Method for measuring metal content of MLCC electrode slurry

Abstract

The invention relates to a method for measuring the metal content of MLCC electrode slurry. The method comprises the following steps: acquiring the mass m1 of an electrode slurry sample; carrying out glue discharging operation on the electrode slurry sample in a non-oxidation environment, and removing organic matters in the electrode slurry sample to obtain the mass m2 of the electrode slurry sample after glue discharging; putting the electrode slurry sample into an oxidation reactor, introducing air into the oxidation reactor, and heating the electrode slurry from room temperature to a set oxidation reaction temperature range for oxidation; the mass m3 of the oxidized electrode slurry sample is obtained, and the mass difference mx before and after the oxidation reaction is obtained according to the difference value between the mass m2 and the mass m3; according to the molar mass relation between oxygen in the oxidation reaction and metal in the electrode slurry sample, the mass difference mx is converted to obtain the mass m4 of the metal consumed in the oxidation reaction, the method can accurately measure the actual metal content in the electrode slurry, the defects in the prior art can be overcome, and the performance and the production yield of the MLCC are improved.

Description

Technical Field

[0001] The present application relates to the technical field of slurry content analysis of chip-type multilayer ceramic capacitors, and in particular to a method for measuring the metal content of MLCC electrode slurry. Background Art

[0002] In the manufacturing process of multilayer ceramic capacitors (MLCCs), the performance of the internal electrode slurry has an important influence on the electrical properties, stability and manufacturing process of the capacitor. The composition and properties of the internal electrode slurry determine the conductivity, sintering performance and bonding with the ceramic medium of the electrode layer, thereby affecting the overall performance of the MLCC.

[0003] The electrode paste of MLCC includes internal electrode paste and terminal electrode paste. Taking the internal electrode paste as an example, its function is to form a conductive layer in the ceramic dielectric layer. Except for additives and solvents, the main components of the internal electrode paste include metals (such as nickel, gold, silver, silver-palladium, copper, or alloys, etc.) and ceramic barium titanate. The metal content in the electrode paste is closely related to the electrical performance and reliability of the MLCC. The more metal content in the internal electrode, the thicker the printing thickness will be, and the higher the capacity of the MLCC will be. The metal content in the electrode paste is determined by the ratio in the original design. However, during the production process, the metal content will deviate from the design. Therefore, it is necessary to measure the actual metal content in the paste before the MLCC printing electrode process.

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

[0005] Based on this, the present application provides a method for measuring the metal content of MLCC electrode slurry that can solve the above-mentioned technical problems, can accurately measure the actual metal content in the electrode slurry, can improve the deficiencies in the existing technology, and improve the performance and production yield of MLCC.

[0006] The above-mentioned purpose of the present application is achieved through the following technical solutions:

[0007] The present application provides a method for measuring the metal content of an MLCC electrode slurry, comprising the following steps:

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

[0009] Performing a debinding operation on the electrode slurry sample in a non-oxidizing environment to remove organic matter therein, and obtaining a mass m2 of the electrode slurry sample after debinding;

[0010] The electrode slurry sample is placed in an oxidation reactor, air is introduced into the oxidation reactor, and the temperature of the electrode slurry sample is raised to a set oxidation reaction temperature range to perform an oxidation reaction;

[0011] Obtain the mass m3 of the electrode slurry sample after the oxidation reaction, and obtain the mass difference mx before and after the oxidation reaction according to the difference between the mass m2 and the mass m3;

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

[0013] According to the mass m4 of the metal and the mass m1 of the electrode slurry sample, the percentage content of the metal in the electrode slurry sample is calculated.

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

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

[0016] In an optional embodiment, the debinding temperature is set to 300-600° C., and the heating rate is set to 0.2-2° C. / min.

[0017] In an optional embodiment, the method further comprises the following steps:

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

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

[0020] Nitrogen, hydrogen, argon.

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

[0022] The metal in the electrode slurry sample is nickel, the oxidation reaction temperature is set in the range of 900-1200°C, and the heating rate is 1-10°C / min;

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

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

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

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

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

[0028] During the oxidation reaction, the insulation time is 2-10h.

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

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

[0031] The total mass of the metal m4 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 the MLCC electrode slurry in the embodiment of the present application first removes the organic matter in the electrode slurry, and then performs an oxidation operation in which only the metal participates on the electrode slurry including metals, inorganic substances, ceramic particles, etc., and obtains the mass of the oxygen participating in the oxidation reaction based on the mass difference before and after the oxidation reaction, and calculates the mass of the metal participating in the oxidation reaction based on the molar mass relationship between the oxygen in the oxidation reaction and the metal in the electrode slurry sample, so as to accurately calculate the metal content in the electrode slurry, thereby improving the deficiencies in the prior art and improving the performance and production yield of MLCC; the present application further can, under the condition of including multiple metals or metal alloys, combine the mass ratio of each metal to deduce the total mass of the metal, thereby obtaining the content of each metal or alloy in the electrode slurry. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0035] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

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

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0038] In response to the technical problems in the background technology, the present application provides a method for measuring the metal content of MLCC electrode paste, which can accurately detect the content of a single metal that can produce an oxidation reaction in the MLCC electrode paste.

