GOST 11930.9-79

• gost-119309-79.pdf (202.54 KiB)
  ГОСТ 11930.9-79

GOST 11930.9−79 Materials surfacing. Methods for the determination of boron (with Amendments No. 1, 2)

GOST 11930.9−79

Group B09

INTERSTATE STANDARD

MATERIALS SURFACING

Methods of boron determination

Hard-facing materials. Methods of boron 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 specifies a volumetric method for the determination of boron (at a mass fraction of boron from 0.7 to 17%) and photocolorimetric method for the determination of boron (if boron mass fraction from 0.02 to 0.2%).

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 11930.0−79.

2. VOLUMETRIC METHOD FOR THE DETERMINATION OF BORON

2.1. The essence of the method

The method is suitable for analysis of powders of alloys for welding, powder mixtures for welding and boride of chromium.

The method is based on the formation of boric acid and titration with alkali solution in the presence of mannitol.

2.2. Apparatus, reagents and solutions

Analytical scale, VLA-200M, ADV-200 or any other type provides a weighing accuracy of 0.0002 g. more

Ion meter EV-74 or other device with a margin of error of ±0.05 pH.

The glass electrode type ECL-41 G-05.

The electrode chlorocarbonyl ml-1.

Magnetic stirrer.

Burette glass according to GOST 1770−74.

Barium hydroxide 8-water according to GOST 4108−72 with a mass fraction of 5%.

Hydrochloric acid by the GOST 3118−77, diluted 1:1.

Sulfuric acid GOST 4204−77, diluted 1:4.

Nitric acid GOST 4461−77.

The sodium sulfate Piro on the other 6−09−5404−88*.
________________
* The one mentioned here and below are author’s development. For additional information, please refer to the link. — Note the manufacturer’s database.

Boric acid according to GOST 9656−75 svezheprigotovlennaja.

Sodium hydroxide according to GOST 4328−77, with a mass fraction of 20,10% and 0.1 M (fixanal).

In the absence of fiksanal 0.1 M solution of sodium hydroxide prepared as follows: 4 g of sodium hydroxide in 1 DMdistilled water, add 3 cmof a solution of barium hydroxide with a mass fraction of 5%, stirred and allowed to settle upset during the day. The solution was stored in a sealed plastic container.

The mass concentration of sodium hydroxide solution set on boric anhydride in the following way: precrystallization boric acid is calcined in a platinum Cup or crucible, first at a temperature of 200−250 °C, then at 800−850 °C for 30−40 min to constant weight. A portion of the resulting boric anhydride with a mass of 3.48 g, carefully dissolve in water when heated, and pour the solution into volumetric flask with a capacity of 1 DM, svejeprokipachenna diluted to the mark with water and mix.

Select the 10 cmstandard solution of boric anhydride in a beaker with a capacity of 200 cm, 150 cm pourboiled water, set 0.1 M sodium hydroxide solution pH value of 6.9. Pour the invert sugar solution or mannitol and titrate with 0,1 M sodium hydroxide solution until the return arrow of the galvanometer to a pH of 6.9.

Mass concentration of 0.1 M sodium hydroxide solution according to Bohr calculated by the formula

,

where  — the amount of sodium hydroxide solution consumed for titration, cm;

0,31057 — the ratio of boric oxide to boron.

Congo red or Congo paper. Preparation of Congo red solution: dissolve 0.1 g indicator in 100 cmof water.

Methyl red with a mass fraction of 0.1%: 0.2 g of the indicator dissolved in a mixture of 60 mof ethyl alcohol and 40 mof water.

Mannitol on the other 6−09−5484−90 or sucrose according to GOST 5833−75. Preparation of sucrose solution: dissolve 600 g of sucrose in 200 cmsvejeprokipachenna water with gentle heating and stirring until full enlightenment of a solution. The hot solution is filtered through a glass filter, heated almost to boiling and add 5 cm3 M sulfuric acid, 1−2 minutes strongly shaken, poured 300 cmof water, to which add 5 cm3 M sodium hydroxide free from carbonates. The solution is well stirred and after cooling, check the reaction for methyl red. The reaction should be neutral; the solution contains 55% invert sugar.

Barium hydroxide 8-water according to GOST 4107−78 with a mass fraction of 5%.

The technical rectified ethyl alcohol GOST 18300−87.

(Changed edition, Rev. N 2).

2.3. Analysis

2.3.1. A sample weight in accordance with table.1 is placed in a conical flask with reflux condenser and dissolved in 40 cmof sulphuric acid, diluted 1:4, or 40 cmof hydrochloric acid diluted 1:1. Then pour 2 cmof nitric acid.

