GOST 11930.11-79
GOST 11930.11−79 Materials surfacing. Method for the determination of molybdenum (with Amendments No. 1, 2)
GOST 11930.11−79
Group B09
INTERSTATE STANDARD
MATERIALS SURFACING
Method for the determination of molybdenum
Hard-facing materials. Method of molybdenum determination
ISS 25.160.20
AXTU 1709
Date of introduction 1980−07−01
The decision of the State Committee USSR on standards on March 21, 1979 N 982 date of introduction is established 01.07.80
Limitation of actions taken by Protocol No. 4−93 of the Interstate Council for standardization, Metrology and certification (ICS 4−94)
EDITION (August 2011) with Amendments No. 1, 2 approved in December 1984, December 1989 (IUS 3−85, 3−90)
This standard establishes photocolorimetric method for the determination of molybdenum content (in mass fraction of molybdenum from 0.08 to 3.0%) in rods for welding and powder alloys for surfacing.
The method is based on formation of colored complex compounds of molybdenum with thiocyanate in the presence of thiourea.
(Changed edition, Rev. N 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 11930.0−79.
2. REAGENTS AND SOLUTIONS
Tartaric acid according to GOST 5817−77, a solution with a mass fraction of 10%.
Hydrochloric acid by the GOST 3118−77.
Copper sulfate according to GOST 4165−78, a solution with a mass fraction of 1%.
Thiourea according to GOST 6344−73, a solution with a mass fraction of 10%.
Ammonium radamisty, a solution with a mass fraction of 50%.
The recrystallized ammonium molybdate according to GOST 3765−78.
Solutions of molybdenum standard:
Solution A, prepared as follows: 0,184 g of ammonium molybdate dissolved in distilled water. The solution is transferred into a measuring flask with volume capacity of 1000 cm, diluted with distilled water to the mark and mix.
1 cmstandard solution contains 0.0001 g of molybdenum.
Solution B is prepared by diluting with water solution And 10 times.
1 cmof solution B contains 0,00001 g of molybdenum.
(Changed edition, Rev. N 2).
3. ANALYSIS
3.1. Molybdenum is determined from the filtrate obtained after separation of iron by GOST 11930.10−79. Of volumetric flasks with a capacity of 100 cmis taken 5−10 cm
of the analyzed solution in a volumetric flask with a capacity of 50 cm
. Into the flask pour 5 cm
of solution with a mass fraction of 10% tartaric acid, 15 cm
of hydrochloric acid diluted 1:1, 2 cm
of solution with a mass fraction of 1% copper sulphate, 10 cm
of a 10% solution of thiourea, 5 cm
solution with a mass fraction of 10% ammonium Rodenstock. After addition of each reagent the contents of the flask was stirred, diluted with distilled water to the mark and mix again.
The optical density of colored solutions are measured on a photoelectrocolorimeter with a green optical filter (490 nm) in a cuvette with a thickness of the absorbing layer is 50 mm. Simultaneously through all stages of the analysis carried out control experience solution which is used as a solution of comparison. The molybdenum content found by the calibration schedule.
(Changed edition, Rev. N 1, 2).
3.2. Construction of calibration curve
Nine volumetric flasks with a capacity of 50 cmplaced 1, 2, 3, 4, 5, 6, 7, 8, 9 cm
standard solution molybdenum B. In the tenth flask standard solution does not flow. It is used for the reference experiment.
In each flask pour 5 cmof solution with a mass fraction of 10% tartaric acid and further analysis are as indicated in claim 3.1.
According to the obtained results build a calibration curve.
3.1, 3.2. (Changed edition, Rev. N 2).
4. PROCESSING OF THE RESULTS
4.1. Fraction of total mass of molybdenum () in percent is calculated by the formula:
where — weight of molybdenum, was found in the calibration schedule g;
— aliquota part of the analyzed solution, cm
;
— the weight of the portion,
4.2. The difference between the largest and smallest results of the three parallel measurements, and the two results of the analysis at a confidence level of 0.95, should not exceed the values of permissible differences given in the table.
| Mass fraction of molybdenum, % | The allowable divergence of the three parallel definitions % |
Permissible discrepancies in the results of the analysis % | ||||
| From | 0,080 | to | 0,100 | incl. | 0,005 | 0,010 |
| SV. | 0,100 | « | 0,150 | « | 0,010 | 0,015 |
| « | 0,150 | « | 0,200 | « | 0,020 | 0,030 |
| « | 0,200 | « | 1,000 | « | 0,050 | 0,060 |
| « | 1,000 | « | 2,000 | « | 0,100 | 0,150 |
| « | 2,000 | « | 3,000 | « | 0,150 | 0,200 |
(Changed edition, Rev. N 2).
