SJ/Z 2782-1987 Atmosphere analysis method for the whole process of activation of non-evaporable getter SJ/Z2782-1987 standard download decompression password: www.bzxz.net

Standard of Ministry of Electronics Industry of the People's Republic of China SJ/Z2782-87
Non-evaporable getters
Atmosphere analysis method for the whole activation process
Published on March 12, 1987
Implementation on December 31, 1987
Ministry of Electronics Industry of the People's Republic of China
Standard of Ministry of Electronics Industry of the People's Republic of China Non-evaporable getters
Atmosphere analysis method for the whole activation process
SJ/Z2782-87
This method is applicable to the analysis of the outgassing components of non-evaporable getters during the activation process and the changes in the ambient atmosphere after activation. The test conditions should comply with the relevant provisions of SJ2156-82 "General Rules for Getter Performance Test Methods". Purpose
To determine the degassing composition and degassing amount during the activation of non-evaporable getters, as well as the changes in the ambient atmosphere before and after activation, and to understand the law of the change of various gas components with the getter temperature and its related vacuum performance, so as to provide a basis for the selection of getters for various electric vacuum devices, vacuum devices, etc. 2 Principle
Under dynamic conditions, a vacuum mass spectrometer is used to analyze the degassing composition during the activation of non-evaporable getters, and its degassing amount is calculated by flow conductance.
The static constant volume method is used to analyze the changes in the ambient atmosphere after the activation of non-evaporable getters. . Equipment and Instruments
3.1 The test system is shown in Figure 1.
Test system diagram
Released by the Ministry of Electronic Industry on March 12, 1987
Implemented on December 31, 1987
1, 14——Mechanical pump:
2, 13——Solenoid valve;
3, 12Diffusion pump
4, 11Ultra-high vacuum valve,
5, 8—Ultra-high vacuum ionization gauge,
SJ/Z2782-87
6-—Small hole flow conductance, 0.5~0.6L/S
7——Sample chamber,
9—Vacuum mass spectrometer tube:
10—Sample tube.
3.2 Vacuum mass spectrometer
Use cyclotron mass spectrometer or quadrupole mass spectrometer.
Mass number: 1~100;
Sensitivity: 1×10-°A/P
Scanning speed: The whole scanning time is not more than 50S. 3.3Ultra-high vacuum gauge
To ensure the test accuracy, the emission current must be regulated to work at 10~100uA and must be calibrated with test gas.
3.4Thermocouple
Thermocouple material: Nickel-chromium-nickel-aluminum or nickel-chromium-nickel-silicon thermocouple wire diameter is not more than 0.3mm.
3.5Analytical balance
Sensitivity is not more than 0.1mg
3.6High frequency induction heater
Power: 3~3.5kw.
Frequency: 300~400kHz.
4 Test steps
4.1 Calibration
Thermocouples shall be calibrated in accordance with JJG351--84 "National Metrology Verification Regulations of the People's Republic of China". The ultra-high vacuum gauge shall be calibrated by the measurement unit, and the error shall be less than 3%. 4.2 Sample tube installation
4.2.1 Carrier ring-shaped and disc-shaped getter samples. Spot weld two thermocouple wires on both sides of the getter carrier (in symmetrical positions). The other two ends of the thermocouple wire are welded to the electrode lead wire, and the getter sample is directly supported by the thermocouple wire. 4.2.2 Getter sample without carrier. First weld the thermocouple wire to a nickel strip with a thickness of 0.1mm and a width of 1.5mm, and then roll the nickel strip around the middle of the getter sample, and spot weld it at the nickel strip joint. 4.2.3 Bundled strip samples. Cut the required length from the tape, with the side with the getter powder facing outward, and circle it into a ring. The overlap is fixed by spot welding on the powder-free edge. Spot weld the thermocouple wires symmetrically at the same end away from the welding point and not covered with powder.
4.3 Connect the sample tube to the system.
SJ/Z2782-87
4.4 Exhaust test
4.4.1 Open the ultra-high vacuum valves (4) and (11) and wait until the vacuum system is evacuated to 6×10-\P. Bake the vacuum system at a temperature of 320±20℃.
After baking, the ultra-high vacuum gauge tubes (5) and (8) are degassed, and the mass spectrometer tube (9) is degassed. After degassing, the system pressure should not be higher than 5×10-P.
4.4.2 Close the ultra-high vacuum valves (4) and (11), and use the vacuum mass spectrometer to monitor the static background changes of the sample chamber (7) within 30 minutes.
