GOST 1429.5-77
GOST 1429.5−77 Solders tin-lead. Method of determination of bismuth (with Amendments No. 1, 2)
GOST 1429.5−77*
Group B59
STATE STANDARD OF THE USSR
SOLDERS TIN-LEAD
Method for the determination of bismuth
Tin-lead solders.
Method for the determination of bismuth*
AXTU 1709**
_________________
* The name of the standard. Changed the wording, Rev. N 2.
** Added, Rev. N 2.
Date of introduction 1978−01−01
The decision of the State standards Committee of the USSR Council of Ministers dated 11 April 1977, N 886 the period of validity set with 01.01.78
PROVEN in 1982 by the Resolution of Gosstandart from
_____________
** Expiration removed Protocol MGS (IUS N 2, 1993). — Note the manufacturer’s database.
REPLACE GOST 1429.5−69
* REPRINT March 1983 with the Change in N 1, approved in January 1983; Post. N 324 from
The Change N 2 approved and put into effect with
Change No. 2 made by the manufacturer of the database in the text IUS N 11, 1987
This standard establishes photocolorimetric method for the determination of bismuth in tin-lead solder (with a mass fraction of bismuth from 0.002 to 0.20%).
The method is based on decomposition of the sample in the mixture bromatological acid and bromine, removing tin and antimony in the form of bromides, the formation of complex compounds of bismuth with thiourea and measuring the optical density of the resulting solution.
(Changed edition, Rev. N 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 1429.0−77.
2. APPARATUS, REAGENTS AND SOLUTIONS
Photoelectrocolorimeter or spectrophotometer.
Nitric acid GOST 4461−77 and diluted 1:1.
Bromatologia acid according to GOST 2062−77.
Bromine according to GOST 4109−79.
Mix to dissolve (mixture I); is prepared as follows: to 90 cmbromatological acid, carefully add 10 cm
of bromine, and mix.
Perchloric acid, a solution with a mass fraction of 57%.
Phosphoric acid (orthophosphoric acid) according to GOST 6552−80.
Boric acid according to GOST 9656−75, saturated solution.
Hydrofluoric acid according to GOST 10484−78.
A mixture of perchloric and phosphoric acids (mixture II); prepared as follows: to 160 cmof phosphoric acid poured 840 cm
of perchloric acid, mix.
A mixture of boric and hydrofluoric acids (mixture III); is prepared as follows: to 45 cmsaturated solution of boric acid poured 5 cm
hydrofluoric acid and diluted with water to a volume of 600 cm
. The mixture was stored in a plastic container.
Thiourea according to GOST 6344−73, a solution with a mass fraction of 8%; prepared as follows: 20 g of thiourea was dissolved in 150 cmof water, transfer the solution into a measuring flask with a capacity of 250 cm
, was adjusted to the mark with water, mix. The solution should be freshly prepared, if necessary, it is filtered.
Bismuth brands VIO GOST 10928−75.
A standard solution of bismuth; prepared as follows: 0.1 g of bismuth were placed in a glass with a capacity of 100 cmand dissolved in 30 cm
of nitric acid, diluted 1:1, heated to remove oxides of nitrogen, cooled, transferred into a measuring flask with volume capacity of 1000 cm
, adjusted to the mark with water, mix. 1 cm
of the solution contains 0.0001 g of bismuth.
(Changed edition, Rev. N 2).
3. ANALYSIS
3.1. A portion of the solder mass 0.5 g is placed in a low glass with a capacity of 250 cm. Pour 20 cm
of the mixture to dissolve, cover the beaker watch glass, and dissolve with a moderate heat. After dissolution of the sample watch glass is removed and the solution evaporated to dryness, without bringing it to boil. As soon as the contents of the beaker evaporated to dryness, the glass is immediately removed from the heat. Repeat the process of evaporation with a 10 cm
mixture for dissolving two more times.
Add to the dry residue of 2 cmof concentrated nitric acid and heated to decompose the bromide of lead not assuming that the contents of the glass evaporate to dryness. Then pipette add 12 cm
of a mixture of perchloric and phosphoric acids (mixture II) and heated until the appearance of dense white fumes of perchloric acid*. If the solution after evaporation to fumes of perchloric acid will be cloudy, add 5 ml of the mixture for dissolving, evaporated to fumes of perchloric acid, add 1−2 drops of concentrated nitric acid and again evaporated to dense white fumes.
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* Since adding 12 cmof a mixture of perchloric and phosphoric acids, the analysis is carried out with a small batch of samples, as the addition of reagents and measurement of optical density should be carried out without interruption in time (8−10 portions).
The clear solution is cooled to stop the allocation of fumes of perchloric acid and warm transferred to a volumetric flask with a capacity of 100 cm, add 5 cm
of the solution bridgestation acid (compound III) and mixed. Then immediately add 25 cm
of freshly prepared solution of thiourea, is cooled to room temperature, adjusted to the mark with water, mix.
Optical density of the solution is measured on photoelectrocolorimeter at a wavelength of 440 nm in a cuvette with a layer thickness of 5 cm.
As a solution comparison using the solution in the reference experiment.
When measuring optical density of the solutions the temperature should not change more than ±1 °C.
At the same time through the analysis of spend control experience. The contents of bismuth find the calibration schedule, taking into account the correction for the reagents.
(Changed edition, Rev. N
1).
3.2. Construction of calibration curve
In glasses with a capacity of 100 cmplaced 0; 0,5; 1,0; 2,0; 3,0; 4,0; 5,0; 7,0; 9,0; 11,0 cm
standard solution of bismuth, added 12 cm
of a mixture of perchloric and phosphoric acids (mixture II), is heated until the appearance of dense white fumes of perchloric acid and further analysis is carried out as specified in clause 3.1.
On the found values of optical density of solutions and the corresponding content of bismuth build the calibration graph, taking into account the correction for the reagents.
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of bismuth () in percent is calculated by the formula
where — weight of bismuth, was found in the calibration schedule g;
— the weight of the portion,
(Changed edition, Rev. N 2).
4.2. Allowable absolute differences the results of the analysis at a confidence level of 0.95, should not exceed the values given in the table.
| Mass fraction of bi, % |
Allowable absolute differences, % |
| From 0.002 to 0.005 |
0,001 |
| SV. 0,005 «0,01 |
0,002 |
| «Is 0.01» to 0.03 | 0,005 |
| «To 0.03» to 0.05 | 0,01 |
| «0,05» 0,1 | 0,02 |
| «0,1» 0,2 | 0,03 |
(Changed edition, Rev. N 1, 2).
