GB/T 2424.12-1982 Basic environmental testing procedures for electrical and electronic products - Guidelines for hydrogen sulfide testing of contact points and connectors
Some standard content:
1 Introduction
National Standard of the People's Republic of China
Basic environmental testing procedures for electric and electronic productsGuidance for hydrogen sulphide test for contacts and connections
UDC 621.3
GB 2424.12-82
The good performance of contacts and connections during their expected life depends on many parameters, some of which are determined by their design (such as type, material, force, etc.), and others are determined by the environment that affects them. Considering the impact of the environment, special attention should be paid to pollutants contained in the atmosphere (usually in small amounts). Silver and some silver-gold are particularly sensitive to trace amounts of hydrogen sulfide present in many environments, and thus change color. The color change product is dark and mainly composed of β-silver sulfide. The use of these metals as contact materials for separable electrical connectors results in an increase in contact resistance and contact noise.
2 Hydrogen sulfide in the atmosphere
Hydrogen sulfide is released due to the reduction of sulfates in plants, soil, sewage and animal excrement by bacteria. Hydrogen sulfide is converted into sulfur dioxide and then sulfate, which returns to the ground through sedimentation and is then absorbed by organisms. In the natural cycle of sulfur, hydrogen sulfide is much more important than sulfur dioxide because it is the main source of sulfur and because it stays in the atmosphere for a longer time, its pollution is more widespread than sulfur dioxide. Although sulfur dioxide is one of the main causes of widespread corrosion of various materials, it is dominant in urban areas because these areas produce large amounts of sulfur dioxide from the burning of fossil fuels, see GB24 23.19-81 "Sulfur dioxide test method for contact points and connectors" refers to 1GB2424.11-82 "Sulfur dioxide test guide for contact points and connectors". Although hydrogen sulfide in the natural environment is the main source of sulfur, hydrogen sulfide can also be produced in industrial production processes: refineries, chemical plants and gas plants are the main sources. The commonly reported concentration of hydrogen sulfide in the atmosphere is 1 to 30 ppb (1 ppb = 10-9 volume ratio). The peaks in many places exceed it, especially near the source, where the concentration is higher. Table 1 is an example of the statistical distribution of hydrogen sulfide measurement concentrations. Table 2 lists representative hydrogen sulfide measurements in certain areas. concentrations. These concentrations are sufficient to cause natural discoloration of silver. Other sulfur contaminants are far less important. Sulfur dioxide has almost no effect on silver when the concentration and humidity are not high, so its discoloration products are difficult to detect in practice; the two most common organic sulfur contaminants, methyl mercaptan and carbon disulfide, do not discolor silver at all. Some organic sulfur derivatives discolor silver like sulfur vapor, but they only exist in certain environments. 3 Test purpose and scope of use
3.1 Types of contacts and connectors
This test is specifically used for certain types of contacts and connectors (except welding and brazing). It is helpful to briefly describe these types of contacts and connectors.
Contacts and connectors can be divided into two types: permanent or temporary. In both types, the external force of permanent connectors is very large, and the metal surfaces are bonded together by external forces. This often causes permanent deformation of the metal and even peripheral welding. Such connectors must not be disconnected during their service life. Permanent connections such as wrapping and wrapping. Issued by the National Bureau of Standards on September 23, 1982
Implemented on June 1, 1983
GB2424.12-82
The forces acting on the contact metals of temporary connections are relatively light. Naturally, these connections can be connected or disconnected many times during their service life. Temporary connections include connectors, switches, and relays. In temporary connections, the metal surfaces that touch each other are sometimes called contact points.
The contact points or contact surfaces of temporary connections can be made of various metals depending on the load and purpose. Most metals except precious metals are subject to atmospheric corrosion. When the contact material corrodes, the contact resistance increases. The widespread use of precious metal contacts is expensive, so in many applications, precious metal alloys or coatings of precious metals and their alloys on base metals are usually used as contact materials.
For permanent connections, precious metals are usually not used, and general corrosion of the surface caused by hydrogen sulfide is expected. In properly designed and manufactured wrap-around or wrap-around connections, however, corrosion between the contact surfaces due to cold welding and high pressure does not occur. However, when the connection is poorly made or the connection is weakened by temperature cycling, corrosive gases will penetrate these contact surfaces, resulting in an increase in contact resistance. 3.2 Purpose of the Test
This test is used to evaluate the discoloration results of silver and certain silver alloys. Although only limited testing has been conducted on the non-components of certain silver alloy contacts, it has been basically confirmed by laboratory tests and field tests on silver. When the above discoloration test is applied to specimens of different contact materials, the test conditions can cause different acceleration effects (see Chapter 5: Test severity), requiring extensive experience and a large number of tests to evaluate the corresponding results. Silver and palladium contact alloys show that this test is suitable.
