Method for inlaying and detecting micron coating sample

Abstract

The invention discloses an inlaying and detection method of a micron coating sample, which adopts bakelite powder with low price to inlay the sample, the sample and a tin-bismuth alloy plate are attached and fixed before inlaying, the inlaying process is simple and convenient, and the inlaying material is low in price. And the selected tin-bismuth alloy plate can just counteract the shrinkage of the bakelite powder in the cooling process by volume expansion during cooling, and can provide better support and protection for the coating, so that the coating is prevented from being separated and damaged from a matrix due to cooling or curing shrinkage of the inlay material, and the coating is prevented from being damaged in the subsequent grinding process. When the coating sample is observed by an electron microscope, conductive adhesive tapes can be conveniently adhered to the outer side edges of the tin-bismuth alloy plate and the coating sample to be connected with an electron microscope sample table, so that the influence on measurement and observation caused by image deformity due to electron beam drift is avoided. The method is suitable for most mosaic scenes needing electroplating protection, and particularly provides effective support for special mosaic scenes which cannot be electroplated or are difficult to electroplate.

Description

Technical Field

[0001] The invention belongs to the field of experiment and test technology, and in particular relates to an inlay and detection method for a micron coating sample. Background Art

[0002] The coating is located at the edge of the sample. The coating thickness measurement and interface bonding test require the coating sample to be inlaid first. Inlaying can protect the coating. The current edge-protecting inlay material is to add some hard particles to the inlay material to protect the edge. Electroplating of copper, nickel, silver and other metals before inlay can also play a good edge protection effect. Regardless of whether hot inlay or cold inlay is used, the inlay material will have a certain degree of shrinkage during the curing or cooling process. This shrinkage will cause the coating to be subjected to tensile stress and separate along the interface or crack.

[0003] Although electroplated metal protection can resist some shrinkage stress, electroplating metal on the coating requires special methods, and its applicability is greatly limited. When testing hydrophobic coatings below 2 microns, electroplating metal becomes difficult, and the coating is more likely to separate and peel off along the interface during the inlay and grinding process; secondly, when measuring coatings below 2 microns, metallographic microscopy becomes difficult, and it is generally carried out through a scanning electron microscope. However, the coating and the inlay material are not conductive, and the electron beam drift also affects the observation and measurement results of the coating, which requires the inlay material in contact with the coating to have good conductivity. At present, micron coatings are easily damaged during the process of inlaying and grinding metallographic samples, and it is difficult to electroplate metal on hydrophobic coatings. Summary of the invention

[0004] In order to solve the above problems, the present invention aims to provide a method for embedding and detecting micron coating samples.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme: a method for inlaying a micron coating sample, comprising the following steps:

[0006] Step 1: Material preparation, clean the surface of the tin-bismuth alloy plate, cut the coating sample and clean and dry it;

[0007] Step 2: Place the tin-bismuth alloy plate on the coating side of the coating sample and fix the two with a sample clamp to ensure that light is not transmitted between the coating sample and the tin-bismuth alloy plate after fixation;

[0008] Step 3: Place the fixed coating sample and the tin-bismuth alloy plate on the end face of the lower plunger of the mounting machine, the surface to be tested of the coating sample and the lower end face of the tin-bismuth alloy plate are fitted with the end face of the lower plunger of the mounting machine, and adjust the lower end face of the sample clamp to fit with the end face of the lower plunger of the mounting machine to support the coating sample and prevent the coating sample from falling over. Preferably, the mounting machine with a prefabricated chamfered convex edge on the lower plunger of the mounting machine is used for mounting, so as to prevent the tin-bismuth alloy from flowing into the gap of the lower plunger of the mounting machine after melting;

[0009] Step 4: Hot mounting is used to mount the coating sample, the mounting material is bakelite powder, the mounting temperature is 150°C, and the mounting pressure is 50Bar~200Bar;

[0010] Step 5: Use an automatic grinder to grind the mounted specimen to reduce rounding, clean and dry the specimen.

[0011] Preferably, the contents of Sn and Bi in the tin-bismuth alloy plate used in step 1 are 42% and 58% respectively, and the surface of the tin-bismuth alloy plate is smooth, defect-free, and non-oxidized, and the surface roughness is not greater than Ra3.2.

[0012] Preferably, the coating should not be damaged during the process of cutting the coating sample in step 1.

