KR100384701B1 - Micro-tribo tester in situation in scanning electron microscopy - Google Patents

Abstract

The present invention relates to a micro tribo tester that implements friction wear experiments and visualization in a scanning electron microscope. By installing the government to maintain a certain angle with the specimen to observe in real time the phenomenon occurring at the pin and disk contact point.

The present invention comprises a pin-on disk device with a disk on which a specimen is installed and a signal output device for detecting a state of the specimen; A micro tribo tester embodying a friction wear test and visualization in a scanning electron microscope, comprising a data output device connected to the signal output device and outputting a detected signal as a character, the disk rotation for rotating the disk at a low speed. Means (10); A pin fixing part (40) installed in the interior of the cell by forming a stage fixing part to which the stage is inserted while fixing the pin in contact with the specimen installed on the disk rotating at a low speed; And a display means 70 for outputting the signal detected by the signal output device as an image and data.

Description

Micro-tribo tester in situation in scanning electron microscopy

The present invention relates to a micro tribo tester that implements friction wear test and visualization in a scanning electron microscope. In particular, the disk is rotated at low speed by using a disk rotating means, and a pin fixing part is installed on the upper stage of the cell. The present invention relates to a micro tribo tester that implements friction wear experiments and visualizations in a scanning electron microscope that allows a predetermined angle to be observed in real time at a pin and disk contact point.

In general, Scanning Electron Microscopy (SEM) refers to a microscope that is observed by using a secondary electron protruding by irradiating the electron beam on the sample surface.

As shown in FIG. 7, the scanning electron microscope includes an electron gun portion, which is an electron generating unit, a lens for collecting and inspecting electrons, a sample stage where a sample is placed and a tester, and an image output and a data output stage for outputting data. The filament of the electron gun portion is powered to accelerate the emitted electrons to a high voltage (10-40 kV), collect them with a focusing lens and irradiate them on the surface of the sample to detect secondary electrons emitted from the sample to make an image. The principle was used.

There are two ways to produce electrons from an electron gun. One is to heat the filament to a high temperature so that free electrons are released into the vacuum from the surface of the filament. The other is to apply a high-voltage potential difference to the surface of the filament under high vacuum. To emit electrons. The former is called a hot electron, and the latter is called a field emission electron.

The electrons emitted from the electron gun are accelerated by the acceleration voltage, collected by the focusing lens, and irradiated onto the sample. The primary electrons irradiated onto the sample emit electrons with various kinds of information such as secondary electrons and X-rays, and scanning electron microscopes detect only secondary electrons and make an image.

Injecting an accelerated electron beam into a sample, the most widely used to observe the microstructure and shape of small samples in a solid state, causes incident and incident electron beams to have elastic and non-elastic impacts on the surface of the sample (SecondaryElectron). , Back Scanning Electron, X-ray, Photon, Auger).

At this time, the material is selectively detected by an electron detector and imaged, and when there is motion between the counterpart materials, energy loss and motion resistance are generated, which causes friction and wear of the counterpart materials.

The research subjects in the field of friction and abrasion are also aimed at preventing irreversible energy loss and finding the causes of friction and wear by reducing the friction coefficient.

Experimental methods include pin-on-disk, pin-on-cylinder, or cylinder-on-cylinder, depending on the type of contact of the frictional and abrasive mechanical elements. Comparative experiments such as these are mainly conducted. Through these experiments, the friction and abrasion phenomena generated in mechanical parts are predicted through the change of the friction force, the change of the friction coefficient, and the measurement of the amount of wear.

As described above, in order to move the stage of the SEM, the disk is realized by rotating the disk by hand holding and turning, but in this case, it is not possible to maintain a steady steady state speed. In order to observe the movements of the abrasive particles generated between the materials, and the movement of the pins when the abrasive particles are formed, it is necessary to maintain a constant speed until the abrasive particles are generated. In this case, it is impossible to control by hand.

In addition, the friction and abrasion phenomena are predicted through a change in the friction force, a change in the coefficient of friction, the measurement of the amount of wear, there was a problem that it is difficult to calculate the accurate data.

Another problem was the limitation of not being able to observe the phenomenon between the specimen on the pin and the disk.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to install a pin rotating means connected to a disk to enable low speed rotation, and to install a pin fixing part on the upper stage of the inside of the sample and a predetermined angle. It is to provide a friction wear test apparatus in a scanning electron microscope that can observe in real time the phenomenon occurring at the pin and disk contact point by forming a

1 is an exemplary view showing a configuration of the present invention.