When the test is applied to silver alloys and silver contacts and connections connected to other materials, it can be expected that the test results of silver specimens with precious metals are more realistic than those of silver alloys containing a certain amount of precious metal. The following examples are illustrated: a. Gold contacts are basically unaffected by the test. b. Contacts containing a gold layer on silver or gold contacts in close proximity to silver will be affected by the spread of silver sulfide. Both phenomena are a true reflection of the situation on site.
c. Copper and high copper alloys (such as phosphor bronze and brass) are severely discolored in the test gas due to the production of copper sulfide. However, in practice this form of darkening rarely plays a major role, because the growth of sulfide is prevented where the oxide is produced. If the color change characteristics of the test are required to be similar to those occurring naturally, then this test is not suitable for this occasion. 4 Test parameters
This test is applicable to contacts and connectors made mainly of silver and silver alloys (see Chapter 3). The basis for judging its quality is the contact resistance. The effect of the discoloration layer produced by the test conditions on the contact resistance must be similar to the effect of the discoloration layer produced naturally on the contact resistance, and the test must accelerate the growth of the discoloration film. However, these two requirements are often contradictory. Since the rapidly growing discoloration layer is often softer and less adherent than the naturally grown discoloration layer, an appropriate solution must be found between the accelerated test (achieved by increasing the pollution concentration and humidity) and the actual contact resistance change process. The purpose of the highest hydrogen sulfide concentration and relative humidity used in the current test is to be consistent with the actual contact resistance change process. The main parameters of the test are:
ammonia sulfide concentration,
b. relative humidity,
c, temperature;
d. flow rate,
e. test duration,
f. illumination.
4.1 Hydrogen sulfide concentration
Experience shows that when the hydrogen sulfide concentration is greater than 15ppm, the silver deposit becomes soft, which is inconsistent with the actual situation. In fact, the discoloration speed of silver is not very sensitive to the hydrogen sulfide concentration, so there is no need to use a higher hydrogen sulfide concentration. If very low concentrations of hydrogen sulphide are adopted, difficulties may arise due to surface adsorption on the test chamber walls and its strong dependence on the rear airflow around the specimen, and concentrations which are too low may have too little accelerating effect on certain types of specimens (see Chapter 5). 572
GB2424.12--82
4.2 Relative humidity
Small changes in humidity have a great influence on the discoloration. The data show that corrosion hardly occurs below a relative humidity of 70%, while the rate of discoloration increases rapidly above 85%, but the discoloration layers formed are not at all of the type that has been found in practice. In view of the observation of silver sulphide needle-like growths, capillary condensation may occur at a relative humidity of 85%. For this reason, care must be taken to control the humidity within the specified range throughout the test. Any known method may be used to determine the relative humidity, provided that it is accurate enough to measure the specified tolerances. The dry-wet-bulb method is an effective method for measuring relative humidity. 4.3 Temperature
When the temperature is higher than 30℃, there is a tendency to change the natural corrosion mechanism. When the temperature is lower, the test time is too long. The temperature of 25±2℃ is the most satisfactory moderate solution. In order to keep the relative humidity within the specified range, the temperature must be strictly controlled. 4.4 Flow rate
Use a continuous flow of gas through the test chamber so that the concentration of hydrogen sulfide remains constant and does not decrease due to absorption of gas by adsorption surfaces in the chamber. Move the specimen or stir the gas in the chamber so that the relative velocity between the test gas and the specimen is within the specified range. This avoids local low concentrations caused by static gas pockets in the test chamber. Care must be taken to ensure that there is airflow around the specimens in the chamber and that the chamber is not overloaded. These measures are necessary to ensure that all specimens are under the same test conditions throughout the test. 4.5 Test duration
The discoloration and performance degradation of the test contacts caused by exposure to the test gas increase with the extension of the exposure time. Although the relationship is not proportional, different severity levels of the test can be obtained by extending the exposure time. This is shown in Chapter 5 and the figure below. 1000
Thickness of discoloration layer (micrometer)
4.6Illuminance
15 ppm H, S
0.01Ppm H, S
Test time1 hour
Comparison of darkening kinetics of silver at RH75% and field test dataLaboratory test data: ×15ppmH, S75%RH, +0.01ppm75%RH (extrapolation)Indoor field test data: continuous measurement in various cities in the United StatesA New York
○Various T industrial sites and cities
STL test data: light industry along the coast of the United Kingdom and heavy industry in HaikouTime (hours)
GB 2424.12-82
It is known that silver changes color faster in light than in darkness, so the illumination of the test is specified. The selected lighting method should make the illumination of the test box within the specified range. Sunlight should be avoided in the box. 4.7 Control of test conditions
To ensure the reproducibility of the test results, the test conditions need to be strictly controlled. Special attention should be paid to the control of relative humidity (see 4.2) and temperature (see 4.3). To ensure that the specified test parameters are maintained throughout the test, the test conditions need to be continuously or frequently tested. 5 Severity of the test
In principle, the test conditions cannot be the only accelerating factor, because the acceleration depends on the structure, materials and conditions of use of the specimen. This document is a general guide based on current experience, and this guide will be improved as test experience accumulates. When evaluating test results or selecting the appropriate test duration for special occasions, the following considerations should be made. If the contact surface is exposed to the circulating test gas without shielding or sealing, then increasing the concentration of hydrogen sulfide in the test gas has a relatively small effect on the darkening rate of the contact surface. When the concentration increases from 10 ppb (natural concentration) to 15 ppm (test concentration), the darkening rate increases by 10 times. The figure is a comparison of laboratory and field tests of the same type of specimen under the above conditions. Obviously, the acceleration effect of the current test method on the specimen is less than that of some harsh field environmental tests. Therefore, it should be noted that the figure applies to material tests, and the test acceleration factor of the actual contact will also depend on the contact type. The internal contacts of most actual specimens are usually partially sealed or shielded by components or component structures. When the concentration of naturally occurring hydrogen sulfide is very low, the color change rate is limited by the amount of contaminant migration through the atmosphere to the contacts (that is, the concentration of hydrogen sulfide close to the contact surface is lower than the concentration around the specimen).
