Method for preparing silicon nitride ceramic electron microscope test sample through microwave digestion

Abstract

The invention discloses a method for preparing a silicon nitride ceramic chip electron microscope test sample through microwave digestion, and relates to the technical field of electron microscope test, and the method comprises the following operation steps: S1, adding a silicon nitride ceramic chip into a dilute sulfuric acid solution to obtain a prefabricated silicon nitride ceramic chip; s2, performing microwave digestion on the prefabricated silicon nitride ceramic chip, taking out the prefabricated silicon nitride ceramic chip, cleaning the prefabricated silicon nitride ceramic chip with pure water, and drying the prefabricated silicon nitride ceramic chip to obtain a silicon nitride ceramic chip electron microscope test sample; s3, after the silicon nitride ceramic chip electron microscope test sample is subjected to metal spraying, the crystal grain growth condition is observed through an electron microscope.

Description

Technical Field

[0001] The invention relates to the technical field of electron microscope testing, in particular to a method for preparing silicon nitride ceramic piece electron microscope testing samples by microwave digestion. Background Art

[0002] The grain size has a great influence on the performance of silicon nitride ceramics. It is very unfavorable if the grains are too large or too small, so it is necessary to observe the size of the grains in order to adjust the process. The observation of grains is generally achieved through an electron microscope, but untreated silicon nitride ceramics contain a large amount of glass phase, which is not conducive to observing the grain size. At present, the commonly used silicon nitride corrosion methods are high-temperature molten sodium hydroxide or high-concentration hydrofluoric acid, but both methods have the same problems and are relatively dangerous; the corrosion process is uncontrollable, which can easily lead to excessive corrosion in some areas and damage to the silicon nitride grains, and the glass phase in some areas is not completely corroded. Therefore, it is necessary to develop a treatment method that is less dangerous, has a controllable process, and will not damage the silicon nitride grains. Summary of the invention

[0003] The object of the present invention is to provide a method for preparing silicon nitride ceramic chip electron microscope test samples by microwave digestion, so as to solve the problems raised in the above background technology.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] A method for preparing silicon nitride ceramic chip electron microscope test samples by microwave digestion, comprising the following steps:

[0006] S1: adding a silicon nitride ceramic sheet into a dilute sulfuric acid solution to obtain a prefabricated silicon nitride ceramic sheet;

[0007] S2: taking out the prefabricated silicon nitride after microwave digestion, washing it with pure water and drying it to obtain a silicon nitride ceramic piece electron microscope test sample;

[0008] S3: After gold is sprayed on the silicon nitride ceramic sample for electron microscopy test, the grain growth is observed using an electron microscope.

[0009] The more optimized process conditions of the microwave digestion are: microwave digestion pressure of 1-2.5 MPa, microwave digestion temperature of 150-250° C., microwave digestion time of 30-60 minutes, and microwave power of 600W-1000W.

[0010] Preferably, the concentration of the dilute sulfuric acid solution is 10-30 wt %.

[0011] Preferably, the mass ratio of the silicon nitride ceramic sheet to the dilute sulfuric acid solution is 1:2-5.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] (1) The method used in the present invention uses dilute sulfuric acid when treating silicon nitride samples, which is safer than using hydrofluoric acid and molten sodium hydroxide.

[0014] (2) The present invention uses a microwave digestion instrument to process samples, which is simple to operate, has unified parameters, and has better controllability and repeatability.

[0015] (3) When the silicon nitride sample is treated by the method provided by the present invention, the glass phase is removed without causing damage to the grains, thereby affecting the determination of the grain growth condition. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a flow chart for preparing silicon nitride ceramic samples for electron microscope testing;

[0017] Figure 2 This is a graph showing the electron microscope test results of the silicon nitride ceramic sheet electron microscope test sample of Example 1;

[0018] Figure 3 This is a graph showing the electron microscope test results of the silicon nitride ceramic sheet electron microscope test sample of Example 2;

[0019] Figure 4 This is a graph showing the electron microscope test results of the silicon nitride ceramic piece electron microscope test sample of Example 3;

[0020] Figure 5 This is a graph showing the electron microscope test results of the silicon nitride ceramic piece electron microscope test sample of Example 4;

[0021] Figure 6 This is a graph showing the electron microscope test results of the silicon nitride ceramic sample of comparative example 1. DETAILED DESCRIPTION

[0022] The following embodiments are parts by mass; the technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1: A method for preparing silicon nitride ceramic sample for electron microscopy test by microwave digestion;

[0024] S1: adding 50 mg of silicon nitride ceramic piece into 250 mg of dilute sulfuric acid solution (10 wt % dilute sulfuric acid) to obtain a prefabricated silicon nitride ceramic piece;

[0025] S2: The prefabricated silicon nitride ceramic piece is subjected to microwave digestion for 30 minutes under the conditions of microwave digestion pressure of 2.5 MPa, microwave digestion temperature of 150°C and microwave power of 600 W, and then taken out, washed with pure water and dried to obtain an electron microscope test sample;

[0026] S3: After the electron microscope test sample is sprayed with gold, the grain growth is observed using an electron microscope.

