CN111009713A - Surface treatment method of microwave dielectric ceramic filter - Google Patents
Surface treatment method of microwave dielectric ceramic filter Download PDFInfo
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- CN111009713A CN111009713A CN201911257919.8A CN201911257919A CN111009713A CN 111009713 A CN111009713 A CN 111009713A CN 201911257919 A CN201911257919 A CN 201911257919A CN 111009713 A CN111009713 A CN 111009713A
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- dielectric ceramic
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P11/00—Apparatus or processes specially adapted for manufacturing waveguides or resonators, lines, or other devices of the waveguide type
- H01P11/007—Manufacturing frequency-selective devices
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Abstract
The invention discloses a surface treatment method of a microwave dielectric ceramic filter, which forms a protective layer on a non-functional surface of the microwave dielectric ceramic filter subjected to drying treatment by using a printing or spraying mode, so that the non-functional surface of the microwave dielectric ceramic filter can be prevented from being eroded by external environment in the using process of the microwave dielectric ceramic filter through the protective layer, the corrosion resistance and the like of the microwave dielectric ceramic filter are obviously improved, and the reliability of the microwave dielectric ceramic filter is further improved.
Description
Technical Field
The invention relates to the technical field of surface treatment of microwave dielectric ceramic filters, in particular to a surface treatment method of a microwave dielectric ceramic filter.
Background
The microwave dielectric ceramic filter is a filter made of microwave dielectric ceramic materials, and has the characteristics of low loss, stable frequency temperature coefficient, small thermal expansion coefficient, high power capacity, small volume and the like, so the microwave dielectric ceramic filter is widely applied to electronic countermeasure, navigation communication, warning radar, household satellite direct broadcast television receivers, mobile phones and other equipment.
However, the devices such as electronic countermeasure, navigation communication, surveillance radar, a household satellite direct broadcast television receiver, a mobile phone and the like are often located outdoors, so that the microwave dielectric ceramic filter can be subjected to severe environmental conditions in the use process, the surface of the microwave dielectric ceramic filter is corroded, and if the surface of the microwave dielectric ceramic filter is corroded, the performance of the microwave dielectric ceramic filter is affected, the reliability of the microwave dielectric ceramic filter is reduced, and the probability of failure of the microwave dielectric ceramic filter is increased.
Disclosure of Invention
The invention aims to provide a surface treatment method of a microwave dielectric ceramic filter, which is easy for large-scale production and low in treatment cost and can also obviously improve the reliability of the microwave dielectric ceramic filter.
In order to solve the technical problems, the technical scheme adopted by the invention specifically comprises the following contents:
a surface treatment method of a microwave dielectric ceramic filter comprises the following steps:
metallization step: carrying out metallization treatment on the surface of the microwave dielectric ceramic filter;
a cleaning step: cleaning the surface of the microwave dielectric ceramic filter subjected to metallization treatment;
and (3) drying: drying the surface of the microwave dielectric ceramic filter after cleaning treatment;
forming a protective layer: and forming a protective layer on the non-functional surface of the microwave dielectric ceramic filter subjected to drying treatment by using a printing or spraying mode.
Preferably, the cleaning of the surface of the microwave dielectric ceramic filter is performed by ultrasonically cleaning the surface of the metallized microwave dielectric ceramic filter with a cleaning liquid in an ultrasonic cleaning device.
Preferably, the cleaning solution is a mixture of deionized water and a detergent.
Preferably, when the surface of the metallized microwave dielectric ceramic filter is cleaned by ultrasonic waves by using a mixed solution of deionized water and a detergent, the working power of an ultrasonic cleaning device is 100W, and the cleaning time is 10-15 min.
Preferably, the drying temperature for drying the surface of the microwave dielectric ceramic filter subjected to the cleaning treatment is 100-150 ℃, and the drying time is 30-60 min.
Preferably, the protective layer is made of three-proofing paint.
Preferably, the thickness of the protective layer is 0.005-0.03 mm.
