MODERATELY DISPERSED NANO DY2O3

Abstract

Dy.sub.2O.sub.3 particles of a nanoparticle scale have beneficial properties for ceramic and electronic uses. Disclosed herein are moderately dispersed Dy.sub.2O.sub.3 particles having regular morphology and lateral size ranging from about 10 nm to 1 μm. The Dy.sub.2O.sub.3 particles may exhibit a narrow particle size distribution such that the difference between D.sub.10 and D.sub.90 is about 0.1 μm to 1 μm. Further disclosed are processes of producing these moderately dispersed Dy.sub.2O.sub.3 particles. These processes do not include grinding to obtain the particles. Also disclosed herein are uses for these Dy.sub.2O.sub.3μ particles.

Claims

1. A composition comprising moderately dispersed Dy.sub.2O.sub.3 particles having regular morphology and lateral size ranging from about 10 nm to 1 μm.

2. The composition of claim 1, wherein the lateral size ranges from about 40 nm to 1 μm.

3. The composition of claim 1, wherein the lateral size ranges from about 100 nm to 1 μm.

4. The composition of claim 1, wherein the particles have a particle size distribution wherein D.sub.10 and D.sub.90 is about 0.1 μm to 1 μm.

5. The composition of claim 1, wherein the particles have a D.sub.10 of about 10 nm to 100 nm, a D.sub.50 of about 0.1 μm to about 0.8 μm, and a D.sub.90 of about 0.25 μm to 10 μm.

6. The composition of claim 5, wherein the particles have a D.sub.90 of about 0.25 μm to 5 μm.

7. The composition of claim 5, wherein the particles have a D.sub.90 of about 0.25 μm to 1 μm.

8. The composition of claim 1, wherein the particles are spheres, ovals, or cubes.

9. The composition of claim 1 comprising about 0 to 50 ppm chloride.

10. The composition of claim 1, wherein the particles have a single cubic phase.

11. A process of producing moderately dispersed Dy.sub.2O.sub.3 particles comprising: (a) mixing a dysprosium salt, polymeric additive, and chelating agent in water to provide a dysprosium precursor solution; (b) heating the dysprosium precursor solution to form a precipitate; and (c) calcining the precipitate to provide moderately dispersed Dy.sub.2O.sub.3 particles.

12. The process of claim 11, wherein the chelating agent is selected from the group consisting of diethanolamine, 2-amino-2-(hydroxymethyl)-1,3-propanediol, triethanolamine, ethylenediamine, 6-aminohexanoic acid, L-histidine, L-lysine, and mixtures thereof.

13. The process of claim 11, wherein the polymeric additives is selected from the group consisting of Polyvinylpyrrolidone (PVP), Poly(vinyl alcohol) (PVA), Polyethylenimine (PEI), and mixtures thereof.

14. The process of claim 11, wherein the dysprosium salt is a water-soluble salt.

15. The process of claim 14, wherein the water-soluble salt of dysprosium is a chloride or nitrate salt.

16. The process of claim 11, wherein the dysprosium precursor solution of step (a) has a dysprosium concentration of about 0.2 mol/L to 1.5 mol/L.

17. The process of claim 11, wherein the dysprosium precursor solution of step (a) has a dysprosium oxide concentration of about 25 to 75 g/L.

18. The process of claim 11, wherein about 2 to 3 moles of chelating agent are mixed per mole of dysprosium in step (a).

19. The process of claim 11, wherein the heating is conducted at a temperature ranging from about 100° C. to 350° C. and for from about 15 mins to 24 hours.

20. The process of claim 11, wherein the heating of (b) provides a single crystalline precipitate before calcining.

21. The process of claim 11, wherein the calcining is conducted at a temperature ranging from about 400° C. to 1000° C. and for from about 15 mins to 24 hours.

22. The process of claim 11, wherein the calcining provides moderately dispersed Dy.sub.2O.sub.3 particles having regular morphology and lateral size ranging from about 40 nm to 1 μm.

23. The process of claim 11, wherein the process does not include grinding.

24. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 illustrates a flowchart of an embodiment of the process of producing moderately dispersed Dy.sub.2O.sub.3 particles.

[0014] FIG. 2A is a SEM of nano Dy.sub.2O.sub.3 made by a chloride precursor/hydrothermal process.

[0015] FIG. 2B is a graph of particle size distribution of nano Dy.sub.2O.sub.3 made by the chloride precursor/hydrothermal process.

