Patent Publication Number: US-2022219234-A1

Title: Channeled hardfacing wear protection incorporating matrix composite and hard elements

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 63/135,058, filed Jan. 8, 2021, the contents of which are fully incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTIONS 
     1. Field of the Inventions 
     The present inventions generally pertain to hardfacing wear protection, and more particularly to hardfacing wear protection incorporating matrix composite and hard elements with integrated channeling. 
     2. Description of the Related Art 
     Hardfacing wear protection has the purpose of providing a surface with wear resistant properties. Those familiar in the art will recognize that the most common type of hardfacing is a matrix composite comprising of an alloy material with fine and/or ultrafine tungsten carbide particles dispersed within it and the matrix composite fused to the substrate material of the surface to be protected. Another common wear resistant surface has relatively large hard elements arrayed and fused in place with matrix composite or braze alloy to provide additional wear resistance to the surface. In the most common manufacturing method, the hard elements are located on the hard surface manually, and then tacked in place metallurgically before the matrix composite or braze alloy is applied using brazing, plasma transfer arc welding, or laser welding or a similar process to complete the hardfacing. Other methods use induction heating to fuse the hard elements and matrix composite in place, but they each require sacrificial forms and can only be used in particular configurations (for example a flat surface is not possible). 
     Channeled hardfacing wear protection has the purpose of providing a surface with wear resistant properties with the added purpose of providing channels for fluid circulation, improved lubrication, and improved cooling of the hardfacing materials. In each case above the hardfacing process cannot include the channeling of the hardsurface with the application of the hardfacing itself. The only means of channeling the hard facing is post fusion finishing by means of extensive and expensive grinding or machining; the channel pattern cannot be optimized to be focused solely on the matrix composite between the hard elements; and the ability to create a fine or precise channel pattern is extremely difficult. 
     There remains a need for a channeled hardfacing that contains hard elements with matrix composite that has the channels formed prior to finish machining or finish grinding of the component in a cost-effective, customizable manner. 
     SUMMARY OF THE INVENTIONS 
     The present inventions described herein overcome many of the deficiencies of previous art listed above and provides the following benefits: (1) channels in the hardfacing are created at the time of fusion rather than mechanically added in post fusion processing; (2) the channels only exist where the less abrasion resistant matrix composite occur in the hardfacing; (3) the hard elements that provide the strongest material for the hardfacing do not have their surface area coverage affected by the channeling; (4) the scale of the channel pattern can be easily controlled by changing the sizes and distributions of the hard elements and the preforms; (5) channeling distribution can be easily controlled such that preselected surfaces of the hardfacing can contain channels, and other surfaces can contain no channels; (6) components making up the hardfacing are pre-assembled before being applied to the part, a process that can be automated more easily than being assembled on the finished part; (7) the parts can be fused in large batches instead of individually; (8) does not require any sacrificial parts or additional machining processing as compared to some other methods; (9) results in a very high hard particle density and homogeneous distribution in matrix composite; (10) improved accuracy on post fusion surface finish which results in reduced finish grinding time of part; (11) base layer ensures metallurgical bond to substrate with a matrix composite and/or fused alloy located on the underside of the hard elements, reduces stresses in the hardfacing, and provides crack mitigation; (12) the positioning of the hard elements are not disturbed in the process when using vacuum brazing which will result in a more cosmetically pleasing product; (13) does not need to have a cavity in which to cast the hardsurface unlike many other methods; and (14) the hard elements are not degraded by the fusion process because the local fusion temperatures are not as high and are more controlled. 
