CN118032580A - High-precision solid material surface equilibrium state net desorption gas amount testing instrument and method - Google Patents

Abstract

The invention provides a high-precision solid material surface equilibrium state net desorption gas quantity testing instrument and a method. The test instrument consists of a sample chamber, a reference chamber, a flow limiting element, a measuring chamber, a pressure gauge and an air extractor set. The pressure of the sample chamber and the pressure of the measuring chamber are sequentially measured by a pressure gauge, and the pressure difference is calculated. The same pressure gauge refers to the pressure of the chamber and the measuring chamber in sequence through the same flow limiting element, and calculates the pressure difference. Since the conductance of the flow restriction element is known, the amount of sample gas in the sample chamber can be calculated. By the instrument structure of the same current limiting element and the method for switching measurement of the same pressure gauge, the influence of inconsistent parameters of the multiple current limiting elements on the calculation of the test result in the current common measurement method is avoided, errors caused by state differences of the multiple pressure gauges are avoided, and the accuracy of the measurement result is ensured; meanwhile, the sample chamber and the reference chamber are symmetrically arranged relative to the flow limiting element, so that measurement errors caused by inconsistent surface areas in the pipeline can be avoided, and the test precision is effectively improved.

Description

A high-precision solid material surface equilibrium net desorption gas quantity test instrument and method

Technical Field

The present invention relates to the field of material science and technology, and in particular to a high-precision solid material surface equilibrium net desorption gas quantity testing instrument and method.

Background technique

In the field of materials science and technology, the constant volume method and the fixed conductance method are usually used to test the changes in the desorption and release of gas molecules on the surface of solid materials, that is, the change in the amount of gas. The constant volume method uses a method in which the molecules on the surface of solid materials in a closed container of fixed volume desorb to increase the pressure in the container, and tests the change in the pressure difference within a certain period of time to calculate the amount of gas. Since this method makes the gas molecules on the surface of the material in a non-equilibrium state dominated by the adsorption process, it will affect the adsorption and desorption process of the gas molecules on the surface of the material during the measurement process, thereby affecting the measurement results. The fixed conductance method uses a flow limiting element with a fixed conductance value installed on one side of the sample chamber, and connects the measuring chamber through the flow limiting element. The sample desorbed gas flows through the flow limiting element into the measuring chamber. By testing the pressure difference on both sides of the flow limiting element, the gas amount is calculated, avoiding the influence of the material desorption state on the measurement results. However, in order to eliminate the influence of the desorbed gas on the measurement results of the inner wall material of the test instrument, this method symmetrically installs a set of no-load systems for comparative testing, and symmetrically installs multiple flow limiting elements and test pressure gauges for comparative testing, but its complex container and pipeline structure differences, the inconsistency of the flow limiting pore structure parameters and the state differences of multiple test pressure gauges all affect the accuracy of the measurement results.

Summary of the invention

In order to eliminate the influence of symmetrical structure differences, inconsistent parameters of multiple limiting elements and measurement errors of multiple pressure gauges, the present invention provides a high-precision solid material surface equilibrium net desorption gas amount testing instrument and method.

The high-precision solid material surface equilibrium net desorption gas quantity testing instrument is composed of a sample chamber, a reference chamber, a current limiting element, a measuring chamber, a pressure gauge, and a vacuum unit.

Among them, the solid material is arranged inside the sample chamber; the sample chamber and the reference chamber are connected with the current limiting element; the current limiting element is connected with the measuring chamber; the pressure gauge is connected with the sample chamber, the reference chamber and the measuring chamber respectively; and the measuring chamber is connected with the exhaust unit.

A first valve is arranged on the pipeline between the sample chamber and the flow limiting element.

A second valve is arranged on the pipeline between the reference chamber and the flow limiting element.

A third valve is arranged on the pipeline between the pressure gauge and the sample chamber.

A fourth valve is arranged on the pipeline between the pressure gauge and the reference chamber.

A fifth valve is arranged on the pipeline between the pressure gauge and the measuring chamber.

Manometers are used to measure the gas pressure in the sample chamber, reference chamber and measurement chamber.

The conductance of the current limiting element is known, and its conductance value is not specifically limited.

