Method for Measuring Metal Content in MLCC Electrode Paste

Abstract

This application relates to a method for measuring the metal content of MLCC electrode paste, comprising the following steps: obtaining the mass m1 of an electrode paste sample; performing a debinding operation on the electrode paste sample in a non-oxidizing environment to remove organic matter, obtaining the mass m2 of the debinded electrode paste sample; placing the electrode paste sample in an oxidation reactor, introducing air into the oxidation reactor, and oxidizing the electrode paste by raising the temperature from room temperature to a set oxidation reaction temperature range; obtaining the mass m3 of the oxidized electrode paste sample, and obtaining the mass difference m before and after the oxidation reaction based on the difference between mass m2 and mass m3. x Based on the molar mass relationship between oxygen and the metal in the electrode slurry sample during the oxidation reaction, the mass difference m is... x The method of this application, which calculates the mass m4 of metal consumed in the oxidation reaction, can accurately measure the actual metal content in the electrode paste, thus overcoming the shortcomings of the prior art and improving the performance and production yield of MLCCs.

Description

Technical Field

[0001] This application relates to the technical field of paste content analysis for multilayer ceramic capacitors, and in particular to a method for measuring the metal content of MLCC electrode paste. Background Technology

[0002] In the manufacturing process of multilayer ceramic chip capacitors (MLCCs), the performance of the internal electrode paste has a significant impact on the electrical performance, stability, and manufacturing process of the capacitor. The composition and performance of the internal electrode paste determine the conductivity, sintering performance, and bonding with the ceramic dielectric of the electrode layer, thereby affecting the overall performance of the MLCC.

[0003] MLCC electrode pastes include internal electrode pastes and terminal electrode pastes. Taking the internal electrode paste as an example, its function is to form a conductive layer within the ceramic dielectric layer. Aside from additives and solvents, the main components of the internal electrode paste include metals (such as nickel, gold, silver, silver-palladium, copper, or alloys) and barium titanate ceramic. The metal content in the electrode paste is closely related to the electrical performance and reliability of the MLCC. A higher metal content in the internal electrode results in a thicker printing layer and a higher capacitance. The metal content in the electrode paste is determined by the ratio in the original design; however, during production, the metal content may deviate from the design. Therefore, it is necessary to determine the actual metal content in the paste before the MLCC electrode printing process.

[0004] Traditional techniques can only determine the solid content in electrode slurry, that is, the total content of metal + inorganic matter and ceramic particles after removing organic matter, but cannot accurately determine the metal content in electrode slurry. Summary of the Invention

[0005] Based on this, this application provides a method for measuring the metal content of MLCC electrode paste that can solve the above-mentioned technical problems. This method can accurately measure the actual metal content in the electrode paste, which can improve the shortcomings of the prior art and enhance the performance and production yield of MLCC.

[0006] The above-mentioned objective of this application is achieved through the following technical solution:

[0007] This application provides a method for measuring the metal content of MLCC electrode paste, including the following steps:

[0008] Obtain the mass m1 of the electrode slurry sample;

[0009] In a non-oxidizing environment, the electrode slurry sample is degummed to remove organic matter and obtain the mass m2 of the degummed electrode slurry sample.

[0010] The electrode slurry sample is placed in the oxidation reactor, and air is introduced into the oxidation reactor to raise the temperature of the electrode slurry sample to the set oxidation reaction temperature range for oxidation reaction.

[0011] Obtain the mass m3 of the electrode slurry sample after oxidation reaction, and obtain the mass difference mx before and after oxidation reaction based on the difference between the mass m2 and the mass m3.

[0012] Based on the molar mass relationship between oxygen and metal in the electrode slurry sample during the oxidation reaction, the mass difference mx is converted to obtain the mass m4 of metal consumed in the oxidation reaction.

[0013] The percentage content of the metal in the electrode slurry sample is calculated based on the mass m4 of the metal and the mass m1 of the electrode slurry sample.

[0014] In an optional embodiment, the electrode slurry sample is subjected to a debinding operation in a non-oxidizing environment to remove organic matter therein, including:

[0015] The electrode slurry sample is placed in a glue removal box, and an inert gas is introduced into the box to raise the temperature to the set glue removal temperature for glue removal.