     In one aspect, the present inventions may include a method of making a channeled composite article comprising: creating a plurality of preforms including at least a base layer preform, a perforated hard particle preform including a plurality of cavities, and a perforated braze preform including a plurality of cavities corresponding to the cavities in the perforated hard particle preform; assembling on a flat surface the base layer preform, the perforated hard particle preform, the perforated braze preform, and hard elements into a layered preform coating mat; applying the layered preform coating mat to a substrate with the base layer preform of the layered preform coating mat disposed adjacent the substrate; and fusing the layered preform coating mat to the substrate with braze from the perforated braze preform, thereby forming channels between the hard elements over at least a portion of the layered preform coating mat. Another feature of this aspect of the present inventions may be that the method may further include adding a nonperforated braze preform to the layered preform coating mat on top of the perforated braze preform before fusing the layered preform coating mat to the substrate. Another feature of this aspect of the present inventions may be that the plurality of cavities in the perforated hard particle preform may be aligned with the plurality of cavities in the perforated braze preform, and the hard elements are positioned within the aligned cavities. Another feature of this aspect of the present inventions may be that upper surfaces of the hard elements may be generally flush with an upper surface of the perforated braze preform before the layered preform coating mat is fused to the substrate. Another feature of this aspect of the present inventions may be that upper surfaces of the hard elements may be generally projected above the upper surface of the perforated braze preform before the layered preform coating mat is fused to the substrate. Another feature of this aspect of the present inventions may be that upper surfaces of the hard elements may be generally recessed below the upper surface of the perforated braze preform before the layered preform coating mat is fused to the substrate. Another feature of this aspect of the present inventions may be that the entire surface of the layered preform coating mat includes channels between the hard elements after the layered preformed coating mat is fused to the substrate. Another feature of this aspect of the present inventions may be that materials from the layered preform coating mat that are fused to the substrate consist of at least one of hard elements, hard particles, metallic particles, and ceramic particles. Another feature of this aspect of the present inventions may be that the layered preform coating mat is fused to the substrate with braze from the perforated braze preform using one of (a) a vacuum furnace, (b) vacuum induction heating, and (c) laser heating. Another feature of this aspect of the present inventions may be that the method may further include post fusion heat treating the substrate and fused layered preform coating mat. Another feature of this aspect of the present inventions may be that the composite article is a radial bearing. Another feature of this aspect of the present inventions may be that the hard elements are one of tungsten carbide tiles and polycrystalline diamond solid. Another feature of this aspect of the present inventions may be that the hard particle preform layer includes a plurality of hard elements disposed in a pattern with a hard particle preform located between and partially filling the space around the hard elements to define a plurality of channels between the hard elements. Another feature of this aspect of the present inventions may be that the substrate is cylindrical. Another feature of this aspect of the present inventions may be that the base layer preform is formed of at least one of fine or ultrafine metallic particles, and fine or ultrafine ceramic or cermet particles, the particles being held together with a fibrillated polymer. Another feature of this aspect of the present inventions may be that creating the hard particle preform includes applying alternating cuts to a preform material, and expanding the cut preform material to form cavities to receive the hard elements. Another feature of this aspect of the present inventions may be that creating the perforated hard particle preform and the perforated braze preform includes using the hard elements as punches to perforate the perforated hard particle preform and the perforated braze preform. Another feature of this aspect of the present inventions may be that the layered preform coating mat further includes a second preform layer disposed between the base layer preform and the depressed hard particle preform layer. 
     In another aspect, the present inventions may include a method of making a partially channeled composite article comprising: creating a plurality of preforms including at least a base layer preform, a depressed perforated hard particle preform including a plurality of cavities and a depressed section, a perforated braze preform inlay including a plurality of cavities corresponding to a portion of the cavities in the depressed perforated hard particle preform and adapted to be received within the depressed section of the depressed perforated hard particle preform, and an unperforated braze preform having an opening corresponding to the depressed section and the perforated braze preform inlay; assembling on a flat surface the base layer preform, the depressed perforated hard particle preform over the top of the base layer preform, the perforated braze preform inlay in the depressed section of the depressed perforated hard particle preform, and the hard elements into the corresponding cavities into a hybrid layered preform coating mat; applying the hybrid layered preform coating mat to a substrate with the base layer preform of the hybrid layered preform coating mat disposed adjacent the substrate; applying unperforated braze preform over the depressed perforated hard particle preform with the opening aligned to the depressed section and the perforated braze preform inlay; and fusing the hybrid layered preform coating mat to the substrate with braze from the perforated braze preform and the unperforated braze