Brake pad backing plate
A coated backing plate for a brake pad and method of manufacturing a brake pad having a coated backing plate, where the coating for the backing plate includes a bond layer. The bond layer includes an inboard surface, an outboard surface, a closed pore network toward the outboard surface that faces the inboard surface of the reinforcement plate, and an open pore network at the inboard surface of the bond layer. The open pore network includes a recessed topology having a plurality of craters configured to interlock a friction material of a friction pad or one or more intermediate layers, such as a transition layer and/or a thermal barrier layer.
1. A coated backing plate for a brake pad, comprising:
a reinforcement plate having an outboard surface and an inboard surface; and
a thermal barrier coating comprising a bond layer, a transition layer, and a thermal barrier layer, the bond layer having a closed pore network toward an outboard surface of the bond layer that faces the inboard surface of the reinforcement plate, and the thermal barrier coating having an open pore network at an inboard surface of the thermal barrier layer, wherein the open pore network includes a recessed topology having a plurality of craters configured to interlock a friction material of a friction pad, and wherein the bond layer, the transition layer, and the thermal barrier layer each have a different material composition.
2. The coated backing plate of claim 1 , wherein the open pore network and the closed pore network create a pore space geometry having an architecture, wherein the architecture of the pore space geometry is influenced by a parameter in a thermal spray process.
3. The coated backing plate of claim 2 , wherein a tortuosity of the open pore network defines a sinuosity and an interconnectedness of the pore space geometry.
4. The coated backing plate of claim 1 , wherein one or more craters of the plurality of craters includes a tortuous side wall.
5. The coated backing plate of claim 4 , wherein the tortuous side wall includes two or more separate undercuts, each undercut having an area that generally opposes the inboard surface of the reinforcement plate.
6. The coated backing plate of claim 1 , wherein the bond layer includes hollow sphere particles, spray dried particles, sintered particles, sol-gel particles, fused particles, crushed particles, or a combination of hollow sphere particles, spray dried particles, sintered particles, sol-gel particles, fused particles, and/or crushed particles.
7. The coated backing plate of claim 1 , wherein the thermal barrier coating has a porosity by volume between 5% and 25%, inclusive.
8. The coated backing plate of claim 1 , wherein the transition layer and the thermal barrier layer include a ceramic material with a thermal conductivity that is less than 1 W/mk.
9. The coated backing plate of claim 1 , wherein the thermal barrier coating has a gradient structure that transitions from 100% of a metal bond material for the bond layer to 100% of a ceramic material for the thermal barrier layer.
10. The coated backing plate of claim 9 , wherein 10% to 90%, inclusive, of a thickness of the thermal barrier coating is formed of the bond layer, up to 80% of the thickness of the thermal barrier coating is formed of the gradient structure, and 10% to 90%, inclusive, of the thickness of the thermal barrier coating is formed of the thermal barrier layer.
11. A brake pad, comprising:
the coated backing plate of claim 1 ; and
a friction pad of a friction material, wherein the friction material is interlocked with the open pore network.
12. A coated backing plate for a brake pad, comprising:
a reinforcement plate having an outboard surface and an inboard surface; and
a bond layer having an inboard surface and an outboard surface, wherein the outboard surface of the bond layer faces the inboard surface of the reinforcement plate, wherein the inboard surface of the bond layer includes a plurality of craters configured to interlock friction material of a friction pad or one or more intermediate layers, wherein one or more craters of the plurality of craters includes a tortuous side wall, wherein the tortuous side wall includes two or more separate undercuts, each undercut having an area that generally opposes the inboard surface of the reinforcement plat; and wherein a material for the bond layer and a material for the reinforcement plate are separate materials.
13. A brake pad, comprising:
the coated backing plate of claim 12 ; and
a friction pad of a friction material, wherein the friction material is interlocked with the plurality of craters at the inboard surface of the bond layer, or the friction material is interlocked with a plurality of craters at an inboard surface of an intermediate layer of the one or more intermediate layers.
14. A method of manufacturing a brake pad, comprising the steps of:
preparing a reinforcement plate, the reinforcement plate having an inboard surface and an outboard surface;
spraying a bond layer material to the inboard surface of the reinforcement plate;
adjusting a velocity of a spray plume to generate larger metal droplets to collide while in flight to the inboard surface of the reinforcement plate and forming a coated backing plate; and
pressing a friction pad to the coated backing plate such that a friction material of the friction pad interlocks with an open pore network of the coated backing plate.
15. The method of claim 14 , wherein the open pore network includes a recessed topology having a plurality of craters configured to interlock the friction material of the friction pad.
16. The method of claim 14 , wherein the bond layer is sprayed by high velocity oxy-fuel (HVOF) spraying.
17. The method of claim 16 , further comprising the step of plasma spraying a gradient structure and a thermal barrier layer on the bond layer.