[0016] FIG. 3A is a SEM of nano Dy.sub.2O.sub.3 made by a nitrate precursor/hydrothermal process. These particles were made using aminohexanoic acid as the chelating agent and polyvinylpyrrolidone (PVP) as the polymeric additive.

[0017] FIG. 3B is a graph of particle size distribution of nano Dy.sub.2O.sub.3 made by a nitrate precursor/hydrothermal process and the chelating agent and polymeric additive as described for FIG. 3A.

[0018] FIG. 4A is a SEM of Dy.sub.2O.sub.3 synthesized using a nitrate precursor which involved precipitation at room temperature followed by a supercritical drying process, as described in Comparative Example 1.

[0019] FIG. 4B is a graph of particle size distribution of Dy.sub.2O.sub.3 as described for FIG. 4A and in Comparative Example 1.

[0020] FIG. 5A is a SEM of Dy.sub.2O.sub.3 synthesized using nitrate precursor which involved precipitation at room temperature followed by heating in isopropanol, as described in Comparative Example 2.

[0021] FIG. 5B is a graph of particle size distribution of Dy.sub.2O.sub.3 as described for FIG. 3E and in Comparative Example 2.

[0022] FIG. 6A is a SEM of Dy.sub.2O.sub.3 synthesized using nitrate precursor which involved precipitation at room temperature in the presence of carboxylic acid, as described in Comparative Example 3.

[0023] FIG. 6B is a graph of particle size distribution of Dy.sub.2O.sub.3, as described for FIG. 3G and in Comparative Example 3.

[0024] FIG. 7A is a Transmission Electron Micrograph (TEM) and selected area electron diffraction (SAED) pattern image of the dried precipitate using polyethylenimine (PEI) as the polymeric additive after hydrothermally reacting and drying.

[0025] FIG. 7B is a TEM and SAED of Dy.sub.2O.sub.3 using polyethylenimine as the polymeric additive after calcined.

[0026] FIG. 8A is a TEM and SAED image of dried precipitate using polyvinylalcohol (PVA) as the polymeric additive after hydrothermally reacting and drying.

[0027] FIG. 8B is a TEM and SAED of Dy.sub.2O.sub.3 using PVA as the polymeric additive after calcined.

[0028] FIG. 9 is an x-ray diffractogram of calcined Dy.sub.2O.sub.3.

[0029] FIG. 10 is an illustration of lateral size.

DETAILED DESCRIPTION

[0030] Before the moderately dispersed Dy.sub.2O.sub.3 particles and processes are disclosed and described, it is to be understood that this disclosure is not limited to the particular structures, process steps, or materials disclosed herein, but is extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting. It must be noted that, as used in this specification, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a step” may include multiple steps, reference to “producing” or “products” of a reaction or treatment should not be taken to be all of the products of a reaction/treatment, and reference to “treating” may include reference to one or more of such treatment steps. As such, the step of treating can include multiple or repeated treatment of similar materials/streams to produce identified treatment products.

[0031] Numerical values with “about” include typical experimental variances. As used herein, the term “about” means within a statistically meaningful range of a value, such as a stated particle size, concentration range, time frame, molecular weight, temperature, or pH. Such a range can be within an order of magnitude, typically within 10%, and even more typically within 5% of the indicated value or range. Sometimes, such a range can be within the experimental error typical of standard methods used for the measurement and/or determination of a given value or range. The allowable variation encompassed by the term “about” will depend upon the particular system under study, and can be readily appreciated by one of ordinary skill in the art. Whenever a range is recited within this application, every whole number integer within the range is also contemplated as an embodiment of the invention.

[0032] The present application relates to moderately dispersed Dy.sub.2O.sub.3 particles. Herein, dispersity is a measure of the heterogeneity (or uniformity) of particle sizes in a mixture. It can be indicated by the polydispersity index (PDI) parameter as derived from the dynamic light scattering (DLS) technique, which is commonly used to determine the size distribution of particles in suspension by measuring the fluctuations in intensity of the scattered light. Specifically, from the particle size distribution (PSD) profile, the mean and standard deviation (stddev) are obtained and expressed in the form of (stddev/mean).sup.2 to yield the PDI value. Information on this analysis technique also can be found at https://www.materials-talks.com/blog/2017/10/23/polydispersity-what-does-it-mean-for-dls-and-chromatography/, which is herein incorporated by reference as needed.

