Ceramic parts, methods for manufacturing the same, and methods for sorting the same

Abstract

To provide a ceramic component that can improve solderability. [Solution] The ceramic component 1 comprises a sintered body 11, an internal electrode 12 provided inside the sintered body 11, and an external electrode 13 provided so as to cover a part of the sintered body 11 and electrically connected to the internal electrode 12. The external electrode 13 includes a Sn plating layer 16 as its outermost layer. The sum of the R, G, and B values ​​of the RGB values ​​indicating the color of the surface of the Sn plating layer 16 after heating at 200°C for 72 hours is between 0 and 300.

Description

[Technical Field]

[0001] The present disclosure relates to a ceramic component, a method for manufacturing a ceramic component, and a method for sorting a ceramic component, and in particular, to a ceramic component including an external electrode, a method for manufacturing the ceramic component, and a method for sorting the ceramic component. [Background Art]

[0002] Various electronic devices, electronic devices and the like use various ceramic components such as varistors. Varistors are used for purposes such as protecting mounted electronic devices and the like from abnormal voltages caused by lightning surges, static electricity and the like, and preventing malfunctions of electronic devices and the like due to noise generated in circuits.

[0003] Patent Document 1 discloses a multilayer varistor. This multilayer varistor includes a sintered body, an internal electrode, a high resistance layer, and an external electrode, and the arithmetic mean roughness of the surface of the high resistance layer is 0.06 µm or more. The external electrode includes a primary electrode and a plating electrode, and the plating electrode includes a Ni electrode provided to cover at least a part of the primary electrode, and a Sn electrode provided to cover at least a part of the Ni electrode. [Prior Art Literature] [Patent Literature]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2023-71558 [Summary of Invention] [Problem to be Solved by the Invention]

[0005] Ceramic components such as the multilayer varistor disclosed in Patent Document 1 are generally used by soldering the outermost Sn electrode or the like of the external electrode to a circuit board such as an electronic component to be mounted. Accordingly, ceramic components are required to have good solder wettability on the surface of the external electrode during soldering, and improvement of solderability is demanded.

[0006] The object of this disclosure is to provide a ceramic component that can improve solderability, a method for manufacturing a ceramic component, and a method for sorting a ceramic component. [Means for solving the problem]

[0007] A ceramic component according to one aspect of the present disclosure comprises a sintered body, an internal electrode provided inside the sintered body, and an external electrode provided so as to cover a part of the sintered body and electrically connected to the internal electrode, wherein the external electrode includes a tin plating layer as its outermost layer, and the sum of the R, G, and B values ​​of the RGB values ​​indicating the color of the surface of the tin plating layer after heating at 200°C for 72 hours is between 0 and 300.

[0008] A method for manufacturing a ceramic component according to one aspect of the present disclosure comprises: a first step of preparing a sintered body having internal electrodes provided inside; a second step of forming an external electrode that covers a part of the sintered body, is electrically connected to the internal electrodes, and includes a Sn plating layer as the outermost layer; and a third step of selecting components in which the sum of the R, G, and B values ​​of the RGB values ​​indicating the color of the surface of the Sn plating layer after heating at 200°C or higher for 72 hours or more is between 0 and 300.

[0009] A method for manufacturing a ceramic component according to another aspect of the present disclosure comprises: a first step of preparing a sintered body having internal electrodes provided inside; a second step of forming an external electrode that covers a part of the sintered body, is electrically connected to the internal electrodes, and includes a Sn plating layer as the outermost layer; and a third step of taking a test sample from a part of a manufacturing lot and determining whether it is acceptable or unacceptable based on whether the sum of the R, G, and B values ​​of the RGB values ​​indicating the color of the surface of the Sn plating layer after heating the test sample at 200°C or higher for 72 hours or more is between 0 and 300.