Preferably, the metallization of the surface of the microwave dielectric ceramic filter is to form a metal layer on the surface of the microwave dielectric ceramic filter by printing or spraying.
Preferably, the metal layer is made of gold or silver.
Preferably, the metal layer is made of silver, and the thickness of the metal layer is 7 to 15 μm.
Compared with the prior art, the invention has the beneficial effects that:
according to the surface treatment method of the microwave dielectric ceramic filter, the protective layer is formed on the non-functional surface of the microwave dielectric ceramic filter subjected to drying treatment in a printing or spraying mode, so that the non-functional surface of the microwave dielectric ceramic filter can be prevented from being eroded by the external environment in the using process, the corrosion resistance of the microwave dielectric ceramic filter is obviously improved, and the reliability of the microwave dielectric ceramic filter is further improved.
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understandable, the following specific preferred embodiments are described in detail.
Detailed Description
To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined objects, the following detailed description of the embodiments, structures, features and effects according to the present invention with reference to the preferred embodiments is as follows:
the invention discloses a surface treatment method of a microwave dielectric ceramic filter, which comprises the following steps:
metallization step: carrying out metallization treatment on the surface of the microwave dielectric ceramic filter;
a cleaning step: cleaning the surface of the microwave dielectric ceramic filter subjected to metallization treatment;
and (3) drying: drying the surface of the microwave dielectric ceramic filter after cleaning treatment;
forming a protective layer: and forming a protective layer on the non-functional surface of the microwave dielectric ceramic filter subjected to drying treatment by using a printing or spraying mode.
Because impurities such as dust, oil stains and the like exist on the surface of the microwave dielectric ceramic filter subjected to metallization treatment, if the microwave dielectric ceramic filter is not cleaned, the impurities can be mixed in the protective layer, so that the adhesive force between the protective layer and the surface of the microwave dielectric ceramic filter is reduced, the possibility that the protective layer falls off, peels and the like is increased, and the durability of the microwave dielectric ceramic filter is further influenced.
In the present invention, the nonfunctional surface of the microwave dielectric ceramic filter is a non-welded surface of the microwave dielectric ceramic filter, and the microwave dielectric ceramic filter needs to be welded to another member when in use.
Preferably, the cleaning of the surface of the microwave dielectric ceramic filter is performed by ultrasonically cleaning the surface of the metallized microwave dielectric ceramic filter with a cleaning liquid in an ultrasonic cleaning device.
Preferably, the cleaning solution is a mixture of deionized water and a detergent.
Preferably, when the surface of the microwave dielectric ceramic filter subjected to the metallization treatment is subjected to ultrasonic cleaning by using a mixed solution of deionized water and a detergent, the working power of an ultrasonic cleaning device is 100W, and the cleaning time is 10-15min, because the cleaning time cannot be too short, otherwise the cleaning effect is influenced; and too long cleaning time will waste time.
Preferably, the drying temperature for drying the surface of the microwave dielectric ceramic filter subjected to the cleaning treatment is 150 ℃ below zero and the drying time is 30-60 min, because the drying is to remove the moisture on the surface of the microwave dielectric ceramic filter subjected to the cleaning treatment, and the drying temperature is set within 150 ℃ below zero and 100 ℃, the moisture on the surface of the microwave dielectric ceramic filter can be gasified, so as to achieve the drying purpose.
Preferably, the protective layer is made of a three-proofing paint, because the three-proofing paint has good high temperature resistance, low temperature resistance, weather resistance, electrical insulation, moisture resistance, salt mist resistance, mildew resistance and other properties. Moreover, the three-proofing paint can be acrylate three-proofing paint, polyurethane three-proofing paint, organic silicon three-proofing paint and the like, and can be selected according to actual conditions.
Preferably, the thickness of the protective layer is 0.005-0.03mm, because if the thickness of the protective layer is less than 0.005mm, the protective layer basically cannot achieve the purpose of protection; and if the thickness of the protective layer is more than 0.03mm, the protective layer needs to be sprayed or printed for many times during formation, so that the processing efficiency is reduced.
