Glass powder, conductive paste containing glass powder and thick-film resistor

Abstract

The invention relates to the field of electronic paste, in particular to glass powder, conductive paste containing the glass powder and a thick-film resistor. The glass powder is prepared from the following components in percentage by weight: 15 to 32 percent of SrO, 14 to 25 percent of BaO, 20 to 38 percent of SiO2, 7 to 15 percent of ZnO, 7 to 16 percent of TiO2 and 8 to 20 percent of B2O3. The conductive paste comprises the following components in percentage by mass: 58-70% of a conductive material, 2-12% of glass powder, 18-34% of an organic carrier and 0.5-8% of an inorganic additive. According to the glass powder, high-cost raw materials and waste gas are avoided, meanwhile, the glass powder has good mechanical performance due to introduction of Ti, and the glass powder has good thermal shock resistance due to symmetry of silicon. According to the conductive paste, the binding force between a conductive layer formed after the conductive paste is cured and the substrate can be effectively improved, and the sheet resistance of the conductive layer is reduced.

Description

Technical Field

[0001] This invention relates to the field of electronic pastes, specifically to a glass powder, a conductive paste containing the glass powder, and a thick-film resistor. Background Technology

[0002] Conductive pastes for thick-film resistors are mainly used in electronic circuits. They are formed on a substrate by screen printing technology and then sintered at high temperature, so that the silver powder particles in the conductive paste form a conductive network. The composition includes silver powder, organic carrier, glass powder and inorganic additives. Among them, glass powder is the key functional phase in conductive pastes for thick-film resistors. The glass system focuses on the precise control of resistivity, the adjustment of temperature stability and the bonding force.

[0003] In conductive pastes for thick-film resistors, glass powder acts as a sintering aid. During sintering, it melts to form a liquid phase that promotes the bonding between silver particles, allowing them to adhere to the substrate. Simultaneously, through interfacial reactions (such as forming Ag-O-Si bonds with silver), it influences the connectivity of the conductive network, thereby adjusting the resistance value. Furthermore, the melted glass powder can coat the silver particles to form a glass layer, preventing oxidation and improving their high-temperature aging performance. Moreover, the coefficient of thermal expansion of the glass powder must match that of the substrate (such as ceramic) to prevent cracking after sintering.

[0004] Currently, common glass powder systems include PbO-B2O3-SiO2, Bi2O3-B2O3-ZnO, TeO2-V2O5, and P2O5-ZnO-Al2O3. PbO-B2O3-SiO2 glass powder is suitable for high-temperature sintering above 850℃, which can optimize the electrode contact resistance of chip resistors and improve adhesion. However, lead-containing glass is environmentally unfriendly and requires high sintering temperatures. Currently, lead-free glass is being developed as an alternative to achieve lower sintering temperatures and no adverse environmental impact. Lead-free Bi2O3-B2O3-ZnO glass is used for chip resistor electrodes, with a sintering temperature of 550~650℃. Lead-free TeO2-V2O5 glass is also suitable for low-temperature sintering and can be used in high-precision resistors, but the high cost of Bi2O3 and TeO2 raw materials limits its large-scale application. Lead-free glass based on the P2O5-ZnO-Al2O3 system exhibits good moisture resistance and is suitable for high-reliability resistors. However, the high-temperature melting process of P2O5 generates a certain amount of waste gas. Furthermore, the asymmetry of the [PO4] structure can cause the glass to crack at extreme high or low temperatures. All of these glass powder systems have drawbacks that significantly impact the application of conductive pastes. Summary of the Invention

[0005] In order to overcome at least one of the technical problems existing in the prior art, one of the objectives of the present invention is to provide a glass powder.

[0006] The second objective of this invention is to provide a method for preparing glass powder.

[0007] The third objective of this invention is to provide a conductive paste.

[0008] The fourth objective of this invention is to provide a thick-film resistor.

[0009] The fifth objective of this invention is to provide an electronic product.

