Electronic component

Abstract

The present disclosure provides an electronic component (10) in which peeling of an insulating film (50) from a base body (20) is suppressed. The electronic component (10) includes the base body (20) and the insulating film (50) that covers an outer surface (21) of the base body (20). The insulating film (50) has a mixed layer (51) and a glass layer (56). The mixed layer (51) has glass (52) and a powder particle (53). The glass layer (56) contains glass (57), and the content ratio of the powder particle (53) in the glass layer is smaller than the content ratio of the powder particle (53) in the mixed layer (51). The mixed layer (51) is located on the base body (20) side as viewed from the glass layer (56).

Description

Technical Field

[0001] This invention relates to electronic components. Background Technology

[0002] The electronic component described in Patent Document 1 has a blank and an insulating film covering the outer surface of the blank. The insulating film is a glass layer made of glass.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2002-043167

[0004] There is a possibility that an external impact may be applied to the electronic component described in Patent Document 1. If an external impact is applied to the electronic component, the load generated by the impact and the internal stress of the glass layer may combine to exert a large force at a specific location within the glass layer. Furthermore, when a large force is applied to the glass layer, there is a concern that a portion of the glass layer may peel off from the outer surface of the preform. Summary of the Invention

[0005] To address the aforementioned issues, the present invention provides an electronic component comprising a blank and an insulating film, wherein the insulating film covers the outer surface of the blank, the insulating film having a mixing layer and a glass layer, wherein the mixing layer comprises glass and powder particles, the glass layer comprises glass, the proportion of powder particles in the glass layer is less than the proportion of powder particles in the mixing layer, and the mixing layer is located on the blank side when viewed from the glass layer.

[0006] According to the above structure, the insulating film has a hybrid layer and a glass layer. Furthermore, the hybrid layer comprises glass and powder particles. In the hybrid layer, the proportion of powder particles is larger than that in the glass layer, thereby mitigating the internal stress of the glass. Moreover, at each location where powder particles are present, the internal stress of the glass is interrupted by the individual powder particles, thus preventing large internal stresses from concentrating on specific areas. Therefore, when an external impact is applied to the electronic component, it is possible to suppress the peeling of the insulating film from the preform due to internal stress.

[0007] It can prevent the insulating film from peeling off from the blank. Attached Figure Description

[0008] Figure 1 It is a 3D diagram of an electronic component.

[0009] Figure 2 This is a side view of the electronic component.

[0010] Figure 3 It is along Figure 2 A sectional view along line 3-3.

[0011] Figure 4 It is along Figure 2Enlarged view of the cross section of line 4-4.

[0012] Figure 5 It is an explanatory diagram illustrating the manufacturing method of electronic components.

[0013] Figure 6 It is an explanatory diagram illustrating the manufacturing method of electronic components.

[0014] Figure 7 It is an explanatory diagram illustrating the manufacturing method of electronic components.

[0015] Figure 8 It is an explanatory diagram illustrating the manufacturing method of electronic components.

[0016] Figure 9 It is an explanatory diagram illustrating the manufacturing method of electronic components.

[0017] Figure 10 It is an explanatory diagram illustrating the manufacturing method of electronic components.

[0018] Figure 11 This is an enlarged view of the cross-section of the modified electronic component. Detailed Implementation

[0019] <An Implementation of the Electronic Component>

[0020] Hereinafter, one embodiment of the electronic component will be described with reference to the accompanying drawings. Furthermore, for ease of understanding, the drawings sometimes show enlarged views of the constituent elements. The dimensional ratios of the constituent elements may differ from the actual dimensional ratios or those shown in other drawings. Additionally, while shading lines are used in the sectional views, some shading lines on the constituent elements may be omitted for clarity.

[0021] (Regarding the overall structure)

[0022] like Figure 1 As shown, the electronic component 10 is, for example, a surface-mount type negative characteristic thermistor component mounted on a circuit board or the like. Furthermore, the negative characteristic thermistor component has the characteristic that its resistance decreases as the temperature rises.

[0023] The electronic component 10 includes a blank 20. The blank 20 is generally a quadrangular prism and has a central axis CA. Hereinafter, an axis extending along the central axis CA is designated as a first axis X. One of the axes orthogonal to the first axis X is designated as a second axis Y. Furthermore, an axis orthogonal to both the first axis X and the second axis Y is designated as a third axis Z. A direction along the first axis X is designated as a first positive direction X1, and a direction along the first axis X opposite to the first positive direction X1 is designated as a first negative direction X2. Similarly, a direction along the second axis Y is designated as a second positive direction Y1, and a direction along the second axis Y opposite to the second positive direction Y1 is designated as a second negative direction Y2. Finally, a direction along the third axis Z is designated as a third positive direction Z1, and a direction along the third axis Z opposite to the third positive direction Z1 is designated as a third negative direction Z2.

[0024] The outer surface 21 of the blank 20 has six planar planes 22. The six planes 22 extend in different directions. The six planes 22 are roughly divided into a first end face 22A facing the first positive direction X1, a second end face 22B facing the first negative direction X2, and four side faces 22C. The four side faces 22C are respectively the face facing the third positive direction Z1, the face facing the third negative direction Z2, the face facing the second positive direction Y1, and the face facing the second negative direction Y2.

[0025] The outer surface 21 of the blank 20 has twelve boundary surfaces 23. The boundary surfaces 23 include curved surfaces existing at the boundaries of adjacent planes 22. That is, the boundary surfaces 23 include, for example, curved surfaces formed by rounding the corners that form adjacent planes 22.

[0026] Furthermore, the outer surface 21 of the blank 20 has eight spherical corner faces 24. Each corner face 24 is a boundary portion of three adjacent planes 22. In other words, each corner face 24 includes a curved surface at the intersection of the three boundary planes 23. That is, for example, each corner face 24 includes a curved surface formed by rounding the corners formed by the three adjacent planes 22.

[0027] In addition, Figure 1 and Figure 2 In this drawing, the surface of the insulating film 50, which will be described later, is considered to be the same as the outer surface 21 of the blank 20 and is marked with reference numerals.

[0028] like Figure 2 As shown, the dimension of the blank 20 along the first axis X is greater than the dimension along the third axis Z. Additionally, as... Figure 1As shown, the dimension of the blank 20 along the first axis X is larger than the dimension along the second axis Y. Furthermore, the blank 20 is made of ceramic fired from a metal oxide composed of at least one of Mn, Fe, Ni, Co, Ti, Ba, Al, and Zn.