If the concentration of contaminants is high, the protective effect of contacts with partial sealing or shielding measures is very small. As pointed out earlier, unshielded specimens will quickly change color in an atmosphere containing several Ppb of hydrogen sulfide, so the test has a small acceleration effect on such specimens. The color change rate of specimens with partial sealing or shielding in the field environment is lower, so the test has a greater acceleration effect on such specimens.
6 Evaluation of test results
The main evaluation criterion for this test is the change in contact resistance, followed by the change in appearance. It must be pointed out that most metals and alloys will change color in this test, and this corrosion is expected, so the performance is judged by the change in contact resistance. When testing permanent connectors such as wraps and wraps, the resistance of the tested contacts will change. Since the joints are not airtight or are poorly joined, the contact resistance increases significantly. When testing temporary connectors, the contacts can be in contact or non-contact state (i.e. closed or open). The contact resistance of the contacting contacts (closed state) must be measured after the test is completed without interference. The contact resistance of the non-contacting contacts (open state) is measured only at the first contact after the test is completed. This test is mainly designed for contacts, and these contacts are used to transmit low current and low voltage signals. In order not to destroy the generated corrosion film, a low voltage and low current measurement method (maximum 20mV, 50mA) must be used. 7 Notes for testers and standard setters This test provides an accelerated means for evaluating the effects of an atmosphere containing hydrogen sulfide on contacts and connectors. It is particularly suitable as a comparative test.
The relationship between the test results and the service life is affected by many factors and can only be roughly estimated based on many years of test experience and on-site working conditions. Therefore, it cannot be expected that this test will make a direct and accurate determination of the actual service life of the test contact points and connectors used in any natural atmosphere. This test is not suitable as a "general corrosion test", that is, it cannot predict the corrosion effect of most corrosive agents in the atmospheric composition that are different from hydrogen sulfide. Compare GB2424.10--81 "General Guidelines for Accelerated Atmospheric Corrosion Tests". In addition, this test is very suitable for comparing the performance of mass-produced components with similar components. Eventually, people may find that this test has other uses.
GB2424.12-82
Appendix A
(Supplement)
Example of statistical distribution of hydrogen sulfide measurement concentration (Oakland District, Pittsburgh) Concentration range ppb
10 ~19
New York office building
New Jersey chemical plant
New Jersey refinery
Los Angeles office building
Tractor foundry
Alabama paper mill
London summer
London winter
December 1962
Detroit
4 Dutch regions
Pittsburgh||tt| |Shikoku Island (Japan)
STL Harlow, Essex, UK (urban area) Hydrogen sulfide concentration in some areas
Average value
Number of occurrences
Rotorua (New Zealand)
London winter
Suburban area (near the sea)
Complete residential area
Main roads in the city
Dense city center
Heavy industrial area
GB 2424.12-82
Continued Table A2
Average value
Southeast Wales (UK)Www.bzxZ.net
GB 2424.12--82
Appendix B
(Supplement)
B.1 This standard should be used in conjunction with the following standards: GB 2421-81 "General principles for basic environmental test procedures for electronic products"
GB 2422-81 "Terms and definitions of basic environmental test procedures for electronic products" GB 2423.20-81 "Basic environmental test procedures for electronic products - Test Kd: hydrogen sulphide test method for contacts and connections" B.2 This standard is in conjunction with the Central Office 216 document of the 50th Technical Committee 50B of the International Electrotechnical Commission IEC, 68-2-43 standard "Guidelines for the hydrogen sulphide test for contacts and connections" (Draft) [50B (Central Office) 216 Guidance to publication 68-2-43, Test Kd: hydrogen sulphide test for contacts and connections" (Draft) [50B (Central Office) 216 Guidance to publication 68-2-43, Test Kd: hydrogen sulphide test for contacts and connections The 4.6 illumination in the standard stipulates that "when using normal indoor lighting." is changed to "the selected lighting method should use the illumination inside the test chamber within the specified range." In addition, the rest is consistent with the IEC standard (draft). Additional notes:
This standard was proposed by the National Electric Power Environmental Conditions and Environmental Testing Standardization Technical Committee (hereinafter referred to as the Environmental Standards Committee). This standard was drafted by the Fourth Working Group of the Environmental Standards Committee. 57701Ppm H,S
Test time 1 hour
Comparison of darkening kinetics of silver at RH75% and field test data Laboratory test data: ×15ppmH,S75%RH, +0.01ppm75%RH (extrapolation) Indoor field test data: Continuous measurement in various cities in the United States A New York