[0016] In an optional embodiment, the set glue discharge temperature is 300-600℃, and the heating rate is 0.2-2℃ / min.

[0017] In an optional embodiment, the following steps are also included:

[0018] The duration of the glue removal process is 10-30 hours.

[0019] In an optional embodiment, the inert gas includes at least one of the following:

[0020] Nitrogen, hydrogen, and argon.

[0021] In an optional embodiment, the oxidation reactor is a muffle furnace;

[0022] The metal in the electrode slurry sample is nickel, and the oxidation reaction temperature range is set to 900-1200℃, with a heating rate of 1-10℃ / min.

[0023] Alternatively, the metal in the electrode slurry sample is silver, and the oxidation reaction temperature range is set to 600-800℃, with a heating rate of 1-6℃ / min;

[0024] Alternatively, the metal in the electrode slurry sample is palladium, and the oxidation reaction temperature range is set to 900-1100℃, with a heating rate of 1-10℃ / min;

[0025] Alternatively, the metal in the electrode slurry sample is copper, and the oxidation reaction temperature range is set to 600-800℃, with a heating rate of 1-8℃ / min;

[0026] Alternatively, the metal in the electrode slurry sample is a silver-palladium alloy, and the oxidation reaction temperature range is set to 900-1100℃, with a heating rate of 1-10℃ / min.

[0027] In an optional embodiment, the following steps are also included:

[0028] During the oxidation reaction, the holding time is 2-10 hours.

[0029] In an optional embodiment, the metal in the electrode slurry sample includes multiple metals or is an alloy of metals. Based on the molar mass relationship between oxygen and the metal in the electrode slurry sample during the oxidation reaction, the mass difference mx is converted to obtain the mass m4 of the metal consumed in the oxidation reaction, including:

[0030] Based on the relationship between oxygen in the oxidation reaction and the molar mass of each metal in the electrode slurry sample, the oxygen consumption per unit mass of each metal is obtained.

[0031] The total mass m4 of the metals is calculated based on the mass difference mx, the oxygen consumption per unit mass of each metal, and the mass ratio of each metal.

[0032] This application has the following beneficial effects:

[0033] The method for measuring the metal content of MLCC electrode paste in this application first removes organic matter from the electrode paste, and then performs an oxidation operation involving only metals on the electrode paste, which includes metals, inorganic matter, ceramic particles, etc. The mass of oxygen participating in the oxidation reaction is obtained based on the mass difference before and after the oxidation reaction. The mass of metals participating in the oxidation reaction is calculated based on the molar mass relationship between oxygen and metals in the electrode paste sample during the oxidation reaction. This allows for accurate calculation of the metal content in the electrode paste, thereby overcoming the shortcomings of the prior art and improving the performance and production yield of MLCCs. Furthermore, this application can calculate the total mass of metals by combining the mass ratio of each metal under the condition of including multiple metals or metal alloys, thereby obtaining the content of each metal or alloy in the electrode paste. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the steps of a method for measuring the metal content of MLCC electrode paste in an exemplary embodiment. Detailed Implementation

[0035] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, a detailed description of specific embodiments of this application is provided below. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0036] Furthermore, the terms "first" and "first" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "first" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0038] To address the technical problems in the background art, this application provides a method for measuring the metal content of MLCC electrode paste, which can accurately detect the content of a single metal in the MLCC electrode paste that can produce an oxidation reaction.

[0039] like Figure 1 As shown, in one embodiment, the method for measuring the metal content of MLCC electrode paste according to this application includes the following steps:

[0040] S01: Obtain the mass m1 of the electrode slurry sample.

[0041] The electrode paste can be an internal electrode paste or an end electrode paste, and includes a metal capable of undergoing an oxidation reaction. In this embodiment, the metal may include one or more of nickel, silver, copper, etc., or the metal may be a silver-palladium alloy, etc. In addition, the electrode paste also includes non-metallic materials such as organic matter, inorganic matter, and ceramic particles.

[0042] In this embodiment, the mass of a crucible can be weighed first and recorded as m0. Then, a certain mass of electrode slurry sample can be taken using a stainless steel spoon, poured into the crucible, and weighed together. The mass of the crucible m0 is then subtracted from the mass of the crucible to obtain the mass m1 of the electrode slurry sample. In subsequent weighing processes, the real-time mass of the electrode slurry sample in the crucible can be obtained by weighing the crucible and subtracting its mass m0.

