This standard is applicable to the determination of boron content in nickel-based alloy powders that do not contain tungsten or molybdenum. Determination range: 1.00% to 5.00%. This standard complies with GB 1467-78 "General Principles and General Provisions for Chemical Analysis Methods for Metallurgical Products". GB/T 8638.1-1988 Chemical analysis method for nickel-based alloy powders - Determination of boron content by neutralization titration GB/T8638.1-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical analysis method of nickel-based alloy powder
Neutralization titration method for boron content
Nickel base alloy powder-- Determination ofboron content-Alkalimctric methodUDC 669.245-492.2
GB 8638. 1---- 88
This standard is applicable to the determination of boron content in nickel-based alloy powder without tungsten and saw. Determination range: 1.00%~~5.00%. This standard complies with GB1467-78 "General Principles and General Provisions of Chemical Analysis Methods for Metallurgical Products". 1 Method Summary
The sample is melted with sodium peroxide, acidified with hydrochloric acid, chromium is reduced with sodium sulfite, and iron, chromium, nickel and other elements are separated with strong alkali. The solution is adjusted to be neutral. Aluminum is separated with barium (calcium) carbonate. In the presence of mannitol, phenolic acid is used as an indicator and the boron content is titrated with sodium hydroxide standard solution. 2 Reagents
2.1 Sodium peroxide.
2.2 Sodium sulfite.
2.3 Sodium hydroxide.
2.4 Barium carbonate (calcium).
2.5 Mannitol.
2. 6 Hydrochloric acid (p1.19 g/mL).
2.7 Hydrochloric acid (1+20).
2.8 p-Nitrophenol solution (0.1%): Prepare with ethanol (4+1). 2.9 Phenolyl solution (0.5%): Weigh 0.25g phenolphthalein and dissolve it in 30mL ethanol, dilute with water to 50mL, and mix well. 2.10 Boron standard solution: Weigh 5.7158g high-purity boric acid and dissolve it in boiled water, transfer it into a 500mL volumetric flask, dilute to the mark with boiled water, and mix. This solution contains 2.00mg boron in 1mL. 2.11 Hydrochloric acid standard solution [c (HC1) = 0.05 mol / L]: 2.11.1 Preparation: Take 4.2mL hydrochloric acid (2.6) and place it in a 1000mL volumetric flask, dilute with water to the mark, and mix. 2.11.2 Calibration: Transfer 25.00mL hydrochloric acid standard solution (2.11.1) to a 200mL conical flask, add 20mL water, 4 drops of phenol solution (2.9), and titrate with sodium hydroxide standard solution (2.12.1) until the solution turns red. Calculate the ratio of sodium hydroxide standard solution to hydrochloric acid standard solution according to formula (1): Vi
Where: V, · Volume of sodium hydroxide standard solution consumed during titration, mL; V. ·… Volume of hydrochloric acid standard solution transferred, mL. 2.12 Sodium hydroxide standard solution Cc (NaOH) = 0.05 mol/LJ: (1)
2.12.1 Preparation: Weigh 2 g of sodium hydroxide (2.3) and dissolve it in 250 mL of water. Add 1 mL of calcium chloride solution (10%), boil for 1 to 2 min, cool slightly, transfer to a 1000 mL volumetric flask, dilute to the mark, and mix. Let stand until the barium carbonate sinks, then siphon the supernatant into another bottle and use it after calibration.