TABLE-US-00001 TABLE 1 Approximate values for dispersity parameters Distribution Type monodisperse polydisperse Definition uniform narrow moderate broad PDI from =(stddev/mean).sup.2 0.0 0.0-0.1 0.1-0.4 >0.4 DLS
As illustrated in Table 1, the PDI value for a perfectly uniform sample is 0.0. As used herein, “moderately dispersed” means that the PDI value of Dy.sub.2O.sub.3 particles is in the range of about 0.1 to 0.4.

[0033] As used herein, “moderately dispersed Dy.sub.2O.sub.3 particles” means Dy.sub.2O.sub.3 particles having a particle size distribution wherein D.sub.10 to D.sub.90 is not more than about 1 μm. In some embodiments, the particles have a particle size distribution wherein D.sub.10 and D.sub.90 is about 0.1 μm to 1 μm.

[0034] As used herein, “regular morphology” means that the characteristics of particles, including their size, shape and structure, are clearly defined and common across different particles in the same batch. It includes small aspect ratio configurations, such as uniform spheres, ovals or cubes, as well as high aspect ratio configurations such as uniform rods or wires.

[0035] As used herein, in two-dimensional nanostructures “lateral size” refers to the length extending from one side to the other side. FIG. 10 provides an illustration of lateral size and how it is measured. Herein, the lateral size of particles can be measured from electron microscopy images, specifically the transmission electron and scanning electron microscopy (TEM and SEM) images.

[0036] Disclosed herein is a composition comprising moderately dispersed Dy.sub.2O.sub.3 particles having regular morphology and lateral size ranging from about 10 nm (0.01 μm) to 1000 μm. In certain embodiments, the present compositions comprise moderately dispersed Dy.sub.2O.sub.3 particles having regular morphology and lateral size ranging from about 10 nm to 1 μm. In some embodiments, dispersed Dy.sub.2O.sub.3 particles have lateral size ranging from about 40 nm (0.04 μm) to 100 μm. In some embodiments, dispersed Dy.sub.2O.sub.3 particles have lateral size ranging from about 40 nm (0.04 μm) to 1 μm. In other embodiments, dispersed Dy.sub.2O.sub.3 particles have lateral size ranging from about 100 nm (0.1 μm) to 1 μm. In these embodiments of lateral size, the particles have a particle size distribution wherein D.sub.10 and D.sub.90 is about 0.1 μm to 1 μm.

[0037] In all of the above set forth embodiments relating to particle size distribution and lateral size, the Dy.sub.2O.sub.3 particles can have a D.sub.10 of about 10 nm to 100 nm, a D.sub.50 of about 0.1 μm to about 0.8 μm, and a D.sub.90 of about 0.25 μm to 10 μm. In some embodiments, the Dy.sub.2O.sub.3 particles can have a D.sub.10 of about 10 nm to 100 nm, a D.sub.50 of about 0.1 μm to about 0.8 μm, and a D.sub.90 of about 0.25 μm to 5 μm. In certain of these embodiments, the Dy.sub.2O.sub.3 particles can have a D.sub.90 of about 0.25 μm to 1 μm.

[0038] In particular embodiments, the Dy.sub.2O.sub.3 particles have a D.sub.50 of about 10 nm to 0.2 μm and a D.sub.90 of about 0.2 μm to about 1 μm. In certain of these embodiments, the Dy.sub.2O.sub.3 particles have a D.sub.50 of about 10 nm to 0.15 μm and a D.sub.90 of about 0.2 μm to 0.75 μm.

[0039] The Dy.sub.2O.sub.3 particles disclosed herein can have a round or faceted shape, and do not agglomerate in any significant way. In addition, the Dy.sub.2O.sub.3 particles disclosed herein have a crystalline structure. In certain embodiments, the X-ray diffraction pattern of the Dy.sub.2O.sub.3 particles illustrates a single cubic phase, which can serve as a fingerprint for the periodic atomic arrangements in the material.

[0040] In any of the embodiments set forth above, the Dy.sub.2O.sub.3 particles also can have a low chloride content and in certain of these embodiments the chloride content can be about 0 to 50 ppm. Such low chloride content would prevent or reduce the likelihood of corrosion and is especially important for applications of the Dy.sub.2O.sub.3 particles in multilayer ceramic capacitors. Thus, achieving the low chloride content is an important characteristic of the Dy.sub.2O.sub.3 particles.