[0029] like Figure 3 As shown, the electronic component 10 has two first internal electrodes 41 and two second internal electrodes 42. The first internal electrodes 41 and the second internal electrodes 42 are embedded inside the blank 20.

[0030] The first internal electrode 41 is made of a conductive material. For example, the first internal electrode 41 is made of palladium. Furthermore, the second internal electrode 42 is made of the same material as the first internal electrode 41.

[0031] The first internal electrode 41 is rectangular in shape. The main surface of the first internal electrode 41 is orthogonal to the second axis Y. The second internal electrode 42 is also rectangular in shape, similar to the first internal electrode 41. The main surface of the second internal electrode 42 is also orthogonal to the second axis Y, just like the first internal electrode 41.

[0032] The dimension of the first internal electrode 41 along the first axis X is smaller than the dimension of the blank 20 along the first axis X. Additionally, as... Figure 1 As shown, the dimension of the first internal electrode 41 along the third axis Z is approximately two-thirds of the dimension of the blank 20 along the third axis Z. The dimensions of the second internal electrode 42 in each direction are the same as those of the first internal electrode 41.

[0033] like Figure 3 As shown, the first internal electrode 41 and the second internal electrode 42 are staggered in the direction along the second axis Y. That is, they are arranged in the order of first internal electrode 41, second internal electrode 42, first internal electrode 41, and second internal electrode 42 from the side 22C facing the second positive direction Y1 to the second negative direction Y2. In this embodiment, the distance between each internal electrode in the direction along the second axis Y is equal.

[0034] like Figure 1 As shown, the two first internal electrodes 41 and the two second internal electrodes 42 are all located at the center of the blank 20 in the direction along the third axis Z. On the other hand, as Figure 3 As shown, the first internal electrode 41 is located near the first positive direction X1. The second internal electrode 42 is located near the first negative direction X2.

[0035] Specifically, the end of the first internal electrode 41 on the first positive direction X1 side coincides with the end of the blank 20 on the first positive direction X1 side. The end of the first internal electrode 41 on the first negative direction X2 side is located inside the blank 20 and does not reach the end of the blank 20 on the first negative direction X2 side. On the other hand, the end of the second internal electrode 42 on the first negative direction X2 side coincides with the end of the blank 20 on the first negative direction X2 side. The end of the second internal electrode 42 on the first positive direction X1 side is located inside the blank 20 and does not reach the end of the blank 20 on the first positive direction X1 side.

[0036] The electronic component 10 includes an insulating film 50. The insulating film 50 covers the outer surface 21 of the blank 20. In this embodiment, the insulating film 50 covers the entire area of ​​the outer surface 21 of the blank 20.

[0037] like Figure 3 As shown, the electronic component 10 includes a first external electrode 61 and a second external electrode 62. The first external electrode 61 has a first base electrode 61A and a first metal layer 61B. The first base electrode 61A includes a portion of a first end face 22A on the outer surface 21 of the blank 20 and is stacked on the insulating film 50. Specifically, the first base electrode 61A is a five-sided electrode covering a portion of the first end face 22A and the first positive direction X1 side of the four sides 22C of the blank 20. In this embodiment, the material of the first base electrode 61A is silver and glass.

[0038] The first metal layer 61B covers the first base electrode 61A from the outside. Therefore, the first metal layer 61B is stacked on the first base electrode 61A. Specifically, the first metal layer 61B has a double-layer structure of nickel plating and tin plating.

[0039] The second external electrode 62 has a second base electrode 62A and a second metal layer 62B. The second base electrode 62A includes a portion of a second end face 22B on the outer surface 21 of the blank 20 and is stacked on the insulating film 50. Specifically, the second base electrode 62A is a five-sided electrode covering a portion of the second end face 22B and the first negative direction X2 side of the four sides 22C of the blank 20. In this embodiment, the material of the second base electrode 62A is the same as that of the first external electrode 61, which is silver and glass.

[0040] The second metal layer 62B covers the second base electrode 62A from the outside. Therefore, the second metal layer 62B is stacked on the second base electrode 62A. Specifically, the second metal layer 62B, like the first metal layer 61B, is a double-layer structure consisting of a nickel plating and a tin plating.

[0041] The second external electrode 62 does not reach the first external electrode 61 on the side surface 22C, and is disposed separately from the first external electrode 61 in the direction along the first axis X. Furthermore, on the side surface 22C of the blank 20, the first external electrode 61 and the second external electrode 62 are not stacked in the central portion along the first axis X, and the insulating film 50 is exposed. Additionally, in Figures 1-3 In the diagram, the first external electrode 61 and the second external electrode 62 are illustrated by double-dotted lines.

[0042] like Figure 3 As shown, the ends of the first external electrode 61 and the first internal electrode 41 in the first positive direction X1 are connected via a first through-hole 71 that penetrates the insulating film 50. Further details will be described later, but the first through-hole 71 is formed during the manufacturing process of the electronic component 10 by extending palladium constituting the first internal electrode 41 toward the first external electrode 61.

[0043] Furthermore, the ends of the second external electrode 62 and the second internal electrode 42 on the first negative direction X2 side are connected via a second through-hole 72 penetrating the insulating film 50. The second through-hole 72, like the first through-hole 71, is formed during the manufacturing process of the electronic component 10 by extending palladium constituting the first internal electrode 41 towards the second external electrode 62. Furthermore, in Figure 3 In the illustration, the first internal electrode 41 and the first through-hole 71 are depicted as distinct components with boundaries, but in reality, there is no clear boundary between them. The same applies to the second through-hole 72. Furthermore, in Figure 1 and Figure 2 The illustration of the first through section 71 is omitted.

[0044] (Regarding insulating film)

[0045] like Figure 4 As shown, the insulating film 50 has a mixing layer 51 and a glass layer 56. The mixing layer 51 comprises glass 52 and powder 53. The mixing layer 51 is laminated on the outer surface 21 of the blank 20. That is, the mixing layer 51 covers the outer surface 21 of the blank 20 without passing through other layers. In addition, when viewed from the glass layer 56, the mixing layer 51 is located on the side of the blank 20.