Table 1

If the linkage is not fully dissolved, the solution was filtered, washed with water the filter (the filtrate and washings retain) and fuse the sample with sodium pyroterrorism at 650−700 °C. the smelt is leached with water and attach to the filtrate. The solution is neutralized with a solution with a mass fraction of 20% sodium hydroxide on the Congo and transferred to a volumetric flask with a capacity of 250 cm, 25−30 cm containinghot sodium hydroxide solution. The cooled solution is diluted to the mark with water and mix. The contents of the flask was filtered into a dry beaker and taken 150−200 cmof solution for the determination of boron. To the solution was added hydrochloric acid diluted 1:1 until the color of methyl red indicator from yellow to red and 1 cmin excess. Removal of carbon dioxide the solution was boiled for 10 min, quickly cooled and neutralized with a solution with a mass fraction of 10%, and then by pH meter with a 0.1 M sodium hydroxide solution, establishing a pH of 6.9. To the solution was added to mannitol (0.01 g of boron consumed 10 g of mannitol) and begin to titrate boric acid with a 0.1 M solution of sodium hydroxide to return the pH of the solution to a pH of 6.9. Add the mannitol and, if the pH of the solution remains equal to 6.9, the titration is complete.

At the same time through all stages of the analysis carried out control experience on the boron content in the reagents.

2.4. Processing of the results

2.4.1. Mass fraction of boron () in percent is calculated by the formula

,

where is the mass concentration of 0.1 M sodium hydroxide solution, expressed in g/cmof boron;

 — aliquota part of the analyzed solution, cm;

 — the volume of 0,1 M solution of sodium hydroxide, spent on titration of forest, cm;

 — the volume of 0,1 M solution of sodium hydroxide, spent on titration of a solution in the reference experiment, cm;

 — the weight of the portion,

2.4.2. 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 table.2.

Table 2

2.4.1, 2.4.2. (Changed edition, Rev. N 2).

3. PHOTOCOLORIMETRIC METHOD FOR THE DETERMINATION OF BORON

3.1. The essence of the method

The method is intended for analysis of rods for surfacing.

The method is based on the formation in the sulfate medium painted chelation of boric acid with Carmine.

3.2. Apparatus, reagents and solutions

Photoelectrocolorimetry brands FEK-56, FEK-56M or any other type.

Sulfuric acid GOST 4204−77, a solution with a mass fraction of 20% and diluted 1:4.

Nitric acid GOST 4461−77.

Sodium carbonate according to GOST 83−79, a solution with a mass fraction of 30%.

Orthophosphoric acid according to GOST 6552−80.

Carminic acid, a solution with a mass fraction of 0.01%; prepared by dissolving the reagent in concentrated sulfuric acid.

Boric acid according to GOST 9656−75, standard boron solution; prepared as follows: 0,1425 g of boric acid are dissolved in 1000 cmof solution with a mass fraction of 20% sulfuric acid.

1 cmof the solution contains 0,000025 g of boron.

3.3. Analysis

3.3.1. A sample weighing 0.3 g was dissolved in 10 cmof sulphuric acid, diluted 1:4, followed by the addition of 0.5 cmof nitric acid. The dissolution is carried out in conical flask under reflux for 1.5−2 h. After decomposition of the sample flask is removed, cooled and washed the fridge with a little water.

The solution in the flask is neutralized in the Congo with sodium carbonate solution and injected into an excess of 2−2. 5 cm. The contents of the flask heated to boiling, poured into a volumetric flask with a capacity of 50 cm, is diluted to the mark with water and mix. Part of the solution was filtered into a dry beaker through a dry filter and to determine the boron taken aliquot part 2−5 cmof the analyzed solution in a beaker with a capacity of 50 cm. The contents of the beaker evaporated to dryness, then pour 0.5 cmof phosphoric acid, 20 cmcarminic acid and 4.5 cmsolution with a mass fraction of 20% sulfuric acid, stirred well and left for the formation of stable colored complex compounds. After 30 min the optical density of colored solutions are measured on a photoelectrocolorimeter with a yellow filter (582 nm) in a cuvette with a thickness of the absorbing layer is 50 mm.

The boron content in grams found by the calibration schedule.

At the same time spend three reference experiment to determine the boron content in the reagents. The solution in the reference experiment used as a comparison solution.

3.1−3.3. (Changed edition, Rev. N 2).

3.3.2. Construction of calibration curve

In a glass pour 0.5 cmof a solution of phosphoric acid and from 0.2 to 1 cmof a standard solution of boric acid with an interval of 0.2 cmand further analysis are as indicated in claim 3.3.1.

3.4. Processing of the results

3.4.1. Mass fraction of boron () in percent is calculated by the formula

,

where is the mass of boron was found in the calibration schedule g;

 — aliquota part of the analyzed solution, cm;

 — the weight of the portion,

3.4.2. 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 table.3.

Table 3

(Changed edition, Rev. N 2).