[0041] The moderately dispersed Dy.sub.2O.sub.3 particles as disclosed herein are made by a process comprising: (a) mixing a dysprosium salt, polymeric additive, and chelating agent in water to provide a dysprosium precursor solution; (b) heating the dysprosium precursor solution to form a precipitate; and (c) calcining the precipitate to provide moderately dispersed Dy.sub.2O.sub.3 particles. From this process, the moderately dispersed Dy.sub.2O.sub.3 particles as disclosed herein can be isolated.

[0042] It is important to note that the processes disclosed herein do not include a grinding or milling step. As such, the disclosed Dy.sub.2O.sub.3 particles are obtained without any grinding or milling step. Accordingly, the disclosed process provides the Dy.sub.2O.sub.3 particles as disclosed and described above.

[0043] The starting dysprosium salt is water soluble and in the process, the dysprosium salt is dissolved in water. The salts can be salts of inorganic or organic acids, for example chloride, sulfate, nitrate, acetate, and the like. In certain embodiments, the dysprosium salt can be either a chloride or nitrate salt. The starting dysprosium salt can affect the particle shape, particle size, and particle size distribution achieved.

[0044] The chelating agent used in the processes described herein can be any chelating agent. The chelating agents are organic compounds capable of linking metal ions to form chelates. In certain embodiments, the chelating agent can be advantageously selected from among diamines (e.g. ethylenediamine), alkanolamines (e.g. diethanolamine, 2-amino-2-(hydroxymethyl)-1,3-propanediol and triethanolamine) or amino acids (e.g. 6-aminohexanoic acid, L-histidine, L-lysine), and mixtures thereof. One or more chelating agents can also be present in the same reaction mixture. During calcination, the chelating agent is removed.

[0045] The polymeric additive can be any polymer that assists in processability of the dysprosium precursor solution and is removed during calcination. Herein, the role of the polymeric additive is to affect the particle size and morphology by providing selective surface stabilization and/or access to kinetically controlled growth conditions. The polymeric additive can be selected from the group consisting of Polyvinylpyrrolidone (PVP), Poly(vinyl alcohol) (PVA), Polyethyleneimine (PEI), and mixtures thereof.

[0046] The chelating agent and polymeric additive are dissolved in water when added to the process. The chelating agent may be added as a water mixture that is approximately 0.1 to 2 M, and in some embodiments about 0.5 to 1 M. The polymeric additive may be added as a water mixture that is approximately 2 to 15 g/L, and in some embodiments about 6.25 to 12.5 g/L.

[0047] For the addition to create the dysprosium precursor solution, the water mixtures of chelating agent, polymeric additive, and dysprosium salt can be added simultaneously or individually with mixing. Any order of addition can be utilized, if not added simultaneously. In some embodiments, about 2 to 3 moles of chelating agent are added per mole of dysprosium in step (a) of the process.

[0048] In certain embodiments, the dysprosium precursor solution of step (a) has a dysprosium concentration of about 0.2 mol/L to 1.5 mol/L.

[0049] The dysprosium precursor solution of step (a) can have a dysprosium oxide concentration of about 25 to 75 g/L.

[0050] The dysprosium precursor solution is heated in step (b) to form a precipitate. The heating can be conducted at a temperature of about 100° C. to 350° C. and for from about 15 mins to 24 hours. In certain embodiments, the heating can be conducted at a temperature of about 120° C. to 160° C. and for from about 45 min to 2 hours. The heating provides a crystalline precipitate. In particular, the heating can provide a single crystalline precipitate.

[0051] The crystalline precipitate from the heating process of step (b) can be washed with water to remove residual quantities of bound or adsorbed ions, such as nitrates and chlorides, and then dewatered with an appropriate solvent, such as ethanol, before calcining. In certain embodiments, the crystalline precipitate is particularly pure in anionic impurities, as characterized by a conductivity of less than about 10 mS/cm after washing.

[0052] The crystalline precipitate is calcined in step (c) to result in Dy.sub.2O.sub.3 particles as disclosed and described herein. The calcining can be conducted at a temperature ranging from about 400° C. to 1000° C. and for from about 15 mins to 24 hours. The calcining should be sufficient to remove the polymeric additive and the chelating agent. In certain embodiments the calcining can be conducted at a temperature of from about 600° C. to 800° C. and for from about 1 to 4 hours.

[0053] The calcining results in the Dy.sub.2O.sub.3 particles with the properties as set forth herein. Similar to the precipitate of step (b), the calcined products can exhibit a single crystalline SAED (selected area (electron) diffraction).