[0043] S02: Perform a debinding operation on the electrode slurry sample in a non-oxidizing environment to remove organic matter and obtain the mass m2 of the electrode slurry sample after debinding.

[0044] Organic matter in electrode slurry includes, but is not limited to, solvents, binders, plasticizers, dispersants, etc. Under the subsequent high-temperature oxidation reaction conditions, organic matter will volatilize. Therefore, it is necessary to remove organic matter from the electrode slurry sample first.

[0045] In this embodiment, to avoid affecting the subsequent oxidation reaction, the debinding operation needs to be carried out in a non-oxidizing environment. The oxidizing environment requires high temperature and air (oxygen). That is, if the debinding operation is carried out in a high temperature environment, it needs to be carried out in a vacuum or inert gas environment; if the debinding operation is carried out in an air environment, high temperatures that can produce oxidation reactions need to be avoided.

[0046] In one implementation, an alcohol solvent can be injected into the crucible to dissolve the organic matter in the electrode slurry sample. After removing the alcohol solvent, the sample is dried to remove the organic components.

[0047] In another implementation, the electrode slurry sample can be heated in an oxygen-free, high-temperature environment to allow the organic matter to volatilize and be removed from the sample.

[0048] In the specific operation process, in order to check whether all organic matter has been discharged, step S02 can be repeated, and the mass m2 after the second discharge operation can be checked to see if there is a change.

[0049] S03: Place the electrode slurry sample into the oxidation reactor, introduce air into the oxidation reactor, and heat the electrode slurry sample to the set oxidation reaction temperature range to carry out the oxidation reaction.

[0050] In this embodiment, the oxidation reaction temperature is set differently depending on the different metal compositions.

[0051] S04: Obtain the mass m3 of the electrode slurry sample after the oxidation reaction, and calculate the mass difference m before and after the oxidation reaction based on the difference between the masses m2 and m3. x The calculation formula is as follows: .

[0052] S05: Based on the molar mass relationship between oxygen and the metal in the electrode slurry sample during the oxidation reaction, the mass difference m x The mass m4 of the metal consumed in the oxidation reaction is calculated.

[0053] Specifically, if the metal in the electrode slurry sample is nickel, the calculation process is as follows:

[0054] The oxidation reaction equation for nickel is:

[0055] ;

[0056] The molar mass of nickel is 58.7 g / mol, and the molar mass of oxygen is 16 g / mol. According to the reaction equation, 1 mole of nickel reacts with 0.5 moles of oxygen to produce 1 mole of nickel oxide (NiO). Therefore, the mass ratio of oxygen to nickel is:

[0057] .

[0058] This means that for every 1 gram of oxygen added, 3.67 grams of nickel are consumed.

[0059] The mass m of oxygen absorbed during the oxidation process x The mass of nickel consumed during the oxidation process, m4, can be calculated.

[0060] .

[0061] Similarly, if the metal in the electrode paste sample is copper, then the mass m4 of copper consumed during the oxidation process is:

[0062] .

[0063] If the metal in the electrode paste sample is silver, then the mass m4 of silver consumed during the oxidation process is:

[0064] .

[0065] If the electrode slurry sample contains multiple metals or is an alloy of metals, the content of each metal needs to be calculated separately because different metals have different oxidation behaviors.

[0066] Taking silver-palladium alloy as an example, the following is the calculation process and formula for the oxidation of each of the two metals or alloys.

[0067] First, based on the molar mass relationship between oxygen and each metal in the alloy of the electrode slurry sample during the oxidation reaction, the oxygen consumption per unit mass of each metal is obtained. Based on the above principle, the oxygen consumption per unit mass of silver, U... Ag =13.49; Oxygen consumption per unit mass of palladium, U Pd =6.65.

[0068] Based on the mass difference m x The total mass m4 of the alloy is calculated by considering the oxygen consumption per unit of each metal and the mass proportion of each metal in the alloy. The specific calculation process is as follows:

[0069] Total oxygen consumption coefficient K totalThe formula:

[0070] ;

[0071] Among them, R Ag and R Pd It is the mass ratio of silver and palladium in the alloy. If there are two or more metals, it is the preset mass ratio of each metal.

