GOST 16883.2-71
GOST 16883.2−71 Silver-copper-zinc solders. Method for the determination of copper content (with Amendments No. 1, 2)
GOST 16883.2−71*
Group B59
STATE STANDARD OF THE USSR
SILVER-COPPER-ZINC SOLDERS
Method for the determination of copper content
Silver-copper-zinc solders. Method for determination of copper content
AXTU 1709
Date of introduction 1972−07−01
The decision of the State standards Committee of the USSR Council of Ministers dated 9 April 1971 N 713 introduction installed with 01.07.72
Proven in 1985 by the Resolution of Gosstandart from
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** Expiration removed by Protocol No. 5−94 of the Interstate Council for standardization, Metrology and certification (I & C N 11/12, 1994). — Note the manufacturer’s database.
INSTEAD of OST 2987 in the determination of copper
* REVISED (July 1986) with Amendments No. 1, 2 approved in March 1981, February 1985 (IUS 6−81, 5−85).
This standard applies to silver-copper-zinc solders and sets the titrimetric iodometric method for the determination of copper (at a mass fraction of copper from of 15.0 to 55.0 per cent).
The method is based on the oxidation of ions of bivalent copper potassium iodide. Released during this octarepeat iodine with sodium thiosulfate in presence of starch indicator.
(Changed edition, Rev. N 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 22864−83.
(Changed edition, Rev. N 1).
2. REAGENTS AND SOLUTIONS
Nitric acid GOST 4461−77.
Copper marks M1 according to GOST 859−78*.
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* On the territory of the Russian Federation GOST 859−2001. — Note the manufacturer’s database.
Potassium iodide according to GOST 4232−74.
The soluble starch according to GOST 10163−76, 1% solution.
Sodium thiosulfate crystal according to GOST 244−76, 0.1 N. solution.
The titer determination of 0.1 N. solution of sodium thiosulfate by copper.
To install caption weigh of 0.15−0.20 g of copper marks M1, dissolve in 10 cmdiluted 1:1 nitric acid and evaporated to 2−3 cm
. Then pour 25 cm
of hot water and heated until complete dissolution of the precipitate. The solution was cooled, added 1 g of potassium iodide and titrated with 0.1 n sodium thiosulfate to a straw yellow color, then pour 5 cm
of 1% starch solution and continue titration until the disappearance of blue staining solution.
Titer of sodium thiosulfate (), expressed in g/cm
of copper, calculated by the formula
where — the amount of sodium thiosulfate consumed in the titration, cm
;
— linkage of copper,
(Changed edition, Rev. N 1).
3. ANALYSIS
Two sample alloy 0.5 g (for the mass concentration of copper up to 40%) or 0.4 g (for the mass concentration of copper in excess of 40%) is placed in a flask with a capacity of 250 cm, was dissolved with heating in 10 cm
diluted 1:1 nitric acid and evaporate the solution to syrupy state (2−3 cm
). Then pour 25 cm
of hot water and heated until complete dissolution of turbidity. The solutions are cool, add 1.0 g of potassium iodide and titrated with 0.1 n sodium thiosulfate to a light yellow color, then pour 5 cm
of 1% starch solution and continue titration until the disappearance of blue color.
4. CALCULATION OF RESULTS OF ANALYSIS
4.1. Mass fraction of copper () in percent is calculated by the formula
where — the amount of sodium thiosulfate consumed in the titration, cm
;
the titer of sodium thiosulfate, expressed in g/cm
of copper;
— hanging,
4.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level of 0.95 shall not exceed 0.20%.
(Changed edition, Rev. N 2).