○ Various T industrial sites and cities
STL test data: light industry along the coast of the United Kingdom and heavy industry in Haikou Time (hours)
GB 2424.12-82
It is known that silver changes color faster in light than in darkness, so the illumination of the test is specified. The lighting method selected should keep the illumination of the test box within the specified range. Sunlight should be avoided in the box. 4.7 Control of test conditions
In order to ensure the reproducibility of the test results, the test conditions need to be strictly controlled. Special attention should be paid to the control of relative humidity (see 4.2) and temperature (see 4.3). To ensure that the specified test parameters are maintained during the entire test period, continuous or frequent verification of the test conditions is required. 5 Severity of the test
In principle, the test conditions cannot be the only accelerating factor, because the acceleration depends on the structure, material and use conditions of the specimen. This document is a general guide based on current experience, and this guide will be improved as test experience accumulates. When evaluating test results or selecting the appropriate test duration for special occasions, the following considerations should be made. If the contact surface is not shielded or sealed and is exposed to the circulating test gas, then increasing the concentration of hydrogen sulfide in the test gas will have a relatively small effect on the darkening rate of the contact surface. When the concentration increases from 10 ppb (natural concentration) to 15 ppm (test concentration), the darkening rate increases by 10 times. The figure is a comparison of laboratory and field tests of the same type of specimen under the above conditions. Obviously, the current test method has a smaller acceleration effect on the specimen than some severe field environmental tests. Therefore, it should be noted that the figure applies to material tests, and the test acceleration factor of the actual contact will also depend on the contact type. The internal contacts of most actual specimens are usually partially sealed or shielded by the component or part structure. When the naturally occurring hydrogen sulfide concentration is very low, the discoloration rate is limited by the amount of contaminant migration through the atmosphere to the contacts (i.e., the hydrogen sulfide concentration close to the contact surface is lower than the concentration around the specimen).
If the contaminant concentration is high, the protective effect of the contacts with partial sealing or shielding measures is very small. As pointed out earlier, unshielded specimens will quickly discolor in an atmosphere containing several ppb of hydrogen sulfide, so the test has a small accelerating effect on such specimens. The discoloration rate of specimens with partial sealing or shielding in the field environment is lower, so the test has a greater accelerating effect on such specimens.
6 Evaluation of Test Results
The primary evaluation criterion for this test is the change in contact resistance, followed by the change in appearance. It must be pointed out that most metals and alloys will discolor in this test, and this corrosion is expected, so their performance is judged based on the change in contact resistance. When testing permanent connections that are wrapped and wrapped, the resistance of the contact under test will change. Since the joint is not airtight or poorly joined, the contact resistance increases significantly. When testing temporary connectors, the contacts can be in contact or non-contact state (i.e. closed or open). The contact resistance of the contacting contacts (closed state) must be measured without interference after the test. The contact resistance of the non-contacting contacts (open state) is measured only at the first contact after the test. This test is mainly designed for contacts, which are used to transmit small current and low voltage signals. In order not to destroy the generated corrosion film, a low voltage and low current measurement method (maximum value of 20mV, 50mA) must be used. 7 Notes for testers and standard setters This test provides an accelerated means for evaluating the effects of atmospheres containing hydrogen sulfide on contacts and connectors. It is particularly suitable for use as a comparative test.
The relationship between the test results and the service life is affected by many factors and can only be roughly estimated based on many years of test experience and on-site working conditions. Therefore, it cannot be expected that this test will make a direct and accurate determination of the actual service life of the tested contacts and connectors used in any natural atmosphere. This test is not suitable as a "general corrosion test", that is, it cannot predict the corrosion effect of most corrosive agents in the atmosphere other than hydrogen sulfide. Compare GB2424.10--81 "General Guidelines for Accelerated Atmospheric Corrosion Tests". In addition, this test is very suitable for comparing the performance of mass-produced components with similar components. Eventually, people may find that this test has other uses.