preform, thereby forming channels between the hard elements located within the depressed section of the depressed perforated hard particle preform. Another feature of this aspect of the present inventions may be that the method may further include adding a nonperforated braze preform to the hybrid layered preform coating mat on top of the perforated braze preform inlay before fusing the layered preform coating mat to the substrate. Another feature of this aspect of the present inventions may be that the plurality of cavities in the depressed section of the depressed perforated hard particle preform are aligned with the plurality of cavities in the perforated braze preform inlay and the hard elements are positioned within the aligned cavities. Another feature of this aspect of the present inventions may be that before the hybrid layered preform coating mat is fused to the substrate, upper surfaces of the hard elements are generally flush with an upper surface of the perforated braze preform inlay and an upper surface of the depressed perforated hard particle preform. Another feature of this aspect of the present inventions may be that after the hybrid layered preform coating mat is fused to the substrate, upper surfaces of the fused hard elements outside of the depressed section are generally flush with an upper surface of a fused matrix composite formed from the fused depressed perforated hard particle preform and unperforated braze preform to form an unchanneled hard facing wear protection outside of the depressed section, and upper surfaces of the fused hard elements in the depressed section extend upwardly to define a plurality of channels between the hard elements. Another feature of this aspect of the present inventions may be that upper surfaces of the hard elements are generally projected above the upper surface of the perforated braze preform inlay before the hybrid layered preform coating mat is fused to the substrate. Another feature of this aspect of the present inventions may be that upper surfaces of the hard elements are generally recessed below the upper surface of the perforated braze preform inlay before the hybrid layered preform coating mat is fused to the substrate. Another feature of this aspect of the present inventions may be that the entire surface of the hybrid layered preform coating mat includes channels between the hard elements after the hybrid layered preformed coating mat is fused to the substrate. Another feature of this aspect of the present inventions may be that materials from the hybrid layered preform coating mat that are fused to the substrate consist of at least one of hard elements, hard particles, metallic particles, and ceramic particles. Another feature of this aspect of the present inventions may be that the hybrid layered preform coating mat is fused to the substrate with braze from the perforated braze preform inlay using one of (a) a vacuum furnace, (b) vacuum induction heating, and (c) laser heating. Another feature of this aspect of the present inventions may be that the method may further include post fusion heat treating the substrate and fused hybrid layered preform coating mat. Another feature of this aspect of the present inventions may be that the composite article is a radial bearing. Another feature of this aspect of the present inventions may be that the hard elements are one of tungsten carbide tiles and polycrystalline diamond solid. Another feature of this aspect of the present inventions may be that the depressed hard particle preform layer includes a plurality of hard elements disposed in a pattern with a hard particle preform located between and filling the space around the hard elements in some of the surface and partially filling the space around the hard elements in the rest of the surface to define a plurality of channels between the hard elements over a portion of the surface. Another feature of this aspect of the present inventions may be that the substrate is cylindrical. Another feature of this aspect of the present inventions may be that the base layer preform is formed of at least one of fine or ultrafine metallic particles, and fine or ultrafine ceramic or cermet particles, the particles being held together with a fibrillated polymer. Another feature of this aspect of the present inventions may be that creating the depressed hard particle preform includes applying alternating cuts to a preform material, and expanding the cut preform material to form cavities to receive the hard elements. Another feature of this aspect of the present inventions may be that creating the depressed perforated hard particle preform and the perforated braze preform inlay includes using the hard elements as punches to perforate the depressed perforated hard particle preform and the perforated braze preform inlay. Another feature of this aspect of the present inventions may be that the hybrid layered preform coating mat further includes a second preform layer disposed between the base layer preform and the depressed hard particle preform layer. 
     In yet another aspect, the present inventions may include a hybrid preform coating mat for attachment as part of a hardfacing wear protection to a substrate comprising: a base layer preform; a depressed perforated hard particle preform positioned on top of the base layer preform, and including a plurality of cavities and a depressed section; a perforated braze preform inlay including a plurality of cavities corresponding to the cavities in the depressed perforated hard particle preform and positioned within the depressed section of the depressed perforated hard particle preform; and, a plurality of hard elements, a portion of the hard elements positioned within the cavities in the depressed hard particle preform, and another portion of the hard elements positioned within the cavities in the perforated braze preform inlay and the corresponding cavities in the depressed section of the depressed hard particle preform. Another feature of this aspect of the present inventions may be that upper surfaces of the hard elements are generally flush with an upper surface of the perforated braze preform inlay. Another feature of this aspect of the present inventions may be that an upper surface of the perforated braze preform inlay is generally flush with an upper surface of the depressed perforated hard particle preform. 