2 is a perspective view showing a structure of a pin fixing part installed inside a cell.

Figure 3 is a perspective view showing the installation state of the pin and disk and the specimen.

Figure 4 is a graph measuring the force acting in the vertical direction of the specimen.

5 is a graph measuring the force acting on the tangential direction of the specimen.

6 is a graph measuring the change of the friction coefficient with time.

7 is a block diagram of a typical scanning electron microscope.

※ Explanation of code for main part of drawing ※

10: disc rotating means 20: specimen

40: pin fixing portion 41: stage fixing portion

42: bracket 44: pin fixing hole

45: pin 46: rotation bar

46a: weight 46b: screw

47: sensor 50: signal output unit

60: Shem 70: Display means

80: stage 90: disk

The object of the present invention comprises a pin-on disk device with a disk on which the specimen is placed and a signal output device for detecting the state of the specimen; A micro tribo tester embodying a friction wear test and visualization in a scanning electron microscope, comprising a data output device connected to the signal output device and outputting a detected signal as a character, the disk rotation for rotating the disk at a low speed. Means; A pin fixing part and a mechanism installed inside the cell by forming a stage fixing part to which a stage is inserted while fixing a pin contacting a specimen installed on an upper portion of the disk rotating at a low speed; It is achieved by a micro tribo tester embodying friction wear experiments and visualization in a scanning electron microscope comprising a display means for outputting a signal detected by the signal output device as an image and data.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an exemplary view showing the configuration of the present invention, Figure 2 is a perspective view showing the structure of the pin fixing portion installed in the interior of the micro-fiber wear friction experiment and visualization in the scanning electron microscope of the present invention The tribo tester is composed of a pin-on disk device in which a disk for installing a specimen is installed and a signal output device for detecting a state of the specimen; A micro tribo tester embodying a friction wear test and visualization in a scanning electron microscope, comprising a data output device connected to the signal output device and outputting a detected signal as a character, the disk rotation for rotating the disk at a low speed. Means; A pin fixing part and a mechanism in which a stage is installed on the upper part of the disk and fixed in contact with the specimen installed on the upper part of the disk rotating means and installed in the interior of the cell; And display means for outputting a signal detected by the signal output device as an image and data.

Specifically, the disk rotation means 10 is a device for rotating the disk 90 existing on the stage inside the machine at a low speed. The gear ratio using a worm gear and a spur gear is about 60: 1. , The rotation speed of the disk 90 is implemented less than 0.01RPM.

The disk 90 rotating at a low speed by the disk rotating means 10 and the specimen 20 attached thereto are rotated at the same time, and at this time, friction wear generated at the contact point between the specimen 20 and the pin 45 is performed. Will be measured.

In other words, the present invention is composed of a pin fixing unit 40 and a signal output unit 50 for transmitting a signal measured by the pin fixing unit 40 to which a conventional pin on disk device is applied. 40 has a stage fixing part 41, a bracket 42 on which a shaft and a bearing are mounted, and a pin fixing hole 44 for inserting the pin 45 while being positioned between the bracket 42 at one side thereof. The provided rotary bar 46, the weight 46a which is screwed to the screw 46b protruding upward while being located on the rotary bar 46, and the contact with the pin 45 and the specimen 20 It is a structure consisting of a sensor 47 for detecting and measuring, the display means 70 is composed of an image output unit 71 and a data output unit 72 for simultaneously outputting the detected signal as an image and data.

Referring to the operation and effect of the present invention having a structure as described above as shown in Figure 1 to 2, the pin 45 is in contact with the desired position of the specimen 20 to apply a constant load to the pin 45 When the disk 90 is rotated by driving the disk rotating means 10 in the applied state, the specimen 20 on the disk 90 rotates at a low speed so that friction between the pin 45 and the specimen 20 occurs. This occurs and the friction wear phenomenon can be observed through the SEM (SEM) (60).