Preferably, the surface of the microwave dielectric ceramic filter is metallized by forming a metal layer on the surface of the dielectric ceramic filter by printing or spraying.
Preferably, the metal layer is made of gold or silver, because gold and silver have relatively high electrical conductivity and are excellent in solderability.
Preferably, the metal layer is made of silver, and the thickness of the metal layer is 7 to 15 μm.
The following are specific examples of the present invention.
Example one
In this embodiment, three sets of samples of a microwave dielectric ceramic filter with a specification of 50mm by 20mm by 6mm, i.e., sample 1, sample 2, and sample 3, are prepared, and then the surfaces of the three sets of samples are treated, which includes the following steps:
metallization step: and forming a silver layer on the surface of the microwave dielectric ceramic filter by using a printing mode, wherein the thickness of the silver layer is 7 mu m.
A cleaning step: placing the microwave dielectric ceramic filter treated by the metallization step into a cleaning solution of ultrasonic cleaning equipment for ultrasonic cleaning, wherein: the cleaning solution is prepared from sodium alkyl sulfonate-containing liquid detergent and deionized water according to the volume ratio of 1: 10, and the working power of the ultrasonic cleaning equipment is 100W.
And (3) drying: drying the surface of the microwave dielectric ceramic filter treated by the cleaning step, wherein the drying temperature is 140 ℃, and the drying time is 60 min;
forming a protective layer: and uniformly printing acrylic ester three-proofing paint on the non-functional surface of the microwave dielectric ceramic filter treated by the drying step by using printing equipment to serve as a protective layer.
In this embodiment, in order to determine the influence of the ultrasonic cleaning time on the surface cleaning effect of the microwave dielectric ceramic filter processed by the metallization step, the inventors performed cleaning experiments on three groups of samples, and then recorded the surface cleanliness of the three groups of samples after being cleaned for different cleaning times, and the specific experimental results are shown in table 1:
TABLE 1 Effect of cleaning time on cleaning Effect
Remarking: a, B and C in Table 1 correspond to different cleaning effects, respectively, wherein: a represents no visible and obvious dirt residue on the surface; b indicates that there is a small amount of visible stain remaining on the surface; c indicates that there is a significant visible stain remaining on the surface.
As can be seen from table 1, when the cleaning time was less than 12min, no visible significant stain residue was left on the surface of sample 1, and a small amount of visible stain residue was left on the surfaces of samples 2 and 3; when the cleaning time is 15min or more, no obvious stain is visible on the surfaces of the samples 1, 2 and 3, but the cleaning time is too long, which wastes time, therefore, in the embodiment, the cleaning time is preferably 15 min.
Example two
In this embodiment, three sets of samples of a microwave dielectric ceramic filter with a specification of 50mm by 20mm by 6mm, i.e., sample 4, sample 5, and sample 6, are prepared, and then the surfaces of the three sets of samples are treated, which includes the following steps:
metallization step: silver layers were formed on the surfaces of the three sets of samples by printing, and the thickness of the silver layer was 15 μm.
A cleaning step: placing the three groups of samples processed by the metallization step into a cleaning solution of ultrasonic cleaning equipment for ultrasonic cleaning, wherein: the cleaning solution is prepared from sodium alkyl sulfonate-containing liquid detergent and deionized water according to the volume ratio of 1: 20, the working power of the ultrasonic cleaning equipment is 100W, and the cleaning time is 15 min.
And (3) drying: drying the three groups of samples treated by the cleaning step at the drying temperature of 150 ℃ for 60 min;
forming a protective layer: and (5) uniformly spraying acrylic ester three-proofing paint with different thicknesses on the surfaces of the sample 5 and the sample 6 treated in the step (4) by using spraying equipment to serve as protective layers.