     In still another aspect, the present inventions may include a composite article comprising: a substrate; and a fused matrix composite fused to the substrate, the fused matrix composite including a plurality of hard elements, a depressed section and a non-depressed section, the hard elements in the depressed section defining channels therebetween. Another feature of this aspect of the present inventions may be that upper surfaces of the hard elements in the fused matrix composite in the non-depressed section are generally flush with an upper surface of the fused matrix composite to define an unchanneled hard facing wear protection in the non-depressed section. 
     In another aspect, the present inventions may include a composite article comprising: a substrate; and a fused matrix composite fused to the substrate, the fused matrix composite including a plurality of hard elements, upper surfaces of which are disposed above an upper surface of the fused matrix composite to define a plurality of channels between the hard elements extending above the fused matrix composite. 
     Other features, aspects and advantages of the present inventions will become apparent from the following discussion and detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an illustrated isometric view of a radial bearing where the outer surface is the channeled hardfacing wear protection coating as an example of a finished part with the channeled hardfacing wear protection. 
         FIG. 2  is a flow chart explaining the manufacturing process for the channeled hardfacing wear protection. 
         FIG. 3  is an illustrated isometric view of the layered preform coating mat. 
         FIG. 4  is an illustrated detail view of the cross-section of the layered preform coating mat shown in  FIG. 3 . 
         FIG. 5  is an illustrated isometric view of a pre-fusion blank. 
         FIG. 6  is an illustrated detail view of the cross-section of the pre-fusion blank from  FIG. 5  showing the layered preform coating mat applied to a tubular substrate. 
         FIG. 7  is an illustrated isometric view of the fused blank. 
         FIG. 8  is an illustrated detail view of the cross-section of the fused blank from  FIG. 7  showing the channeled hardfacing wear protection on the tubular substrate. 
         FIG. 9  is an illustrated section view of another embodiment of the layered preform coating mat on a tubular substrate where the perforated braze particle preform is recessed below the top of the hard elements. 
         FIG. 10  is an illustrated section view of another embodiment of the layered preform coating mat on a tubular substrate where the perforated braze particle preform is projected above the top of the hard elements. 
         FIG. 11  in an illustrated section view of another embodiment of the layered preform coating mat on a tubular substrate where the perforated braze particle preform is flush to the top of the hard elements and supplemental braze particle preform is applied. 
         FIG. 12  is an illustrated isometric view of embodiment of a partially channeled radial bearing. 
         FIG. 13  is a flow chart explaining the manufacturing process for the partially channeled hardfacing wear protection. 
         FIG. 14  is an illustrated isometric view of an embodiment of a hybrid layered preform coating mat. 
         FIG. 15  is an illustrated isometric view of an embodiment of a depressed perforated hard particle preform. 
         FIG. 16  is an illustrated isometric view of an embodiment of a perforated braze particle preform inlay. 
         FIG. 17  is an illustrated section view taken along line A-A of  FIG. 14  showing the hybrid layered preform coating mat in  FIG. 14  through the section not incorporating a perforated braze particle preform inlay. 
         FIG. 18  is an illustrated section view taken along line B-B of  FIG. 14  showing the hybrid layered preform coating mat in  FIG. 14  through the section incorporating a perforated braze particle preform inlay. 
         FIG. 19  is an illustrated isometric view of the hybrid pre-fusion blank. 
         FIG. 20  is an illustrated detail view of a cross section of the hybrid pre-fusion blank of  FIG. 19  at the perforated braze particle preform inlay showing the transition between the perforated braze particle preform inlay, hard elements, and depressed perforated hard particle preform, with the unperforated braze particle preform. 
         FIG. 21  is an illustrated detail section view of the cross section of the fused substrate of  FIG. 12  in the same plane and location as the detail section view of  FIG. 20 , but after fusion has been completed. 
         FIG. 22  is a side view of an embodiment of a multilayer preform. 
         FIG. 23A  is a specific embodiment for a method of manufacturing a perforated multilayer preform, illustrating an unexpanded condition. 
         FIG. 23B  shows the perforated multilayer preform from  FIG. 23A  in its expanded form. 
         FIG. 24  is a hard element with a raised edge along its perimeter on one face. 
         FIG. 25  is an illustration for a method of perforating a multilayer preform using hard elements as punches showing the hard elements prior to their punching through the multilayer preform. 