In order for the specimen 20 to rotate, the disk 90 must be rotated, and the rotation speed of the disk 90 must be kept at a very low speed because the magnification of the image sent from the cell 60 is very high. This is because it is impossible to observe the phenomenon occurring at the contact point in real time. In the past, the disk was rotated by rotating the disc by hand holding and rotating to move the stage. none. In order to observe the movement of the abrasive particles between the two relative movement materials or the movement of the pin when the abrasive particles are formed, the speed must be kept constant until the abrasive particles are formed. In this case, it is impossible to control by hand. If the disk rotating hand is replaced with an existing motor, 0.3RPM is possible, but when the magnification is enlarged at high magnification within the count, it can be said that the speed is difficult to observe.

By rotating the disk 90 by driving the disk rotating means 10, it is possible to realize a very low rotational speed using the manufactured gear box and observe the friction wear phenomenon between the pin 45 and the specimen 20 by counting. It is possible to maintain a stable steady state of the disk 90 rotation speed is possible to accurately experiment friction wear.

Meanwhile, the stage fixing part 41 serves to fix the pin fixing part 40 to the stage 80. At this time, the pin fixing part 41 may adjust the position where the pin 45 contacts the specimen 20. In addition, the rotation bar 46 serves to fix the pin 45 and maintain the angle between the pin 45 and the disk 90 and detect the signal from the pin 45.

Looking at the features of the pin fixing portion 40 in detail, the stage fixing portion 41 is a portion that is attached to the stage 80 to be fixed to any position of the stage 80 by tightening and loosening screws. Produced. Therefore, since the pin fixing portion 40 can be freely positioned on the stage 80 in the direction of ①, movement in the X direction to allow the pin 45 to be positioned at the correct position on the specimen 20 is possible.

② direction movement also shows that the pin 45 is capable of movement in the Y direction of the pin fixing portion 40 to be placed in the correct position on the specimen (20).

③ direction movement is separated so that the bracket 42 is attached to any position of the stage fixing portion 41 and can be engaged by screwing in the desired position, the pin 45 is the It indicates that the movement in the Z-axis (height) direction is possible to be in the correct position.

The movement in the ④ direction represents the movement in the rotational direction of the rotation bar 46 connected to the bracket 42 by a bearing. Due to the rotational movement of the rotation bar 46, the pin 45 can be rotated even when the disc 90 is inclined at an arbitrary angle in space, and the test piece 20 and the pin 45 attached to the disc 90 can be rotated. ) Can always be maintained at 90 °, allowing accurate measurement of the coefficient of friction between two materials.

The measurement of the frictional force means the tangential force at the point of contact with respect to the vertical load force acting on the pin 45 as indicated by the arrow in FIG. 3. The frictional force is measured through the sensor 47 attached to the rotary bar 46, and the sensor 47 shows the magnitude of the small deformation with respect to the micro load as a change in the resistance, which is a ratio of the voltage to the output voltage applied to the sensor. In conclusion, the present invention allows the pin 45 to be placed at any position of the specimen 20 in measuring the frictional force between the pin 45 and the specimen 20 attached to the disk 90. In addition, even when the disk 90 is tilted at an arbitrary angle, the angle between the pin 45 and the disk 90 can be maintained to be vertical, so that accurate friction experiments are possible.

FIG. 3 is an example of a contact state between the pin 45 installed in the cell and the specimen 20 placed on the disk 90. The pin 45 is fixed to the end of the rotation bar 46 by the pin fixing hole 44 and the specimen 20 attached to the disk 90 is inclined at an angle to observe the friction phenomenon at the contact point. It's in a gin.

In this case, as described above, the pin fixing portion 40 may move in any X, Y, and Z directions, and at the same time, the rotation bar 46 and the bracket 42 of the pin fixing portion 46 may move to the bearing. Since the rotary bar 46 is also rotatable by the rotational angle of the disk 90, the specimen 20 and the pin 45 can always maintain 90 ° and can accurately measure the friction force.

On the other hand, since the pin holder 40 is mounted in the interior of the cell, in order to connect the frictional force signal from the sensor 47 to the atmospheric pressure from the interior of the vacuum cell, the vacuum inside the cell 60 is maintained at the connection site. In the present invention, the signal output unit 50 is sealed with silicon so that the vacuum is maintained.

Since the friction coefficient represents the tangential force according to the vertical force acting on the test piece 20, the tangential friction force does not work unless the vertical force acts on the test piece 20. In the present invention, a dead weight method is used to apply a vertical load.

