The implementation of the national standard for molybdenum disulfide (MoS2) provides a unified technical basis for product quality evaluation. GB/T 23271 "Molybdenum Disulfide" specifies the classification, technical requirements, test methods, and inspection rules for MoS2 products, making it the most frequently cited core standard for quality determination by manufacturers, testing institutions, and end users. The standard applies to MoS2 products produced by natural or synthetic methods, with the molecular formula MoS2 and a relative molecular weight of 160.07 (based on 2003 international atomic weights). It covers application fields including solid lubricants, lubricant additives, friction modifiers, and catalyst raw materials, classifying products into five grades with differentiated chemical composition indicators for each grade. Understanding the technical requirements and test methods of this standard is essential for accurate quality evaluation during procurement inspection and production control.

Standard Evolution and Scope of Application

GB/T 23271 was first published in 2009 as GB/T 23271-2009 and later revised into the current version GB/T 23271-2023. The standard is administered by the National Technical Committee on Nonferrous Metals and supervised by the State Administration for Market Regulation. The 2009 version classifies products into five grades from FMoS2-1 to FMoS2-5, where FMoS2-1 is primarily used for catalysts or catalyst raw materials, and FMoS2-2 through FMoS2-5 are used for solid lubricants, lubricant additives, and friction modifiers. The 2023 version updated some referenced test method documents on the original framework to maintain consistency with the current chemical product testing system. The standard specifies that the product appearance shall be black or silver-gray extremely fine powder, free of visible foreign matter.

Key Testing Indicators

The standard's testing indicator system covers four dimensions: main content, impurity content, oil content, and acid value. Taking grade FMoS2-4 as an example, its MoS2 main content (mass fraction) shall not be less than 97.0%, total insolubles not more than 2.0%, iron content not more than 0.15%, MoO3 content not more than 0.20%, silicon dioxide content not more than 0.20%, moisture not more than 0.5%, oil content (acetone extraction) not more than 0.5%, and acid value (as KOH) not more than 5.0 mg/g. The indicators progress with the precision requirements of each grade, with FMoS2-1 having the highest MoS2 content requirement of 98.0% or above. These indicators are directly related to the tribological performance of the product — iron and MoO3, as the main impurity phases, can weaken the friction-reduction effect and accelerate base oil oxidation when present in elevated concentrations.

Test Methods and Referenced Standards

The standard references multiple basic test method standards, forming a complete testing system. Iron content determination follows GB/T 3049 "General Method for Determination of Iron Content in Industrial Chemical Products — o-Phenanthroline Spectrophotometric Method," which reduces Fe3+ to Fe2+ with hydroxylamine hydrochloride, forms an orange complex with o-phenanthroline, and measures absorbance at 510 nm wavelength, with a detection limit below 0.05%. Acid-base value determination references ASTM D974 "Standard Test Method for Acid and Base Number by Color-Indicator Titration," using potassium hydroxide standard solution titrated to the endpoint. Moisture testing uses the gravimetric method, where the sample is dried to constant weight in an oven at 105 degrees C plus or minus 2 degrees C, and moisture content is calculated from weight loss. Oil content determination uses acetone as the extraction solvent, employing a Soxhlet extractor for reflux extraction of 4 hours or more, followed by solvent evaporation and residue weighing. The MoS2 main content is calculated by difference — subtracting the sum of all impurity contents from 100%.

Inspection Rules and Quality Control Significance

The standard specifies that product inspection is conducted on a batch basis, with each batch not exceeding 5,000 kg. Sampling follows GB/T 6678 "General Principles for Sampling Chemical Products," determining the number of sampling units based on batch size, with the final sample quantity not less than 250 g after reduction. If any indicator in the inspection results fails, a double sample may be taken from the same batch for re-testing, with the re-test results serving as the final determination. This design ensures traceability and reproducibility in quality disputes. Incorporating GB/T 23271 testing indicators into the factory Certificate of Analysis (COA), combined with particle size analysis and XRD phase identification, establishes a complete quality evaluation chain from chemical composition to crystal structure.

Conclusion

As the fundamental national standard for molybdenum disulfide products, GB/T 23271 provides standardized criteria for quality evaluation across different application scenarios through its five-grade classification system and testing indicators covering main content, impurities, oil content, and acid value. The method standards referenced by GB/T 23271, such as GB/T 3049 and ASTM D974, ensure the accuracy and inter-laboratory comparability of test results. Procurement parties citing the standard's provisions during acceptance inspection can effectively constrain supply quality and reduce batch variation risks.

---

SEO Tags: Molybdenum Disulfide, GB/T 23271, National Standard, MoS2, Quality Control, Testing Indicators, 二硫化钼, 国家标准, Quality Assurance, Iron Content Testing