         FIG. 26  is an illustration for a method of perforating a multilayer preform using hard elements as punches showing the hard elements after they have perforated the multilayer preform and positioned the hard elements in the perforations. 
         FIG. 27  is an illustrated isometric of an embodiment of a hybrid multilayer preform containing a braze particle preform inlay. 
         FIG. 28  is an illustrated section view in cross-section of another specific embodiment of a layered preform coating mat with the addition of another preform layer under the hard elements and perforated hard particle preform. 
     
    
    
     While the inventions will be described in connection with the specific embodiments disclosed, it will be understood that the scope of protection is not intended to limit the inventions to those embodiments. On the contrary, the scope of protection is intended to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the inventions as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings in detail, wherein like numerals denote identical elements throughout the several views,  FIG. 1  shows an example of a finished part or composite article  10  with a channeled hardfacing wear protection coating  12 . In this example the composite article  10  is a radial bearing. The radial bearing  10  consists of a tubular substrate  14  that has the channeled hardfacing wear protection coating  12  on it, the surface of which is the area of sliding contact for the radial bearing  10 . The channeled hardfacing wear protection coating  12  is made up of an array of hard elements  16  that are fused to the tubular substrate  14  with fused matrix composite  18  and fused base layer  20 . Between the hard elements  16 , the fused matrix composite  18  is recessed below the surface of the hard elements  16  resulting in channels  22  over the sliding contact surface of the radial bearing  10 . Those familiar in the art know the radial bearing  10  can have the channeled hardfacing wear protection coating  12  on an outer surface  24  of the tubular substrate  14 , or the channeled hardfacing wear protection coating  12  can be on an inner surface  26  of the tubular substrate  14 . The channeled hardfacing wear protection coating  12  can also be applied to a variety of substrates, such as flat or undulating surfaces depending on the application and can be used in applications not limited to radial bearings. 
       FIG. 2  describes a specific embodiment of a channeled hardfacing wear protection manufacturing process  28 . It describes the process for applying a channeled hardfacing wear protection coating  12  that has channels  22  over the entire coating surface to a substrate  14 . To begin the process, at step  30 , pre-forms for the various layers needed to form a specific embodiment of the coating  12  are prepared. At minimum, as further discussed below such as in connection with  FIGS. 3 and 4 , there are preferably at least three pre-forms prepared at step  30 , namely: (1) a base layer preform  32 ; (2) a perforated hard particle preform  34  and (3) a perforated braze particle preform  36 . Next, with reference to  FIG. 2 , at step  38 , materials that are to be used for the layered preform coating mat  40  (e.g., the base layer preform  32 , the perforated hard particle preform  34 , the perforated braze particle preform  36 , and hard elements  42 ) are assembled into a layered preform coating mat  40  on a flat surface (see  FIG. 3 ). Next, at step  44 , the layered preform coating mat  40  is applied to the surface of a tubular substrate that it is to be fused to (e.g., outer surface  24  of tubular substrate  14  shown in  FIG. 1 ). Next, at step  46 , the layered preform coating mat  40  is fused to the substrate  14  using any one of a number of high temperature processes (including but not limited to vacuum radiant heating, vacuum induction heating, or laser heating). Specifically, the braze from the perforated braze particle preform  36  fuses the hard elements  42 , the hard particles of the perforated hard particle preform  34  and the ceramic or metallic particles of the base layer preform  32  to the tubular substrate  14 . Afterward, at step  48 , if required, the entire assembly is heat treated to give the substrate the material properties required for the finished part. Finally, at step  50 , the fused substrate is then finished with any required grinding and/or finish machining operations to have the part fit the end user&#39;s dimensional specifications. Additional alternatives concerning steps  38  and  44  are discussed below. 