[0010] The sixth objective of this invention is to provide applications of the aforementioned glass powder, conductive paste, thick-film electronics, or electronic products in the fields of consumer electronics, automotive electronics, industrial control, communication equipment, medical equipment, new energy, or power equipment.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of the present invention provides a glass powder comprising the following components in weight percentages: SrO 15~32%, BaO 14~25%, SiO2 20~38%, ZnO 7~15%, TiO2 7~16%, and B2O3 8~20%.

[0012] The glass powder in this invention contains strontium oxide (SrO) and barium oxide (BaO), both of which act as network modifiers and can provide free oxygen ions (O2). 2- The Si-O network is broken, reducing melt viscosity and improving flowability; SrO (thermal expansion coefficient CTE≈10×10) -6 / K) and BaO (CTE≈12×10 -6 / K) can optimize the overall CTE of the glass powder, making the glass powder match the ceramic substrate.

[0013] In some embodiments of the present invention, the weight percentage of SrO is any value or a range formed by any two of the following: 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, and 32%. When the weight percentage of SrO is within the range defined by the present invention, sufficient free oxygen ions can be provided, thereby adjusting the softening temperature and viscosity of the glass powder. If the weight percentage of SrO is too high, it will affect the strength of the sintered product, leading to easy cracking. In some preferred embodiments of the present invention, the weight percentage of SrO is 15% to 28%.

[0014] In some embodiments of the present invention, the weight percentage of BaO is any value or a range formed by any two of 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, and 25%; in some preferred embodiments of the present invention, the weight percentage of BaO is 14% to 20%. When the weight percentage of SrO is within the range defined by the present invention, sufficient free oxygen ions can be provided, thereby adjusting the softening temperature and viscosity of the glass powder, improving the wettability of the glass, and matching the sintering temperature.

[0015] In some embodiments of the present invention, the weight percentages of SrO and BaO are 29-46%. The present invention can optimize the balance between sintering activity and thermal stress by adjusting the content of SrO and BaO, resulting in a resistive layer with both excellent acid resistance and bonding strength. Even better results can be achieved when the weight percentage of SrO+BaO is between 29-42%. Furthermore, BaO enhances acid resistance, and SrO improves solderability; introducing SrO and BaO into the glass powder can improve the overall chemical stability of the glass powder.

[0016] In some embodiments of the present invention, the weight percentage of SiO2 is any value or a range formed by any two of the following: 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, and 38%. In some preferred embodiments of the present invention, the weight percentage of SiO2 is 25% to 38%. In some preferred embodiments of the present invention, the weight percentage of SiO2 is 25% to 32%. Silica (SiO2), as a network forgery, is a major component of the glass skeleton, forming a stable [SiO4] tetrahedral structure, providing mechanical strength and chemical inertness, while also increasing the softening point of the glass and enhancing its high-temperature stability. If the SiO2 content is too low, it will affect the network structure of the glass, resulting in excessively low strength and hardness; if the SiO2 content is too high, its thermal expansion coefficient will not match that of the ceramic substrate, leading to cracking and peeling of the sintered product.

[0017] In some embodiments of the present invention, the weight percentage of ZnO is any value or a range formed by any two of 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, and 15%; in some embodiments of the present invention, the weight percentage of ZnO is 8% to 14%. Zinc oxide (ZnO), as an intermediate oxide, can act as a network modifier (breaking Si-O bonds) and participate in network formation ([ZnO4]); zinc oxide (ZnO) and B2O3 synergistically reduce the glass softening point; in addition, Zn 2+It can fill the gaps in the glass network, blocking the diffusion path of silver ions and thus inhibiting silver migration. If the ZnO content is too low, the alkali resistance will decrease and it will not be conducive to inhibiting silver migration; if the ZnO content is too high, it will not be conducive to clarification, resulting in the formation of non-uniform glass, unstable quality, easy precipitation of zinc siliceous minerals, shortened material properties, narrowed processing window, and weak sealing.

