GOST 1219.7-74
GOST 1219.7−74 calcium Babbits. Method of determination of bismuth (with Change No. 1)
GOST 1219.7−74
Group B59
INTERSTATE STANDARD
CALCIUM BABBITS
Method for determination of bismuth
Lead-calcium bearing alloys.
Method for determination of bismuth content
ISS 77.160.20*
____________________
* In the index «National standards» 2006
ISS
Date of introduction 1975−01−01
The decision of the State standards Committee of the Council of Ministers of the USSR from January 17, 1974 N 150 date of introduction is established 01.01.75
Limitation of actions taken by Protocol No. 2−92 of the Interstate Council for standardization, Metrology and certification (ICS 2−93)
REPLACE GOST 1219−60 in part of sec. VIII
EDITION (September 2003) with amendment No. 1, approved in November 1979 (ICS 1−80).
This standard applies to calcium babbits and sets photocolorimetric method for determination of bismuth (with bismuth mass fraction of from 0.005 to 0.2%).
The method is based on the reaction of formation of complex compound of bismuth with thiourea and measuring the optical density of the solution, painted in yellow color. The influence of interfering elements can be eliminated by introduction of tartaric and citric acids.
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 1219.0−74.
2. APPARATUS, REAGENTS AND SOLUTIONS
Photoelectrocolorimeter or spectrophotometer.
Nitric acid GOST 4461−77 diluted 1:2.
Tartaric acid according to GOST 5817−77.
Citric acid according to GOST 3652−69.
The mixture of acids to dissolve the alloy: 300 g of tartaric acid and 200 g of citric acid dissolved in 500 cmof water and 100 cm
of nitric acid.
Thiourea according to GOST 6344−73, 10% solution.
Bismuth GOST 10928−90, brand ВИ0.
A solution of bismuth; prepared as follows: 0.1 g of bismuth was dissolved with heating in 60 cmof nitric acid, diluted 1:2, boiling removes oxides of nitrogen. After cooling, transfer the solution into a volumetric flask with a capacity of 1 DM
, made up to the mark with water and mix.
3. ANALYSIS
3.1. A portion of the babbit 1 g dissolved in 50 cmof the mixture for dissolution while heating to 70 °C. After dissolution and cooling add 20 cm
of nitric acid, transfer the solution into a volumetric flask with a capacity of 100 cm
, adjusted to the mark with water and mix (solution A). Take the dry pipette 50 cm
of solution A and placed in a volumetric flask with a capacity of 100 cm
(solution B). Solution And topped up to the mark with water, this solution is solution comparisons.
To the solution B was added from a pipette dropwise 20 cmof a solution of thiourea, adjusted to the mark with water and mix. Immediately measure the optical density of a solution on photoelectrocolorimeter at a wavelength of 465 nm (blue filter) in a cuvette with a layer thickness of 50 mm.
At the same time conducting follow-up experience with all the applied reagents. On the found values of optical density of the analyzed solution with the adjusted control experience find the content of bismuth on the calibration schedule.
3.2. Construction of calibration curve
In a volumetric flask with a capacity of 100 cmpoured from microburette 0; 0,5; 1,5; 2.0 cm
of a solution of bismuth, which corresponds to 0,05; 0,1; 0,15; 0,2 mg of bismuth. Add 50 cm
of the solvent mixture and further receives, as described in Chapter 3.1.
According to the measurement of the optical density of solutions to build the calibration graph.
4. PROCESSING OF THE RESULTS OF THE ANALYSIS
4.1. Mass fraction of bismuth () in percent is calculated by the formula
where the amount of bismuth found in the calibration graphics mg;
— hanging Babbitt corresponding aliquote part of the solution, g;
— a conversion factor of milligrams to grams.
4.2. Allowable absolute differences between the extreme results of the analysis should not exceed 0,002% when the mass fraction of bismuth from 0.005 to 0.01%; 0,004% when the mass fraction of bismuth of more than 0.01 to 0.03%; 0,008% when the mass fraction of bismuth in excess of 0.03 to 0.08% and 0.02% when the mass fraction of bismuth of more than 0.08 to 0.2%.
(Changed edition, Rev. N 1).