The vacuum unit is used to vacuum the test instrument, and its vacuum rate value f is not specifically limited.

Preferably, the valves are all-metal ultra-high vacuum valves.

The technical principle of the present invention to achieve high-precision solid material surface equilibrium net desorption gas quantity testing is:

Put the solid material into the sample chamber, start the vacuum unit, and evacuate the sample chamber, reference chamber, and measuring chamber. Use a pressure gauge to measure the pressure values of the sample chamber, reference chamber, and measuring chamber respectively. When the pressure values are stable, start the test; use a pressure gauge to measure the pressure P1 in the sample chamber, use a pressure gauge to measure the pressure P2 in the measuring chamber, and calculate the pressure difference ΔP1 between pressure P1 and pressure P2 ; use a pressure gauge to measure the pressure P3 in the reference chamber, and use a pressure gauge to measure the pressure P4 in the measuring chamber, and calculate the pressure difference ΔP2 between pressure P3 and pressure P4 ; use the formula Calculate the net desorbed gas amount Q at the solid material surface in equilibrium state, where C is the conductance value of the current limiting element.

In summary, since the present invention adopts symmetrical installation and connection of current limiting elements in the sample chamber and the reference chamber, the test error caused by the complex structure of the multi-channel measurement system is simplified; the same current limiting element avoids the influence of inconsistent parameters of multiple current limiting elements on the calculation of test results in the currently commonly used methods; the method of switching measurements with the same pressure gauge eliminates the error caused by the state difference of each pressure gauge introduced by multi-pressure gauge measurement; in the test method of the present invention, by performing pressure switching measurements on the sample chamber and the reference chamber, and calculating the pressure difference respectively, the influence of desorbed gas on the inner wall of the test system is effectively eliminated, and the test accuracy and precision are further improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a high-precision solid material surface equilibrium net desorption gas quantity testing instrument according to the present invention.

Icons: 0-solid material, 1-sample chamber, 2-reference chamber, 3-third valve, 4-fourth valve, 5-first valve, 6-second valve, 7-flow limiting element, 8-pressure gauge, 9-fifth valve, 10-measuring chamber, 11-vacuum unit.

It should be understood that the above drawings are only schematic and are not drawn to scale.

Detailed ways

FIG1 is a high-precision solid material surface equilibrium net desorption gas quantity testing instrument provided in this embodiment.

The high-precision solid material surface equilibrium net desorption gas quantity testing instrument comprises a sample chamber 1, a reference chamber 2, a current limiting element 7, a pressure gauge 8, a measuring chamber 10, and a vacuum unit 11.

Among them, the solid material 0 is arranged inside the sample chamber 1; the sample chamber 1 and the reference chamber 2 are connected to the current limiting element 7; the current limiting element 7 is connected to the measuring chamber 10; the measuring chamber 10 is connected to the vacuum unit 11; the pressure gauge 8 is connected to the sample chamber 1, the reference chamber 2 and the measuring chamber 10 respectively.

A first valve 5 is provided on the pipeline between the sample chamber 1 and the flow limiting element 7 ; the first valve 5 is used to control the flow of gas between the sample chamber 1 and the flow limiting element 7 .

A second valve 6 is provided on the pipeline between the reference chamber 2 and the flow limiting element 7 ; the second valve 6 is used to control the gas flow between the reference chamber 2 and the flow limiting element 7 .

A third valve 3 is provided on the pipeline between the pressure gauge 8 and the sample chamber 1; the third valve 3 is used to control the gas flow between the pressure gauge 8 and the sample chamber 1; when the third valve 3 is opened and the second valve 6, the fourth valve 4 and the fifth valve 9 are closed, the pressure gauge 8 measures the gas pressure in the sample chamber 1.

A fourth valve 4 is provided on the pipeline between the pressure gauge 8 and the reference chamber 2; the fourth valve 4 is used to control the gas flow between the pressure gauge 8 and the reference chamber 2; when the fourth valve 4 is opened and the first valve 5, the third valve 3 and the fifth valve 9 are closed, the pressure gauge 8 measures the gas pressure in the reference chamber 2.