[0010] A method for sorting ceramic components according to one aspect of the present disclosure comprises a sintered body, an internal electrode disposed inside the sintered body, and an external electrode covering a part of the sintered body, electrically connected to the internal electrode, and including a metal plating layer, wherein the ceramic components are sorted into good products and defective products based on the measured values ​​of the R, G, and B values ​​of the RGB values ​​indicating the color of the surface of the metal plating layer after heating at a predetermined temperature for a predetermined time. [Effects of the Invention]

[0011] According to this disclosure, it is possible to provide ceramic components with improved solderability. Furthermore, according to this disclosure, ceramic components with improved solderability can be easily obtained. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic cross-sectional view of a ceramic component according to an embodiment of this disclosure. [Figure 2] Figure 2 is a schematic perspective view of a ceramic component according to an embodiment of the present disclosure. [Modes for carrying out the invention]

[0013] 1. Overview The following describes a ceramic component 1 according to an embodiment, its manufacturing method, and its sorting method. The embodiments described below are only one of many embodiments of this disclosure. The embodiments described below can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure are achieved.

[0014] In order to solve the above problems with respect to ceramic component 1, the inventors diligently conducted research and discovered that there is a relationship between the solder wettability of a specific metal plating layer and a numerical value representing the surface color of this metal plating layer after treatment under specific conditions using a specific color system, and thus completed this disclosure.

[0015] The ceramic component 1 of this embodiment comprises a sintered body 11, an internal electrode 12 provided inside the sintered body 11, and an external electrode 13 provided so as to cover a part of the sintered body 11 and electrically connected to the internal electrode 12. The external electrode 13 includes a Sn plating layer 16 as its outermost layer. The sum of the R, G, and B values ​​of the RGB values ​​indicating the color of the surface of the Sn plating layer 16 after heating at 200°C for 72 hours is between 0 and 300.

[0016] The ceramic component 1 according to this embodiment can improve solderability. The reason why the ceramic component 1 achieves the above effect by having the above configuration can be inferred, for example, as follows. The solderability of the ceramic component 1 is related to the good solder wettability of the surface of the Sn plating layer 16. This good solder wettability indicates high contact between the surface of the Sn plating layer 16 and the solder, and this high contact is thought to be related to the density or compactness of the metallic Sn on the surface layer of the Sn plating layer 16. Furthermore, the higher the density of the metallic Sn on this surface layer, the smaller the reflection and scattering of light on the surface of the Sn plating layer 16 tends to be. And these slight differences in the reflection and scattering of light on the surface can be clearly detected as differences in the RGB values ​​of the surface of the Sn plating layer 16 after heat treatment, as the oxidation of the metallic Sn on the surface of the Sn plating layer 16 progresses by performing heat treatment under the above-mentioned specific temperature and specific time conditions. In other words, the higher the solderability of the ceramic component 1, the better the solder wettability, the higher the density or compactness of the metallic Sn on the surface of the Sn plating layer 16, the less light reflection and scattering occurs on the surface, and the lower the RGB values ​​of the surface of the Sn plating layer after heat treatment. Thus, when the sum of the R, G, and B values ​​of the RGB values ​​on the surface of the Sn plating layer 16, which is the outermost layer of the external electrode 13 of the ceramic component 1, falls within the above-mentioned specific range, the solderability of the ceramic component 1 is considered to be good and improved.

[0017] A method for manufacturing ceramic component 1 according to the present embodiment (hereinafter also referred to as manufacturing method (P)) comprises a first step, a second step, and a third step. In the first step, a sintered body 11 having an internal electrode 12 provided therein is prepared. In the second step, an external electrode 13 that covers a part of the sintered body 11, is electrically connected to the internal electrode 12, and includes a Sn plating layer 16 as the outermost layer is formed. In the third step, ceramic components in which the sum of the R value, G value, and B value of RGB values indicating the surface color of the Sn plating layer 16 after heating at 200° C. or higher for 72 hours or more is 0 or more and 300 or less are sorted.

[0018] The RGB values on the surface of the Sn plating layer 16 after the heat treatment hardly change even if the heating temperature is set to 200° C. or higher or the heating time is set to 72 hours or more. Therefore, according to manufacturing method (P), by performing sorting based on the RGB values after heating at 200° C. or higher for 72 hours or more in the third step, the ceramic component 1 with improved solderability can be easily obtained without performing a solderability evaluation test or the like on the ceramic component 1.