[0046] If the mixed layer 51 is viewed in section, the powder particles 53 are dispersed within the glass 52. The material of the powder particles 53 is the same as that of the preform 20. Furthermore, the coefficient of thermal expansion of the powder particles 53 is greater than that of the glass 52. The average particle size of the powder particles 53 is 100 nm or more. Moreover, the average particle size can be calculated as the average of the particle sizes of several, for example, ten powder particles 53 randomly extracted from a single cross-sectional image. Additionally, there is a case where multiple powder particles 53 agglomerate into a block. In this case, as long as the particle interface can be observed within the agglomerated block, the portion surrounded by its boundary is considered a single powder particle 53. Furthermore, the particle size is the maximum dimension passing through the geometric center of a single powder particle 53 when viewed in section.

[0047] Glass layer 56 is a layer in which the proportion of powder 53 is smaller than that of mixing layer 51. In this embodiment, glass layer 56 is composed of approximately only glass 57. Furthermore, the glass 57 of glass layer 56 and the glass 52 of mixing layer 51 are integrated and do not have a clear boundary line.

[0048] Glass layer 56 has a crack 58. Crack 58 opens on the surface of glass layer 56 opposite to the mixing layer 51. Moreover, crack 58 does not reach the preform 20. The tip of crack 58 exists within the mixing layer 51. Therefore, powder particles 53 are present near the tip of crack 58. Furthermore, as described above, glass 52 and powder particles 53 are present in the mixing layer 51. Moreover, the coefficient of thermal expansion of powder particles 53 is greater than that of glass 52. Therefore, when the mixing layer 51 is heated, the portion near the powder particles 53 in glass 52 is subjected to force from the powder particles 53 that are to expand. Due to this force, crack 58 is generated in the insulating film 50, particularly near the powder particles 53 in glass 52.

[0049] In a cross-sectional view orthogonal to the outer surface 21 of the blank 20, the powder 53 farthest from the outer surface 21 of the blank 20 is designated as a specific powder 53S. Furthermore, the point in the specific powder 53S farthest from the outer surface 21 of the blank 20 is designated as a specific point P. The shortest distance from the outer surface 21 of the blank 20 to the specific point P is designated as a first thickness T1. The shortest distance from the specific point P to the surface of the glass layer 56 covering the powder 53 is designated as a second thickness T2. In this case, the first thickness T1 is greater than the second thickness T2.

[0050] <An embodiment of a method for manufacturing electronic components>

[0051] (Overall structure)

[0052] Next, the manufacturing method of electronic component 10 will be described.

[0053] like Figure 5As shown, the manufacturing method of electronic component 10 includes: a laminate preparation step S11, a chamfering step S12, a solvent addition step S13, a catalyst addition step S14, a preform addition step S15, a polymer addition step S16, and a metal alkoxide addition step S17. Furthermore, the manufacturing method of electronic component 10 also includes: a film formation step S18, a drying step S19, a conductor coating step S20, a curing step S21, and a plating step S22.

[0054] First, during the formation of the green body 20, in the laminate preparation step S11, a laminate is prepared that is a green body 20 without boundary surfaces 23 and corner surfaces 24. That is, the laminate is in its state before the R-bevel, and is a cuboid with six planes 22. For example, first, multiple ceramic sheets that will become the green body 20 are prepared. These sheets are relatively thin plates. A conductive paste that forms the first internal electrode 41 is laminated on the sheet. A ceramic sheet that forms the green body 20 is laminated on the conductive paste. A conductive paste that forms the second internal electrode 42 is laminated on the sheet. In this way, the ceramic sheet and the conductive paste are laminated. Then, an unfired laminate is formed by cutting it to a specified size. Then, the unfired laminate is prepared by firing it at a high temperature.

[0055] Next, the R-beveling process S12 is performed. In the R-beveling process S12, the laminate prepared in the laminate preparation process S11 is used to form a boundary surface 23 and a corner surface 24. For example, the corners of the laminate are R-beveled by using a tumbler grinder to form a curved boundary surface 23 and a curved corner surface 24. As a result, a green body 20 is formed. In addition, a portion of the ceramic flakes constituting the laminate is attached as powder 53 to the outer surface 21 of the green body 20. Therefore, the material of the powder 53 is the same as that of the green body 20.

[0056] Next, the solvent addition process S13 is performed. For example... Figure 6 As shown, in the solvent addition step S13, 2-propanol is added into the reaction vessel 81 as solvent 82.

[0057] Next, as Figure 5 As shown, the catalyst feeding step S14 is performed. Figure 7 As shown, in the catalyst addition step S14, firstly, the solvent 82 in the reaction vessel 81 is stirred. Then, ammonia water is added to the reaction vessel 81 as an aqueous solution 83 containing the catalyst. The catalyst in this embodiment is hydroxide ions, which function as a catalyst to promote the hydrolysis of the metal alkoxide 85 described later.

[0058] Next, as Figure 5 As shown, the billet feeding process S15 is carried out. Figure 8As shown, in the blank feeding process S15, a plurality of blanks 20 pre-formed in the R chamfering process S12 as described above are fed into the reaction vessel 81.

[0059] Next, as Figure 5 As shown, the polymer input step S16 is performed. Figure 9 As shown, in the polymer input step S16, polyvinylpyrrolidone is input into the reaction vessel 81 as polymer 84. The polymer 84 input into the reaction vessel 81 is then adsorbed onto the outer surface 21 of the preform 20.

[0060] Next, as Figure 5 As shown, the metal alkoxide feeding process S17 is performed. (As indicated...) Figure 10 As shown, in the metal alkoxide addition step S17, liquid tetraethyl orthosilicate is added into the reaction vessel 81 as metal alkoxide 85. Alternatively, tetraethyl orthosilicate may also be referred to as tetraethoxysilane. In this embodiment, the amount of metal alkoxide 85 added in the metal alkoxide addition step S17 is calculated based on the area of ​​the outer surface 21 of the blank 20 added in the blank addition step S15. Specifically, it is calculated by multiplying the amount of metal alkoxide 85 required for each blank 20 to form the insulating film 50 covering the outer surface 21 of the blank 20 by the number of blanks 20.

[0061] Next, as Figure 5 As shown, the film-forming process S18 is performed. In the film-forming process S18, after the metal alkoxide 85 is added into the reaction vessel 81 through the metal alkoxide addition process S17, the stirring of the solvent 82, which started in the solvent addition process S13 above, is continued for a predetermined time.