In this embodiment, in order to determine the influence of the thickness of the protective layer on the performance of the microwave dielectric ceramic filter, the inventor performs a salt spray test and an aging test on the three groups of samples respectively, where the specific test method is as follows:
(1) salt spray test
Standard reference GB/T2423.17
The concrete conditions are as follows:
concentration of the salt solution: (5 ± 1)%;
temperature of the test chamber: (35. + -. 2) deg.C
pH (25 ℃ C.): 6.5-7.2;
salt spray settling rate: (1.0 to 2.0)/(80cm ^2 x h)
(2) Aging test
Standard reference JESD22
The concrete conditions are as follows:
the temperature is 130 DEG C
Humidity 85 percent
Time 96H
The test results of the three groups of samples are shown in table 2:
TABLE 2 influence of protective layer thickness on the performance of microwave dielectric ceramic filters
Remarking: a in Table 2 indicates that no local discoloration of the surface occurred; b represents the appearance of local discoloration on the surface; c represents that the surface is not corroded by salt fog: d indicates that the surface was locally attacked by salt spray.
As can be seen from Table 2, when the thickness of the protective layer is less than 0.005mm or no protective layer is present during the salt spray test, the surface of the microwave dielectric ceramic filter will be eroded; when the thickness of the protective layer is more than 0.09mm, the surface of the microwave dielectric ceramic filter is not corroded by salt spray when the salt spray test is carried out on the microwave dielectric ceramic filter; in addition, when the microwave dielectric ceramic filter is subjected to an aging test, when the thickness of the protective layer is less than 0.005mm or no protective layer is formed, the surface of the microwave dielectric ceramic filter is subjected to a local color change phenomenon; when the thickness of the protective layer is larger than 0.05mm, the surface of the microwave dielectric ceramic filter does not have the phenomenon of local color change when the microwave dielectric ceramic filter is subjected to an aging test.
From this, it was confirmed that the protective layer had substantially no protective effect when the thickness of the protective layer was less than 0.009 mm; when the thickness of the protective layer is greater than 0.03mm, the protective layer needs to be printed or sprayed for multiple times, which significantly reduces the processing efficiency, and therefore, in the embodiment, the thickness of the protective layer is 0.009-0.03 mm.
The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are within the protection scope of the present invention.
Claims (10)
1. A surface treatment method of a microwave dielectric ceramic filter is characterized by comprising the following steps:
metallization step: carrying out metallization treatment on the surface of the microwave dielectric ceramic filter;
a cleaning step: cleaning the surface of the microwave dielectric ceramic filter subjected to metallization treatment;
and (3) drying: drying the surface of the microwave dielectric ceramic filter after cleaning treatment;
forming a protective layer: and forming a protective layer on the non-functional surface of the microwave dielectric ceramic filter subjected to drying treatment by using a printing or spraying mode.
2. The surface treatment method of a microwave dielectric ceramic filter according to claim 1, wherein the cleaning of the surface of the microwave dielectric ceramic filter is ultrasonic cleaning of the surface of the microwave dielectric ceramic filter subjected to the metallization treatment in an ultrasonic cleaning apparatus with a cleaning liquid.
3. A surface treatment method for a microwave dielectric ceramic filter according to claim 2, wherein the cleaning liquid is a mixture of deionized water and a detergent.
4. The method of claim 3, wherein when the metallized surface of the microwave dielectric ceramic filter is cleaned by ultrasonic waves using a mixture of deionized water and a detergent, the power of the ultrasonic cleaning device is 100W and the cleaning time is 10-15 min.
5. The surface treatment method of a microwave dielectric ceramic filter as claimed in claim 1, wherein the drying temperature for drying the surface of the microwave dielectric ceramic filter subjected to the cleaning treatment is 100-150 ℃, and the drying time is 30-60 min.
6. The surface treatment method of a microwave dielectric ceramic filter as claimed in claim 1, wherein the protective layer is made of three-proofing paint.
7. A surface treatment method for a microwave dielectric ceramic filter as claimed in claim 1, wherein the thickness of said shielding layer is 0.005 to 0.030 mm.
8. A surface treatment method for a microwave dielectric ceramic filter according to any one of claims 1 to 7, wherein the surface of the microwave dielectric ceramic filter is metallized by forming a metal layer on the surface of the microwave dielectric ceramic filter by printing or spraying.