[0019] A method for manufacturing ceramic component 1 according to another embodiment of the present invention (hereinafter also referred to as manufacturing method (Q)) comprises a first step, a second step, and a third step. In the first step, a sintered body 11 having an internal electrode 12 provided therein is prepared. In the second step, an external electrode 13 that covers a part of the sintered body 11, is electrically connected to the internal electrode 12, and includes a Sn plating layer 16 as the outermost layer is formed. In the third step, a test sample is extracted from a part of a production lot, and pass / fail judgment is performed based on whether the sum of the R value, G value, and B value of RGB values indicating the surface color of the Sn plating layer 16 after heating the test sample at 200° C. or higher for 72 hours or more is 0 or more and 300 or less.

[0020] According to manufacturing method (Q), in the third step, by performing pass / fail judgment based on the RGB values after heat treatment on the test sample which is a part of the production lot, the ceramic component 1 with improved solderability can be obtained more easily without performing a solderability evaluation test or the like on the ceramic component 1, and by measuring RGB values for a smaller number of ceramic components 1.

[0021] A method for sorting a ceramic component 1 according to the present embodiment (hereinafter also referred to as sorting method (R)) is a method for sorting a ceramic component 1 including a sintered body 11, an internal electrode 12 disposed inside the sintered body 11, and an external electrode 13 that covers a part of the sintered body 11, is electrically connected to the internal electrode 12, and includes a metal plating layer (hereinafter also referred to as metal plating layer (M)). In the sorting method (R), the ceramic component 1 is sorted into non-defective products and defective products based on measured values of an R value, a G value, and a B value of RGB values indicating the color of a surface of the metal plating layer (M) after heating at a predetermined temperature for a predetermined time.

[0022] According to the sorting method (R), after performing a heat treatment under conditions of a predetermined temperature and a predetermined time corresponding to the type of metal constituting the metal plating layer (M), sorting is performed based on measured values of RGB values of the color of the surface of the metal plating layer (M). This makes it possible to easily obtain the ceramic component 1 with improved solderability without performing a solderability evaluation test or the like on the ceramic component 1 having the metal plating layer (M).

[0023] 2. Details <Ceramic Component> The ceramic component 1 according to the present embodiment will be described with reference to the drawings. The drawings shown below are schematic diagrams, and the ratios of the sizes and thicknesses of the respective constituent elements in the drawings do not necessarily reflect actual dimensional ratios.

[0024] Examples of the ceramic component 1 include varistors, thermistors, ceramic capacitors, and the like. Hereinafter, a case where the ceramic component 1 is a varistor 1 will be described as an example.

[0025] As shown in FIG. 1 and FIG. 2, the varistor 1 includes a sintered body 11, an internal electrode 12, and an external electrode 13. The external electrode 13 includes a Sn plating layer 16 as an outermost layer. The internal electrode 12 is provided inside the sintered body 11. The external electrode 13 is provided so as to cover a part of the sintered body 11. The external electrode 13 is electrically connected to the internal electrode 12.

[0026] The varistor 1 is provided with at least one pair of internal electrodes 12 and one pair of external electrodes 13. The varistor 1 in Figure 1 is provided with one pair of internal electrodes 12 and one pair of external electrodes 13. The pair of internal electrodes 12 includes, for example, a first internal electrode 12A and a second internal electrode 12B. The pair of external electrodes 13 includes, for example, a first external electrode 13A provided on one end face of the sintered body 11 and a second external electrode 13B provided on the other end face of the sintered body 11. The first internal electrode 12A is electrically connected to the first external electrode 13A, and the second internal electrode 12B is electrically connected to the second external electrode 13B. In the varistor 1, one of the first external electrode 13A and the second external electrode 13B is the high-potential electrode, and the other of the first external electrode 13A and the second external electrode 13B is the low-potential electrode.

[0027] The external electrode 13 typically includes a primary electrode 14 that covers a portion of the sintered body 11, and a metal plating layer (M) that covers at least a portion of the primary electrode 14. The metal plating layer (M) typically includes a Ni plating layer 15 that covers at least a portion of the primary electrode 14, and a Sn plating layer 16 that covers at least a portion of the Ni plating layer 15 and is the outermost layer of the external electrode 13. In the varistor 1 of Figure 1, the first external electrode 13A includes a first primary electrode 14A, a first Ni plating layer 15A, and a first Sn plating layer 16A, and the second external electrode 13B includes a second primary electrode 14B, a second Ni plating layer 15B, and a second Sn plating layer 16B.