[0062] Next, a drying step S19 is performed. In the drying step S19, after stirring continuously for a predetermined time in the film-forming step S18, the preform 20 is removed from the reaction vessel 81 and dried. As a result, the sol-like insulating film 50 is dried, becoming a gel-like insulating film 50. At this time, in particular, glass 52 grows, covering the powder particles 53 attached to the outer surface 21 of the preform 20. Therefore, an insulating film 50 having a mixed layer 51 and a glass layer 56 is formed. Furthermore, in this embodiment, the film-forming method for producing an insulating film 50 on the preform 20 is constituted by a solvent addition step S13, a catalyst addition step S14, a preform addition step S15, a polymer addition step S16, a metal alkoxide addition step S17, and a film-forming step S18.

[0063] Next, a conductive coating process S20 is performed. In the conductive coating process S20, conductive paste is applied to two portions of the insulating film 50, one covering a portion of the first end face 22A of the blank 20 and the other covering a portion of the second end face 22B of the blank 20. Specifically, conductive paste is applied to the insulating film 50 to cover the entire area of ​​the first end face 22A and a portion of the four sides 22C. Additionally, conductive paste is applied to the insulating film 50 to cover the entire area of ​​the second end face 22B and a portion of the four sides 22C.

[0064] Next, a curing process S21 is performed. Specifically, the curing process S21 involves heating the insulating film 50 and the blank 20 coated with the conductive paste. As a result, water and polymer 84 vaporize from the gel-like insulating film 50, such as... Figure 3 As shown, the insulating film 50 covering the outer surface 21 of the blank 20 is fired and cured. Simultaneously, the conductive paste coated in the conductive coating step S20 is fired, forming a first base electrode 61A and a second base electrode 62A. Thus, the base electrode forming process is constituted by the conductive coating step S20 and the curing step S21. That is, in this embodiment, the curing step S21 serves not only as a process for curing the insulating film 50 but also as part of the base electrode forming process.

[0065] In this embodiment, during heating in the curing process S21, due to the Kirkendall effect caused by the difference in diffusion rates between the first internal electrode 41 and the first base electrode 61A, the palladium contained in the first internal electrode 41 is attracted to the silver-containing first base electrode 61A. As a result, the insulating film 50 extends through the first through-hole 71 from the first internal electrode 41 to the first base electrode 61A, thus connecting the first internal electrode 41 and the first base electrode 61A. The same applies to the second through-hole 72 connecting the second internal electrode 42 and the second base electrode 62A.

[0066] Next, plating process S22 is performed. Electroplating is performed on portions of the first base electrode 61A and the second base electrode 62A. This forms a first metal layer 61B on the surface of the first base electrode 61A. Additionally, a second metal layer 62B is formed on the surface of the second base electrode 62A. Although not shown in the figure, the first metal layer 61B and the second metal layer 62B form a double-layer structure by using nickel and tin for electroplating. Thus, electronic component 10 is formed.

[0067] (Regarding the role of the implementation method)

[0068] Assume the insulating film 50 is composed solely of glass 57. In this case, the internal stresses of various parts of the glass 57 combine, resulting in significant internal stresses at specific locations. Therefore, if an external impact is applied, the impact from the outside overlaps with the internal stresses, causing the glass 57 to deform. As a result, cracks may develop in the glass 57, or the glass 57 may bend in the thickness direction, causing the glass 57 to peel off from the outer surface 21 of the preform 20.

[0069] (Regarding the effects of the implementation method)

[0070] (1) According to the above embodiment, the insulating film 50 includes a mixing layer 51 and a glass layer 56. Furthermore, the mixing layer 51 includes glass 52 and powder particles 53. Therefore, in the mixing layer 51, the proportion of powder particles 53 is larger than that of the glass layer 56, and correspondingly, the internal stress of the glass 52 is mitigated. Moreover, tiny voids are easily generated at each location where the powder particles 53 are present. Specifically, because tiny voids are generated between particles within the powder particles 53 and between the powder particles 53 and the glass 52, areas with lower adhesion than the adhesion between the glass particles 52 themselves are created. Through these tiny voids, the internal stress of the glass 52 is broken up by each powder particle 53 at each location where the powder particles 53 are present, thus preventing large internal stress from concentrating on specific areas. Therefore, when an external impact is applied to the electronic component 10, it is possible to suppress the peeling of the insulating film 50 from the blank 20 due to internal stress.

[0071] (2) Assuming that during the manufacturing process, the first metal layer 61B and the second metal layer 62B are formed while the insulating film 50 is peeled off from the outer surface 21 of the blank 20, then the plating solution for the first metal layer 61B and the second metal layer 62B will enter the area where the insulating film 50 is peeled off. Therefore, there is a concern that the blank 20 may dissolve in the plating solution. According to the above embodiment, the insulating film 50 covers the entire outer surface 21 of the blank 20. Therefore, by preventing the blank 20 from contacting the plating solution, it is possible to prevent the blank 20 from dissolving in the plating solution during the plating process S22.

[0072] (3) According to the above embodiment, the material of the powder 53 is the same as that of the blank 20. Therefore, the labor and time required to prepare special materials are saved by using the powder 53. In addition, in the above embodiment, a portion of the ceramic sheet produced in the R-beveling process S12 is retained as is and used as the powder 53. Therefore, the labor and time required to contain the powder 53 in the insulating film 50 are also eliminated.

[0073] (4) According to the above embodiment, the average particle size of the powder 53 is 100 nm or more. Therefore, in the mixing layer 51, the area of ​​the boundary between the powder 53 and the glass 52 can be ensured to be sufficient. Therefore, it is difficult to produce a situation where the average particle size of the powder 53 is too small, and the internal stress cannot be sufficiently broken at the boundary between the powder 53 and the glass 52.

[0074] (5) The first thickness T1 corresponds to the thickness of the mixed layer 51. Furthermore, the second thickness T2 corresponds to the thickness of the glass layer 56. That is, according to the above embodiment, the thickness of the mixed layer 51 is greater than the thickness of the glass layer 56. Thus, the proportion of the mixed layer 51 in the insulating film 50 is quite large, making it more difficult for the insulating film 50 to peel off from the outer surface 21 of the blank 20.