GB2424.12-82
Appendix A
(Supplement)
Example of statistical distribution of hydrogen sulfide measurement concentration (Oakland District, Pittsburgh) Concentration range ppb
10 ~19
New York office building
New Jersey chemical plant
New Jersey refinery
Los Angeles office building
Tractor foundry
Alabama paper mill
London summer
London winter
December 1962
Detroit
4 Dutch regions
Pittsburgh||tt| |Shikoku Island (Japan)
STL Harlow, Essex, UK (urban area) Hydrogen sulfide concentration in some areas
Average value
Number of occurrences
Rotorua (New Zealand)
London winter
Suburban area (near the sea)
Complete residential area
Main roads in the city
Dense city center
Heavy industrial area
GB 2424.12-82
Continued Table A2
Average value
Southeast Wales (UK)
GB 2424.12--82
Appendix B
(Supplement)
B.1 This standard should be used in conjunction with the following standards: GB 2421-81 "General principles for basic environmental test procedures for electronic products"
GB 2422-81 "Terms and definitions of basic environmental test procedures for electronic products" GB 2423.20-81 "Basic environmental test procedures for electronic products - Test Kd: hydrogen sulphide test method for contacts and connections" B.2 This standard is in conjunction with the Central Office 216 document of the 50th Technical Committee 50B of the International Electrotechnical Commission IEC, 68-2-43 standard "Guidelines for the hydrogen sulphide test for contacts and connections" (Draft) [50B (Central Office) 216 Guidance to publication 68-2-43, Test Kd: hydrogen sulphide test for contacts and connections" (Draft) [50B (Central Office) 216 Guidance to publication 68-2-43, Test Kd: hydrogen sulphide test for contacts and connections The 4.6 illumination in the standard stipulates that "when using normal indoor lighting." is changed to "the selected lighting method should use the illumination inside the test chamber within the specified range." In addition, the rest is consistent with the IEC standard (draft). Additional notes:
This standard was proposed by the National Electric Power Environmental Conditions and Environmental Testing Standardization Technical Committee (hereinafter referred to as the Environmental Standards Committee). This standard was drafted by the Fourth Working Group of the Environmental Standards Committee. 57701Ppm H,S
Test time 1 hour
Comparison of darkening kinetics of silver at RH75% and field test data Laboratory test data: ×15ppmH,S75%RH, +0.01ppm75%RH (extrapolation) Indoor field test data: Continuous measurement in various cities in the United States A New York
○ Various T industrial sites and cities
STL test data: light industry along the coast of the United Kingdom and heavy industry in Haikou Time (hours)
GB 2424.12-82
It is known that silver changes color faster in light than in darkness, so the illumination of the test is specified. The lighting method selected should keep the illumination of the test box within the specified range. Sunlight should be avoided in the box. 4.7 Control of test conditions
In order to ensure the reproducibility of the test results, the test conditions need to be strictly controlled. Special attention should be paid to the control of relative humidity (see 4.2) and temperature (see 4.3). To ensure that the specified test parameters are maintained during the entire test period, continuous or frequent verification of the test conditions is required. 5 Severity of the test
In principle, the test conditions cannot be the only accelerating factor, because the acceleration depends on the structure, material and use conditions of the specimen. This document is a general guide based on current experience, and this guide will be improved as test experience accumulates. When evaluating test results or selecting the appropriate test duration for special occasions, the following considerations should be made. If the contact surface is not shielded or sealed and is exposed to the circulating test gas, then increasing the concentration of hydrogen sulfide in the test gas will have a relatively small effect on the darkening rate of the contact surface. When the concentration increases from 10 ppb (natural concentration) to 15 ppm (test concentration), the darkening rate increases by 10 times. The figure is a comparison of laboratory and field tests of the same type of specimen under the above conditions. Obviously, the current test method has a smaller acceleration effect on the specimen than some severe field environmental tests. Therefore, it should be noted that the figure applies to material tests, and the test acceleration factor of the actual contact will also depend on the contact type. The internal contacts of most actual specimens are usually partially sealed or shielded by the component or part structure. When the naturally occurring hydrogen sulfide concentration is very low, the discoloration rate is limited by the amount of contaminant migration through the atmosphere to the contacts (i.e., the hydrogen sulfide concentration close to the contact surface is lower than the concentration around the specimen).
If the contaminant concentration is high, the protective effect of the contacts with partial sealing or shielding measures is very small. As pointed out earlier, unshielded specimens will quickly discolor in an atmosphere containing several ppb of hydrogen sulfide, so the test has a small accelerating effect on such specimens. The discoloration rate of specimens with partial sealing or shielding in the field environment is lower, so the test has a greater accelerating effect on such specimens.
6 Evaluation of Test Results
The primary evaluation criterion for this test is the change in contact resistance, followed by the change in appearance. It must be pointed out that most metals and alloys will discolor in this test, and this corrosion is expected, so their performance is judged based on the change in contact resistance. When testing permanent connections that are wrapped and wrapped, the resistance of the contact under test will change. Since the joint is not airtight or poorly joined, the contact resistance increases significantly. When testing temporary connectors, the contacts can be in contact or non-contact state (i.e. closed or open). The contact resistance of the contacting contacts (closed state) must be measured without interference after the test. The contact resistance of the non-contacting contacts (open state) is measured only at the first contact after the test. This test is mainly designed for contacts, which are used to transmit small current and low voltage signals. In order not to destroy the generated corrosion film, a low voltage and low current measurement method (maximum value of 20mV, 50mA) must be used. 7 Notes for testers and standard setters This test provides an accelerated means for evaluating the effects of atmospheres containing hydrogen sulfide on contacts and connectors. It is particularly suitable for use as a comparative test.
The relationship between the test results and the service life is affected by many factors and can only be roughly estimated based on many years of test experience and on-site working conditions. Therefore, it cannot be expected that this test will make a direct and accurate determination of the actual service life of the tested contacts and connectors used in any natural atmosphere. This test is not suitable as a "general corrosion test", that is, it cannot predict the corrosion effect of most corrosive agents in the atmosphere other than hydrogen sulfide. Compare GB2424.10--81 "General Guidelines for Accelerated Atmospheric Corrosion Tests". In addition, this test is very suitable for comparing the performance of mass-produced components with similar components. Eventually, people may find that this test has other uses.