[0018] In some embodiments of the present invention, the weight percentage of TiO2 is any value or a range formed by any combination of 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, and 16%; in some embodiments of the present invention, the weight percentage of TiO2 is 9% to 14%. Titanium dioxide (TiO2) acts as a stabilizer, improving the hardness and wear resistance of glass, while also enhancing its alkali resistance. If the TiO2 content is too low, the strength improvement is not significant and cannot be matched with practical applications; if the TiO2 content is too high, the cost increases and the melting temperature needs to be increased to avoid problems such as difficulty in refining and non-uniform glass.

[0019] In some embodiments of the present invention, the weight percentage of B2O3 is any value or a range formed by any two of 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, and 20%; in some embodiments of the present invention, the weight percentage of B2O3 is 9% to 18%; in some embodiments of the present invention, the weight percentage of B2O3 is 9% to 16%. Boron oxide (B2O3), as a flux, can lower the melting temperature of glass. During the formation of [BO3] triangles, it partially converts to [BO4], reducing viscosity. Boron oxide also plays a role in regulating the coefficient of thermal expansion (CTE). By changing the BO bond ratio, the glass powder can match the coefficient of thermal expansion of the ceramic substrate (e.g., the CTE of Al2O3 is approximately 7 × 10⁻⁶). -6 / K); it can also enhance adhesion by promoting the interfacial reaction between glass and substrate (such as Si, ceramic). If the B2O3 content is too low, the stability of the glass decreases, crystals easily precipitate, and the interfacial reaction between the glass and the substrate is affected, resulting in a decrease in adhesion; if the B2O3 content is too high, it will lead to a mismatch with the thermal expansion coefficient of the substrate, resulting in cracking and peeling of the sintered product.

[0020] In some embodiments of the present invention, the average particle size of the glass powder is 1~3μm.

[0021] The second aspect of the present invention provides a method for preparing the glass powder described in the first aspect of the present invention, comprising the following steps: melting and mixing the raw materials at 1000~1300℃, followed by quenching and cooling to obtain the powder.

[0022] In some embodiments of the present invention, the melting temperature is any value or a range formed by any two of the following: 1000°C, 1020°C, 1040°C, 1050°C, 1060°C, 1080°C, 1100°C, 1120°C, 1140°C, 1150°C, 1160°C, 1180°C, 1200°C, 1220°C, 1240°C, 1250°C, 1260°C, 1280°C, and 1300°C.

[0023] A third aspect of the present invention provides a conductive paste comprising the glass powder described in the first aspect of the present invention.

[0024] In some embodiments of the present invention, the conductive paste comprises the following components by mass percentage: 58-70% conductive material, 2-12% glass powder, 18-34% organic carrier, and 0.5-8% inorganic additives.

[0025] In some embodiments of the present invention, the mass percentage of the conductive material is any value or a range formed by any two of 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, and 70%; in some preferred embodiments of the present invention, the mass percentage of the conductive material is 60% to 65%. When the content of the conductive material is within the range defined by the present invention, the conductive paste has good leveling properties, which is beneficial to improving the conductivity and compositional uniformity of the conductive layer formed by the cured conductive paste. The conductive paste has a lower cost while ensuring conductivity.

[0026] In some embodiments of the present invention, the conductive material includes at least one of spherical silver powder, near-spherical silver powder, and flake silver powder. In some embodiments of the present invention, the conductive material contains 70-90% by mass of spherical and / or near-spherical silver powder and 10-30% by mass of flake silver powder, based on the total mass of the conductive material. The present invention uses a combination of spherical or near-spherical silver powder and flake silver powder, which can improve the density of the conductive layer formed after the conductive paste has cured and enhance its adhesion to the substrate.

[0027] In some embodiments of the present invention, the mass percentage of the spherical and / or near-spherical silver powder is any value or a range formed by any two of the following: 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%.

[0028] In some embodiments of the present invention, the mass percentage of the flake silver powder is any value or a range formed by any two of the following: 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%.

