Some standard content:
National Standard of the People's Republic of China
Test method for viscosity of electronic glass while hiyh temperatureGB9622.6—88
Reduced to SJ/T1104096
This standard is applicable to the continuous determination of the viscosity of glass. The viscosity range is 10~10%5Pa·5 and the temperature range is 1450~900℃. 1 Method Summary
When the inner cylinder and the outer cylinder of the same axis are filled with glass viscous fluid, when the two cylinders rotate at different speeds, torque is generated on the cylinder due to viscous resistance. The relationship between the viscosity coefficient of the glass fluid and the torque and the shape and size of the inner and outer cylinders conforms to the formula (1) M(rr)
= 4(h+ )rir(o,-)
In the formula, — viscosity coefficient of glass fluid (viscosity for short), Pa·sM-torque between glass fluid and inner cylinder, N·m, P
- radius of inner cylinder, m,
r2— radius of outer cylinder, m,
— angular velocity of rotation of inner cylinder, rad/s,
g— angular velocity of rotation of outer cylinder, rad/s,
h— depth of inner cylinder immersed in fluid, m,
f correction coefficient of cylinder end, m
This standard adopts outer cylinder fixed (i.e. g=0), if it is used to express the rotation velocity of inner cylinder (=2), then =d×
such as:|| tt||Then formula (2) can be simplified as:
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**··(3)
The viscosity of the glass can be calculated by measuring the torque and rotation speed through experiments. It is called the device belt number. It is usually not calculated, but measured by experiments using standard glass samples with known viscosity. 2 Equipment and instruments
2.1 Vertical tubular furnace
The outer diameter is 380mm, the inner diameter is 55mm, and the height is 420mm, see Figure 1. The furnace bottom can be moved up and down by a handle. In order to ensure the heating and cooling speed, two kinds of heating bodies are used. When it is below 900℃, the outer ring of sickle chrome aluminum heating body is used. When it is above 900℃, the outer ring of sickle chrome aluminum heating body is used. Platinum-zirconium alloy heating element is used. The furnace temperature is adjusted by automatic control loading. The highest temperature can reach 1480℃. During the measurement, the temperature can be controlled within the set temperature ±2℃. The temperature difference between the three thermocouples in the furnace does not exceed 3℃.
GB9622.6-88
Figure 1 Schematic diagram of the test device
1 Rotating shaft; 2 Thermo-electromotive force output ring and brush, 3-Cooling water sleeve; 4-Connecting nut, 5-Measurement rotating body, 6-Thermocouple: 7-Furnace top: 8-Furnace core, 9-Furnace jacket Cylinder: 10—measurement container; 11—measurement thermocouple: 12—internal electric heating wire: 13—external electric heating wire: 14—silicon-clay filler, 15—measurement container bracket 16—furnace bottom, 17 lifting device, 18—potentiometer, 19—viscometer, 20—recorder 2.2 Measuring temperature The container
is composed of a calibrated platinum-germanium-platinum thermocouple (according to GB1578 "Standard Thermocouple Uses Platinum-Germanium 10-Platinum Couple Wire") and a standard potentiometer. The measured millivolt value is converted into a temperature value (C) according to the appendix of GB1578. 2.3 Platinum (containing 10%) alloy measurement container
, that is, the outer cylinder, with an inner diameter of 40mm, a height of 100mm, and a thickness of 1mm. There are four feet at the bottom, see Figure 2. 2
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2.4 Platinum (containing 10%) alloy measurement rotating body GB9622.6-88
Figure 2 Measurement container
That is, the inner cylinder, the length is 337mm, the cone angle is 45°, see Figure 3. 6
3 Measurement rotating body
2.5 Rotational viscometer
The rotation speed can be adjusted to 512r/min, and the measurement torque accuracy is 1%. 3
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2.6 Vertical high-temperature furnace
For sample preparation, the maximum temperature is 1450℃. 3 Sample preparationwwW.bzxz.Net
GB9622.6-88
3.1 Select about 500g of glass without defects such as stones, bubbles and streaks, cut it into blocks with each side of about 20mm, clean it with water and anhydrous ethanol, and dry it.
