Powder characterisation according to Ma-0015

Ma-0015 is a document written by SAFRAN which describes the general conditions of supply, processing and reception of metal powders intended for the manufacture of SAFRAN-designed articles or parts of articles.

In order to guarantee the quality of the parts produced, the metal powders must therefore meet numerous requirements. Thus, the parameters regularly assessed are :

1. granulometry, generally carried out by laser granulometry in accordance with standard ISO 13320 and allowing access to the granulometric distribution with determination of the characteristic parameters (d10, d50, d90)
2. flowability characterised by a flow time using a calibrated funnel of the Hall cone type according to ISO 4490 and ASTM B 213 or Carney cone according to ASTM B 964,
   
3. the apparent density and the tapped density, which characterise by mechanical effect the ability of a powder to organise itself by expelling air between the grains. These tests are carried out using a packing volumeter in accordance with ASTM B 527 and ISO 3953. The Hausner index is the ratio of the tapped density to the bulk density,
   
4. the true density determined by pycnometry according to ISO 12154 or ASTM B 923. This quantity makes it possible to determine the internal porosity rate by calculation using the theoretical density (of a solid material for example),
   
5. morphology qualified by Scanning Electron Microscopy (SEM-FEG) and Optical Microscopy in order to assess granulo-morphology, sphericity, satelliteness (small diameter powder agglomerated on large diameter powder for recycled materials)
   
6. the moisture content determined gravimetrically after drying according to ASTM E 1868,
   
7. the chemical composition of metal powders. It is determined by spectroscopic techniques such as ICP-AES and ICP-MS and elemental analysis techniques after combustion for the quantification of the elements C, S, N, O and H.
   

Compliance with the requirements associated with these different characteristics enables the metal powder to generate a low defect rate (porosity, inclusion, etc.) and a high level of compactness on the part produced, which are synonymous with excellent mechanical properties.