Approved by China National Nonferrous Metals Industry Corporation in 1988-0111, implemented in 1989-01-01
GB 8638.1—88
2.12.2 Calibration: Take three portions of 10.00mL of the boron standard solution (2.10), place them in 300mL conical flasks respectively, add appropriate amount of water, 1 drop of phenolphthalein solution (2.9), 2g of mannitol (2.5), titrate with sodium hydroxide standard solution (2.12.1) until the solution turns red and the excess is 0.5mL, record the volume V consumed, then back-titrate with hydrochloric acid standard solution (2.11) until the solution turns colorless, record the volume V consumed. The extreme difference of the volume of sodium hydroxide standard solution consumed by the three solutions shall not exceed 0.05mL, and the average value shall be taken. Calculate the titer of sodium hydroxide standard solution for boron according to formula (2): T=VV.K
V:c:10-1
Wherein: T-titer of sodium hydroxide standard solution for boron, B/mL; Volume of boron standard solution transferred, mL;
-concentration of boron standard solution, mg/mL;
V,——volume of sodium hydroxide standard solution consumed in titration, mL, V-volume of hydrochloric acid standard solution consumed in titration, mL; K-ratio of sodium hydroxide standard solution to hydrochloric acid standard solution. 3 Analysis steps
3.1 Number of determinations
Measure twice in parallel and take the average value.
3.2 Sample size
Weigh 0.5000g sample.
3.3 Blank test
Perform a blank test with the sample. bZxz.net
3.4 ​​Determination
3.4.1 Place the sample (3.2) in a graphite crucible with 1g of sodium hydroxide (2.3) melted in advance, add 4g of sodium peroxide (2.1), stir with a fine wire, cover with about 1g of sodium peroxide (2.1), heat to melt, cool slightly, place in a polytetrafluoroethylene beaker, soak with boiling water, clean the crucible, add 20mL of hydrochloric acid (2.6), add sodium sulfite (2.2) in batches, and shake until all chromium is reduced. Pour the solution into a polytetrafluoroethylene beaker containing 8g of sodium hydroxide (2.3), stir well, cool after the reaction is complete, transfer to a 250mL volumetric flask, dilute to the mark, and mix well.
3.4.2 Filter with double-layer medium-speed filter paper, transfer 100mL of filtrate to a 400mL polytetrafluoroethylene beaker, add 34 drops of p-nitrophenol solution (2.8), adjust to acidity with hydrochloric acid (2.6) and add 2mL excess, add barium (calcium) carbonate (2.4), boil until the solution turns yellow, continue to evaporate at low temperature to a volume of about 50mL, and cool. Filter with double-layer medium-speed filter paper, wash the beaker and filter paper with boiled hot water. Collect the filtrate in a 300mL conical flask.
3.4.3 Add 2 drops of p-nitrophenol solution (2.8), adjust to colorless solution with hydrochloric acid (2.7). Add 5g of mannitol (2.5) and 4 drops of phenolic acid solution (2.9), and titrate with sodium hydroxide standard solution (2.12) until the solution turns red, with an excess of 0.5mL, record the volume consumed, and then titrate with hydrochloric acid standard solution (2.11) until the solution turns yellow as the end point, record the volume consumed. 4 Calculation of analysis results
Calculate the percentage of boron according to formula (3):
B(%) - V.. T . (Vi=V=K . (V.-V.)) × 100Vem
Where: V, total volume of sample solution, mL; V. ...-volume of sample solution transferred, mL; V, --- volume of sodium hydroxide standard solution consumed in titrating the sample solution, mL; V. ---The volume of hydrochloric acid standard solution consumed in titrating excess sodium hydroxide standard solution, mL; The titer of 7-sodium hydroxide standard solution for boron, g/mL; 368
GB8638.188
The volume of sodium hydroxide standard solution consumed in the titration blank test, mL; Vi——The volume of hydrochloric acid standard solution consumed in the titration blank test, mL; K -——The ratio of sodium hydroxide standard solution to hydrochloric acid standard solution; m-The weight of the sample, ·.
Allowable difference
The difference in the analysis results between laboratories should not be greater than the allowable difference listed in Table 1. Table 1
1. 00~～2. 00
>2. 00~4. 00
>4.00~6.00
Additional remarks:
This standard was drafted by the Iron and Steel Research Institute of the Ministry of Metallurgical Industry. This standard was drafted by the Iron and Steel Research Institute of the Ministry of Metallurgical Industry. The main drafter of this standard is Ma Sanqing.
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