GB2424.12-82
Appendix A
(Supplement)
Example of statistical distribution of hydrogen sulfide measurement concentration (Oakland District, Pittsburgh) Concentration range ppb
10 ~19
New York office building
New Jersey chemical plant
New Jersey refinery
Los Angeles office building
Tractor foundry
Alabama paper mill
London summer
London winter
December 1962
Detroit
4 Dutch regions
Pittsburgh||tt| |Shikoku Island (Japan)
STL Harlow, Essex, UK (urban area) Hydrogen sulfide concentration in some areas
Average value
Number of occurrences
Rotorua (New Zealand)
London winter
Suburban area (near the sea)
Complete residential area
Main roads in the city
Dense city center
Heavy industrial area
GB 2424.12-82
Continued Table A2
Average value
Southeast Wales (UK)
GB 2424.12--82
Appendix B
(Supplement)
B.1 This standard should be used in conjunction with the following standards: GB 2421-81 "General principles for basic environmental test procedures for electronic products"
GB 2422-81 "Terms and definitions of basic environmental test procedures for electronic products" GB 2423.20-81 "Basic environmental test procedures for electronic products - Test Kd: hydrogen sulphide test method for contacts and connections" B.2 This standard is in conjunction with the Central Office 216 document of the 50th Technical Committee 50B of the International Electrotechnical Commission IEC, 68-2-43 standard "Guidelines for the hydrogen sulphide test for contacts and connections" (Draft) [50B (Central Office) 216 Guidance to publication 68-2-43, Test Kd: hydrogen sulphide test for contacts and connections" (Draft) [50B (Central Office) 216 Guidance to publication 68-2-43, Test Kd: hydrogen sulphide test for contacts and connections The 4.6 illumination in the standard stipulates that "when using normal indoor lighting." is changed to "the selected lighting method should use the illumination inside the test chamber within the specified range." In addition, the rest is consistent with the IEC standard (draft). Additional notes:
This standard was proposed by the National Electric Power Environmental Conditions and Environmental Testing Standardization Technical Committee (hereinafter referred to as the Environmental Standards Committee). This standard was drafted by the Fourth Working Group of the Environmental Standards Committee. 5773). To ensure that the specified test parameters are maintained during the entire test period, continuous or frequent testing of the test conditions is required. 5 Severity of the test
In principle, the test conditions cannot be the only accelerating factor, because the acceleration depends on the structure, material and use conditions of the specimen. This document is a general guide based on current experience, and this guide will be improved as test experience accumulates. When evaluating test results or selecting the appropriate test duration for special occasions, the following considerations should be made. If the contact surface is not shielded or sealed and is exposed to the circulating test gas, then increasing the concentration of hydrogen sulfide in the test gas will have a relatively small effect on the darkening rate of the contact surface. When the concentration increases from 10 ppb (natural concentration) to 15 ppm (test concentration), the darkening rate increases by 10 times. The figure is a comparison of laboratory and field tests of the same type of specimen under the above conditions. Obviously, the current test method has a smaller acceleration effect on the specimen than some severe field environmental tests. Therefore, it should be noted that the figure applies to material tests, and the test acceleration factor of the actual contact will also depend on the contact type. The internal contacts of most actual specimens are usually partially sealed or shielded by the component or part structure. When the naturally occurring hydrogen sulfide concentration is very low, the discoloration rate is limited by the amount of contaminant migration through the atmosphere to the contacts (i.e., the hydrogen sulfide concentration close to the contact surface is lower than the concentration around the specimen).
If the contaminant concentration is high, the protective effect of the contacts with partial sealing or shielding measures is very small. As pointed out earlier, unshielded specimens will quickly discolor in an atmosphere containing several ppb of hydrogen sulfide, so the test has a small accelerating effect on such specimens. The discoloration rate of specimens with partial sealing or shielding in the field environment is lower, so the test has a greater accelerating effect on such specimens.
6 Evaluation of Test Results
The primary evaluation criterion for this test is the change in contact resistance, followed by the change in appearance. It must be pointed out that most metals and alloys will discolor in this test, and this corrosion is expected, so their performance is judged based on the change in contact resistance. When testing permanent connections that are wrapped and wrapped, the resistance of the contact under test will change. Since the joint is not airtight or poorly joined, the contact resistance increases significantly. When testing temporary connectors, the contacts can be in contact or non-contact state (i.e. closed or open). The contact resistance of the contacting contacts (closed state) must be measured without interference after the test. The contact resistance of the non-contacting contacts (open state) is measured only at the first contact after the test. This test is mainly designed for contacts, which are used to transmit small current and low voltage signals. In order not to destroy the generated corrosion film, a low voltage and low current measurement method (maximum value of 20mV, 50mA) must be used. 7 Notes for testers and standard setters This test provides an accelerated means for evaluating the effects of atmospheres containing hydrogen sulfide on contacts and connectors. It is particularly suitable for use as a comparative test.