[0072] Total mass of the alloy, m4:

[0073] .

[0074] The combined formula is:

[0075] .

[0076] Therefore, the total mass m4 of the alloy can be calculated.

[0077] After obtaining the mass m4 of the metal consumed in the oxidation reaction, the following steps are also included:

[0078] S06: Calculate the percentage content of the metal in the electrode slurry sample based on the mass m4 of the metal and the mass m1 of the electrode slurry sample.

[0079] In one specific embodiment, a debinding operation is performed on the electrode slurry sample to remove organic matter therein, including:

[0080] The electrode paste sample is placed in a desizing box, and an inert gas is introduced into the box. The temperature inside the box is raised from room temperature to 300-600℃ for desizing, with a heating rate of 0.2-2℃ / min.

[0081] In this embodiment, high-temperature debinding is performed under inert gas conditions to prevent oxidation of the electrode slurry sample at high temperatures. A slower heating rate ensures uniform temperature distribution within the electrode slurry sample, contributing to the uniformity of the organic matter decomposition process and preventing localized overheating or organic matter accumulation.

[0082] In a preferred embodiment, the duration of the degelation process is 10-30 hours to ensure that the organic matter is completely decomposed and discharged, to ensure uniform temperature distribution inside and on the surface of the sample, and to provide a stable sample state for subsequent high-temperature treatment.

[0083] In specific embodiments, the inert gas includes at least one of the following: nitrogen, hydrogen, and argon.

[0084] In one embodiment, the oxidation reactor is a muffle furnace, and the preferred reaction temperature range and heating rate vary depending on the metal composition of the electrode slurry sample. Preferably, the following temperature range and heating rate range can be used:

[0085] Nickel: The oxidation reaction temperature range is set to 900-1200℃, and the heating rate is 1-10℃ / min.

[0086] Silver: Set the oxidation reaction temperature range to 600-800℃, and the heating rate to 1-6℃ / min.

[0087] Palladium: The oxidation reaction temperature range is set to 900-1100℃, and the heating rate is 1-10℃ / min.

[0088] Copper: The oxidation reaction temperature range is set to 600-800℃, and the heating rate is 1-8℃ / min.

[0089] Silver-palladium alloy: The oxidation reaction temperature range is set to 900-1100℃, and the heating rate is 1-10℃ / min.

[0090] Optionally, the holding time during the oxidation reaction is 2-10 hours to ensure that the oxidation reaction is complete.

[0091] In the specific operation process, in order to check whether the oxidation is completely completed, step S04 can be repeated, and the mass m4 after the second oxidation operation can be checked to see if there is a change.

[0092] Table 1. Measured data of Ni electrode slurry at different debinding temperatures and oxidation temperatures.

[0093]

[0094] Groups 1-4 tested the Ni metal content in Ni electrode slurry at different debinding temperatures. At debinding temperatures of 400-600℃, the relative error between the measured Ni content and the theoretical design composition was within ±2%. When the debinding temperature was ≤300℃, insufficient removal of organic matter from the electrode slurry resulted in a higher mass (m2) after debinding. As organic matter continued to be removed during subsequent oxidation, the mass (m3) after oxidation was not significantly different from the normal value, leading to a lower calculated Ni content than the theoretical value.

[0095] Groups 5-8 tested the Ni metal content in Ni electrode slurry at different debinding temperatures. At oxidation temperatures of 1000-1200℃, the relative error between the experimentally measured Ni content and the theoretically designed composition was within ±2%. When the oxidation temperature was ≤900℃, the Ni electrode oxidation was incomplete, resulting in a smaller mass m4 after oxidation, and the final calculated Ni content was lower than the theoretical value.

