Systems and methods for forming a layer onto a surface of a solid substrate and products formed thereby
A method for forming a vehicular brake rotor involving loading a shaped metal substrate with a mixture of metal alloying components and ceramic particles in a dieheating the contents of the die while applying pressure to melt at least one of the metal components of the alloying mixture whereby to densify the contents of the die and form a ceramic particle-containing metal matrix composite coating on the metallic substrate; and cooling the resulting coated product.
1. A method for forming a vehicular brake rotor comprising a friction surface layer bonded to a surface of a solid metal substrate, the method comprising the steps of:
(A) providing a solid metal substrate;
(B) employing a scanning plasma torch to direct a high temperature are plasma stream onto a surface of the substrate; said plasma stream comprising a metal selected from the group consisting of aluminum, cobalt, copper, iron, nickel, titanium, vanadium and zinc, or a metal alloy comprising two or more metallic elements, selected from the group consisting of aluminum, cobalt, copper, iron, nickel, titanium, vanadium, zinc, chromium, magnesium, manganese, niobium and silicon, a ceramic material in powder form selected from the group consisting of a metal carbide, a metal nitride, a metal silicide and an intermetallic composition, and an ionizable gas, said substrate forming an electrode and completing an electrical circuit with said plasma arc and a torch power supply, said plasma having sufficient energy to ionize the gas so as to heat and melt an area on a surface of the substrate; and
(C) causing a reaction between a melted metal in the area of the substrate and a metal or metal alloy in the plasma steam whereby to form a composite surface area incorporating the ceramic material in powder form on the substrate without any intervening layer; and
(D) moving the scanning plasma touch and repeating steps (B) and (C) to form a surface layer across a surface of the metal substrate, whereupon the ceramic material in powder form is directly bonded to the surface of the metallic substrate whereby to increase friction and enhance wear resistance of the surface of the metal substrate.
2. The method of claim 1 , including the step of impinging a cooling jet stream of gas onto the plasma heated area of the substrate following formation of the composite surface.
3. The method of claim 1 wherein the substrate comprises a metal selected from the group consisting of aluminum, titanium, iron, nickel, copper or zinc, or an alloy thereof, and the ceramic material in powder form comprises silicon carbide.
4. The method of claim 1 , wherein the ionizable gas comprises at least one of Ar, He, a mixture of Ar, He and N 2 , or a carbon-containing gas.
5. The method of claim 1 , wherein the substrate is in a shape of a full size disc, including a hub.