4.4.3 Open the ultra-high vacuum valves (4) and (11) to restore the vacuum degree of the sample chamber (7). 4.4.4 Close the ultra-high vacuum valve (11), and use the vacuum mass spectrometer to measure the dynamic background of the system. 4.4.5 Turn on the high-frequency induction heater to heat the sample. The sample is heated from room temperature to 300 ± 20°C within 1 minute, and kept warm for 2 minutes. Then, the temperature is raised in a regular manner of 100 ± 10°C per minute and kept warm for 2 minutes until the optimal activation temperature is reached. The holding time of the optimal activation temperature should be carried out according to the activation specifications. During the process of heating the getter, the vacuum mass spectrometer and recorder must work continuously to record the atmosphere at each holding point.
4.4.6 After activation, cool down. At the same time, close the ultra-high vacuum valve (4) to seal the sample chamber (7). The vacuum mass spectrometer continues to work for 30 minutes to measure the atmosphere changes.
The test is over.
4.5 Peel off the getter material and weigh it
The mass m (mg) of the getter material can be obtained by the differential weight method: m=m.-mr\.
Where: m is the original mass of the sample, mg;
mr-the mass of the carrier, mg.
5 Data processing
5.1 Determination of gas composition
The gas composition is determined by the peak position of the mass spectrum recorded by the recorder during the operation of the vacuum mass spectrometer. The selected peak must be judged by referring to the secondary peak. 5.2 Determination of the amount of outgassing
5.2.1 Determination of partial pressure
(1)
According to the image coefficients of the various gas fragmentation peaks of the vacuum mass spectrometer and the relative sensitivity of various gases and the flow values ​​of the ions at the corresponding mass numbers in the mass spectrum obtained by the test, a linear equation system is established to solve the partial pressure. 5.2.2 Determination of the amount of various gases released by the sample In time t, the amount of n-th gas released by the sample Q. (mL, Pa) can be calculated by the following formula: QF.t(P..-Pm)dt+△P...V..
Where: F is the conductance of the n-th gas, mL/SP-the pressure of the n-th gas in the sample chamber (7), P: (2)
SJ/Z2782-87
Pm is the pressure of the n-th gas at the ultrahigh vacuum ionization gauge (5), P. :t-degassing time, S:
^P.:---pressure increment of the nth gas in the sample chamber (7) at time t, P.: V-volume of the sample chamber (7), mL.
If the time t is divided into a number of small time intervals △t, and P>P, then Q can be calculated by the following formulax
QaFwP.i-At.+AP....
where: Fnitrogen flow conductance, mL/S:
--nth gas correction factor, α-
where, Ms2--nitrogen molecular weight, M. ——nth gas molecular weightX--the number of time intervals △t into which the time t is divided; △t, the i-th time interval, S
pressure of the fifth gas in the sample chamber (7) at the i-th time interval, P. 5.2.3 Determination of total outgassing Q (mL, P.) n
5.2.4 Specific outgassing of various gases released by the sample.
Wherein, q.
-Specific outgassing of the nth gas released by the sample, mL·P./mg. 5.2.5 Specific outgassing of all gases released by the sample g (mL·P/mg) qo
6 Test report
Degassing characteristic curve of getter activation process
t Q (mL·Pa)
T℃）
The ordinate is the outgassing amount Q, and the abscissa is the getter temperature T. 6.2 Changes in ambient atmosphere after activation of getter
（3）
（5）www.bzxz.net
（6）
SJ/Z2782-87
t(min）
Use single logarithmic coordinate paper, the ordinate (logarithmic coordinate) is pressure P (P.), and the abscissa is time t (min).6.3 Specific degassing volume table
Specific degassing volume
7 Main sources of error
7.1 Calibration and test error of vacuum mass spectrometer. 7.2 Weighing error.
7.3 Temperature calibration and measurement error.
7.4 Conductance calibration error.
7.5 Calibration and measurement error of ultra-high vacuum gauge. 8 Precautions
8.1 When spot welding the getter sample in the sample tube, it is forbidden to use alcohol to avoid contaminating the sample. Ar
8.2 The position of the getter sample should be far away from the seal to avoid oxidation of the getter when sealing. 8.3 When weighing the peeled getter material, it must be peeled off cleanly. In order to reduce the error caused by incomplete peeling, 10 samples should be peeled off for each sample analysis, and then the average value should be taken. 8.4 The test requires that the ratio of the mass m (mg) of the getter material to the volume V (ml) of the sample chamber satisfies the following relationship. 0.03≤-
8.5 The data for monitoring the static background change is used to analyze and judge the impact of the background on the test results. The environmental atmosphere change diagram recorded after the getter is activated can be used for reference. 8.6 The various gas fragment peak image coefficients of the mass spectrometer and the relative sensitivity of various gases can be obtained by calibrating by injecting pure gases of known mass numbers under a constant mass spectrometer working state. Additional notes:
This standard was drafted by the Standardization Institute of the Ministry of Electronics Industry: This standard was drafted by the Vacuum Electronic Devices Institute of the Ministry of Electronics Industry; the main drafters of this standard were Fei Lanxiang and Dai Rongdao. 5
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.