[0075] (6) According to the above embodiment, the insulating film 50 has a crack 58. The crack 58 opens on the surface of the glass layer 56 opposite to the mixed layer 51. The internal stress of the insulating film 50 binds, thus avoiding the internal space of the crack 58. Therefore, compared with the case without crack 58, the internal stress of the insulating film 50 is difficult to bind. In addition, due to external impact, when a new crack is generated, the development of the crack is hindered by the existing crack 58. Therefore, it is difficult to generate a large crack that would cause the insulating film 50 to peel off. Furthermore, the crack 58 does not reach the preform 20. Therefore, the possibility that the crack 58 itself is the cause of the insulating film 50 peeling off is low.

[0076] (7) According to the above embodiment, the material of the green body 20 is ceramic. Furthermore, the mixing layer 51 does not cover the outer surface 21 of the green body 20 via other layers. As a result, when viewed from a direction orthogonal to the outer surface 21, the powder particles 53 in the mixing layer 51 are more likely to be located at the grain boundaries between the particles covering the green body 20. Therefore, even if new cracks appear in the insulating film 50 due to an impact applied from the outside, the powder particles 53 can prevent the development of new cracks and suppress the development of new cracks to the grain boundaries of the green body 20. As long as the development of new cracks to the grain boundaries of the green body 20 can be suppressed, the development of new cracks in the insulating film 50 along the grain boundaries of the green body 20 is prevented.

[0077] <Other Implementation Methods>

[0078] The above-described embodiments can be implemented by modification as follows. The above-described embodiments and the following modifications can be combined and implemented within the scope of technical inconsistency.

[0079] In the above embodiments, the electronic component 10 is not limited to a negative characteristic thermistor component. For example, it may be a thermistor component other than a negative characteristic thermistor component, or it may be a multilayer capacitor component or an inductor component.

[0080] The material of the blank 20 is not limited to the examples of the above embodiments. For example, the material of the blank 20 may also be a composite of resin and metal powder.

[0081] The shape of the blank 20 is not limited to the examples of the embodiments described above. For example, the blank 20 may also be a polygonal column shape other than a quadrilateral column shape with a central axis CA. In addition, the blank 20 may also be the core of a wound inductor component. For example, the core may also be a so-called drum-shaped core. Specifically, the core may also have a columnar core portion and flange portions provided at each end of the core portion.

[0082] • The outer surface 21 of the blank 20 may also not have a corner face 24 containing a curved surface. For example, if the boundary of an adjacent plane 22 on the outer surface 21 of the blank 20 is not chamfered, there is no curved surface at that boundary. Therefore, there are also cases where there is no corner face 24 containing a curved surface at the intersection of three such boundaries.

[0083] • The powder particles 53 originate not only from the ceramic sheets constituting the laminate, but also, for example, from the abrasive used in grinding the laminate. Figure 11 In the example shown, the green body 20 has a small recess 26. The inner surface of the recess 26 is recessed inward relative to the outer surface 21 of the green body 20. Furthermore, the recess 26 is formed during the R-beveling process S12 by ceramic particles detaching from the green body 20, and then remains in the green body 20 if it cannot be sufficiently ground. Figure 11 In the example shown, abrasive particles 53B of the abrasive used in the R-beveling process S12 are present in the internal space of the recess 26. A portion of one abrasive particle 53B is fixed to the blank 20. In this case, the abrasive particles 53B remaining in the internal space of the recess 26 function as powder particles 53. The material of the abrasive particles 53B can be, for example, alumina and zirconium oxide.

[0084] In addition, Figure 11 In the example shown, when viewed from a direction orthogonal to the outer surface 21, the opening of the recess 26 in the outer surface 21 is smaller than the maximum extent of the internal space. Therefore, particles 53A derived from the blank 20, which are part of the blank 20 ground in the R-beveling process S12, exist as powder particles 53 within the internal space of the recess 26. Thus, if the blank 20 has a recess 26, a large number of particles 53A derived from the blank 26 are easily present within the internal space of the recess 26. Therefore, this is preferable in terms of facilitating the formation of the mixed layer 51. Furthermore, Figure 11 The shape of the recess 26 shown is a simplified shape. Various shapes of recesses 26 can be formed in the blank 20.

[0085] ·exist Figure 11In the examples shown, there are cases where the grinding particles 53B are fixed and embedded in the blank 20, cases where the grinding particles 53B are attached to the surface of the blank 20 by electrostatic attraction, and cases where both exist in combination.

[0086] In the above embodiments, the material of the powder 53 may not be the same as that of the blank 20 and the abrasive. For example, the powder 53 may be mixed into the coating liquid beforehand. It can be 0.6 × 10⁻⁶. －6 Above and 15×10 －6 ( / K) or less, so that the coefficient of thermal expansion of the powder 53 is greater than that of the glass 52.

[0087] In the above embodiment, the average particle size of the powder particles 53 may also be 100 nm or less. In this case, the multiple powder particles 53 can either agglomerate or diffuse. Furthermore, the smaller the average particle size of the powder particles 53, the easier it is for the multiple powder particles 53 to agglomerate with each other.

[0088] In the above embodiments, the shapes of the first internal electrode 41 and the second internal electrode 42 are only required to ensure electrical conduction with the corresponding first external electrode 61 and the second external electrode 62. Furthermore, regardless of the number of the first internal electrode 41 and the second internal electrode 42, the number of the first internal electrode 41 can be one or more.

[0089] The structure of the first external electrode 61 is not limited to the examples described in the above embodiments. For example, the first external electrode 61 may consist only of the first base electrode 61A, and the first metal layer 61B may not be a double-layer structure. Furthermore, if the first external electrode 61 includes the first metal layer 61B, then by covering the entire outer surface 21 of the blank 20 with the insulating film 50, the dissolution of the blank 20 into the plating solution can be suppressed. The same applies to the second external electrode 62.

[0090] In the above embodiments, the combination of materials for the first internal electrode 41 and the first base electrode 61A is not limited to palladium and silver. For example, it could also be a combination of copper and nickel, copper and silver, silver and gold, nickel and cobalt, or nickel and gold. Alternatively, for example, one electrode could be silver, and the other a combination of silver and palladium. Alternatively, for example, one electrode could be palladium, and the other a combination of silver and palladium; or one electrode could be copper, and the other a combination of silver and palladium. Alternatively, for example, one electrode could be gold, and the other a combination of silver and palladium.

