GOST 11930.3-79

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  ГОСТ 11930.3-79

GOST 11930.3−79 Materials surfacing. Method for determination of silicon (with Amendments No. 1, 2)

GOST 11930.3−79

Group B09

INTERSTATE STANDARD

MATERIALS SURFACING

Method for determination of silicon

Hard-facing materials. Method of silicon 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)

REPLACE GOST 11930−66 in part of sec. 4

EDITION (August 2011) with Amendments No. 1, 2 approved in December 1984, December 1989 (IUS 3−85, 3−90)


This standard specifies the gravimetric method for the determination of silicon (with a mass fraction of silicon of from 0.2 to 10%) in the surfacing materials.

The method is based on the ability of silicon as the result of acid hydrolysis to stand out in a precipitate slightly soluble silicic acid. The resulting precipitate was calcined and treated with hydrofluoric acid in the presence of a small amount of sulfuric acid. Under these conditions, the silicon forms a volatile compound of silicon fluoride.

(Changed edition, Rev. N 2).

1. GENERAL REQUIREMENTS

General requirements for method of analysis according to GOST 11930.0−79.

2. APPARATUS, REAGENTS AND SOLUTIONS

Types of analytical balance VLA-200 M ADV-200 or any other type provides a weighing accuracy of 0.0002 g. more

Platinum crucibles N 7 GOST 6563−75.

Crucibles of iron, Nickel or glassy carbon.

Sulfuric acid GOST 4204−77, diluted 1:4 and 1:99.

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

Nitric acid GOST 4461−77.

Hydrofluoric acid according to GOST 10484−78.

Sodium carbonate according to GOST 83−79.

Preservatory sodium or potassium ironically according to GOST 7172−76.

Sodium peroxide.

(Changed edition, Rev. N 2).

3. ANALYSIS

3.1. For powders based on Nickel

A sample of alloy weighing 0.2 g were placed in a glass with a capacity of 200−300 cmand is dissolved in 40 cmof hydrochloric acid. After the dissolution of the main part of the sample poured 10 cmof sulphuric acid and the solution is evaporated twice with water to 70−100 cm, heated to 70−80 °C and filtered on the filter medium density containing a small amount filtrowanie mass. The residue and the beaker was washed 5−8 times with warm sulphuric acid (60−70 °C), diluted 1:99, and three times with distilled water.

The filtrate and the washings saved.

Washed the filter cake was placed in a platinum crucible, dried, carefully incinerated and calcined at a temperature of 1000−1100 °C to constant weight. Suspended sediment is treated with hydrofluoric and sulphuric acids. To do this, poured into a platinum crucible with 2−3 drops of sulphuric acid, 3−5 cmhydrofluoric acid, carefully evaporated to dryness, and then calcined at a temperature of 1000−1100 °C to constant weight.

At the same time through all stages of the analysis carried out control experience for contamination of reagents with silicon. If after the distillation of the silicon in the crucible residue remains, it domplast with carbonate of sodium at 900−950 °C or pyroterrorism sodium at 650−700 °C. the Melt is leached in the filtrate obtained after separation of silica, transferred to a volumetric flask with a capacity of 200 cm, is diluted to the mark with water and mix.

The solution was stored for determination of chromium, manganese, Nickel, iron and phosphorus.

(Changed edition, Rev. N 1, 2).

3.2. For rods for surfacing and powders of alloys for surfacing

A portion of the sample mass given in table.1, is placed in a beaker with a capacity of 200−300 cmand is dissolved by heating in 50 cmof sulphuric acid, diluted 1:4. After the dissolution of the main part of the sample poured 1 cmof nitric acid and the solution is twice evaporated to weak fumes of sulphuric anhydride. The solution is diluted with distilled water and further analysis are as indicated in claim 3.1.

Note. For alloys containing tungsten, the precipitate was calcined at 750−800 °C.

Table 1

(Changed edition, Rev. N 2).

3.3. (Deleted, Rev. N 2).

4. PROCESSING OF THE RESULTS

4.1. Mass fraction of silicon () in percent is calculated by the formula

,

where is the mass of the crucible with the precipitate of silicon dioxide prior to processing hydrofluoric acid, g;

 — weight of crucible with residue after treatment with hydrofluoric acid, g;

 — the mass of the crucible with the precipitate obtained in control experiment, before treatment with hydrofluoric acid, g;

 — the mass of the crucible with the precipitate obtained in control experiment, after treatment with hydrofluoric acid, g;

 — dilution of the test solution, cm;

 — aliquota part of the analyzed solution, cm;

 — the mass of sample, g;

0,4672 — the ratio of silicon dioxide to silicon.

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

(Changed edition, Rev. N 2).