[0029] In some embodiments of the present invention, the mass percentage of the glass powder is any value or a range formed by any two of 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, and 12%; in some preferred embodiments of the present invention, the mass percentage of the glass powder is 3% to 10%; in some embodiments of the present invention, the mass percentage of the glass powder is 4% to 8%. When the content of glass powder is within the range defined by the present invention, it can play an excellent bonding role, with a low resistance value, which is beneficial to improving the conductivity of the conductive layer formed by the curing of the conductive paste.

[0030] In some embodiments of the present invention, the mass percentage of the organic carrier is any value or a range formed by any two of 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, and 34%; in some preferred embodiments of the present invention, the mass percentage of the organic carrier is 20%-30%. When the content of the organic carrier is within the range defined by the present invention, the conductive paste has good fluidity, can form a uniform printing pattern when using screen printing, and has very low carbon residue and porosity during sintering, which is beneficial for obtaining a high-performance conductive layer.

[0031] In some embodiments of the present invention, the organic carrier contains resin, organic additives and solvent.

[0032] In some embodiments of the present invention, the organic carrier comprises the following components by weight percentage: 5-20% resin, 2-5% organic additives, and 55-75% solvent, based on the total weight of the organic carrier.

[0033] In some embodiments of the present invention, the weight percentage of the resin is any value or a range formed by any combination of 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, and 20%. The resin in the present invention serves to provide mechanical strength, adhesion, and regulate the sintering behavior of the conductive paste.

[0034] In some embodiments of the present invention, the resin includes at least one of rosin resin, ethyl cellulose, and methyl cellulose.

[0035] In some embodiments of the present invention, the weight percentage of the organic additive is any value selected from 2%, 3%, 4%, and 5%, or a range formed by any combination of both. The organic additive in the present invention serves to improve the dispersibility and rheological properties of the conductive paste.

[0036] In some embodiments of the present invention, the organic additive is selected from at least one of polyvinylpyrrolidone, hexadecyltrimethylammonium bromide, and sodium dodecylbenzenesulfonate.

[0037] In some embodiments of the present invention, the weight percentage of the solvent is any value or a range formed by any combination of 55%, 56%, 58%, 60%, 62%, 64%, 66%, 68%, 70%, 72%, 74%, and 75%. The solvent in the present invention serves to adjust the viscosity of the conductive paste and improve its printing performance.

[0038] In some embodiments of the present invention, the solvent includes at least one of terpineol, N-methylpyrrolidone, and diethylene glycol butyl ether.

[0039] In some embodiments of the present invention, the mass percentage of the inorganic additive is any value or a range formed by any two of 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, and 8%; in some preferred embodiments of the present invention, the mass percentage of the inorganic additive is 1%-5%; in some embodiments of the present invention, the mass percentage of the inorganic additive is 2%-4%. When the content of the inorganic additive is within the range defined by the present invention, the conductive layer formed by the curing of the conductive paste can have a stable resistance value, and the shrinkage rate of the conductive paste during the curing process can be controlled, so that the conductive paste can match the coefficient of thermal expansion of the substrate, enhance the adhesion of the conductive layer formed by the curing of the conductive paste, and improve the solderability of the conductive layer. Without the addition of inorganic additives, it is difficult to obtain the required strength and coefficient of thermal expansion.

[0040] In some embodiments of the present invention, the inorganic additive is selected from at least one of Al2O3, ZnO, Fe2O3, NiO, and SiO2.

[0041] In some embodiments of the present invention, the viscosity of the conductive paste measured at 25°C is 10~50 Pa·s (measured with a Brookfield viscometer); in some embodiments of the present invention, the viscosity of the conductive paste measured at 25°C is any value or a range formed by any two of the following: 10 Pa·s, 15 Pa·s, 20 Pa·s, 25 Pa·s, 30 Pa·s, 35 Pa·s, 40 Pa·s, 45 Pa·s, and 50 Pa·s.

[0042] In some embodiments of the present invention, the conductive paste is prepared by a method comprising the following steps: mixing the raw materials, then rolling, and degassing.

[0043] In some embodiments of the present invention, the mixing time is 30 to 60 minutes.