The vertical force on the specimen 20 shown in FIG. 3 is the force resulting from the dead weight applied to the pin 45 and the tangential force is the ratio of the friction coefficient to the vertical force. The frictional force determined by

The force measured by the sensor 47 attached to the rotation bar 46 of the pin fixing part 40 is the friction force that appears in the tangential direction of the specimen 20 at the contact point, and the vertical force is applied to the weight 46a. While the frictional force in the tangential direction varies depending on the material, the rotational speed, and the surface state, etc., the frictional force detected by the sensor 47 passes through the signal output unit 50 to the outside of the cell 60. Will be connected to your computer and analyzed.

In the accompanying drawings, in the apparatus of the present invention, various weights 46a having a weight of 10g or less are placed on the rotation bar 46 of the pin fixing portion 40 while the disk 90 is inclined at 30 °. In this case it shows the measurement results for the force in the vertical direction acting on the specimen (20). Since the vertical force cannot be measured directly, the gravity component of the vertical force is measured using a micro balance.

On the other hand, in the tangential force, since the value of the voltage output from the sensor is input to the computer and converted into a force value, the ratio of the output voltage and the magnitude of the force should be constant. 5 shows that the correlation between the voltage and the magnitude of the force is constant at a ratio of about 2.1092 magnitudes.

From the two measurement results shown in FIGS. 4 and 5, it can be seen that the method of applying a dead weight load and the performance of the attached sensor are reliable.

On the other hand, the actual experiment was performed on the following conditions based on the measurement result of the vertical and tangential force.

Experimental conditions:

Specimen Material dead weight Disk speed Diamond Copper 2.04 g 0.3 RPM (200 m / s) Result: The vertical and tangential forces input to the computer from the sensor of the pinned part through the signal output part appear as friction coefficients through calculations. The value of is shown to be around 1, but it remains lower after 40 seconds when the rotation stops.

The measurement signal detected as described above is sent to the data output unit 72 through the signal output unit 50, and the phenomenon of friction wear occurring at the contact point passes through the image output unit 71 and appears to the measurer in friction wear phenomenon. Provide a variety of information.

The micro tribo tester embodying the friction wear test and visualization in the scanning electron microscope according to the present invention is equipped with a staging pin fixing part inside the cell and a disk rotating means capable of rotating the disk at a low speed. Regardless of the test specimen, the specimen and the pin remain vertical, and the friction wear phenomenon occurring at the contact point between the pin and the specimen can be observed in real time, and accurate friction coefficient can be measured.

Claims (5)

A pin-on disk device with a disk on which the specimen is installed and a signal output device for detecting the state of the specimen; In the micro tribo tester embodying the friction wear experiment and visualization in a scanning electron microscope consisting of a data output device connected to the signal output device for outputting the detected signal numerically, Disk rotating means (10) for rotating the disk (90) at low speed; A pin fixing part installed inside the saw 60 by forming a stage fixing part 41 into which the stage is inserted while fixing the pin 45 in contact with the specimen 20 installed on the disk rotating means 10. 40; A micro tribo tester embodying friction wear experiments and visualization in a scanning electron microscope, characterized in that it comprises a display means for outputting the signal detected by the signal output device as an image and data. According to claim 1, wherein the pin fixing portion 40 is a stage fixing portion 41 fixed on the stage, the bracket 42 for supporting the rotating bar while forming the tip of the stage fixing portion, and the bracket 42 between A rotary bar 46 fixed to the pin 46 and having a pin fixing hole 44, a weight 46a coupled to one end of the rotary bar 46, and a sensor 47 for detecting contact between the pin and the specimen. Micro tribo tester embodying the friction wear experiment and visualization in a scanning electron microscope, characterized in that consisting of. The microtree of claim 1, wherein the frictional wear experiment and visualization in a scanning electron microscope capable of measuring a tangential frictional force with respect to the specimen 20 on the disk 90 having a three degree of freedom in space is realized. Bo tester. The scanning electron microscope according to claim 1, wherein the disk rotating means (10) is composed of a worm gear and a spur gear, and a reduction gear ratio of about 60: 1 and a rotation speed of 0.01 RPM. Micro tribo tester with friction wear test and visualization The frictional wear experiment and visualization in a scanning electron microscope which can freely change the contact angle by adjusting the angle of the fixed pin 45 and the angle of the moving specimen 20 alone or together. Implemented micro tribo tester.