GB/T 20975.5-2020 in English

VALID

Methods for chemical analysis of aluminium and aluminium alloys—Part 5：Determination of silicon content

Issued on:2020-06-02
Implemented on:2021-04-01
File Format:PDF
Delivery:Via email within 1~3 business days

Price(USD)： $160.00
$156.00

Standard No:	GB/T 20975.5-2020
Document status:	VALID
Title in English:	Methods for chemical analysis of aluminium and aluminium alloys—Part 5：Determination of silicon content
Title in Chinese:	铝及铝合金化学分析方法第5部分：硅含量的测定
Language:	English
File Format:	Electronic (PDF)
Delivery:	Via email within 1~3 business days
Issued on:	2020-06-02
Implemented on:	2021-04-01
Superseding:	GB/T 20975.5-2008 Methods for chemical analysis of aluminium and aluminium alloys - Part 5：Determination of silicon content
ICS Classification:	77.120.10-Aluminium and aluminium alloys
Chinese Classification:	H12-Light metals and their alloys analysis method
Professional Classification:	GB-National Standard
Related Keywords:	content gravimetric method r=1.00 % silicon content introduction standard overview silicon content aluminium alloys part 1-amino-2-naphthol-4-sulfonic acid perchloric acid
Related Topics:	Silicon content Determination of silicon content Silicon content Determination of silicon content Aluminum silicon chemical composition Gold Chemical Analysis Methods Silicon Silicon Determination of silicon content Aluminum and Aluminum Alloy Manganese Analysis Determination of silicon content Silicon content of aluminum GB/T20975.5-2008 Aluminum analysis and detection Silicon content Aluminum, silicon, titanium chemical determination method Chemical analysis method of aluminum-niobium alloy Aluminum content test method Chemical analysis method of aluminum-niobium alloy Composition and content analysis GB/T 20975.5 GB/T 20975.5-2008 GB/T 20975.5-2020 Aluminum and Aluminum Alloy Method for measuring aluminum content in lithium-aluminum alloys Test method for hydrogen content of aluminum alloys What are the methods for detecting hydrogen content in aluminum alloys? Aluminum content detection method Common analytical and measurement methods for aluminum elements in aluminum ingots Common analytical and measurement methods for aluminum elements in aluminum ingots Silicon content in electrical aluminum rods Determination of silicon to aluminum ratio Aluminum to silicon ratio test Aluminum content assay method The test method for indium in aluminum and aluminum alloys is Method for analyzing the components of compounds containing benzene groups

《GB/T 20975.5-2020铝及铝合金化学分析方法第5部分：硅含量的测定》由TC243（全国有色金属标准化技术委员会）归口，TC243SC1（全国有色金属标准化技术委员会轻金属分会）执行，主管部门为中国有色金属工业协会。

Introduction

Standard Overview and Technical Evolution

GB/T20975.5-2020 replaces the 2008 version of the standard. The main updates include: Expansion of measurement range (upper limit of spectrophotometry increased from 0.40% to 15.00%), Strengthening of safety warnings, Revision of precision data and Adjustment of sample weighing table. This standard keeps pace with the relevant ISO methods and reflects the technological progress in the field of non-ferrous metal analysis in my country.

Comparison of Method Principles

Dimensionality	Molybdenum blue spectrophotometry	Gravimetric method
Measurement range	0.0010%-15.00%	10.00%-63.00%
Principle	Silico-molybdenum heteropoly acid reduction color development, 650-810nm absorbance measurement	Perchloric acid dehydration weighing SiO₂, hydrofluoric acid volatilization subtraction method
Key reagents	Ammonium molybdate, 1-amino-2-naphthol-4-sulfonic acid	Perchloric acid, hydrofluoric acid
Applicable scenarios	Low-content samples, batch testing	High-content arbitration analysis

Core operating points

Molybdenum blue spectrophotometry

Sample dissolution uses a polytetrafluoroethylene beaker, sodium hydroxide-hydrogen peroxide system
The acidification stage needs to strictly control the color development acidity of pH≈0.9
After color development, the determination must be completed within 30 minutes to prevent complex decomposition

Gravimetric method

The dehydration process needs to maintain Platinum crucibleConstant weight state
Sulfuric acid needs to be added during hydrofluoric acid treatment to prevent volatilization of other elements
Constant weight needs to be achieved when burning at 1000℃ (mass change ≤0.0002g)

Precision control

The standard provides strict repeatability (r) and reproducibility (R) requirements:

Spectrophotometry r=0.0004%, R=0.0008% at 0.001% content
Gravimetric method r=1.00%, R=1.10% at 50% content

The laboratory should regularly use standard substances to verify the precision of the method.

Implementation suggestions

Case: An aluminum alloy factory detected a silicon content of 11.25%, and the result of the gravimetric method was 11.18%-11.32%, which met the standard requirement of r=0.38%. Key control points:

The perchloric acid dehydration time is strictly controlled within 15-20 minutes
Use medium-speed quantitative filter paper for filtration and wash until neutral
Operate in a fume hood when treating with hydrofluoric acid

For samples with a boundary content of 10%-15%, it is recommended to use the gravimetric method as the arbitration method.

More samples: YD/T 3934-2021 GB 50021-2001(2009) JC/T 2453-2018

Sample only — not a preview of GB/T 20975.5-2020