[0091] Furthermore, the Kirkendall effect is sometimes not obtained depending on the combination of the first internal electrode 41 and the first base electrode 61A. In this case, before the external electrode forming process, for example, a portion of the insulating film 50 can be physically removed by grinding the first end face 22A side of the blank 20, exposing the first internal electrode 41. Then, by performing the base electrode forming process, the first internal electrode 41 and the first base electrode 61A can be connected. Alternatively, for example, after forming the first base electrode 61A, the insulating film 50 can also be formed on the surface of the first base electrode 61A, and the insulating film 50 covering the surface of the first base electrode 61A can be removed. The same applies to the combination of materials for the second internal electrode 42 and the second base electrode 62A.

[0092] The configuration of the first external electrode 61 is not limited to the examples of the above embodiments. For example, the first external electrode 61 may be configured only on the first end face 22A and one side face 22C. The same applies to the second external electrode 62.

[0093] • For the insulating film 50, the glass layer 56 may also contain powder particles 53, as long as the proportion of powder particles 53 in the glass layer 56 is less than the proportion of powder particles 53 in the mixed layer 51.

[0094] • The first thickness T1 can also be less than or equal to the second thickness T2. The insulating film 50 may have a mixed layer 51 and a glass layer 56. The boundary between the mixed layer 51 and the glass layer 56 may not be clear. As long as the proportion of powder 53 on the side of the blank 20 is larger than that on the surface side of the insulating film 50, it can be said that the insulating film 50 has a mixed layer 51 and a glass layer 56.

[0095] • The location of the crack 58 in the insulating film 50 is not limited to the example of the above embodiment. Furthermore, the crack 58 may be omitted from the insulating film 50. Also, there may be multiple cracks 58.

[0096] • The insulating film 50 may not cover the entire area of ​​the outer surface 21 of the blank 20. That is, a portion of the outer surface 21 of the blank 20 may be exposed from the insulating film 50. The coverage area of ​​the insulating film 50 may be appropriately varied depending on the shape of the blank 20, the position of the first external electrode 61 and the second external electrode 62, etc.

[0097] • In the portion of the insulating film 50 covered by the first base electrode 61A, there is also a case where the glass 52 in the insulating film 50 diffuses into the glass in the first base electrode 61A, and the two become integrated.

[0098] • The mixing layer 51 may not directly cover the outer surface 21 of the blank 20. For example, other layers may be sandwiched between the mixing layer 51 and the outer surface 21. Even in this case, as long as the mixing layer 51 is located on the blank 20 side when viewed from the glass layer 56, the peeling of the insulating film 50 from the other layers can be suppressed. As a result, the peeling of the insulating film 50 from the outer surface 21 of the blank 20 can be suppressed.

[0099] The material of the insulating film 50 is not limited to the examples described in the embodiments above. For example, glass 52 and glass 57 are not limited to silicon dioxide, but can also be multi-component oxides containing Si, such as B-Si, Si-Zn, Zr-Si, and Al-Si oxides. Furthermore, glass 52 and glass 57 can also be multi-component oxides containing alkali metals and Si, such as Al-Si, Na-Si, K-Si, and Li-Si oxides. Moreover, glass 52 and glass 57 can also be multi-component oxides containing alkaline earth metals and Si, such as Mg-Si, Ca-Si, Ba-Si, and Sr-Si oxides. Furthermore, glass 52 and glass 57 may not contain Si, or they may be mixtures of these materials.

[0100] In addition to glass 52 and glass 57, the insulating film 50 may also contain surface treatment agents or antistatic agents such as pigments, silicone flame retardants, silane coupling materials, and titanate coupling agents.

[0101] More specifically, in addition to glass 52 and glass 57 and powder 53, insulating film 50 may also contain fine particles of organic acid salts, oxides, inorganic salts, organic salts, other metal oxides, and nanoparticles.

[0102] Examples of organic acid salts include, for example, oxyacid salts such as soda ash, sodium carbonate, sodium bicarbonate, sodium percarbonate, sodium sulfite, sodium bisulfite, sodium sulfate, sodium thiosulfate, sodium nitrate, and sodium sulfite, as well as halogen compounds such as sodium fluoride, sodium chloride, sodium bromide, and sodium iodide.

[0103] In addition, sodium peroxide can be cited as an oxide, and sodium hydroxide can be cited as a hydroxide.

[0104] Examples of inorganic salts include sodium hydride, sodium sulfide, sodium hydrogen sulfide, sodium silicate, trisodium phosphate, sodium borate, sodium borohydride, sodium cyanide, sodium cyanate, and sodium tetrachloroaurate.

[0105] Examples of inorganic salts include calcium peroxide, calcium hydroxide, calcium fluoride, calcium chloride, calcium bromide, calcium iodide, calcium hydride, calcium carbide, and calcium phosphide.

[0106] Alternatively, additives may include oxyacid salts such as calcium carbonate, calcium bicarbonate, calcium nitrate, calcium sulfate, calcium sulfite, calcium silicate, calcium phosphate, calcium pyrophosphate, calcium hypochlorite, calcium chlorate, calcium perchlorate, calcium bromate, calcium iodate, calcium arsenite, calcium chromate, calcium tungstate, calcium molybdate, magnesium calcium carbonate, and hydroxyapatite. Other examples of additives include calcium acetate, calcium gluconate, calcium citrate, calcium malate, calcium lactate, calcium benzoate, calcium stearate, and calcium aspartate.

[0107] Alternatively, the additives may also be lithium carbonate, lithium chloride, lithium titanate, lithium nitride, lithium peroxide, lithium citrate, lithium fluoride, lithium hexafluorophosphate, lithium acetate, lithium iodide, lithium hypochlorite, lithium tetraborate, lithium bromide, lithium nitrate, lithium hydroxide, lithium aluminum hydride, lithium triethylborohydride, lithium hydride, lithium amino, lithium imino, lithium diisopropylamino, lithium tetramethylpiperidinium, lithium sulfide, lithium sulfate, lithium thiophenol, and lithium phenol.

[0108] Alternatively, the additives may be boron triiodide, sodium cyanoborohydride, sodium borohydride, tetrafluoroboric acid, triethylborane, borax, or boric acid.

