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Product Benefits
Technical Details

Magnetite (iron oxide, chemical formula Fe3O4) is a dense, black powder which can be characterised by:

  • High density
  • Ferro-magnetic properties
  • Potential to heat up when subjected to microwave radiation (microwave induced heating).


Basic properties

Property Value Unit
Moisture 0.1 [%]
Hardness (Mohs) 5.5 [-]
Colour black [-]
Density 5.4 [kg/ dm3]


Product overview

Grade + 45 µm D50




M63 9 10 65

Production location Portafer M

Portafer M is the brand name for Sibelco’s magnetite.



  • Ferro-magnetic properties: unlike micaceous iron oxide magnetite can provide ferro-magnetic properties to a coating. When used in the right amount and applied at a certain film thickness, it is possible to stick magnetic materials to a non-ferrous substrate when coated with this paint.
  • Microwave induced heating: microwave radiation enables rapid processes and curing of sealants and adhesives, even of bond lines that are thick or difficult to access. Where metal substrates are used, they will heat up rapidly as well, allowing very fast curing of the sealant or adhesive. When working with non-conductive substrates (ceramics, polymers or composites), adhesives can be modified with appropriate mineral fillers such as magnetite. This will cause direct heating of the bond line and hence rapid curing.


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