JB 3145-1982 Test method for high concentration hydrogen sulfide of silver plating and evaluation of test results
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Standard of the Ministry of Machinery Industry of the People's Republic of China JB3145-82
Test method for high concentration hydrogen sulfide of silver plating
and evaluation of test results
Published on September 2, 1982
Approved by the Ministry of Machinery Industry of the People's Republic of China and implemented on January 1, 1983
Standard of the Ministry of Machinery Industry of the People's Republic of China Test method for high concentration hydrogen sulfide of silver plating
and evaluation of test results
This standard is applicable to the inspection of the process quality of silver plating after anti-darkening treatment. 1 Test conditions
The conditions for the high-concentration hydrogen sulfide test of silver plating should comply with the following provisions: Hydrogen sulfide concentration
Relative humidity
Test time
2 Test equipment
100±10PPM
40±2℃
75±5%
JB3145—82
2.1 The test box should be made of corrosion-resistant materials, and the box should not react with hydrogen sulfide or absorb hydrogen sulfide gas. 2.2 The test box should be a sealed structure, and the box should have an insulation layer. 2.3 The test box should be able to meet the specified test conditions and be able to test the test conditions in the box at any time. 2.4 There should be air stirring equipment in the test box to keep the gas concentration and humidity uniform. However, the test sample should not be shaken. 2.5 The test box should be able to perform visual inspection of the sample at any time during the test. 2.6 During the test, condensed water is not allowed to drip directly onto the sample. Om3 Test Procedure
3.1 Hang the samples in the test box, keep a certain distance between them, and then close the box cover. 3.2 Raise the temperature and start the stirring fan in the box so that the temperature and humidity in the box reach the requirements specified in Article 1 within half an hour. 3.3 Add hydrogen sulfide gas at the rate specified in Article 1 and reach the test concentration within 15 minutes. This is the start time of the test. Analyze the concentration in the box every 15 minutes (any hydrogen sulfide analysis method that can meet the precise requirements of the specified concentration can be used) and make adjustments to maintain the hydrogen sulfide concentration in the box within the range specified in Article 1 until the end of the 15-hour test. 3.4 Test Results Appearance inspection is conducted at room temperature within 1 hour after the test is completed. Issued by the Ministry of Machinery Industry of the People's Republic of China on September 2, 1982 and implemented on January 1, 1983
Test conditions are shown in the schematic diagram
Evaluation of test results
JB3145-82
H,s gas concentration changes 100+1cFPM
Relative humidity 75±5%
Heating up for 0.5 hours
Sketch diagram of test conditions
The sample is qualified if the main surface does not change color after the test 12.5
Time (hours)
Note: The main surface is required to be the part that does not darken on the key parts, etc. It is generally referred to as the surface that is easily exposed after assembly due to corrosion.
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A.1 Principle
JB3145--82
Appendix A
Example of hydrogen sulfide concentration determination method
(reference)
According to the reducing property of (S) in hydrogen sulfide (H,S), it is absorbed and oxidized by iodine standard solution, and starch is used to indicate the end point of the reaction. The result is determined by the amount of iodine standard solution and the volume of gas extraction. Basic reaction: H,S+I,-→S1+2I-+2HA.2 Reagents
A2.1 Iodine standard solution 0.001N
Weigh 1.3 grams of iodine and 4 grams of potassium iodide (KI), dissolve them in a small amount of water, and prepare 1000 ml. Store in a brown bottle, away from high temperature and sunlight. This is 0.01N iodine solution. (After the concentration is calibrated, take 100 ml accurately, dilute to the mark in a 1000 ml volumetric flask, and store away from light. This is the 0.001N iodine standard solution). A.2.2 Sodium thiosulfate standard solution (Na2S0.) 0.01N Weigh about 1.2 g of Na2SO-5H2O, add 100 ml of boiled steamed stuffing water to dissolve, then add 0.1 g of sodium carbonate (Na2CO3) to make 500 ml, put it in a brown bottle, and place it for one week before use. A.2.3 Starch indicator (0.5%)bzxz.net
