What Is Strontium Ferrite?

2026-08-18

Strontium ferrite, with the chemical formula SrFe₁₂O₁₉, is a black powder at room temperature and is used as a stator or rotor material in permanent magnet motors. Its safety label is Xi (irritating to the eyes). Preparation methods include low-heat solid-state reaction and microwave sintering. In the low-heat method, lattice parameters and magnetic properties can be controlled by adjusting the pH value, with optimal magnetic properties (coercive force of 71.2 A/m) achieved at pH = 10. Microwave sintering technology can shorten the production cycle and improve product yield.

What Are the Properties of Strontium Ferrite?

Melting point	>450 °C(lit.)
density	5.18 g/mL at 25 °C(lit.)
vapor pressure	0Pa at 20℃
solubility	Soluble in organic solvents.
pka	7.1[at 20 ℃]
Specific Gravity	5.10
Water Solubility	80μg/L at 20℃
Hydrolytic Sensitivity	4: no reaction with water under neutral conditions

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Risk and Safety Statements

Hazard Codes	Xi
Risk Statements	36
Safety Statements	26-36
WGK Germany	3
TSCA	TSCA listed
Storage Class	13 - Non Combustible Solids

Barium Ferrite Powder vs. Strontium Ferrite Powder

Depending on the materials used in their manufacture, ferrite magnets are primarily classified as strontium ferrite (SrO.6Fe₂O₃) and barium ferrite (BaO.6Fe₂O₃), with strontium ferrite magnets being the more widely used of the two.

1. Different saturation magnetisation. The saturation magnetisation of strontium ferrite is approximately 1.35 T, which is higher than that of barium ferrite (approximately 1.1 T). This is because strontium atoms have a larger atomic radius, which increases the spacing between ferrous ions and reduces the diamagnetic exchange interaction between them, thereby helping to increase the saturation magnetisation.
2. The anisotropy constants differ. The anisotropy constant of barium ferrite is approximately 4.5 × 10⁵ J/m³, which is greater than that of strontium ferrite (2.7 × 10⁵ J/m³). A higher anisotropy constant means it is more difficult to change the direction of magnetisation; therefore, barium ferrite exhibits stronger anisotropy.
3. Different phase transition temperatures. The phase transition temperature of barium ferrite is approximately 130 K, while that of strontium ferrite is approximately 250 K. Strontium ferrite has a higher phase transition temperature and a wider range of applications.
4. Different resistivities. The resistivity of strontium ferrite is approximately 10⁻⁵ Ω·m, which is lower than that of barium ferrite (10⁻³ Ω·m); therefore, strontium ferrite exhibits better electrical conductivity.
5. Price differences. Since strontium is more abundant than barium, strontium ferrite is less expensive than barium ferrite; this is also a key reason for the wider application of strontium ferrite.

What Is Strontium Ferrite Used For?

Strontium ferrite has a wide range of applications, spanning multiple fields such as magnetic materials, electronic devices, microwave devices, and electromagnetic shielding. In the field of magnetic materials, strontium ferrite is commonly used to manufacture magnetic powders, magnetic recording media, and permanent magnet materials. In the field of electronic devices, strontium ferrite is commonly used to manufacture transformers, inductors, and sensors. In the field of microwave devices, strontium ferrite is commonly used to manufacture antennas, filters, and isolators. In the field of electromagnetic shielding, strontium ferrite is commonly used to manufacture EMI shielding materials and magnetic shielding materials.