0069] Scanning electron microscopy (SEM) was used to characterize the microstructure of gold coatings prepared using the organic gold paste prepared in Example 1 at different annealing temperatures and with different numbers of layers. The gold coatings were prepared using the same method as in Example 1, except that the annealing temperature was set at 450°C or 850°C to produce a single-layer gold coating. In another set of experiments, the organic gold paste application and annealing steps were repeated at 850°C. This process was repeated twice to produce a triple-layer gold coating, based on the single-layer gold coating.

[0070] The results are as follows Figure 2 Specifically, the single-layer gold coating with an annealing temperature of 450°C and the single-layer and triple-layer gold coatings with an annealing temperature of 850°C were characterized respectively.

[0071] The results show that the thickness of a single-layer gold coating prepared by annealing an organic gold paste containing yttrium at 450°C is about 130nm, and the thickness of a single-layer gold coating prepared by annealing an organic gold paste containing yttrium at 850°C is about 100nm. The gold coating prepared by annealing at 450°C has more surface defects, indicating that the higher the annealing temperature, the fewer microscopic defects in the coating and the denser the coating, which is beneficial to improving the corrosion resistance of the coating and extending the service life of the gold coating.

[0072] Test Example 3

[0073] The method for preparing the gold coating is the same as that in Test Example 1, and the near-infrared reflection properties of the gold coatings prepared with different high-temperature resistant agents are analyzed. Figure 3 Shown are the infrared reflectivities of the high-temperature resistant agents yttrium, rhodium, and zirconium. The measured reflectivities are relative values, with the evaporated gold coating as the benchmark.

[0074] The results show that in the near-infrared region of 1000-2500nm, the reflectivity of rhodium as a high-temperature resistant agent can reach 98%; yttrium can reach 96%; the reflectivity of zirconium is slightly lower, at about 90% or more, indicating that when yttrium is used as a high-temperature resistant agent, the near-infrared reflection performance of the gold coating is close to that of rhodium, which can reduce the cost of high-temperature resistant gold coatings.

[0075] Test Example 4

[0076] The near-infrared reflection performance of the gold coating prepared at different annealing temperatures was analyzed. The method for preparing the gold coating was the same as that in Test Example 1, and the high-temperature resistant agent was yttrium. The annealing temperature of the yttrium high-temperature resistant agent gold coating was set to 750°C or 850°C. Figure 4 Shown is the near-infrared reflectivity of gold coatings prepared at different annealing temperatures. The measured reflectivity is a relative value, with the evaporated gold coating as a benchmark.

[0077] The results show that in the near-infrared region of 1000-2500nm, the near-infrared reflection performance of the gold coating containing yttrium high-temperature resistant agent prepared at 750℃ or 850℃ annealing temperature is similar.

[0078] Test Example 5

[0079] The method for preparing the gold coating is the same as that in Test Example 1. The adhesion of the coating determines the lifespan of the coating. Therefore, a scratch tester was used to characterize the adhesion strength of the prepared gold coating on the quartz surface. The surface adhesion strength of the coating refers to the strength of the bonding between the coating and the substrate, that is, the energy required per unit surface area of ​​the coating to peel off from the substrate (or intermediate coating). The bonding strength between the coating and the substrate is an important indicator of coating performance. If the bonding strength is weak, it will cause the coating lifespan to be reduced, premature failure, or the coating to fall off (peel off) and become unusable.

[0080] like Figure 5 As shown, the adhesion strength of the gold coating containing the high-temperature resistant agent yttrium is 33J / m 2 The bonding strength between pure gold and silicon oxide is 0.39 J / m 2 The energy density generated by the difference in thermal expansion coefficients of the quartz surface with a gold coating of 100 nm thickness at a temperature difference of 850°C is 0.90 J / m 2Therefore, the obtained gold coating containing the high-temperature resistant agent yttrium has greater adhesion and stronger high-temperature impact resistance.

[0081] Test Example 6

[0082] The method for preparing the gold coating is the same as that in Example 1. Figure 6 The figure shows the gold coatings prepared by the organic gold slurries of Comparative Example 3 and Example 5. The results show that the surface distribution of the gold coating obtained when the yttrium isooctanoate content is low or removed is uneven. When the yttrium content is 0.1wt%, there is aggregation in the coating; while the gold coating without organic yttrium cannot form a complete film, and the defects in the film will produce stress concentration points, which will cause the coating to fall off and fail.

Claims

1. A high temperature resistant organic gold paste comprising resin acid gold, resin, organic solvent and organic metal additive, characterized in that: The components of the organometallic additive are composed of organic chromium, organic bismuth, organic copper and organic yttrium, wherein the mass percentage of the organometallic additive is 1.5%-3%, and the mass ratio of organic chromium, organic bismuth, organic copper and organic yttrium in the organometallic additive is 1.1:1.3:0.3:0.

3.

2. The high temperature resistant organic gold paste according to claim 1, characterized in that The mass percentage of the resin acid gold in the high-temperature resistant organic gold paste is 20%-30%; the mass percentage of the resin is 10%-20%.

3. The high temperature resistant organic gold paste according to claim 1, characterized in that The gold resinate is obtained by reacting gold chlorate with sulfurized balsam.

4. The high temperature resistant organic gold paste according to claim 1, characterized in that The resin includes one or more of terpene resin, epoxy resin, acrylic resin, alkyd resin and rosin resin.

5. The high temperature resistant organic gold paste according to claim 1, characterized in that The organic solvent is one or more of terpineol, linalool, camphor oil, turpentine, ethylene glycol monobutyl ether, dibutyl phthalate and trichloroethane.

6. A method for preparing an infrared reflective gold coating, characterized in that: Using the high temperature resistant organic gold paste according to any one of claims 1 to 5; The method for preparing the infrared reflective gold coating comprises: applying the high-temperature resistant organic gold slurry on the surface of a high-temperature resistant substrate by brushing or spraying, leveling the slurry, and then performing an annealing process to obtain the gold coating.

7. The method for preparing an infrared reflective gold coating according to claim 6, characterized in that: The leveling is carried out at room temperature for 10-30 minutes.

8. The method for preparing an infrared reflective gold coating according to claim 6, wherein: The annealing process includes two heating steps. The first step is a heating temperature of 80-100°C and a heating time of 10 minutes. The second step is a heating temperature of 750-850°C and a heating time of 10 minutes. The heating rate during the annealing process is 10°C / min. After the heating is completed, the temperature is naturally cooled. When the temperature drops below 100°C, the sample is taken out to obtain a gold coating for infrared reflection.

9. A gold coating for infrared reflection prepared according to the method according to any one of claims 6 to 8.

10. Use of the infrared reflective gold coating according to claim 9 in a coating reactor.

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