[0054] Calcining can be conducted in any way that results in a uniform material.

[0055] For Particle Size Dispersion measurements (PSD) as referenced herein, about 0.1 g of powder was dispersed in 10 mL of 2% Sodium Hexametaphosphate by sonication for 3 minutes. The PSD measurement was then conducted with Microtrac S3500. The sample solution was dropped into the sample delivery controller filled with DI water followed by 3 minute sonication. The solution was then flowed through a transparent cell at a flow rate of 49 mL/sec (75% flow rate). Signals are captured and sample particle size was calculated by the machine.

[0056] FIG. 1 is a flow chart for an embodiment of a process of producing moderately dispersed Dy.sub.2O.sub.3 particles.

[0057] FIGS. 2 and 3 shows typical morphology of claimed Dy.sub.2O.sub.3 by A) SEM or B) Microtrac.

[0058] In the following, Examples are given to illustrate the inventive method for the preparation of Dy.sub.2O.sub.3 particles and characterization thereof in more detail, although the scope of the invention is never limited thereby in any way.

EXAMPLES

Example 1: Synthesis of Nano-Dy.SUB.2.O.SUB.3

[0059] The following was done:

[0060] 1) The polymeric additive PVA and chelating agent diethanolamine are weighed and subsequently dissolved in water with heating at 50° C.

[0061] 2) A stock solution of DyCl.sub.3 (415 g/L, 2.225 M) was added to the above mixture to a final concentration of 0.4 M (74.6 g/L).

[0062] 3) The solution is poured into an autoclave teflon liner and the autoclave was heated to 160° C. and held at this temperature for 1 hour.

[0063] 4) The result was a viscous white material (wetcake/precipitate).

[0064] 5) The wetcake was then centrifuged and the supernatant removed. Subsequently, the wetcake was washed with deionized water to a conductivity of less than 8 mS/cm.

[0065] 6) The wetcake was dewatered by washing with ethanol two times.

[0066] 7) The wetcake was calcined at 700° C. for 2 hours.

[0067] As examined with a scanning electron microscope, the dysprosium oxide comprised discrete non-agglomerated particles with round and faceted morphology (FIG. 2A). PSD of the Dy.sub.2O.sub.3 shows particles with a D.sub.50 value of 0.13 μm (FIG. 2B). TEM and SAED of the Dy.sub.2O.sub.3 showed the material to possess a single crystalline structure.

Example 2: Synthesis of Nano-Dy.SUB.2.O.SUB.3

[0068] The following was done:

[0069] 1) 8 g/L PVP (MW=40K) and PVP (MW=1300K), 0.06M of aminohexanoic acid and 0.8M of DEA were dissolved in water.

[0070] 2) A stock solution of Dy(NO.sub.3).sub.2 (415 g/L, 2.225 M) was added to the above mixture to a final concentration of 0.4 M (74.6 g/L).

[0071] 3) The solution was then poured into an autoclave teflon liner and heated to 160° C. and kept at this temperature for 1 hour.

[0072] 4) The result was a viscous white material (wetcake/precipitate).

[0073] 5) The wetcake was centrifuged, and the supernatant removed. The remaining material was washed with deionized water to a conductivity of less than 8 mS/cm.

[0074] 6) The wetcake was then dewatered by washing with ethanol two times and centrifuged to obtain the final wetcake.

[0075] 7) The wetcake was calcined at 700° C. for 2 hours.

SEM of the resultant dysprosium oxide showed that it comprised discrete non-agglomerated particles with flat morphology and length of less than 500 nm (FIG. 3A). PSD of the resultant Dy.sub.2O.sub.3 showed that the particles had a D.sub.50 of 0.137 μm (FIG. 3B).

Comparative Example 3: Synthesis of Dy.SUB.2.O.SUB.3

[0076] The following was done:

[0077] 1) 1083 ml of 4.5M NH.sub.4OH was prepared.

[0078] 2) A stock solution of 900 ml of Dy(NO.sub.3).sub.3 (100 g/L, 2.225 M) was prepared and added to the above ammonia solution to a final concentration of 0.4 M (74.6 g/L).

[0079] 3) The solution was stirred at room temperature for 1 hour.

[0080] 4) The final pH was 9.90 and the temperature was 24.1° C.