       FIG. 3  is an illustrated isometric of a specific embodiment of the layered preform coating mat  40  that is assembled in step  38  of the channeled hardfacing wear protection manufacturing process  28 . The layered preform coating mat  40  is made up of several components. There is a base layer preform  32  upon which the next layer is attached. In a specific embodiment the base layer preform  32  is an article made up of fine and/or ultrafine metallic or ceramic particles held together with a fibrillated polymer. Over the base layer preform  32  is a second layer containing hard elements  42 , the perforated hard particle preform  34 , and the perforated braze particle preform  36 . In this embodiment the hard elements  42  are arrayed in a pattern such that the spacing between them is even and they cover the area that will become the wear protected area, but they can be patterned in any spacing and orientation that is appropriate for the application. The hard elements  42  can be made from tungsten carbide, polycrystalline diamond solid, or a similar hard composite and can be in any one of a number of shapes (e.g., round, square, rectangular, hexagon, etc.) and may have flat, rounded, curved, ridged, or rippled bottoms. Between the hard elements  42  are two layers formed by the perforated hard particle preform  34  and the perforated braze particle preform  36 . The two layers are organized such that the perforated hard particle preform  34  is located adjacent to the base layer preform  32 , and the perforated braze particle preform  36  is adjacent to opposite side of the perforated hard particle preform  34 . In a specific embodiment, the perforated hard particle preform  34  may be an article made up of fine and/or ultrafine hard particles held together with a fibrillated polymer. The hard particles can be, but not limited to, spherical or crushed tungsten carbide, thermally stable polycrystalline diamond, cubic boron nitride, or a similar hard material. In a specific embodiment, the perforated braze particle preform  36  may consist of fine and/or ultrafine braze particles held together with a fibrillated polymer. An adhesive may be used to secure the hard elements  42 , the perforated hard particle preform  34 , the perforated braze particle preform  36 , and the base layer preform  32  together. In a specific embodiment, the perforated hard particle preform  34  and perforated braze particle preform  36  with hard elements  42  may be positioned on the flat surface first with the perforated braze particle preform  36  against the flat surface, and then the base layer preform  32  may be adhered to the top of the perforated hard particle preform  34  and hard elements  42  using but not limited to adhesive. 
       FIG. 4  is an illustration of a detail of a section view of the layered preform coating mat  40 . The hard elements  42  are located on the base layer perform  32  in the desired pattern. The perforated hard particle preform  34  is located in between the hard elements  42  and is adjacent to the base layer preform  32 . The perforated braze particle preform  36  is located in between the hard elements  42  and is adjacent to and positioned on top of the perforated hard particle preform  34 . In this embodiment the perforated braze particle preform  36  is flush to the tops of the hard elements  42 . In a specific embodiment, the size, spacing and pattern of the perforated hard particle preform  34  and the perforated braze particle preform  36  may be the same. 
     Another aspect of the present inventions is to assemble a pre-fusion blank  52  by placing the layered preform coating mat  40  on a substrate.  FIG. 5  shows a pre-fusion blank  52  with the layered preform coating mat  40  applied to the tubular substrate  14 . The layered preform coating mat  40  can be adhered to the tubular substrate  14  with, but not limited to, adhesives or induction heating. In the case of a tubular substrate  14 , the layered preform coating mat  40  may also meet up at its ends when wrapped on the tubular substrate  14 . 
       FIG. 6  shows a cross-sectional view of the pre-fusion blank  52  with the layered preform coating mat  40  on the tubular substrate  14  prior to fusion. It shows that the base layer preform  32  is in contact with the tubular substrate  14 . The layer with the hard elements  42  has the perforated hard particle preform  34  adjacent to and between the base layer perform  32  and the perforated braze particle preform  36 , and the perforated braze particle preform  36  is adjacent to and above the perforated hard particle preform  34 . 
     The pre-fusion blank  52  is then processed with any one of a number of methods that result in the fine and/or ultrafine metallic or ceramic particles from the base layer preform  32  and the fine and/or ultrafine hard particles from the perforated hard particle preform  34  of the layered preform coating mat  40  being fused to the tubular substrate  14  in step  46  of  FIG. 2 . In a specific embodiment, a vacuum furnace is used. In this embodiment, the pre-fusion blank  52  is heated up in a vacuum through a staged heating cycle that results in adhesives, polymers and any additional contaminants being burned off. Once the fusion temperature is approached, the braze particles in the perforated braze particle preform  36  melt and braze is drawn into voids in the metallic/ceramic particles and hard particles in the base layer preform  32  and the perforated hard particle preform  34 , and around the hard elements  42 , fusing them in place to the tubular substrate  14 . The part is then cooled, creating a fused substrate  54  with a fused matrix composite  58 , as discussed below in connection with  FIGS. 7 and 8 . 