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

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

[0041] The electrode slurry may be an inner electrode slurry or an end electrode slurry, which includes a metal capable of producing an oxidation reaction. In this embodiment, the metal may include one or more of nickel, silver, copper, etc., or the metal may be an alloy of silver-palladium, etc. In addition, the electrode slurry 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, recorded as m0; then a certain mass of electrode slurry sample can be taken with a stainless steel spoon, poured into the crucible, weighed together and then subtracted from the mass of the crucible m0, which is the mass of the electrode slurry sample m1. In the subsequent weighing process, the real-time mass of the electrode slurry sample in the crucible can be obtained by weighing the crucible and subtracting the mass of the crucible m0.

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

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

[0045] In this embodiment, in order to avoid affecting the subsequent oxidation reaction, the debinding operation needs to be carried out in a non-oxidizing environment, and the oxidizing environment requires high temperature + 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, it is necessary to avoid high temperatures that can produce oxidation reactions.

[0046] In one implementation, an alcohol solvent may be injected into the crucible to dissolve the organic matter in the electrode slurry sample in the alcohol solvent, and then the alcohol solvent is removed and the sample is dried to discharge the organic components in the electrode slurry sample.

[0047] In another implementation, the electrode slurry sample may be heated in an oxygen-free high-temperature environment to discharge the organic components in the electrode slurry sample by volatilizing the organic matter.

[0048] In the specific operation process, in order to check whether all organic matter is discharged, step S02 can be repeated, and it can be detected whether the mass m2 after the binder discharge operation is changed.

[0049] S03: placing the electrode slurry sample into an oxidation reactor, introducing air into the oxidation reactor, and heating the electrode slurry sample to a set oxidation reaction temperature range to perform an oxidation reaction.

[0050] In this embodiment, the oxidation reaction temperature is set differently according to different metal components.

[0051] S04: Obtain the mass m3 of the electrode slurry sample after the oxidation reaction, and obtain the mass difference m before and after the oxidation reaction based on the difference between the mass m2 and the mass m3. x , the calculation formula is: mx=m3-m2.

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

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

[0054] The oxidation reaction equation of 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 ratio of the mass of oxygen to the mass of nickel is:

[0057]

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

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

[0060] m4=3.67×m x .

[0061] The principle is similar. If the metal in the electrode slurry sample is copper, the mass m4 of copper consumed during the oxidation process is:

[0062] m4=3.97×(m3-m2).

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

[0064] m4=13.49×(m3-m2).

[0065] If there are multiple metals in the electrode slurry sample, or the metals are alloys, 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 oxidation calculation process and formula for each of the two metals or alloys.

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

[0068] According to the quality difference m x , the unit oxygen consumption of each metal and the mass ratio of each metal in the alloy, and calculate the total mass m4 of the alloy. The specific calculation process is:

[0069] Total oxygen consumption coefficient Ktotal The formula is:

[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] The total mass of the alloy m4:

[0073]

[0074] The combined formula is:

[0075]

[0076] From this, 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 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 a specific embodiment, performing a debinding operation on the electrode slurry sample to remove organic matter therein includes:

[0080] The electrode slurry sample is placed in a debinding box, an inert gas is introduced into the debinding box, and the temperature in the debinding box is increased from room temperature to 300-600°C for debinding, and the heating rate is 0.2-2°C / min.

[0081] In this embodiment, high-temperature debinding is performed under the condition of passing inert gas, which can prevent the electrode slurry sample from being oxidized in a high-temperature environment. A slower heating rate can ensure that the temperature is evenly transferred to the inside of the electrode slurry sample, which helps to ensure the uniformity of the organic matter decomposition process and avoid local overheating or organic matter accumulation.

[0082] In a preferred embodiment, the duration of the debinding 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 a specific embodiment, 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 setting reaction temperature range and heating rate are different according to the different metal components in the electrode slurry sample. Preferably, the following temperature range and heating rate range can be used:

[0085] Nickel: Set the oxidation reaction temperature range to 900-1200°C and the heating rate to 1-10°C / min.

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

[0087] Palladium: Set the oxidation reaction temperature range to 900-1100°C and the heating rate to 1-10°C / min.