[0109] Additionally, additives may include, for example, potassium arsenide, potassium bromide, potassium carbide, potassium chloride, potassium fluoride, potassium hydride, potassium iodide, potassium triiodide, potassium azide, potassium nitride, potassium superoxide, potassium ozonide, potassium peroxide, potassium phosphide, potassium sulfide, potassium selenide, potassium telluride, potassium tetrafluoroaluminate, potassium tetrafluoroborate, potassium tetrahydroborate, potassium methoxide, potassium cyanide, potassium formate, potassium hydrogen fluoride, potassium tetraiodomercurate(II), potassium hydrogen sulfide, potassium octachlorodimolybdate(II), potassium amide, potassium hydroxide, potassium hexafluorophosphate, potassium carbonate, potassium tetrachloroplatinate(II), potassium hexachloroplatinate(IV), potassium hydroxyquinoline(VII), potassium sulfate, potassium acetate, potassium gold(I), potassium hexanitrocobalt(III), potassium hexacyanoferrate(III), and potassium hexacyanoferrate(II). Potassium methoxide, potassium ethoxide, potassium tert-butoxide, potassium cyanate, potassium fulminate, potassium thiocyanate, potassium aluminum sulfate, potassium aluminate, potassium arsenate, potassium bromate, potassium hypochlorite, potassium chlorite, potassium chlorate, potassium perchlorate, potassium carbonate, potassium chromate, potassium dichromate, potassium tetra(peroxy)chromate(V), potassium copper(III)ate, potassium ferrate, potassium iodate, potassium periodate, potassium permanganate, potassium manganate, potassium hypomanganate, potassium molybdate, potassium nitrite, potassium nitrate, tripotassium phosphate, potassium perrhenate, potassium selenate, potassium silicate, potassium sulfite, potassium sulfate, potassium thiosulfate, potassium disulfite, potassium dithionite, potassium disulfate, potassium peroxydisulfate, potassium dihydrogen arsenate, dipotassium hydrogen arsenate, potassium bicarbonate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, potassium hydrogen phosphate, potassium hydrogen selenate, potassium bisulfite, potassium bisulfate, potassium peroxydisulfate.

[0110] Alternatively, additives may include barium sulfite, barium chloride, barium chlorate, barium perchlorate, barium peroxide, barium chromate, barium acetate, barium cyanide, barium bromide, barium oxalate, barium nitrate, barium hydroxide, barium hydride, barium carbonate, barium iodide, barium sulfide, and barium sulfate. Sodium acetate and sodium citrate may also be added.

[0111] Alternatively, the additives can be fine or nanoparticles of metal oxides. Examples of metal oxides include sodium oxide, calcium oxide, lithium oxide, boron oxide, potassium oxide, barium oxide, silicon oxide, titanium oxide, zirconium oxide, aluminum oxide, zinc oxide, and magnesium oxide.

[0112] In the manufacturing method of the electronic component 10 according to the above embodiments, the metal alkoxide 85 is not limited to the examples of the above embodiments. Examples of elements capable of synthesizing the metal alkoxide 85 include Li, Be, B, C, Na, Mg, Al, Si, P, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Cd, In, Sn, Sb, Cs, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Hg, Tl, Pb, Bi, Th, Pa, U, and Pu. Alkoxides of these elements can be used as glass precursors.

[0113] Metal alkoxides 85 can also be, for example, sodium methoxide, sodium ethoxide, calcium diethanoloxide, lithium isopropoxide, lithium ethoxide, lithium tert-butoxide, lithium methoxide, boron alkoxides, potassium tert-butoxide, tetraethyl orthosilicate, allyl trimethoxysilane, isobutyl(trimethoxy)silane, tetrapropyl orthosilicate, tetramethyl orthosilicate, [3-(diethylamino)propyl]trimethoxysilane, triethoxy(octyl)silane, triethoxyvinylsilane, triethoxyphenylsilane, trimethoxyphenylsilane, trimethoxymethylsilane, butyltrichlorosilane, n-propyltriethoxysilane, methyltrichlorosilane, dimethoxy(methyl)octylsilane, dimethoxymethylsilane, tri(tert-butoxy)silanol, tri(tert-pentoxy)silanol, hexadecyltrimethoxysilane, tri( Dipotassium 1,2-phthalic acid-O,O') silicate, tetrabutyl orthosilicate, aluminum silicate, calcium silicate, tetramethylammonium silicate solution, triisopropoxy titanium (IV), isopropoxy titanium (IV), 2-ethylhexyl oxide titanium (IV), titanium ethoxide (IV), titanium butoxide (IV), titanium tert-butoxide (IV), titanium propoxide (IV), titanium methanol (IV), di(diethyl citrate) dipropoxide zirconium (IV), dibutoxide zirconium (IV) (bis-2,4-pentadiate), zirconium 2-ethylhexanoate (IV), zirconium isopropoxide (IV) isopropanol complex, zirconium ethoxide (IV), zirconium butoxide (IV), tert-butoxide zirconium (IV), propoxide zirconium (IV), aluminum tert-butoxide, aluminum isopropoxide, aluminum ethoxide, aluminum trisec-butoxide, aluminum phenol.

[0114] In the manufacturing method of the electronic component 10 according to the above embodiment, a metal complex or acetate, which is a precursor to the metal alkoxide 85, may be used instead of the metal alkoxide 85. In this case, the metal complex or acetate, which is a precursor to the metal alkoxide, may be added in the metal alkoxide addition step S17. Examples of metal complexes include lithium acetylacetonate, titanium acetylacetonate (IV), diisopropoxybis(acetylacetonate)titanium, zirconium trifluoroacetylacetonate (IV), zirconium acetylacetonate (IV), aluminum acetylacetonate, aluminum acetylacetonate (III), calcium acetylacetonate (II), and zinc acetylacetonate (II). Examples of acetates include zirconium acetate, zirconium hydroxide acetate (IV), and basic aluminum acetate.

[0115] • In the manufacturing method of the electronic component 10 described above, the external electrode formation process is not limited to the examples of the embodiments described above. For example, after the film formation process S18, the insulating film 50 may be cured by heat treatment, followed by a conductor coating process S20 and a curing process S21 to form the first external electrode 61 and the second external electrode 62. Alternatively, as in the modified example described above, if a portion of the first internal electrode 41 is exposed from the insulating film 50, the first external electrode 61 may be formed on the exposed portion by a plating method.

[0116] • The curing process S21 is not limited to a process that simultaneously cures the insulating film 50 and the conductive paste. For example, if the conductive paste is a material that is cured by ultraviolet irradiation, then as a curing process for curing the insulating film 50, a heating process can be performed, and as a process for curing the conductive paste, ultraviolet irradiation can be performed.