[0013] Preferably, during the hot embedding process in step 4, the volume expansion of the tin-bismuth alloy plate during cooling can just offset the shrinkage of the bakelite powder during the cooling process, and can provide support and protection for the coating, thereby preventing the cooling or solidification shrinkage of the embedding material from separating and destroying the coating from the substrate, and preventing the coating from being destroyed during the subsequent grinding process.

[0014] A method for detecting a micron coating sample comprises sticking a conductive tape on a prepared sample, sticking the conductive tape on the outer edges of a tin-bismuth alloy plate and the coating sample, placing the stuck sample into a scanning electron microscope and connecting the conductive tape to a sample stage of the electron microscope, and collecting a backscattered electron image of the coating.

[0015] Preferably, a conductive tape is attached to the outer edges of the tin-bismuth alloy plate and the coating sample to prevent the electron beam from drifting and causing image distortion, thereby affecting measurement and observation.

[0016] Preferably, the coating shown in the backscattered electron image is intact and undamaged.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The inlay method of the present invention uses low-cost bakelite powder to inlay the sample. Before inlaying, the sample is attached and fixed to the tin-bismuth alloy plate. The inlay process is simple and the inlay materials are low-cost.

[0019] When the bakelite powder solidifies and shrinks at about 150°C, the tin-bismuth alloy is in a molten state, avoiding the disadvantage of traditional bakelite powder inlay solidification shrinkage damaging the coating. The molten tin-bismuth alloy can effectively fill the gap, preventing the liquid invading the gap from seeping out and contaminating the coating during observation.

[0020] 2. The tin-bismuth alloy plate selected for the inlay method of this method can just offset the shrinkage of the bakelite powder during the cooling process through its volume expansion during cooling, and can provide better support and protection for the coating, thereby avoiding the separation and destruction of the coating from the substrate due to the cooling or solidification shrinkage of the inlay material, and the coating being destroyed during the subsequent grinding process.

[0021] 3. When observing the coating sample under an electron microscope, the detection method of the present invention can conveniently attach conductive tape to the outer edges of the tin-bismuth alloy plate and the coating sample and connect them to the electron microscope sample stage to avoid electron beam drift causing image distortion and affecting measurement and observation.

[0022] 4. The method of the present invention is applicable to most inlay scenes that require electroplating protection, and in particular provides effective support for special inlay scenes that cannot be electroplated or are difficult to electroplated. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 Schematic diagram of the clamping of the coating sample and the tin-bismuth alloy plate in the present invention;

[0025] Figure 2 It is a schematic diagram of the sample prepared in the present invention;

[0026] Figure 3 It is a schematic diagram of the conductive tape being wound around a sample in the present invention;

[0027] Figure 4 This is a schematic diagram of a backscattered electron image of a coating in the present invention;

[0028] In the figure, 1-coated sample; 2-tin-bismuth alloy plate; 3-sample clamp; 4-lower plunger of mounting machine; 5-sample; 6-conductive tape. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but it should not be understood that the scope of the subject matter described in the present invention is limited to the following embodiments. Without departing from the above-mentioned technical ideas of the present invention, various modifications, substitutions and changes made according to the common technical knowledge and customary means in the field are included in the scope of the present invention.

[0030] The objective of the present invention is achieved through the following technical solutions:

[0031] At present, whether it is hot mounting or cold mounting with edge preservation, the mounting material has a certain degree of shrinkage during the solidification and cooling process. This shrinkage will cause the coating to be subjected to tensile stress and separate along the interface or crack. Although electroplating metal protection on the coating can resist part of the shrinkage stress, the electroplating metal process is relatively complicated, especially there is almost no report on electroplating on hydrophobic coatings. When the sample after edge preservation mounting is inspected by scanning electron microscope, the coating and mounting material are not conductive, and the electron beam drift also affects the observation and measurement of the coating. Therefore, the following solutions are adopted to address the above problems:

[0032] The inlay and detection methods are as follows:

[0033] (1) cleaning the surface of the tin-bismuth alloy plate 2, wherein the contents of Sn and Bi in the tin-bismuth alloy are 42% and 58% respectively, and the surface of the tin-bismuth alloy plate 2 is smooth, defect-free, and non-oxidized, and the surface roughness is Ra3.2, and the preferred roughness is less than Ra3.2;

[0034] (2) Cut the coating sample 1, clean and dry the coating sample 1, and the coating shall not be damaged during the cutting process;