3.2 Put the sample into a platinum alloy container (outer cylinder), melt it in a high-temperature furnace (temperature is about 1300℃), take out the container, add a small amount of glass described in 3.1, and melt it again. When the glass liquid surface is about 15mm away from the edge of the container, continue to increase the temperature, and heat it for 1h at a temperature of about 10Pa·s to remove bubbles in the glass liquid. 4 Test steps
4.1 When preparing the sample, heat the vertical tubular furnace, first to 900℃, and then to 1450℃ at a rate of 5℃/min.
4.2 Insert the thermocouple for measuring temperature into the center of the rotating body, and then connect the rotating body to the rotating axis of the viscometer, as shown in Figure 1. The output brush is pressed on the output ring of the rotating shaft to ensure that the rotating body rotates symmetrically on the same axis and the electromotive force output is positive. 4.3 Under no-load conditions, the rotating body is rotated at a certain speed, and the torque value lost at various rotation speeds is recorded on the torque recorder. That is, the blank torque value.
4.4 The lifting device is operated to lower the container bracket on the bottom of the furnace and leave the furnace body, and the container containing the glass liquid is taken out from the high-temperature furnace. Put it on the bracket and let the bracket rise to the center of the furnace. Continue to heat up. When the viscosity of the sample is less than 10Pa·s (generally at a temperature of 1450℃), the handle is operated to slowly immerse the rotating body in the glass liquid and locate it in the center of the container. The penetration depth is about 50mm. At the same time, circulating water is introduced into the cooling jacket and kept at 1450℃ for 1h.
4.5 The viscometer controls the rotating body to rotate at a certain speed, and the tubular furnace is cooled at a rate of 100℃/h. The recorder records the electromotive force millivolt value, torque value, rotation speed, etc. As the temperature decreases, the rotation speed of the rotating body is continuously adjusted. When the rotation speed drops to the minimum, the rotation is stopped.
4.6 The tubular furnace is heated up. When the glass viscosity is about 107Pa·s, the rotating body is lifted to about 10mm away from the glass liquid surface. Continue to heat up to a viscosity of about 10Pa·s, lower the furnace bottom, remove the container with a special clamp, pour out the molten glass, and remove the rotating body. 4.7 At the end of the test, continue to heat the container containing the glass at a high temperature and pour it out. The glass remaining in the rotating body and the container can be dissolved with hydrofluoric acid.
5 Calculation
5.1 Select the measurement temperature point, preferably at intervals of 50℃, and convert it into the corresponding millivolt value. 5.2 Find the torque, rotational speed and blank torque measured at each temperature point from the record chart. 5.3 Substitute the above values into formula (4) to calculate the viscosity at each measured temperature. nmhM-Mo
where: n—viscosity of the sample, Pa·s,
—device constant;
M—measured torque, N·m,
Mo blank torque, N·m
n—rotational speed, s-1.
6 Viscosity-temperature characteristics of glass
6.1 Calculation method
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GB9622.6-88
It is known that the viscosity of glass changes with the change of temperature, and the relationship conforms to formula (5): B
Inn=A+T=T
Wherein: n-—glass viscosity at temperature T, Pa·sA-glass constant, Pa·s,
B-—glass constant, C
To——glass constant, ℃.
.·(5)
After the three pairs of viscosity and temperature data are measured by experiment, the corresponding values of viscosity and temperature between these data can be calculated. 6.2 Plotting method
Plot the viscosity-temperature relationship graph of the measured data on semi-logarithmic coordinate paper. The equally divided coordinates represent the temperature, and the logarithmic coordinates represent the viscosity. The corresponding points are obtained and connected into a curve, which is the viscosity-temperature relationship curve. The viscosity corresponding to any temperature or the temperature corresponding to any viscosity can be found from the curve by interpolation. 7 Determination of device constants
7.1 Use a standard glass sample with a known viscosity-temperature correspondence and follow the above test steps to measure the torque, blank torque and rotation speed at each temperature point.
7.2 Substitute the measured data into formula (6) to calculate the device constant at each temperature point. m
MM.
Where: device constant,
nstandard viscosity value, Pa·s,
-rotation speed, s-\,
Mtorque, N·m
M. Blank torque,N·m.
·（6)
7.3 Draw a temperature-device constant relationship diagram on rectangular coordinate paper, with the horizontal axis representing temperature and the vertical axis representing the device constant, and obtain the corresponding points. Connecting the points is the temperature-device constant curve. When calculating the viscosity of an unknown sample, the device constant corresponding to the temperature can be found from this relationship curve.
8 Test results
There are two ways to express the test results, namely the viscosity corresponding to a certain temperature, or the temperature corresponding to a certain viscosity. Provide a temperature-viscosity relationship diagram when necessary.
In order to ensure the accuracy of the test results, each batch of samples should be measured in parallel 2 to 3 times, and the average value of the measured data should be taken as the test result.
Additional notes:
This standard was drafted by Factory 4400 of the Ministry of Electronics Industry. The main drafters of this standard: Bai Yixiang, Pang Shuqin, and Liu Chengjun. 5
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