[0028] [Sintered body] The shape of the sintered body 11 in the varistor 1 is, for example, a rectangular parallelepiped. The dimensions of the sintered body 11 are, for example, 0.6 mm to 1.6 mm for the longest side, 0.3 mm to 0.8 mm for the width, and 0.3 mm to 0.8 mm for the height. The corners of the sintered body 11 may be chamfered as appropriate, and the corners of the sintered body 11 may be rounded.

[0029] The sintered body 11 of the varistor 1 is composed of, for example, a semiconductor ceramic component having nonlinear resistance characteristics. The sintered body 11 usually contains ZnO as the main component, and Bi2O3, Co2O3, MnO2, Sb2O3, Pr6O as minor components. 11It may also contain CaCO3, Cr2O3, etc. The sintered body 11 is formed, for example, by solid solution sintering of the main component such as ZnO with some of the minor components in the semiconductor ceramic component, and the remaining minor components precipitate at the grain boundaries.

[0030] An insulating layer may be formed on the surface of the sintered body 11 of the varistor 1.

[0031] [Internal electrode] The internal electrode 12 contains a metal such as Ag, Pd, PdAg, or PtAg.

[0032] A sintered body 11 having an internal electrode 12 inside can be manufactured, for example, by applying an internal electrode paste containing the above metal to a ceramic sheet made using a slurry containing ZnO by printing or the like, stacking, pressing, and cutting the resulting ceramic sheet, then heating to remove the binder, followed by firing.

[0033] [External electrode] The external electrode 13 typically includes a primary electrode 14 and a metal plating layer (M). The metal plating layer (M) includes, for example, a Ni plating layer 15 and an outermost Sn plating layer 16.

[0034] (Primary electrode) The primary electrode 14 is provided so as to cover a portion of the sintered body 11 and to be electrically connected to the internal electrode 12. The primary electrode 14 contains, for example, a metal component such as Ag, AgPd, or AgPt, and a glass component such as Bi2O3, SiO2, or B2O3. The primary electrode 14 is preferably mainly composed of metal, and more preferably mainly composed of Ag. The primary electrode 14 can be formed, for example, by applying a primary electrode paste containing the above metal component and the above glass component to a portion of the sintered body 11.

[0035] The external electrode 13 may have a secondary electrode that covers at least a portion of the primary electrode 14.

[0036] (Metal plating layer) The metal plating layer (M) is provided so as to cover at least a portion of the primary electrode 14. The metal plating layer (M) includes, for example, a Ni plating layer 15 provided so as to cover at least a portion of the primary electrode 14, and a Sn plating layer 16 provided so as to cover at least a portion of the Ni plating layer 15.

[0037] (Ni plating layer) The Ni plating layer 15 is typically a layer composed of metallic Ni. The average thickness of the Ni plating layer 15 is, for example, between 1 μm and 7 μm.

[0038] The Ni plating layer 15 can be formed, for example, by performing Ni plating using an electrolytic plating method.

[0039] (Sn plating layer) The Sn plating layer 16 is the outermost layer on the external electrode 13 and is typically composed of metallic Sn. The average thickness of the Sn plating layer 16 is, for example, between 1 μm and 10 μm.

[0040] The Sn plating layer 16 can be formed, for example, by performing Sn plating using an electrolytic plating method.

[0041] The surface color of the Sn plating layer 16 is expressed using RGB values. The RGB color system is a type of additive color mixing that represents colors using the mixing ratios of the three primary colors: red, green, and blue.

[0042] "RGB value" refers to a value in the RGB color system, which is a combination of values ​​(R, G, B) representing red (R value), green (G value), and blue (B value) from 0 to 255. For example, (255,255,255) represents white, (0,0,0) represents black, and (128,128,128) represents gray.

[0043] The RGB values ​​of the surface of the Sn plating layer 16 are measured after heat treatment at 200°C for 72 hours under atmospheric conditions. The RGB values ​​may be measured while the Sn plating layer 16 is at 200°C, as long as it is done after heating at 200°C for 72 hours. Alternatively, if it is within about one day after the heat treatment, the measurement may be performed after the layer has been left to cool to room temperature (25°C).