[0035] (3) placing the tin-bismuth alloy plate 2 on the coating side of the coating sample 1, and fixing the coating sample 1 and the tin-bismuth alloy plate 2 with a sample clamp 3, so that light is not transmitted between the coating sample 1 and the tin-bismuth alloy plate 2;

[0036] (4) placing the coating sample 1 and the tin-bismuth alloy plate 2 on the end surface of the lower plunger 4 of the mounting machine, with the surface of the coating sample 1 to be tested and the lower end surface of the tin-bismuth alloy plate 2 in contact with the end surface of the lower plunger 4 of the mounting machine, and adjusting the lower end surface of the sample clamp 3 to be in contact with the end surface of the lower plunger 4 of the mounting machine to support the coating sample 1 and prevent the coating sample 1 from falling over;

[0037] (5) Mounting the coating sample 1 according to the hot mounting steps, the mounting material is bakelite powder, the mounting temperature is about 150°C, and the mounting pressure is 50Bar to 200Bar;

[0038] (6) During the inlay process, the bakelite powder is plasticized at 70°C to 90°C, has the lowest viscosity and the best fluidity at 90°C to 120°C, and solidifies and shrinks at around 150°C. When the bakelite powder solidifies and shrinks, the tin-bismuth alloy is in a molten state and can effectively fill the gaps caused by the shrinkage. When cooling, the volume expansion of the tin-bismuth alloy just offsets the shrinkage of the bakelite powder, thus preventing the cooling or solidification shrinkage of the inlay material from separating and destroying the coating and the substrate. At the same time, there is no gap between the coating and the tin-bismuth alloy, which can prevent the liquid invading the gap from seeping out and contaminating the coating during observation.

[0039] (7) Use an automatic grinding and polishing machine to grind the mounted specimen to reduce rounding, clean and dry the specimen 5;

[0040] (8) Prepared sample 5 Figure 2 As shown, the tin-bismuth alloy is tightly bonded to the coating surface and the coating is not damaged;

[0041] (9) Pasting a conductive tape on the prepared sample 5, the conductive tape is pasted on the outer edges of the tin-bismuth alloy plate 2 and the coating sample 1 to prevent the electron beam from drifting and causing image distortion;

[0042] (10) Finally, the prepared sample 5 is placed in a scanning electron microscope and the conductive tape is connected to the microscope sample stage. The secondary electron or backscattered electron image of the coating is collected to measure and observe the coating.

[0043] Example 1

[0044] Combine the following Figure 1 , 2 , to further describe the technical solution of the present invention for mounting a sample in a 30 mm diameter mounting cylinder of an automatic mounting machine, the selected lower plunger 4 of the mounting machine has a prefabricated chamfered convex edge. The specific steps are as follows:

[0045] (1) Clean the surface of the tin-bismuth alloy plate 2. The dimensions of the tin-bismuth alloy plate 2 are 20 mm wide, 1 mm thick, and 10 mm high. The contents of Sn and Bi in the tin-bismuth alloy are 42% and 58% respectively. The melting point is about 138° C. The surface of the tin-bismuth alloy plate 2 is smooth, defect-free, and non-oxidized. The surface roughness is Ra3.2. The preferred roughness is better than Ra3.2.

[0046] (2) Cut the coating sample 1, clean and dry the coating sample 1, the size of the sample is 20 mm wide, 2 mm thick, and 15 mm high, and the coating must not be damaged during the cutting process.

[0047] (3) The tin-bismuth alloy plate 2 is placed on the coating side of the coating sample 1, and the coating sample 1 and the tin-bismuth alloy plate 2 are fixed using a sample clamp 3, so that light is not transmitted between the coating sample 1 and the tin-bismuth alloy plate 2.

[0048] (4) The coating sample 1 and the tin-bismuth alloy plate 2 are placed on the end surface of the lower plunger 4 of the mounting machine, the surface to be tested of the coating sample 1 and the lower end surface of the tin-bismuth alloy plate 2 are in contact with the end surface of the lower plunger 4 of the mounting machine, and the lower end surface of the sample clamp 3 is adjusted to be in contact with the end surface of the lower plunger 4 of the mounting machine to support the coating sample 1 and prevent the coating sample 1 from falling over. Figure 1 .

[0049] (5) The coating sample 1 was mounted according to the hot mounting procedure. The mounting material was bakelite powder, the mounting temperature was 150°C, the mounting pressure was 50 Bar, the heating time was 4 minutes, and the cooling time was 2 minutes.