[0096] The method for measuring the metal content of MLCC electrode paste in this application first removes organic matter from the electrode paste, and then performs an oxidation operation involving only metals on the electrode paste, which includes metals, inorganic matter, ceramic particles, etc. The mass of oxygen participating in the oxidation reaction is obtained based on the mass difference before and after the oxidation reaction. The mass of metals participating in the oxidation reaction is calculated based on the molar mass relationship between oxygen and metals in the electrode paste sample during the oxidation reaction. This allows for accurate calculation of the metal content in the electrode paste, thereby overcoming the shortcomings of the prior art and improving the performance and production yield of MLCCs. Furthermore, this application can calculate the total mass of metals by combining the mass ratio of each metal under the condition of including multiple metals or metal alloys, thereby obtaining the content of each metal or alloy in the electrode paste.

[0097] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0098] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for measuring the metal content of MLCC electrode paste, characterized in that, Includes the following steps: Obtain the mass m1 of the electrode slurry sample; In a non-oxidizing environment, the electrode slurry sample is degummed to remove organic matter and obtain the mass m2 of the degummed electrode slurry sample. The electrode slurry sample is placed in the oxidation reactor, and air is introduced into the oxidation reactor to raise the temperature of the electrode slurry sample to the set oxidation reaction temperature range for oxidation reaction. Obtain the mass m3 of the electrode slurry sample after the oxidation reaction, and calculate the mass difference m before and after the oxidation reaction based on the difference between the masses m2 and m3. x ; Based on the molar mass relationship between oxygen and the metal in the electrode slurry sample during the oxidation reaction, the oxygen consumption per unit mass of the metal is obtained; based on the mass difference m x Given the oxygen consumption per unit mass of the metal, the mass m4 of the metal consumed in the oxidation reaction is calculated. The percentage content of the metal in the electrode slurry sample is calculated based on the mass m4 of the metal and the mass m1 of the electrode slurry sample.

2. The method for measuring the metal content of MLCC electrode paste according to claim 1, characterized in that, The electrode slurry sample is subjected to a debinding operation in a non-oxidizing environment to remove organic matter, including: The electrode slurry sample is placed in a glue removal box, and an inert gas is introduced into the box to raise the temperature to the set glue removal temperature for glue removal.

3. The method for measuring the metal content of MLCC electrode paste according to claim 2, characterized in that: The set glue discharge temperature is 300-600℃, and the heating rate is 0.2-2℃ / min.

4. The method for measuring the metal content of MLCC electrode paste according to claim 3, characterized in that: The duration of the glue removal process is 10-30 hours.

5. The method for measuring the metal content of MLCC electrode paste according to claim 2, characterized in that, The inert gas includes at least one of the following: Nitrogen, hydrogen, and argon.

6. The method for measuring the metal content of MLCC electrode paste according to claim 1, characterized in that: The oxidation reactor is a muffle furnace; The metal in the electrode slurry sample is nickel, and the oxidation reaction temperature range is set to 900-1200℃, with a heating rate of 1-10℃ / min. Alternatively, the metal in the electrode slurry sample is silver, and the oxidation reaction temperature range is set to 600-800℃, with a heating rate of 1-6℃ / min; Alternatively, the metal in the electrode slurry sample is palladium, and the oxidation reaction temperature range is set to 900-1100℃, with a heating rate of 1-10℃ / min; Alternatively, the metal in the electrode slurry sample is copper, and the oxidation reaction temperature range is set to 600-800℃, with a heating rate of 1-8℃ / min; Alternatively, the metal in the electrode slurry sample is a silver-palladium alloy, and the oxidation reaction temperature range is set to 900-1100℃, with a heating rate of 1-10℃ / min.

7. The method for measuring the metal content of MLCC electrode paste according to claim 6, characterized in that: During the oxidation reaction, the holding time is 2-10 hours.

8. The method for measuring the metal content of MLCC electrode paste according to claim 1, characterized in that, The electrode slurry sample contains multiple metals or metal alloys. Based on the molar mass relationship between oxygen and the metals in the oxidation reaction, the oxygen consumption per unit mass of the metal is obtained; based on the mass difference m... x Given the oxygen consumption per unit mass of the metal, the mass m4 of the metal consumed in the oxidation reaction is calculated, including: Based on the relationship between oxygen in the oxidation reaction and the molar mass of each metal in the electrode slurry sample, the oxygen consumption per unit mass of each metal is obtained. Based on the mass difference m x The total mass m4 of the metals is calculated by taking the oxygen consumption per unit mass of each metal and the mass ratio of each metal.

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