[0044] In varistor 1, it is important that the sum of the R, G, and B values ​​(hereinafter also referred to as the total value) of the RGB values ​​of the surface of the Sn plating layer 16 after heating at 200°C for 72 hours is between 0 and 300. In this case, varistor 1 can improve solderability. If the total value exceeds 300, solderability deteriorates and cannot be improved. The RGB values ​​of the surface of the Sn plating layer 16 are usually measured in the area of ​​the surface of the Sn plating layer 16 that will be soldered for mounting. The R, G, and B values ​​of the RGB values ​​represent the arithmetic mean of the values ​​measured for multiple (for example, any 30 points) of the Sn plating layer 16.

[0045] The RGB values ​​of the surface of the Sn plating layer 16 can be obtained, for example, by measuring the color using a microscope equipped with an RGB value measurement function. Measurement conditions can include, for example, using a high-brightness LED (color temperature: 5700K) as the light source and setting the illuminance to 500 lux or more.

[0046] The total value is preferably 100 or more, more preferably 200 or more, even more preferably 240 or more, and particularly preferably 260 or more. Furthermore, the total value is preferably 280 or less, and more preferably 270 or less. When the total value falls within the above range, the solderability of varistor 1 can be further improved.

[0047] The R value is preferably 60 or higher, and more preferably 70 or higher. The R value is preferably 100 or lower, and more preferably 90 or lower. The G-value is preferably 50 or higher, and more preferably 60 or higher. The G-value is preferably 120 or lower, and more preferably 90 or lower. The B value is preferably 60 or higher, and more preferably 80 or higher. The B value is preferably 130 or lower, and more preferably 110 or lower.

[0048] As described above, the quality of solderability can be estimated by measuring the RGB values ​​on the surface of the Sn plating layer 16 after heat treatment of the varistor 1 at 200°C for 72 hours.

[0049] Furthermore, it is believed that the solderability of ceramic components 1 according to this embodiment, such as thermistors and ceramic capacitors other than varistor 1, can also be similarly estimated.

[0050] <1 Method for Manufacturing a Barista> The manufacturing method (P) for Barista 1 comprises a first step, a second step, and a third step. The manufacturing method (P) may also include other steps besides the first to third steps.

[0051] [1st step] In this process, a sintered body 11 is prepared, which has internal electrodes 12 inside.

[0052] In this process, specifically, first, an internal electrode paste is applied to a ceramic sheet, for example, prepared using a slurry, by printing or other means. Next, the resulting ceramic sheet is laminated, pressed, and cut, followed by debinding and firing. The slurry consists of, for example, ZnO as the main raw material and Bi2O3, Co2O3, MnO2, Sb2O3, and Pr6O as secondary raw materials. 11 It can be prepared by mixing Co2O3, CaCO3, Cr2O3, etc., with a binder.

[0053] For the internal electrode paste, for example, Ag paste, Pd paste, Pt paste, PdAg paste, PtAg paste, etc., can be used.

[0054] The temperature at which the binder is removed is, for example, 300°C to 500°C. The temperature at which the firing is performed can be appropriately adjusted depending on the structure and composition of the resulting sintered body 11, for example, 800°C to 1300°C.

[0055] In this way, a sintered body 11 with internal electrodes 12 inside can be obtained through this process.

[0056] [Second process] In this process, an external electrode 13 is formed that covers a portion of the sintered body 11, is electrically connected to the internal electrode 12, and includes a Sn plating layer 16 as its outermost layer.

[0057] In this process, specifically, first, a primary electrode paste is applied to a portion of the sintered body 11 obtained in the first step so as to come into contact with a portion of the internal electrode 12, and then a primary electrode 14 is formed by baking at a temperature of 700°C to 800°C. Next, a Ni plating layer 15 is formed to cover at least a portion of the formed primary electrode 14. Then, a Sn plating layer 16 is formed to cover at least a portion of the formed Ni plating layer 15.

[0058] Primary electrode paste can be prepared by mixing a metal component, such as Ag powder, AgPd powder, or AgPt powder, with a glass component, such as Bi2O3, SiO2, or B2O3, and a solvent. Alternatively, a primary electrode paste with Ag as the main component and containing a resin component can also be used.