The relationship between the test results and the service life is affected by many factors and can only be roughly estimated based on many years of test experience and on-site working conditions. Therefore, it cannot be expected that this test will make a direct and accurate determination of the actual service life of the tested contacts and connectors used in any natural atmosphere. This test is not suitable as a "general corrosion test", that is, it cannot predict the corrosion effect of most corrosive agents in the atmosphere other than hydrogen sulfide. Compare GB2424.10--81 "General Guidelines for Accelerated Atmospheric Corrosion Tests". In addition, this test is very suitable for comparing the performance of mass-produced components with similar components. Eventually, people may find that this test has other uses.
GB2424.12-82
Appendix A
(Supplement)
Example of statistical distribution of hydrogen sulfide measurement concentration (Oakland District, Pittsburgh) Concentration range ppb
10 ~19
New York office building
New Jersey chemical plant
New Jersey refinery
Los Angeles office building
Tractor foundry
Alabama paper mill
London summer
London winter
December 1962
Detroit
4 Dutch regions
Pittsburgh||tt| |Shikoku Island (Japan)
STL Harlow, Essex, UK (urban area) Hydrogen sulfide concentration in some areas
Average value
Number of occurrences
Rotorua (New Zealand)
London winter
Suburban area (near the sea)
Complete residential area
Main roads in the city
Dense city center
Heavy industrial area
GB 2424.12-82
Continued Table A2
Average value
Southeast Wales (UK)
GB 2424.12--82
Appendix B
(Supplement)
B.1 This standard should be used in conjunction with the following standards: GB 2421-81 "General principles for basic environmental test procedures for electronic products"
GB 2422-81 "Terms and definitions of basic environmental test procedures for electronic products" GB 2423.20-81 "Basic environmental test procedures for electronic products - Test Kd: hydrogen sulphide test method for contacts and connections" B.2 This standard is in conjunction with the Central Office 216 document of the 50th Technical Committee 50B of the International Electrotechnical Commission IEC, 68-2-43 standard "Guidelines for the hydrogen sulphide test for contacts and connections" (Draft) [50B (Central Office) 216 Guidance to publication 68-2-43, Test Kd: hydrogen sulphide test for contacts and connections" (Draft) [50B (Central Office) 216 Guidance to publication 68-2-43, Test Kd: hydrogen sulphide test for contacts and connections The 4.6 illumination in the standard stipulates that "when using normal indoor lighting." is changed to "the selected lighting method should use the illumination inside the test chamber within the specified range." In addition, the rest is consistent with the IEC standard (draft). Additional notes:
This standard was proposed by the National Electric Power Environmental Conditions and Environmental Testing Standardization Technical Committee (hereinafter referred to as the Environmental Standards Committee). This standard was drafted by the Fourth Working Group of the Environmental Standards Committee. 5773). To ensure that the specified test parameters are maintained during the entire test period, continuous or frequent testing of the test conditions is required. 5 Severity of the test
In principle, the test conditions cannot be the only accelerating factor, because the acceleration depends on the structure, material and use conditions of the specimen. This document is a general guide based on current experience, and this guide will be improved as test experience accumulates. When evaluating test results or selecting the appropriate test duration for special occasions, the following considerations should be made. If the contact surface is not shielded or sealed and is exposed to the circulating test gas, then increasing the concentration of hydrogen sulfide in the test gas will have a relatively small effect on the darkening rate of the contact surface. When the concentration increases from 10 ppb (natural concentration) to 15 ppm (test concentration), the darkening rate increases by 10 times. The figure is a comparison of laboratory and field tests of the same type of specimen under the above conditions. Obviously, the current test method has a smaller acceleration effect on the specimen than some severe field environmental tests. Therefore, it should be noted that the figure applies to material tests, and the test acceleration factor of the actual contact will also depend on the contact type. The internal contacts of most actual specimens are usually partially sealed or shielded by the component or part structure. When the naturally occurring hydrogen sulfide concentration is very low, the discoloration rate is limited by the amount of contaminant migration through the atmosphere to the contacts (i.e., the hydrogen sulfide concentration close to the contact surface is lower than the concentration around the specimen).
If the contaminant concentration is high, the protective effect of the contacts with partial sealing or shielding measures is very small. As pointed out earlier, unshielded specimens will quickly discolor in an atmosphere containing several ppb of hydrogen sulfide, so the test has a small accelerating effect on such specimens. The discoloration rate of specimens with partial sealing or shielding in the field environment is lower, so the test has a greater accelerating effect on such specimens.
6 Evaluation of Test Results
The primary evaluation criterion for this test is the change in contact resistance, followed by the change in appearance. It must be pointed out that most metals and alloys will discolor in this test, and this corrosion is expected, so their performance is judged based on the change in contact resistance. When testing permanent connections that are wrapped and wrapped, the resistance of the contact under test will change. Since the joint is not airtight or poorly joined, the contact resistance increases significantly. When testing temporary connectors, the contacts can be in contact or non-contact state (i.e. closed or open). The contact resistance of the contacting contacts (closed state) must be measured without interference after the test. The contact resistance of the non-contacting contacts (open state) is measured only at the first contact after the test. This test is mainly designed for contacts, which are used to transmit small current and low voltage signals. In order not to destroy the generated corrosion film, a low voltage and low current measurement method (maximum value of 20mV, 50mA) must be used. 7 Notes for testers and standard setters This test provides an accelerated means for evaluating the effects of atmospheres containing hydrogen sulfide on contacts and connectors. It is particularly suitable for use as a comparative test.