[0044] In some embodiments of the present invention, the rolling process is performed 2 to 10 times.

[0045] In some embodiments of the present invention, the fineness of the conductive paste is ≤10μm (as measured by a Hegman fineness meter).

[0046] In some embodiments of the present invention, the degassing is performed using vacuum degassing or centrifugal degassing.

[0047] A fourth aspect of the present invention provides a thick film resistor including a conductive layer formed by curing the conductive paste described in the first aspect of the present invention.

[0048] A fifth aspect of the present invention provides an electronic product comprising a conductive layer made of the conductive paste described in the first aspect of the present invention or comprising a thick film resistor described in the fourth aspect of the present invention.

[0049] The sixth aspect of the present invention provides the application of the glass powder described in the first aspect of the present invention, the conductive paste described in the third aspect of the present invention, the thick film resistor described in the fourth aspect of the present invention, or the electronic product described in the fifth aspect of the present invention in the fields of consumer electronics, automotive electronics, industrial control, communication equipment, medical equipment, new energy or power equipment.

[0050] The beneficial effects of this invention are as follows: The glass powder used in this invention adopts a Sr-Ba-Si-Zn-Ti-B glass system, avoiding high-cost raw materials and waste gas. The introduction of Ti provides better mechanical properties, and the symmetry of silicon gives the glass powder good thermal shock resistance. Furthermore, the glass powder in this invention exhibits high molten interface reactivity during sintering, and after sintering, it has a thermal expansion coefficient compatible with the substrate, thereby improving adhesion. In addition, the glass powder in this invention is lead-free, non-toxic, and environmentally friendly, meeting environmental protection requirements.

[0051] The conductive paste of this invention introduces glass powder of the Sr-Ba-Si-Zn-Ti-B system and adjusts the content ratio of each component to effectively improve the bonding force between the conductive layer formed after the conductive paste is cured and the substrate, and reduce the sheet resistance of the conductive layer. Specifically: (1) The improved bonding force is mainly achieved by optimizing the composition and content of the glass powder, which improves the reactivity of the glass melting interface, so that the substrate and the conductive layer are tightly bonded. At the same time, the glass powder has a suitable coefficient of thermal expansion after sintering, so that the conductive layer and the substrate are free from obvious stress, thereby improving the bonding strength. The stronger bonding force also effectively improves the acid resistance of the thick film resistor. (2) The sheet resistance is effectively reduced, mainly by controlling the composition and content of the glass powder, improving the viscosity and bonding force of the glass, promoting the rearrangement of silver particles to form a continuous conductive network, and improving the interface wettability.

[0052] Furthermore, the conductive layer formed by the curing of the conductive paste in this invention has clear printed lines without obvious jagged edges, resulting in a superior printed appearance. Attached Figure Description

[0053] Figure 1 This is a printed appearance diagram of the conductive layer in Example 1.

[0054] Figure 2 This is a photograph of the conductive layer after acid washing test in Example 1. Detailed Implementation

[0055] The specific implementation of the present invention will be further described in detail below with reference to the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described in detail below are those that can be implemented or understood by those skilled in the art by referring to the prior art. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0056] Example 1 This example provides a conductive paste for the front side of a thick-film resistor, which is composed of the following components by mass percentage: 62% silver powder (based on the total mass of silver powder, 80% by mass of spherical silver powder and 20% by mass of flake silver powder), 5% glass powder, 30% organic carrier (based on the total mass of organic carrier, the organic carrier includes the following components by mass percentage: 20% rosin resin, 5% polyvinylpyrrolidone, and 75% terpineol), and 3% inorganic additive (i.e., Al2O3). Based on the mass percentage of glass powder as 100%, its composition is SrO 28%, BaO 14%, SiO 25%, ZnO 13%, TiO 21%, and B2O 39%.

[0057] Examples 2-6 The only difference between the conductive paste used on the front side of the thick film resistor in Examples 2-6 and that in Example 1 is the composition of the glass powder, as shown in Table 1 below.