[0059] Methods for forming the Ni plating layer 15 and the Sn plating layer 16 include, for example, performing Ni plating and Sn plating sequentially by electrolytic plating.

[0060] In this way, this process makes it possible to form an external electrode 13 that covers a portion of the sintered body 11, is electrically connected to the internal electrode 12, and includes a Sn plating layer 16 as the outermost layer.

[0061] [3rd step] In this process, samples are selected that have a total of 0 to 300 RGB values ​​indicating the color of the Sn plating layer 16 surface after heating at 200°C or higher for 72 hours or more.

[0062] In this process, specifically, first, the varistor 1, which has an external electrode 13 containing a Sn plating layer 16 as its outermost layer, obtained in the second process, is heat-treated at 200°C or higher for 72 hours or more under atmospheric conditions. Next, the RGB values ​​of the surface of the Sn plating layer 16 on the outermost layer of the external electrode 13 of the varistor 1 after the heat treatment are measured. Then, from the varistors 1 whose RGB values ​​have been measured, those with a total RGB value between 0 and 300 are selected.

[0063] The RGB values ​​on the surface of the Sn plating layer 16 after heat treatment hardly change, even if the heating temperature is 200°C or higher, or the heating time is 72 hours or higher. Therefore, in the third step, by selecting those with a total RGB value between 0 and 300, a varistor 1 with improved solderability can be obtained.

[0064] As described above, by the manufacturing method (P), a varistor 1 with improved solderability can be easily obtained without having to perform solderability evaluation tests or the like.

[0065] <2 methods for manufacturing a barista> The manufacturing method (Q) for Barista 1 comprises a first step, a second step, and a third step. The manufacturing method (Q) may further comprise other steps besides the first to third steps.

[0066] Manufacturing method (Q) differs from manufacturing method (P) in the third step. Specifically, the first and second steps of manufacturing method (Q) are the same as those of manufacturing method (P).

[0067] [3rd step] In this process, a test sample is taken from a portion of the manufacturing lot, and the pass / fail determination is made based on whether the sum of the R, G, and B values ​​of the RGB values ​​indicating the color of the surface of the Sn plating layer 16 after heating the test sample at 200°C or higher for 72 hours or more is between 0 and 300.

[0068] Specifically, this process involves first taking a test sample from a portion of the manufacturing lot of varistor 1. Next, the varistor 1 of this test sample is heat-treated at 200°C or higher for 72 hours or more under atmospheric conditions. Then, the RGB values ​​of the surface of the Sn plating layer 16 of the heat-treated varistor 1 are measured. Subsequently, a pass / fail judgment is made, with those whose total RGB value is between 0 and 300 being judged as passable, and those whose total value exceeds 300 being judged as failing.

[0069] The number of varistors 1 constituting a manufacturing lot is, for example, between 1 and 1,000,000. The number of varistors 1 constituting a test sample is, for example, between 1 and 100. By setting the number of varistors 1 constituting the manufacturing lot and test sample within the above ranges, it is possible to obtain varistors 1 with improved solderability by measuring the RGB values ​​of a smaller number of ceramic components 1.

[0070] As described above, by manufacturing method (Q), a varistor 1 with improved solderability can be obtained more easily without having to perform solderability evaluation tests or the like.

[0071] <How to select a barista> The varistor 1 sorting method (R) is a method for sorting ceramic component 1 comprising a sintered body 11, an internal electrode 12 disposed inside the sintered body 11, and an external electrode 13 covering a part of the sintered body 11, electrically connected to the internal electrode 12, and including a metal plating layer (M). The sorting method (R) sorts the varistor 1 into good products and defective products based on the measured values ​​of the R, G, and B values ​​of the RGB values ​​indicating the color of the surface of the metal plating layer (M) after heating at a predetermined temperature for a predetermined time.

[0072] In the sorting method (R), the metal plating layer (M) is usually a layer composed of metal. Examples of metal plating layers (M) include Sn plating layers, Ni plating layers, Ag plating layers, Au plating layers, Cu plating layers, etc. This metal plating layer (M) is preferably the outermost layer on the external electrode 13.