[0027] Example 2: A method for preparing silicon nitride ceramic sample for electron microscopy test by microwave digestion;

[0028] S1: Weigh silicon nitride and dilute sulfuric acid solution (20 wt%) in a ratio of 1:2; add the silicon nitride ceramic piece into the dilute sulfuric acid solution (20 wt%) to obtain a prefabricated silicon nitride ceramic piece;

[0029] S2: The prefabricated silicon nitride ceramic piece is subjected to microwave digestion for 40 minutes under the conditions of microwave digestion pressure of 2 MPa, microwave digestion temperature of 200°C and microwave power of 600 W, taken out, washed with pure water and then dried to obtain an electron microscope test sample;

[0030] S3: After the electron microscope test sample is sprayed with gold, the grain growth is observed using an electron microscope.

[0031] Example 3: A method for preparing silicon nitride ceramic sample for electron microscopy test by microwave digestion;

[0032] S1: Weigh silicon nitride and dilute sulfuric acid solution (30 wt%) in a ratio of 1:3; add the silicon nitride ceramic sheet into the dilute sulfuric acid solution (30 wt%) to obtain a prefabricated silicon nitride ceramic sheet;

[0033] S2: The prefabricated silicon nitride ceramic piece is subjected to microwave digestion for 60 minutes under the conditions of microwave digestion pressure of 1.5 MPa, microwave digestion temperature of 200°C and microwave power of 800 W, and then taken out, washed with pure water and dried to obtain an electron microscope test sample;

[0034] S3: After the electron microscope test sample is sprayed with gold, the grain growth is observed using an electron microscope.

[0035] Example 4: A method for preparing silicon nitride ceramic samples for electron microscopy testing by microwave digestion;

[0036] S1: Weigh silicon nitride and dilute sulfuric acid solution (30 wt%) in a ratio of 1:4; add the silicon nitride ceramic piece into the dilute sulfuric acid solution (30 wt%) to obtain a prefabricated silicon nitride ceramic piece;

[0037] S2: The prefabricated silicon nitride ceramic piece is subjected to microwave digestion for 60 minutes under the conditions of microwave digestion pressure of 1 MPa, microwave digestion temperature of 250°C and microwave power of 1000 W, taken out, washed with pure water and then dried to obtain an electron microscope test sample;

[0038] S3: After the electron microscope test sample is sprayed with gold, the grain growth is observed using an electron microscope.

[0039] Comparative Example 1:

[0040] S1: Add 5g of sodium hydroxide into a graphite crucible, place the graphite crucible on a heating platform at 400°C, heat for 2min, then add a 5mm×10mm silicon nitride sample into the molten sodium hydroxide, and the etching time is 240s;

[0041] S2: After corrosion analysis, take out the sample, wash it with pure water and dry it to obtain the electron microscope test sample

[0042] S3: After the electron microscope test sample is sprayed with gold, the grain growth is observed using an electron microscope.

[0043] Conclusion: Examples 1 to 4 adopt the method of the present invention. Compared with Comparative Example 1, the glass phase in the observable area of ​​Examples 1 to 4 is corroded more thoroughly, with almost no residue, and the grains are not corroded, with a complete structure.

[0044] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing silicon nitride ceramic sample for electron microscope test by microwave digestion, characterized in that: The steps include: S1: adding a silicon nitride ceramic sheet into a dilute sulfuric acid solution to obtain a prefabricated silicon nitride ceramic sheet; S2: taking out the prefabricated silicon nitride ceramic chip after microwave digestion, washing it with pure water and drying it to obtain a silicon nitride ceramic chip electron microscope test sample; S3: After gold is sprayed on the silicon nitride ceramic sample for electron microscopy test, the grain growth is observed using an electron microscope.

2. The method for preparing silicon nitride ceramic chip electron microscope test samples by microwave digestion according to claim 1, characterized in that: The process conditions of the microwave digestion are as follows: microwave digestion pressure is 1-2.5MPa, microwave digestion temperature is 150-250°C, microwave digestion time is 30-60 minutes, and microwave power is 600W-1000W.

3. The method for preparing silicon nitride ceramic chip electron microscope test samples by microwave digestion according to claim 1, characterized in that: The concentration of the dilute sulfuric acid solution is 10-30 wt %.

4. The method for preparing silicon nitride ceramic chip electron microscope test samples by microwave digestion according to claim 1, characterized in that: The mass ratio of the silicon nitride ceramic sheet to the dilute sulfuric acid solution is 1:2-5.

Images