[0058] Examples 7-10 The only difference between the conductive paste used on the front side of the thick film resistor in Examples 7-10 and that in Example 1 is the composition of the glass powder, as shown in Table 1 below.

[0059] Table 1. Formulation of glass powder (by weight %)

[0060] Example 11 This example provides a conductive paste for the front side of a thick-film resistor, which is composed of the following components by mass percentage: 62% silver powder, 3% glass powder, 30% organic carrier, and 5% inorganic additives, as shown in Table 2 below. The composition of silver powder, glass powder, organic carrier, and inorganic additives in this example is the same as in Example 1.

[0061] Examples 12-14 The formulations of the conductive pastes for the front side of the thick film resistors in Examples 12-14 are shown in Table 2 below, and the compositions of silver powder, glass powder, organic carrier and inorganic additives are the same as those in Example 1.

[0062] Examples 15-17 The formulations of the conductive paste for the front side of the thick film resistor in Examples 15-17 are shown in Table 2 below, and the compositions of silver powder, glass powder, organic carrier and inorganic additives are the same as those in Example 1.

[0063] Example 18 In Example 18, the silver powder composition of the conductive paste on the front side of the thick film resistor is 90% spherical silver powder and 10% flake silver powder. The contents of silver powder, glass powder, organic carrier, and inorganic additives are the same as in Example 1, and the compositions of glass powder, organic carrier, and inorganic additives are also the same as in Example 1, as shown in Table 2 below.

[0064] Example 19 In Example 19, the silver powder composition of the conductive paste on the front side of the thick film resistor is 70% by mass of spherical silver powder and 30% by mass of flake silver powder. The contents of silver powder, glass powder, organic carrier, and inorganic additives are the same as in Example 1, and the compositions of glass powder, organic carrier, and inorganic additives are also the same as in Example 1, as shown in Table 2 below.

[0065] Example 20 In Example 20, the silver powder in the conductive paste on the front side of the thick film resistor is all spherical silver powder. The content of silver powder, glass powder, organic carrier, and inorganic additives is the same as in Example 1, and the composition of glass powder, organic carrier, and inorganic additives is the same as in Example 1, as shown in Table 2 below.

[0066] In Example 21, the silver powder in the conductive paste on the front side of the thick film resistor is all flake silver powder. The content of silver powder, glass powder, organic carrier, and inorganic additives is the same as in Example 1, and the composition of glass powder, organic carrier, and inorganic additives is the same as in Example 1, as shown in Table 2 below.

[0067] Table 2 Formulation of conductive paste (mass percentage)

[0068] The conductive paste used on the front side of the thick-film resistors in Examples 1-21 can all be prepared using the following method, with the specific steps as follows: (1) Material preparation: Glass powder preparation: Weigh SrO, BaO, SiO2, ZnO, TiO2, and B2O3 according to the formula, mix them after weighing, melt them at 1200°C, quench them, and then ball mill them to D. 50 =1~3 μm.

[0069] Organic carrier preparation: Mix the resin, organic additives, and organic solvents in proportion, and heat and stir until completely dissolved.

[0070] Slurry mixing: Mix the prescribed amounts of silver powder, glass powder, inorganic additives and organic carrier: stir for 30 minutes.

[0071] (2) Three-roll milling dispersion: Use a three-roll mill to repeatedly roll the slurry 3 times until the fineness of the slurry is ≤10 μm (tested by Hegman fineness tester).

[0072] (3) Degassing treatment: vacuum degassing or centrifugal degassing.

[0073] (4) Viscosity adjustment: Adjust the viscosity according to the printing process (screen printing or inkjet printing) (usually 10–50 Pa·s, measured with a Brookfield viscometer).