9. A surface treatment method of a microwave dielectric ceramic filter as claimed in claim 8, wherein the material of the metal layer is gold or silver.
10. A surface treatment method of a microwave dielectric ceramic filter as claimed in claim 9, wherein the metal layer is made of silver and has a thickness of 7 to 15 μm.
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| CN201911257919.8A CN111009713A (en) | 2019-12-10 | 2019-12-10 | Surface treatment method of microwave dielectric ceramic filter |
| PCT/CN2020/125245 WO2021114946A1 (en) | 2019-12-10 | 2020-10-30 | Surface treatment method for microwave dielectric ceramic filter |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112615124A (en) * | 2020-12-28 | 2021-04-06 | 京信射频技术(广州)有限公司 | Dielectric waveguide filter and method for processing dielectric ceramic silver layer thereof |
| WO2021114946A1 (en) * | 2019-12-10 | 2021-06-17 | 深圳顺络电子股份有限公司 | Surface treatment method for microwave dielectric ceramic filter |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102664055A (en) * | 2012-04-11 | 2012-09-12 | 深圳市大富科技股份有限公司 | Conductive silver paste, method for preparing same and surface metallization method for microwave dielectric ceramics |
| CN103533767A (en) * | 2013-10-23 | 2014-01-22 | 江苏通驰自动化系统有限公司 | Method for performing three-proofing treatment on circuit board by using ultrasonic waves |
| CN104974564A (en) * | 2015-06-30 | 2015-10-14 | 苏州洋杰电子有限公司 | Integrated circuit board high temperature resistant insulation paint and preparation method thereof |
| CN110105867A (en) * | 2019-04-20 | 2019-08-09 | 无锡天杨电子有限公司 | A kind of formula and preparation method thereof of ceramic copper-clad plate high-temperature resistant welding resistance |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100557853B1 (en) * | 2003-09-17 | 2006-03-10 | 재단법인서울대학교산학협력재단 | Phosphate Ceramic Compositions with Low Dielectric Constant |
| JP6685643B2 (en) * | 2013-12-18 | 2020-04-22 | スカイワークス ソリューションズ, インコーポレイテッドSkyworks Solutions, Inc. | Tunable resonator system, filtering system including tunable resonator system, and method of forming tunable resonator system |
| CN108950496A (en) * | 2018-08-22 | 2018-12-07 | 广州鸿葳科技股份有限公司 | A kind of surface treatment method and its application based on the 5G communication technology with ceramic resonance body |
| CN110492215A (en) * | 2019-09-04 | 2019-11-22 | 曹祖峰 | A kind of base station 5G ceramic filter production technology |
| CN111009713A (en) * | 2019-12-10 | 2020-04-14 | 深圳顺络电子股份有限公司 | Surface treatment method of microwave dielectric ceramic filter |
-
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102664055A (en) * | 2012-04-11 | 2012-09-12 | 深圳市大富科技股份有限公司 | Conductive silver paste, method for preparing same and surface metallization method for microwave dielectric ceramics |
| CN103533767A (en) * | 2013-10-23 | 2014-01-22 | 江苏通驰自动化系统有限公司 | Method for performing three-proofing treatment on circuit board by using ultrasonic waves |
| CN104974564A (en) * | 2015-06-30 | 2015-10-14 | 苏州洋杰电子有限公司 | Integrated circuit board high temperature resistant insulation paint and preparation method thereof |
| CN110105867A (en) * | 2019-04-20 | 2019-08-09 | 无锡天杨电子有限公司 | A kind of formula and preparation method thereof of ceramic copper-clad plate high-temperature resistant welding resistance |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021114946A1 (en) * | 2019-12-10 | 2021-06-17 | 深圳顺络电子股份有限公司 | Surface treatment method for microwave dielectric ceramic filter |
| CN112615124A (en) * | 2020-12-28 | 2021-04-06 | 京信射频技术(广州)有限公司 | Dielectric waveguide filter and method for processing dielectric ceramic silver layer thereof |
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| WO2021114946A1 (en) | 2021-06-17 |
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Application publication date: 20200414 |