Friction brake assembly with an abradable metal foam brake pad

1. A brake assembly, comprising:

a substrate; and

a brake pad comprising abradable cellular metal foam, wherein the brake pad is affixed to the substrate, and extends away from the substrate to form a brake pad friction surface, and wherein the metal foam consists essentially of at least one carbide and at least one metal alloy; and

wherein the metal alloy comprises at least one of cobalt, titanium or boron; and

wherein the metal alloy forms a metal alloy matrix which bonds particles of the carbide together.

2. The brake assembly of claim 1 , wherein the metal foam comprises open-cell metal foam.

3. The brake assembly of claim 1 , wherein the metal foam comprises closed-cell metal foam.

4. The brake assembly of claim 1 , wherein the metal foam comprises a lattice structure.

5. The brake assembly of claim 1 , wherein the metal foam has a metal foam pore to metal foam material volumetric porosity of greater than about one to nineteen.

6. The brake assembly of claim 5 , wherein the volumetric porosity is between about three to seventeen and about three to about seven.

7. The brake assembly of claim 1 , wherein the metal foam has a metal foam pore size that is one of less than and equal to about one hundred fifty microns.

8. The brake assembly of claim 1 , wherein the friction surface has a coefficient of friction greater than about 0.3.

9. The brake assembly of claim 1 , wherein the metal foam is operable to withstand a temperature greater than about eight hundred degrees Centigrade, and a compressive load greater than forty mega Pascals.

10. The brake assembly of claim 1 , wherein the metal alloy comprises at least the cobalt.

11. The brake assembly of claim 1 , wherein the substrate includes one of steel and iron.

12. The brake assembly of claim 1 , further comprising a bond layer disposed between the substrate and the brake pad.

13. The brake assembly of claim 1 , wherein the substrate comprises a wedge-shaped brake shoe for an elevator safety brake system.

14. The brake assembly of claim 1 , wherein the substrate is removably connected to a wedge-shaped brake shoe for an elevator safety brake system.

15. The brake assembly of claim 1 , wherein the metal alloy comprises at least the titanium.

16. The brake assembly of claim 1 , wherein the metal alloy comprises at least the boron.

17. A method for manufacturing a brake assembly, comprising:

coating a substrate with brake pad material comprising a metal powder, a plurality of carbide particles and a foaming agent that is a heat activated foaming agent;

heating the coated substrate to a temperature that activates the foaming agent and transforms the brake pad material into abradable cellular metal foam; and

cooling the abradable cellular metal foam coated substrate;

wherein, during the heating of the coated substrate, the metal powder alloys together and bonds with the carbide particles;

wherein the metal comprises at least one of cobalt, titanium or boron; and

wherein the abradable cellular metal foam consists essentially of the alloyed metal powder and the bonded carbide particles.

18. The method of claim 17 , wherein the coating comprises cold spraying the brake pad material onto the substrate.

19. The method of claim 17 , wherein

the brake pad material further comprises a binder; and

the carbide particles comprise a plurality of hardened ceramic particles; and

wherein, during the heating of the coated substrate, the metal powder alloys together and bonds with the hardened ceramic particles and the binder.

20. The method of claim 17 , wherein the metal foam is operable to withstand a temperature greater than about eight hundred degrees Centigrade, and a compressive load greater than about forty mega Pascals.

21. The method of claim 17 , wherein

the metal foam has a metal foam pore-to-metal foam material volumetric porosity between about one to nineteen and about three to two; and

the metal foam has a metal foam pore size that is one of less than and equal to about one hundred and fifty microns.

22. The method of claim 17 , wherein the temperature is above 1250 degrees Centigrade.

23. The method of claim 17 , wherein the alloyed metal powder forms a metal alloy matrix which bonds the carbide particles together.