[0073] The predetermined temperature and time for the heat treatment in the sorting method (R) can be set according to the type of metal of the metal plating layer (M), for example, by pre-evaluating the relationship between the RGB value after heat treatment and the solderability.

[0074] As described above, the sorting method (R) allows for the easy sorting of varistors 1 containing various metal plating layers (M) into good products with improved solderability and defective products with unimproved solderability, without the need to perform solderability evaluation tests. Furthermore, the sorting method (R) allows for the prediction of the solderability of varistors 1 by measuring the RGB values ​​on the surface of the metal plating layer (M) of the external electrode 13.

[0075] According to the manufacturing method (P), manufacturing method (Q), and sorting method (R), it is considered that ceramic components 1 other than varistor 1, such as thermistors and ceramic capacitors according to this embodiment, can also be easily obtained with improved solderability without having to perform solderability evaluation tests. [Examples]

[0076] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0077] [Barista production] A sintered body with internal electrodes was prepared, a primary electrode paste was applied to cover at least a portion of the sintered body, and a primary electrode was formed by baking. A Ni plating layer was formed by electroplating to cover at least a portion of the primary electrode, and a Sn plating layer was formed by electroplating to cover at least a portion of the Ni plating layer to manufacture a varistor. The varistors of Examples 1 and 2, and Comparative Examples 1 and 2, were obtained by varying the current value during the electroplating process to form the Sn plating layer.

[0078] [evaluation] (RGB values) For each of the varistors obtained in Example 1 and Example 2, and Comparative Example 1 and Comparative Example 2, heat treatment was performed at 200°C for 72 hours under atmospheric conditions. After that, the RGB values ​​(R, G, and B values) were measured for the surface of two Sn plating layers (30 points) of each of the 15 varistors. A digital microscope (Keyence VHX-700) was used to measure the RGB values.

[0079] (Solder wettability evaluation) For each of the varistors obtained in Example 1 and Example 2, and Comparative Example 1 and Comparative Example 2, solder wettability tests were actually performed to evaluate their solder wettability. As a solder wettability test, a meniscograph test was performed and the zero-crossing time was measured.

[0080] The meniscography test was performed according to IEC60068-2-69 (JIS-C-60068-2-69) by mounting the varistor in a scissor-type jig, applying flux to the surface of the Sn plating layer, immersing it in solder, and measuring the zero-crossing time. The zero-crossing time was defined as the time it took for the contact angle with the solder to reach 90° after immersion.

[0081] Solder wettability was evaluated as A (good) if the zero-crossing time was 1.2 seconds or less, and B (poor) if it was greater than 1.2 seconds.

[0082] [Table 1]

[0083] The results in Table 1 indicate that the varistors of Examples 1 and 2, whose RGB total values ​​were within the specified range, actually exhibited good solder wettability, suggesting improved solderability. Conversely, the varistors of Comparative Examples 1 and 2, whose RGB total values ​​were outside the specified range, actually exhibited poor solder wettability, suggesting that solderability did not improve.

[0084] (summary) As is clear from the embodiments described above, this disclosure includes the following aspects. In the following, reference numerals are enclosed in parentheses solely to indicate their correspondence with the embodiments.

[0085] The ceramic component (1) of the first embodiment comprises a sintered body (11), an internal electrode (12) provided inside the sintered body (11), and an external electrode (13) provided so as to cover a part of the sintered body (11) and electrically connected to the internal electrode (12). The external electrode (13) includes a Sn plating layer (16) as its outermost layer. The sum of the R, G, and B values ​​of the RGB values ​​indicating the color of the surface of the Sn plating layer (16) after heating at 200°C for 72 hours is between 0 and 300.

[0086] According to the first embodiment, the ceramic component (1) can have improved solderability.

[0087] A method for manufacturing a ceramic component (1) according to a second embodiment comprises a first step, a second step, and a third step. In the first step, a sintered body (11) having an internal electrode (12) inside is prepared. In the second step, an external electrode (13) is formed that covers a part of the sintered body (11), is electrically connected to the internal electrode (12), and includes a Sn plating layer (16) as the outermost layer. In the third step, Sn plating layer (16) is selected if the sum of the R, G, and B values ​​of the RGB values ​​indicating the color of the surface of the Sn plating layer (16) after heating at 200°C or higher for 72 hours or more is between 0 and 300.