A fifth valve 9 is provided on the pipeline between the pressure gauge 8 and the measuring chamber 10 ; the fifth valve 9 is used to control the gas flow between the pressure gauge 8 and the measuring chamber 10 ; when the fifth valve 9 is opened and the third valve 3 and the fourth valve 4 are closed, the pressure gauge 8 measures the gas pressure in the measuring chamber 10 .

The conductance of the current limiting element 7 is known, C is the conductance value of the current limiting element, and the conductance of the current limiting element 7 is C =1×10 ^-4 m ³ s ^-1 .

The vacuum unit 11 is used to vacuum the test instrument.

Preferably, the valves are all-metal ultra-high vacuum valves.

All valves are initially in the open state.

In addition, the present application also provides a method for testing the net desorption gas amount in equilibrium state on the surface of a solid material with high precision, and the testing method is as follows: solid material 0 is placed in the sample chamber 1, and the vacuum unit 11 is started to evacuate the sample chamber 1, the reference chamber 2 and the measuring chamber 10, and the pressure values of the sample chamber 1, the reference chamber 2 and the measuring chamber 10 are measured respectively by the pressure gauge 8 , and the test is started after the pressure values are stable; the second valve 6 is closed, and the pressure P1 = 1.82× ^10-4 Pa of the sample chamber 1 is measured by the pressure gauge 8, and the pressure P2 = 3.56× ^10-5 Pa of the measuring chamber 10 is measured by the pressure gauge 8, and the pressure difference ΔP1 = 1.46× ^10-4 Pa between the pressure P1 and the pressure P2 is calculated, and this step is ended by keeping all valves open; the first valve 5 is closed, and the pressure P3 = 8.65× ^10-5 Pa of the reference chamber 2 is measured by the pressure gauge 8, and the pressure P4 = 1.29× ^10-5 Pa of the measuring chamber 10 is measured by the pressure gauge 8 , and the pressure difference ΔP2 = 7.36× ^10-5 Pa; using the formula The net amount of gas desorbed from the surface of the solid material in equilibrium is calculated to be Q = 7.28×10 ^-9 Pam ³ s ^-1 .

Claims (2)

1. A high-precision solid material surface equilibrium net desorption gas quantity test instrument, characterized in that it includes a sample chamber, a reference chamber, a current limiting element, a measuring chamber, a pressure gauge, and a vacuum unit, wherein: The solid material is arranged inside the sample chamber, and the sample chamber and the reference chamber are connected to the current limiting element; The current limiting element is connected to the measuring chamber; The pressure gauge is connected to the sample chamber, the reference chamber and the measuring chamber respectively; The measuring chamber is connected to the air extraction unit; A first valve is provided on the pipeline between the sample chamber and the flow limiting element; A second valve is provided on the pipeline between the reference chamber and the flow limiting element; A third valve is provided on the pipeline between the pressure gauge and the sample chamber; A fourth valve is provided on the pipeline between the pressure gauge and the reference chamber; A fifth valve is provided on the pipeline between the pressure gauge and the measuring chamber; The pressure gauge is used to measure the gas pressure in the sample chamber, the reference chamber and the measuring chamber; The conductance of the current limiting element is known, and its conductance is not specifically limited; The vacuum unit is used to vacuum the test instrument, and its vacuum rate is not specifically limited. 2. A high-precision method for testing the amount of net desorbed gas in equilibrium on the surface of a solid material, characterized in that the test is performed using the instrument as claimed in claim 1, including placing the solid material in the sample chamber, starting the vacuum unit, vacuuming the sample chamber, the reference chamber and the measuring chamber, respectively measuring the pressure values of the sample chamber, the reference chamber and the measuring chamber with a pressure gauge, and starting the test after the pressure values are stable; closing the second valve, measuring the pressure P1 in the sample chamber with a pressure gauge, measuring the pressure P2 in the measuring chamber with a pressure gauge, and calculating the pressure difference ΔP1 between the pressure P1 and the pressure P2 ; closing the first valve, measuring the pressure P3 in the reference chamber with a pressure gauge, measuring the pressure P4 in the measuring chamber with a pressure gauge, and calculating the pressure difference ΔP2 between the pressure P3 and the pressure P4 ; using the formula Calculate the net desorbed gas amount Q in equilibrium state on the surface of solid material, where C is the conductance value of the current limiting element.