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

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

[0090] Optionally, during the oxidation reaction, the heat preservation time is 2-10 hours to ensure that the oxidation reaction is thorough.

[0091] In the specific operation process, in order to check whether the oxidation is completely completed, step S04 can be repeated, and it can be detected whether the mass m4 after the oxidation operation is changed again.

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

[0093]

[0094] Groups 1-4 tested the measurement results of Ni metal content in Ni electrode slurry at different debinding temperatures. At debinding temperatures of 400-600°C, the relative error between the Ni content measured in the test and the theoretical design composition was within ±2%. When the debinding temperature was ≤300°C, due to insufficient discharge of organic matter in the electrode slurry, the residual organic matter caused the mass m2 after debinding to be too large, and the organic matter continued to be discharged during the subsequent oxidation process. The mass m3 after oxidation was not much different from the normal situation, and the final calculated Ni content was lower 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°C, the relative error between the Ni content measured in the test and the theoretical design composition was within ±2%. When the oxidation temperature was ≤900°C, the Ni electrode was not fully oxidized, 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 the MLCC electrode slurry in the embodiment of the present application first removes the organic matter in the electrode slurry, and then performs an oxidation operation in which only the metal participates on the electrode slurry including metals, inorganic substances, ceramic particles, etc., and obtains the mass of the oxygen participating in the oxidation reaction based on the mass difference before and after the oxidation reaction, and calculates the mass of the metal participating in the oxidation reaction based on the molar mass relationship between the oxygen in the oxidation reaction and the metal in the electrode slurry sample, so as to accurately calculate the metal content in the electrode slurry, thereby improving the deficiencies in the prior art and improving the performance and production yield of MLCC; the present application further can, under the condition of including multiple metals or metal alloys, combine the mass ratio of each metal to deduce the total mass of the metal, thereby obtaining the content of each metal or alloy in the electrode slurry.

[0097] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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 above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims, and the description may be used to interpret the contents of the claims.

Claims

1. A method for measuring the metal content of MLCC electrode slurry, characterized in that: The following steps are involved: Obtain the mass m1 of the electrode slurry sample; Performing a debinding operation on the electrode slurry sample in a non-oxidizing environment to remove organic matter therein, and obtaining a mass m2 of the electrode slurry sample after debinding; The electrode slurry sample is placed in an oxidation reactor, air is introduced into the oxidation reactor, and the temperature of the electrode slurry sample is raised to a set oxidation reaction temperature range to perform an oxidation reaction; Obtain the mass m3 of the electrode slurry sample after the oxidation reaction, and obtain the mass difference m before and after the oxidation reaction based on the difference between the mass m2 and the mass m3. x ; According to the relationship between the molar mass of oxygen in the oxidation reaction and the metal in the electrode slurry sample, the mass difference m x The mass m4 of the metal consumed in the oxidation reaction is converted; According to the mass m4 of the metal and the mass m1 of the electrode slurry sample, the percentage content of the metal in the electrode slurry sample is calculated.

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 therein, including: The electrode slurry sample is placed in a binder removal box, an inert gas is introduced into the binder removal box, and the temperature in the binder removal box is raised to a set binder removal temperature to perform binder removal.

3. The method for measuring the metal content of MLCC electrode slurry according to claim 2, characterized in that: The set debinding 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 debinding 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, 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, the oxidation reaction temperature is set in the range of 900-1200°C, and the heating rate is 1-10°C / min; Alternatively, the metal in the electrode slurry sample is silver, the oxidation reaction temperature is set in the range of 600-800°C, and the heating rate is 1-6°C / min; Alternatively, the metal in the electrode slurry sample is palladium, the oxidation reaction temperature is set in the range of 900-1100° C., and the heating rate is 1-10° C. / min; Alternatively, the metal in the electrode slurry sample is copper, the oxidation reaction temperature is set in the range of 600-800°C, and the heating rate is 1-8°C / min; Alternatively, the metal in the electrode slurry sample is a silver-palladium alloy, the oxidation reaction temperature is set in the range of 900-1100° C., and the heating rate is 1-10° C. / 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 insulation time is 2-10h.

8. The method for measuring the metal content of MLCC electrode paste according to claim 1, characterized in that: The metal in the electrode slurry sample includes multiple metals or metals are alloys. According to the molar mass relationship between oxygen and the metal in the electrode slurry sample in the oxidation reaction, the mass difference m x The mass m4 of metal consumed in the oxidation reaction is converted, including: According to the relationship between the molar mass of oxygen and each metal in the electrode slurry sample in the oxidation reaction, the oxygen consumption per unit mass of each metal is obtained; According to the quality difference m x , the unit mass oxygen consumption of each metal and the mass proportion of each metal, and calculate the total mass of the metal m4.

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