[0050] (6) Use an automatic grinding and polishing machine to grind the mounted specimen to reduce rounding, clean and dry the specimen, and prepare the specimen 5 as shown in the figure. Figure 2 As shown, the tin-bismuth alloy is tightly bonded to the coating surface and the coating is not damaged.

[0051] (7) A conductive tape 6 is pasted on the prepared sample 5. The conductive tape 6 is pasted on the outer edges of the tin-bismuth alloy plate 2 and the coating sample 1. Figure 3 As shown;

[0052] (8) Finally, the prepared sample 5 is placed in a scanning electron microscope and the conductive tape 6 is connected to the microscope sample stage to collect the backscattered electron image of the coating, and the coating is measured and observed. The collected backscattered electron image of the hydrophobic coating is as follows: Figure 4 The gray-black part in the middle is the coating, and the upper and lower sides of the coating are tin-bismuth alloy and metal test pieces respectively.

[0053] The above is a detailed introduction to the embedding and detection method of a micron coating sample provided by the present invention. The structure and working principle of the present invention are described in detail using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, the present invention can also be improved and modified without departing from the principle of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for inlaying a micron coating sample, characterized in that: The following steps are included: Step 1: Material preparation, cleaning the surface of the tin-bismuth alloy plate (2), cutting the coating sample (1) and cleaning and drying; Step 2: placing the tin-bismuth alloy plate (2) on the coating side of the coating sample (1), and fixing the two using a sample clamp (3), ensuring that light is not transmitted between the coating sample (1) and the tin-bismuth alloy plate (2) after fixing; Step 3: placing the fixed coating sample (1) and the tin-bismuth alloy plate (2) on the end face of the lower plunger (4) of the setting machine, the surface to be tested of the coating sample (1) and the lower end face of the tin-bismuth alloy plate (2) are in contact with the end face of the lower plunger (4) of the setting machine, adjusting the lower end face of the sample clamp (3) to be in contact with the end face of the lower plunger (4) of the setting machine, so as to support the coating sample (1) and prevent the coating sample (1) from falling over. Preferably, the setting machine is used for setting with a prefabricated chamfered convex edge on the lower plunger (4) of the setting machine, so as to prevent the tin-bismuth alloy from flowing into the gap of the lower plunger (4) of the setting machine after melting; Step 4: hot mounting is used to mount the coating sample (1), the mounting material is bakelite powder, the mounting temperature is 150° C., and the mounting pressure is 50 Bar to 200 Bar; Step 5: Use an automatic grinding and polishing machine to grind the mounted sample (5) to reduce rounding, clean and dry the sample (5).

2. The method for mounting a micron coating sample according to claim 1, characterized in that: The contents of Sn and Bi in the tin-bismuth alloy plate (2) used in step 1 are 42% and 58% respectively. The surface of the tin-bismuth alloy plate (2) is smooth, free of defects and oxidation, and the surface roughness is not greater than Ra3.

2.

3. The method for mounting a micron coating sample according to claim 1, characterized in that: The process of cutting the coating sample (1) in step 1 must not damage the coating.

4. The method for mounting a micron coating sample according to claim 1, characterized in that: During the hot embedding process of step 4, the volume expansion of the tin-bismuth alloy plate (2) during cooling can just offset the shrinkage of the bakelite powder during the cooling process, and can provide support and protection for the coating, thereby preventing the coating from being separated and damaged from the substrate due to cooling or solidification shrinkage of the embedding material, and preventing the coating from being damaged during the subsequent grinding process.

5. A method for testing the micron coating sample prepared according to claims 1-4, characterized in that: A conductive tape (6) is pasted on the prepared sample (5), and the conductive tape (6) is pasted on the outer edges of the tin-bismuth alloy plate (2) and the coating sample (1). The pasted sample (5) is placed in a scanning electron microscope and the conductive tape (6) is connected to the sample stage of the electron microscope to collect a backscattered electron image of the coating.

6. The method for detecting micron coating samples according to claim 5, characterized in that: The conductive tape (6) is pasted on the outer edges of the tin-bismuth alloy plate (2) and the coating sample (1), so as to prevent the electron beam from drifting and causing image distortion, thereby affecting measurement and observation.

7. The method for detecting micron coating samples according to claim 5, characterized in that: Backscattered electron images show that the coating is intact.

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