[0074] Performance testing: The thick-film resistors from Examples 1-21 were screen-printed onto ceramic substrates using conductive paste, and then sintered at 850°C for 10 minutes to form an 8μm thick conductive layer on the ceramic substrate. The sintering appearance and film quality of the conductive layer were observed using an electron microscope. The sheet resistance, adhesion, and acid resistance of the conductive layer were then tested using the following specific methods: Sintered appearance and film quality: Electron microscope was used to test the clarity of the lines after screen printing, whether there are jagged edges, and the light transmittance of the V-groove. Sheet resistance: Measured using the four-probe method; Adhesion: tested using a tensile test method; Acid resistance test: The substrate (ceramic substrate with conductive layer) is immersed in a 5% H2SO4 solution for 30 minutes, rinsed with tap water, dried, and then peeled off with transparent tape to see if it falls off.

[0075] The performance test results of the conductive layer formed by the conductive paste on the front side of the thick film resistor in Examples 1 to 21, obtained according to the above test method, are shown in Table 3 below.

[0076] Table 3 Performance test results of the conductive layer

[0077] As shown in Table 3, the sheet resistance of the conductive layer in Examples 1-21 is 4.45-16.89 mΩ / □, and the bonding force is 27.12-60.25 N. In addition, by adjusting the formulation of the conductive paste and the glass powder, the present invention can achieve acid resistance of the conductive layer, so that the conductive layer does not fall off after being immersed in a 5% H2SO4 solution for 30 minutes. At the same time, the conductive layers in Examples 1-6, 8, 11-14, 16, and 18-19 of the present invention did not fall off after being immersed in a 1% dilute sulfuric acid aqueous solution for 24 hours.

[0078] Furthermore, the printed lines of the conductive layer in the embodiments of the present invention are all clear and without obvious jagged edges. Specifically, the printed appearance of the conductive layer in Embodiment 1 is as follows: Figure 1 As shown, the actual image of the conductive layer after acid washing test in Example 1 is as follows. Figure 2 As shown, by Figures 1-2 It can be seen that the conductive layer in Example 1 has excellent acid resistance.

[0079] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A glass powder, characterized in that: It includes the following components by weight percentage: SrO 15~32%, BaO 14~25%, SiO2 20~38%, ZnO 7~15%, TiO2 7~16%, B2O3 8~20%.

2. The method for preparing glass powder according to claim 1, characterized in that: Includes the following steps: The raw materials are melted and mixed at 1000~1300℃, then quenched to obtain the product.

3. A conductive paste, characterized in that: Includes the glass powder as described in claim 1.

4. The conductive paste according to claim 3, characterized in that: The conductive paste comprises the following components by mass percentage: 58-70% conductive material, 2-12% glass powder, 18-34% organic carrier, and 0.5-8% inorganic additives.

5. The conductive paste according to claim 4, characterized in that: Based on the total mass of the conductive material, the conductive material contains 70-90% by mass of spherical and / or near-spherical silver powder and 10-30% by mass of flake silver powder.

6. The conductive paste according to claim 4, characterized in that: Based on the total weight of the organic carrier, the organic carrier comprises the following components by weight percentage: 5-20% resin, 2-5% organic additives, and 55-75% solvent.

7. The conductive paste according to claim 6, characterized in that: The resin includes at least one of rosin resin, ethyl cellulose, and methyl cellulose; and / or, the organic additive is selected from at least one of polyvinylpyrrolidone, hexadecyltrimethylammonium bromide, and sodium dodecylbenzene sulfonate. And / or, the inorganic additive is selected from at least one of Al2O3, ZnO, Fe2O3, NiO, and SiO2; And / or, the solvent includes at least one of terpineol, N-methylpyrrolidone, and diethylene glycol butyl ether.

8. A thick-film resistor, characterized in that: It includes a conductive layer, which is formed by curing the conductive paste according to any one of claims 3 to 7.

9. An electronic product, characterized in that: It includes a conductive layer made of the conductive paste according to any one of claims 3 to 7 or includes the thick film resistor according to claim 8.

10. The application of the glass powder of claim 1, the conductive paste of any one of claims 3 to 7, the thick film resistor of claim 8, or the electronic product of claim 9 in the fields of consumer electronics, automotive electronics, industrial control, communication equipment, medical equipment, new energy, or power equipment.

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