Weigh 0.5 g of soluble starch, boil and dissolve it with 50 ml of distilled water, and make 100 ml. This indicator should be used within one week after preparation. If it exceeds one week, it should be discarded and re-prepared.w.docin.comA.3 Standardization of iodine standard solution
A.3.1 Accurately weigh 0.1 g of potassium chromate (K, Cr0.), hydrolyze it with 40 ml, make it into 100 ml, absorb 10 ml, add 10 ml of 10% HCl, 2 g of potassium iodide (solid), let it stand for 5 minutes, and titrate with the prepared sodium thiosulfate solution. Use 0.5% starch solution as the indicator, and blue is the end point. Then the concentration of the prepared sodium thiosulfate standard solution is: G
VNa,S,Os
In the formula, NNa,S,O is the equivalent concentration of the prepared sodium thiosulfate: Na.S,O.——is the amount of sodium thiosulfate solution used during titration; GK,CrO, weighed amount, grams
A,3.2 Use the sodium thiosulfate standard solution with a determined concentration to standardize the prepared iodine standard solution. Accurately draw 10 ml of iodine standard solution, use 0.5% starch solution as indicator, and titrate with sodium thiosulfate standard solution. The blue-to-white is the end point. Then the concentration of the prepared iodine standard solution is:
NI,NNa,SO,xVNa,So
Where: NI is the equivalent concentration of iodine standard solution: VI, - is the amount of magnetic standard solution, 10 milliliters: NNa.SO. is the equivalent concentration of sodium thiosulfate standard solution VNa,S,O, - is the amount of sodium thiosulfate standard solution used during titration, milliliters. 3
A.4 Sampling and determination
JB3145-82
A.4.1 Install the sampling device according to the schematic diagram.
A.4.2 Accurately add 2 ml of iodine standard solution and 5 drops of 0.5% starch indicator to the Borio tube, and add 5 ml of distilled water to seal it.
A.4.3 Open the vent valve, move the liquid storage bottle to position 6, adjust the water level of the meter, A4.4 Connect the inlet of the Borio tube to the inlet pipe, and the outlet to meter A, 4.5 Close the vent valve, move the liquid storage bottle to the sampling location position 5, and start sampling. The blue color of the solution in the Borio tube disappears as the end point. And record the sampling volume at this time, and rise next. do
Schematic diagram of sampling device
1—Bosch absorption tube: 2—500m1 drum (meter), 3—storage space: 4—liquid bottle 5—sampling positioning point: 6—liquid adjustment position before sampling, 7—connecting hose, 8—iron frame A.4.6 After sampling, open the vent valve, move the liquid storage bottle to 6, readjust the water level of the meter, and prepare for the next sampling. A,5 Calculation of results
mg (,S)/=NlxVlx1x1000
PPM=NI×VI×17×22.4×10*
Wherein: NI—is the equivalent concentration of iodine standard solution,
V——is the sampling volume, milliKelvin;
17——is the H,S equivalent constant;
34—is the molecular volume of H,S
JB3145--82
, milliliter.
22,4——H,S
1000g
Additional Notes:
This standard is proposed and managed by Guangzhou Electric Science Research Institute of the Ministry of Machinery Industry. This standard is drafted by Guangzhou Electric Science Research Institutedocin.com
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Ministry Standard of the Ministry of Machinery Industry of the People's Republic of China
Test Method for High Concentration Magnetic Hydrogen of Silver Plating
and Evaluation of Test Results
JB31 45—82
Published by China Standards Press
《Beijing Fuwai Sanlihe）
China Standards Press Printed by Huangdao Printing Factory Distributed by Xinhua Bookstore Beijing Distribution Office Sold by Xinhua Bookstores in various places·
Format 880×12301/16 Printing sheet 1/2 Number of words 8000 First edition in May 1983 Second printing in May 1983 Number of copies 1-5,000
Book number: 15169·2-4899
Science and Technology New Book Day
51-195
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