Coatings for brake discs, method for reducing wear and corrosion and associated brake disc

Patent metadata

Field	Value
Publication number	US-11614134-B2
Application number	US-202017131244-A
Country	US
Kind code	B2
Filing date	Dec 22, 2020
Priority date	Dec 22, 2020
Publication date	Mar 28, 2023
Grant date	Mar 28, 2023

Abstract

Brake pads are prepared using a formulation of friction material of the copper-free type (Low-Steel or Organic Non-Asbestos) and at least one friction surface of a brake disc, which is intended to cooperate with the brake pad, is covered with an anti-wear and anti-corrosion coating consisting of a surface layer of chromium carbide particles (Cr3C2) dispersed in a metallic matrix consisting of a NiCr alloy, and coupled to a second layer consisting of selected combinations of metallic materials, chosen from the group consisting of: Cr3C2-high density NiCr, NiAl alloys, FeNiCrMoSiC alloys, metallic nickel, NiCr alloys, and/or any combination of the above.

First claim

The invention claimed is:

1. An anti-wear and anti-corrosion coating for a brake disc comprising:
a first outermost surface layer; and
an intermediate second layer coupled to the first outermost surface layer, wherein
the intermediate second layer is arranged between the first outermost surface layer and a friction surface of the brake disc,
the first outermost surface layer comprises particles of chromium carbide (Cr3C2) dispersed within a metallic matrix comprising an NiCr alloy,
the first outermost surface layer is applied by means of thermal spray,
the intermediate second layer comprises an alloy of FeNiCrMoSiC (iron-nickel-chromium-molybdenum-silicon-carbon), and
the first outermost surface layer is deposited upon the intermediate second layer previously deposited upon the friction surface of the brake disc.

2. The anti-wear and anti-corrosion coating according to claim 1 , wherein the brake disc is configured to cooperate in use with a braking element.

3. The anti-wear and anti-corrosion coating according to claim 1 , wherein
the particles of chromium carbide (Cr3C2) are dispersed in spheroidal form, and
the first outermost surface layer is applied with a deposition system via HVOF (High Velocity Oxygen Fuel) thermal spray technique.

4. The anti-wear and anti-corrosion coating according to claim 1 , wherein the anti-wear and anti-corrosion coating has a thickness between 20 and 400 micrometers.

5. The anti-wear and anti-corrosion coating according to claim 1 , wherein
the anti-wear and anti-corrosion coating has, after coating and grinding, a surface roughness between 0.05 and 1.0 micrometers, and
the first outermost surface layer and/or the intermediate second layer are applied with a deposition system via HVOF thermal spray technique.

6. A vehicle brake system comprising:
an element to be braked, the element to be braked comprising a brake disc or a drum made from cast iron or steel; and
at least one braking element comprising a brake shoe or a pad, suitable for cooperating by friction with the element to be braked, the element to be braked having at least one friction surface configured to cooperate with the at least one braking element and the at least one friction surface covered with an anti-wear and anti-corrosion coating, wherein
the anti-wear and anti-corrosion coating comprises a first outermost surface layer and an intermediate second layer coupled to the first outermost surface layer,
the intermediate second layer is arranged between the first outermost surface layer and a friction surface of the element to be braked,
the first outermost surface layer comprises particles of chromium carbide (Cr3C2) dispersed within a metallic matrix comprising an NiCr alloy, and
the intermediate second layer comprises an alloy of FeNiCrMoSiC (iron-nickel-chromium-molybdenum-silicon-carbon).

7. The vehicle brake system according to claim 6 , wherein
the first outermost surface layer is applied by means of thermal spray, and
the first outermost surface layer is deposited upon the intermediate second layer previously deposited upon the friction surface of the element to be braked.

8. The vehicle brake system according to claim 6 , wherein
the particles of chromium carbide (Cr3C2) are dispersed in spheroidal form, and
the first outermost surface layer is applied with a deposition system via HVOF (High Velocity Oxygen Fuel) thermal spray technique.

9. The vehicle brake system according to claim 6 , wherein the anti-wear and anti-corrosion coating has a thickness between 20 and 400 micrometers.

10. The vehicle brake system according to claim 6 , wherein
the anti-wear and anti-corrosion coating has, after coating and grinding, a surface roughness between 0.05 and 1.0 micrometers, and
the first outermost surface layer and/or the intermediate second layer are applied with a deposition system via HVOF thermal spray technique.

11. The vehicle brake system according to claim 6 , wherein the braking element comprises at least one friction material block configured to cooperate with the element to be braked, the friction material being of the copper free type (Low Steel or Non-Asbestos Organic).

12. A method for the simultaneous reduction in wear of a brake disc and associated brake pads, the method comprising:
preparing one or more brake pads using an LS (Low Steel) or NAO (Non Asbestos Organics) type friction material formulation;
covering at least one friction surface of a brake disc intended to cooperate in use with a brake pad with an anti-wear and anti-corrosion coating comprising a first surface layer of particles of chromium carbide (Cr3C2) dispersed within a metallic matrix consisting of a NiCr alloy and an intermediate second layer coupled to the first surface layer comprising an alloy of FeNiCrMoSiC (iron-nickel-chromium-molybdenum-silicon-carbon); and
coupling together the prepared one or more brake pads and the brake disc.

13. The method according to claim 12 , wherein the anti-wear and anti-corrosion coating is applied by means of the HVOF (High Velocity Oxygen Fuel) thermal spray technology.

14. The method according to claim 12 , wherein the intermediate second layer is applied by HVOF thermal spray or by galvanic means.

15. The method according to claim 12 , wherein the one or more brake pads manufactured with a friction material belonging to the copper-free family (Low-Steel or Non-Asbestos Organic) are coupled together with the anti-wear and anti-corrosion coating coated on at least one friction surface of the brake disc.

Assignees

• Itt Italia Srl

Inventors

• Sin Xicola Agustin
• Vannucci Francesco
• Ansaloni Simone

Classifications

• F16D69/027

  Compositions based on metals or inorganic oxides · CPC title

• F16D69/026

  containing fibres · CPC title

• F16D2200/0078

  laminated · CPC title

• F16D65/127

  characterised by properties of the disc surface; Discs lined with friction material · CPC title

• F16D65/125 Primary

  characterised by the material used for the disc body · CPC title