The relationship between the test results and the service life is affected by many factors and can only be roughly estimated based on many years of test experience and on-site working conditions. Therefore, it cannot be expected that this test will make a direct and accurate determination of the actual service life of the tested contacts and connectors used in any natural atmosphere. This test is not suitable as a "general corrosion test", that is, it cannot predict the corrosion effect of most corrosive agents in the atmosphere other than hydrogen sulfide. Compare GB2424.10--81 "General Guidelines for Accelerated Atmospheric Corrosion Tests". In addition, this test is very suitable for comparing the performance of mass-produced components with similar components. Eventually, people may find that this test has other uses.
GB2424.12-82
Appendix A
(Supplement)
Example of statistical distribution of hydrogen sulfide measurement concentration (Oakland District, Pittsburgh) Concentration range ppb
10 ~19
New York office building
New Jersey chemical plant
New Jersey refinery
Los Angeles office building
Tractor foundry
Alabama paper mill
London summer
London winter
December 1962
Detroit
4 Dutch regions
Pittsburgh||tt| |Shikoku Island (Japan)
STL Harlow, Essex, UK (urban area) Hydrogen sulfide concentration in some areas
Average value
Number of occurrences
Rotorua (New Zealand)
London winter
Suburban area (near the sea)
Complete residential area
Main roads in the city
Dense city center
Heavy industrial area
GB 2424.12-82
Continued Table A2
Average value
Southeast Wales (UK)
GB 2424.12--82
Appendix B
(Supplement)
B.1 This standard should be used in conjunction with the following standards: GB 2421-81 "General principles for basic environmental test procedures for electronic products"
GB 2422-81 "Terms and definitions of basic environmental test procedures for electronic products" GB 2423.20-81 "Basic environmental test procedures for electronic products - Test Kd: hydrogen sulphide test method for contacts and connections" B.2 This standard is in conjunction with the Central Office 216 document of the 50th Technical Committee 50B of the International Electrotechnical Commission IEC, 68-2-43 standard "Guidelines for the hydrogen sulphide test for contacts and connections" (Draft) [50B (Central Office) 216 Guidance to publication 68-2-43, Test Kd: hydrogen sulphide test for contacts and connections" (Draft) [50B (Central Office) 216 Guidance to publication 68-2-43, Test Kd: hydrogen sulphide test for contacts and connections The 4.6 illumination in the standard stipulates that "when using normal indoor lighting." is changed to "the selected lighting method should use the illumination inside the test chamber within the specified range." In addition, the rest is consistent with the IEC standard (draft). Additional notes:
This standard was proposed by the National Electric Power Environmental Conditions and Environmental Testing Standardization Technical Committee (hereinafter referred to as the Environmental Standards Committee). This standard was drafted by the Fourth Working Group of the Environmental Standards Committee. 577The 6th article on illumination states: "When using normal indoor lighting." is changed to "The selected lighting method should use the illumination inside the test chamber within the specified range." In addition, the rest is consistent with the IEC standard (draft). Additional notes:
This standard was proposed by the National Electric Power Environmental Conditions and Environmental Testing Standardization Technical Committee (hereinafter referred to as the Environmental Standards Committee). This standard was drafted by the Fourth Working Group of the Environmental Standards Committee. 577The 6th article on illumination states: "When using normal indoor lighting." is changed to "The selected lighting method should use the illumination inside the test chamber within the specified range." In addition, the rest is consistent with the IEC standard (draft). Additional notes:
This standard was proposed by the National Electric Power Environmental Conditions and Environmental Testing Standardization Technical Committee (hereinafter referred to as the Environmental Standards Committee). This standard was drafted by the Fourth Working Group of the Environmental Standards Committee. 577The provisions of 4.6 illumination in hydrogen sulphide test for contacts and connections: "When using normal indoor lighting." is changed to "The selected lighting method should use the illumination inside the test chamber within the specified range." In addition, the rest is consistent with the IEC standard (draft). Additional notes:
This standard was proposed by the Environmental Conditions and Environmental Testing Standardization Technical Committee of the State Electric Power Industry (hereinafter referred to as the Environmental Standards Committee). This standard was drafted by the Fourth Working Group of the Environmental Standards Committee. 577The provisions of 4.6 illumination in hydrogen sulphide test for contacts and connections: "When using normal indoor lighting." is changed to "The selected lighting method should use the illumination inside the test chamber within the specified range." In addition, the rest is consistent with the IEC standard (draft). Additional notes:
This standard was proposed by the Environmental Conditions and Environmental Testing Standardization Technical Committee of the State Electric Power Industry (hereinafter referred to as the Environmental Standards Committee). This standard was drafted by the Fourth Working Group of the Environmental Standards Committee. 577
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