[0088] According to the second embodiment, a ceramic component (1) with improved solderability can be easily obtained without having to perform solderability evaluation tests or the like.

[0089] A third embodiment of the method for manufacturing a ceramic component (1) comprises a first step, a second step, and a third step. In the first step, a sintered body (11) having an internal electrode (12) inside is prepared. In the second step, an external electrode (13) is formed that covers a part of the sintered body (11), is electrically connected to the internal electrode (12), and includes a Sn plating layer (16) as the outermost layer. In the third step, a test sample is taken from a part of the manufacturing lot, and the pass / fail determination is made based on whether the sum of the R, G, and B values ​​of the RGB values ​​indicating the color of the surface of the Sn plating layer (16) after heating the test sample at 200°C or higher for 72 hours or more is between 0 and 300.

[0090] According to the third embodiment, ceramic components (1) with improved solderability can be obtained more easily without conducting solderability evaluation tests, etc., and by measuring the RGB value for a smaller number of ceramic components (1).

[0091] The fourth embodiment of the method for sorting ceramic parts (1) is a method for sorting ceramic parts (1) comprising a sintered body (11), an internal electrode (12) disposed inside the sintered body (11), and an external electrode (13) covering a part of the sintered body (11), electrically connected to the internal electrode (12), and including a metal plating layer. After heating at a predetermined temperature for a predetermined time, the ceramic parts (1) are sorted into good products and defective products based on the measured values ​​of the R, G, and B values ​​of the RGB values ​​indicating the color of the metal plating layer surface.

[0092] According to the fourth embodiment, a ceramic component (1) having a metal plating layer can be easily obtained with improved solderability without having to perform solderability evaluation tests or the like. [Explanation of Symbols]

[0093] 1. Ceramic component (varistor) 11 Sintered body 12 Internal electrode 12A 1st internal electrode 12B 2nd internal electrode 13 External electrode 13A 1st external electrode 13B 2nd external electrode 14 Primary electrode 14A 1st primary electrode 14B 2nd primary electrode 15 Ni plating layer 15A First Ni plating layer 15B Second Ni plating layer 16 Sn plating layer 16A First Sn plating layer 16B Second Sn plating layer

Claims

1. Sintered body and, An internal electrode provided inside the sintered body, An external electrode is provided so as to cover a part of the sintered body and is electrically connected to the internal electrode. Equipped with, The external electrode includes a Sn plating layer as its outermost layer. The sum of the R, G, and B values ​​of the RGB values ​​indicating the color of the surface of the Sn plating layer after heating at 200°C for 72 hours is between 0 and 300. Ceramic parts.

2. The first step is to prepare a sintered body in which internal electrodes are provided, A second step involves forming an external electrode that covers a portion of the sintered body, is electrically connected to the internal electrode, and includes a Sn plating layer as its outermost layer. A third step involves selecting materials in which the sum of the R, G, and B values ​​of the RGB values ​​indicating the color of the surface of the Sn plating layer after heating at 200°C or higher for 72 hours or more is between 0 and 300. Equipped with A method for manufacturing ceramic parts.

3. The first step is to prepare a sintered body in which internal electrodes are provided, A second step involves forming an external electrode that covers a portion of the sintered body, is electrically connected to the internal electrode, and includes a Sn plating layer as its outermost layer. A third step involves taking a test sample from a portion of the manufacturing lot and determining whether it passes or fails based on whether the sum of the R, G, and B values ​​of the RGB values ​​indicating the color of the surface of the Sn plating layer after heating the test sample at 200°C or higher for 72 hours or more is between 0 and 300. Equipped with A method for manufacturing ceramic parts.

4. A method for sorting ceramic components comprising a sintered body, an internal electrode disposed inside the sintered body, and an external electrode covering a portion of the sintered body, electrically connected to the internal electrode, and including a metal plating layer, After heating at a predetermined temperature for a predetermined time, the ceramic parts are sorted into good and defective products based on the measured values ​​of the R, G, and B RGB values ​​that indicate the color of the metal plating layer surface. A method for sorting ceramic components.

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