Ceramic substrate with reaction-bonded silicon carbide having diamond particles
A composite material can include: a substrate of a first reaction-bonded silicon carbide (first RB-SiC) material; and a reaction-bonded diamond-retaining silicon carbide (RB-DSiC) layer bonded to a surface of the substrate. In some aspects, the RB-DSiC layer includes diamond particles bonded with a second reaction-bonded silicon carbide (second RB-SiC) material. The diamond particles may be homogeneously distributed through the second RB-SiC or only at the surface thereof. The diamond particles can be in an ordered pattern or un-ordered pattern. For example, a CMP conditioning disc can include the composite material of one of the embodiments.
1. A method of forming a composite, the method comprising:
providing a preform substrate of a reaction-bonded silicon carbide material;
forming a silicon carbide (SiC) paste by mixing silicon carbide particles and an organic binder;
applying the SiC paste onto a surface of the preform substrate;
pressing diamond particles into the SiC paste after applying the SiC paste onto the surface of the preform substrate such that at least a portion of the diamond particles protrude from a surface of the SiC paste, wherein the diamond particles are larger than the silicon carbide particles, and a size of the diamond particle varies across the surface of the SiC paste;
infiltrating the silicon carbide paste with molten silicon; and
firing the SiC paste to carbonize the organic binder and chemically react the molten silicon with the diamond particles and the preform substrate to form a reaction-bonded diamond-retaining silicon carbide (RB-DSiC) layer reaction bonded to the surface of the preform substrate.
2. The method of claim 1 , further comprising mixing fine diamond particles to the SiC paste.
3. The method of claim 2 , wherein the organic binder is selected from the group consisting of polyvinyl alcohol (PVA), epoxy, phenolic, nano-carbon based slurries, and combinations thereof.
4. The method of claim 1 , further comprising:
providing an adhesive sheet;
providing a screen over the adhesive sheet;
screening the diamond particles through the screen onto the adhesive sheet; and
pressing the diamond particles into the surface of the SiC paste while the diamond particles are adhered to the adhesive sheet.
5. The method of claim 4 , further comprising:
removing the screen prior to pressing the diamond particles into the surface of the SiC paste; and
removing the adhesive sheet from the diamond particles that are pressed into the SiC paste.
6. The method of claim 1 , further comprising at least one of:
pressing the diamond particles into the surface of the SiC paste such that the diamond particles protrude a substantially same length from a surface of the SiC paste; or
pressing the diamond particles into the surface of the SiC paste such that the diamond particles have a substantially same length of diamond embedded into the SiC paste.
7. The method of claim 1 , further comprising forming the composite into a CMP conditioning disc.
8. The method of claim 1 , wherein the reaction-bonded silicon carbide material or the preform substrate comprises silicon carbide (SiC) particles, the method further comprising firing the SiC paste to carbonize the organic binder and to form a reaction-bonded diamond-retaining silicon carbide (RB-DSiC) layer reaction bonded to the surface of the preform substrate comprising forming the RB-DSiC layer such that the substrate is distinguishable from the RB-DSiC layer by at least one of:
an interface between the substrate and the RB-DSiC layer;
the substrate has a first average SiC particle size that is different from a second average SiC particle size of the RB-DSiC layer;
the substrate has a first average spacing distance between SiC particles that is different from a second average spacing distance between SiC particles of the RB-DSiC layer;
the substrate has a first average volume of SiC particles per total unit volume that is different from a second average volume of SiC particles per total unit volume of the RB-DSiC layer;
the substrate has a first volume percent of SiC particles that is different from a second volume percent of SiC particles of the RB-DSiC layer; and
the substrate has a first volume percent of unreacted silicon (Si) that is different from a second volume percent of unreacted Si of the RB-DSiC layer.
9. The method of claim 1 , further comprising mixing fine diamond particles into the SiC paste, wherein the fine diamond particles have a size of about 1 μm to about 10 μm.
10. The method of claim 1 , wherein infiltrating the silicon carbide paste with the molten silicon occurs while firing the SiC paste.