[0117] In the manufacturing method of the electronic component 10 described above, the insulating film 50 can also be cured by fully vaporizing water and polymer 84 using the drying step S19. In this case, the drying step S19 functions as a curing step to cure the insulating film 50.

[0118] In the above-described manufacturing method of electronic component 10, regardless of the order of solvent addition step S13, catalyst addition step S14, and preform addition step S15, the metal alkoxide 85 and catalyst can begin to react within the reaction vessel 81 with solvent 82, preform 20, and polymer 84 added.

[0119] In the manufacturing method of the electronic component 10 described above, polymer 84 is not limited to polyvinylpyrrolidone. For example, polymer 84 may also be a homopolymer or copolymer of acrylic acid, methacrylic acid, or their esters, which are acrylic-based. Examples of acrylic-based polymers include acrylate copolymers, methacrylate copolymers, and acrylate-methacrylate copolymers. Additionally, examples of polymer 84 include homopolymers or copolymers of cellulose-based, polyvinyl alcohol-based, polyvinyl acetate-based, polyvinyl chloride-based, and polypropylene carbonate-based polymers. Examples of cellulose-based polymers include hydroxypropyl cellulose, cellulose ethers, carboxymethyl cellulose, acetyl cellulose, and acetylnitrocellulose. Furthermore, polymer 84 may comprise a variety of polymers, and may contain at least one selected from the examples.

[0120] • In the manufacturing method of the electronic component 10 described above, the solvent 82 is not limited to 2-propanol. The solvent 82 can be appropriately changed as long as it can sufficiently disperse the metal alkoxide 85.

[0121] However, the film-forming method described in Japanese Patent Application Publication No. 2020-36002 includes a solvent addition step, a catalyst addition step, a preform addition step, and a metal alkoxide addition step. Furthermore, this film-forming method includes a film-forming step. In the film-forming step, an insulating film composed of silicon oxide is formed on the outer surface of the preform through hydrolysis and polycondensation reactions of the metal alkoxide.

[0122] In the film-forming method described in Japanese Patent Application Publication No. 2020-36002, there is a case where the size of silicon oxide increases excessively during the film-forming process. If there are large silicon oxide particles on the surface of the insulating film, and an impact from outside the blank 20 is applied near these particles, the particles may cause the nearby insulating film 50 to peel off from the outer surface 21 of the blank 20.

[0123] Here, according to the film-forming method in the manufacturing method of the electronic component 10 of the above embodiment, polymer 84 is added in the polymer addition step S16. During the film formation process of the insulating film 50, polymer 84 is adsorbed onto the outer surface 21 of the preform 20. Then, in the metal alkoxide addition step S17, glass particles from the metal alkoxide 85 enter the polymer 84. Moreover, large particles of excessively grown glass cannot enter the polymer 84. As a result, the insulating film 50 does not contain excessively large particles.

[0124] Thus, from the viewpoint of mitigating the excessive growth of coarse glass particles, the hybrid layer 51 in the insulating film 50 is not necessary. That is, for example, the insulating film 50 could also be composed solely of glass 57.

[0125] In addition, by controlling the concentration of metal alkoxide 85, alkali concentration, reaction temperature, reaction time, type of solvent 82, and surface charge of preform 20, the size of coarse glass particles can be further reduced.

[0126] The following notes summarize the technical concepts that can be grasped from the above implementation methods and variations.

[0127] <Postscript 1>

[0128] A film-forming method involves forming an insulating film containing metal oxides on the outer surface of a preform.

[0129] The above film-forming method has the following features:

[0130] In the preform feeding process, the aforementioned preform is fed into the reaction vessel;

[0131] In the polymer feeding process, the polymer adsorbed on the outer surface of the preform is fed into the reaction vessel.

[0132] The metal alkoxide addition process involves adding a metal alkoxide or a metal alkoxide precursor into the aforementioned container.

[0133] The catalyst feeding step involves adding a catalyst that promotes the hydrolysis of the metal alkoxide into the aforementioned reaction vessel; and

[0134] In the film-forming process, the metal alkoxide is hydrolyzed and dehydrated and condensed to form the insulating film on the outer surface of the preform.

[0135] Explanation of reference numerals in the attached figures

[0136] 10…electronic component; 20…form; 21…outer surface; 41…first internal electrode; 42…second internal electrode; 50…insulating film; 51…mixing layer; 52…glass; 53…powder; 56…glass layer; 57…glass; 58…crack; 61…first external electrode; 62…second external electrode; 71…first through-hole; 72…second through-hole; 81…reaction vessel; 82…solvent; 83…aqueous solution; 84…polymer; 85…metal alkoxide.

Claims

1. An electronic component, It has a blank and an insulating film, wherein, The aforementioned insulating film covers the outer surface of the aforementioned blank. The aforementioned insulating film comprises a mixed layer and a glass layer, wherein the mixed layer comprises glass and powder particles, the glass layer comprises glass, and the proportion of powder particles in the glass layer is less than the proportion of powder particles in the mixed layer. Viewed from the glass layer, the mixed layer is located on the side of the preform.

2. The electronic component according to claim 1, wherein, It also includes external electrodes, which are stacked on the insulating film. The aforementioned external electrode contains a metal layer.

3. The electronic component according to claim 1 or 2, wherein, The material of the powder particles is the same as that of the blank.

4. The electronic component according to any one of claims 1 to 3, wherein, The average particle size of the above-mentioned powder particles is above 100 nm.

5. The electronic component according to any one of claims 1 to 4, wherein, In a cross-sectional view orthogonal to the outer surface of the aforementioned blank, When the powder particles furthest from the outer surface of the aforementioned blank are considered as specific powder particles... The shortest distance from the outer surface of the aforementioned blank to the specific point in the aforementioned specific powder that is farthest from the outer surface of the aforementioned blank is greater than the shortest distance from the aforementioned specific point to the surface of the aforementioned glass layer.

6. The electronic component according to any one of claims 1 to 5, wherein, The insulating film has a crack that opens on the side of the glass layer opposite to the mixed layer and does not reach the blank.

7. The electronic component according to any one of claims 1 to 6, wherein, The material of the above-mentioned blank is ceramic. The aforementioned mixed layer does not cover the outer surface of the aforementioned blank through other layers.

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