[0081] 5) The precipitates were collected by decanting the supernatant and replenishing with deionized water several times until the conductivity of filtrate is less than 8 mS/cm.

[0082] 6) Two-thirds of the precipitates obtained from step 5 were dewatered with ethanol and dispersed in a total volume of 600 ml ethanol.

[0083] 7) The slurry was subjected to drying at 300° C. and 130-140 bar.

[0084] 8) The resultant oxide was calcined at 700° C. for 2 hours.

The resultant Dy.sub.2O.sub.3 consisted of agglomerated fine needle-like particles (FIG. 4A). PSD of the material showed that it was comprised of particles with a D.sub.50 of 3.181.1 m (FIG. 4B).

Comparative Example 4: Synthesis of Dy.SUB.2.O.SUB.3

[0085] The following was done:

[0086] 1) Steps 1-5 of Comparative Example 1 were followed.

[0087] 6) One-third of the precipitates obtained were dewatered with isopropanol and dispersed in a total volume of 500 ml isopropanol.

[0088] 7) The slurry was heated to 80° C. for 24 hours.

[0089] 8) The resultant wetcake was calcined at 700° C. for 2 hours.

The resultant Dy.sub.2O.sub.3 consisted of large irregular agglomerates of chunks and clusters (FIG. 5A). PSD of these agglomerates showed that they had a D.sub.50 of 7.08 μm (FIG. 5B).

Comparative Example 5: Synthesis of Dy.SUB.2.O.SUB.3

[0090] The following was done:

[0091] 1) 120 ml of 4.5M NH.sub.4OH was prepared; 5 g of Lauric acid was dissolved in this ammonia solution.

[0092] 2) A stock solution of 100 ml of Dy(NO.sub.3).sub.3 (100 g/L, 2.225 M) was prepared and added to the above mixture.

[0093] 3) The solution is stirred at room temperature for 1 hour.

[0094] 4) The final pH was 9.73 and the temperature was 21.8° C.

[0095] 5) The precipitates were collected by decanting the supernatant and replenishing with deionized water several times until the conductivity of filtrate is less than 8 mS/cm.

[0096] 8) The wetcake was collected by suction filtration using a Buchner funnel.

[0097] 9) The resultant wetcake was calcined at 700° C. for 2 hours.

Clusters of agglomerates of various sizes of Dy.sub.2O.sub.3 resulted (FIG. 6A). PSD showed they had a D.sub.50 of 21.54 μm (FIG. 6B).

Example 6—Forming a Multi-Layer Ceramic Capacitor Using Moderately Dispersed Dy.SUB.2.O.SUB.3 .Particles

[0098] 1. Mix the moderately dispersed Dy.sub.2O.sub.3 particles as prepared herein with barium titanate powder (main ingredient) and other raw material powders (e.g. MgO, Y.sub.2O.sub.3, V.sub.2O.sub.5, Ho.sub.2O.sub.3). [0099] 2. Subject the powder mixture to wet mixing in a mixed solvent system of polyvinyl butyral (PVB) resin solution, toluene and ethanol to form a ceramic slurry. Next, cast the slurry into ceramic green sheets using the doctor blade method. [0100] 3. Imprint the ceramic green sheets with an internal electrode pattern, then laminate on each of the upper and lower sheet surfaces. [0101] 4. Compact the ceramic green sheets together using a pressing machine, then cut the resultant sheet laminate into a specific size. [0102] 5. Fire the sheet laminate for 2 hours at 1120 to 1135° C. to form the capacitor main body, then apply an external electrode paste containing Cu powder and glass to both ends of the fired capacitor main body and print at 850° C. to form the external electrode. [0103] 6. Employ an electrolytic barrel machine to plate Ni and Sn successively, thereby producing a multi-layer ceramic capacitor.

[0104] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained.

[0105] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the technology are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0106] It will be clear that the compositions and methods described herein are well adapted to attain the ends and advantages mentioned as well as those inherent therein. Those skilled in the art will recognize that the methods and systems within this specification may be implemented in many manners and as such are not to be limited by the foregoing exemplified embodiments and examples. In this regard, any number of the features of the different embodiments described herein may be combined into one single embodiment and alternate embodiments having fewer than or more than all of the features herein described are possible.

[0107] While various embodiments have been described for purposes of this disclosure, various changes and modifications may be made which are well within the scope contemplated by the present disclosure. Numerous other changes may be made which will readily suggest themselves to those skilled in the art and which are encompassed in the spirit of the disclosure.