Method of manufacturing magnetic shielding block for wireless power chargers
Embodiments provide a magnetic shield for wireless power chargers and a method of manufacturing the same. The method includes forming flake powder having flake-type particles, forming an oxide film by performing oxygen heat treatment on the surface of the flake powder, performing insulation treatment on the surface of the flake powder provided with the oxide film formed thereon, and producing a sendust block by mixing and melting the insulation-treated flake powder and insulative resin powder. Therefore, a magnetic shield having high insulation characteristics and magnetic permeability may be provided.
1. A method of manufacturing a magnetic shield comprising:
forming flake powder having flake particles;
forming an oxide film by performing oxygen heat treatment on the surface of the flake powder;
forming an insulation layer on the surface of the oxide film of the flake powder by applying a chemical additive to the surface of the oxide film; and
producing a sendust block by mixing and melting the insulation-treated flake powder and insulative resin powder,
wherein the sendust block is produced by mixing the insulation-treated flake powder and the insulative resin powder such that particles of the insulation-treated flake powder are spaced apart from each other and uniformly arranged in the sendust block, and then performing heat treatment so as to melt the insulative resin powder and form the magnetic shield.
2. The method according to claim 1 , wherein formation of the flake powder includes:
producing soft magnetic metal alloy powder having spherical particles using water atomization or gas atomization; and
compressing the soft magnetic metal alloy powder.
3. The method according to claim 1 , wherein the chemical additive includes at least one of phosphate, a lubricant, kaolin, talc, magnesium hydroxide, aluminum oxide (Al 2 O 3 ), Zn-stearate, Mg-stearate and sodium silicate.
4. The method according to claim 1 , further comprising:
performing an insulation test by applying AC current to the produced sendust block; and
upon judging that the sendust block fails the insulation test, performing insulating coating on the surface of the sendust block.
5. The method according to claim 4 , further comprising:
measuring magnetic permeability of the sendust block; and
judging whether or not the sendust block passes inspection based on the measured magnetic permeability.
6. The method according to claim 1 , wherein terminals are formed integrally with the sendust block.
7. The method according to claim 1 , wherein the insulative resin powder is formed of a polyimide-based resin or a phenol-based resin.