       FIG. 7  is an illustrated isometric of one embodiment of a fused substrate  54 . The channeled hard facing wear protection  56  is on the outside surface for nearly the full length of the tubular substrate  14 . The surface of the channeled hard facing wear protection  56  consists of fused hard elements  57  that are fused in place with the fused matrix composite  58  and the fused base layer  60 . The surface of the channeled hard facing wear protection coating  56  also has channels  62  around the fused hard elements  57 , and they are bottomed with fused matrix composite  58 . In a specific embodiment, the depth of the channels  62  may be in the range from approximately ______to ______ inches. 
       FIG. 8  shows a cross-section of the fused substrate  54  in a specific embodiment in the same plane that the cross-section in  FIG. 6  is shown. The base layer preform  32  has had the polymer burnt off and been infiltrated with the braze from the perforated braze particle preform  36  to form a fused base layer  60  that has fused with the hard elements  57 , the fused matrix composite  58 , and with the surface of the tubular substrate  14 . The fine and/or ultrafine metallic or ceramic particles from the base layer preform  32  may or may not have partially or fully alloyed with the braze depending on the alloy or ceramic used for the base layer preform  32 . The perforated hard particle preform  34  has had the polymer burnt off and has also been infiltrated with braze from the perforated braze particle preform  36  to form the fused matrix composite  58  that has fused to the fused base layer  60  and to the sides of the hard elements  57 . The fused hard elements  57  and the fine and/or ultrafine hard particles from the perforated hard particle preform  34  preferentially remain intact. The perforated braze particle preform  36  that existed on the pre-fusion blank  52  is now gone after having the polymer burnt off and the braze particles melted and infiltrated into the layers below. The end result is a channeled hardfacing wear protection coating  56  consisting of fused hard elements  57 , fused matrix composite  58 , and fused base layer  60 , all of which is metallurgically fused to the tubular substrate  14  and to each other. There are channels  62  that have formed adjacent to the surface of the fused blank  54  between the fused hard elements  57  and are bottomed by fused matrix composite  58  that contains fine and/or ultrafine hard particles for excellent erosion protection properties. 
     The next step to be performed is heat treatment of the fused substrate  54  to strengthen the material of the tubular substrate, if it is required. Heat treatment processes including but not limited to, induction heat treating, or oil bath quench and temper techniques are performed on the fused radial bearing blank to give the substrate the material properties required. 
     The final steps to completing the hardfaced wear protected component is to apply conventional finishing techniques (grinding, turning, milling, EDM, etc) to complete the manufacturing of the part as required, as shown at step  50  in  FIG. 2 . 
     Those skilled in the art of hardfaced wear protection coatings will recognize that the above process can be applied to radial bearings with their wear area on their outer surface (OD), or radial bearings with their wear area on the inner surface (ID). It can also be applied to flat, curved, or other continuous surfaces where wear protection is required. 
       FIG. 6  illustrates a preferred embodiment whereby the top of the perforated braze particle preform  36  is flush to the tops of the hard elements  42 . 
       FIG. 9  illustrates the cross section of another embodiment of the pre-fusion blank  52  that uses a modified layered preform coating mat  40 A applied to a tubular substrate  14 A. The layered preform coating mat  40 A consists of the base layer preform  32 A, hard elements  42 A, perforated hard particle preform  34 A, and perforated braze particle preform  36 A. In this specific embodiment, the cumulative thickness of the perforated hard particle preform  34 A and the perforated braze particle preform  36 A layers is less than the thickness of the hard elements  42 A. This results in recesses  64  where the top of the perforated braze particle preform  36 A is recessed back from or below the tops of the hard elements  42 A. This embodiment may be used without any adverse effects to the fusion process or the integrity of the hardfacing wear protection coating. 
       FIG. 10  illustrates the cross section of another embodiment of the pre-fusion blank  52  that uses a modified layered preform coating mat  40 B applied to a tubular substrate  14 B The layered preform coating mat  40 B consists of the base layer preform  32 B, hard elements  42 B, perforated hard particle preform  34 B, and perforated braze particle preform  36 B. The cumulative thickness of the perforated hard particle preform  34 B and the perforated braze particle preform  36 B layers is greater than the thickness of the hard elements  42 B. This results in projections  66  where the top of the perforated braze particle preform  36 B is projected above the tops of the hard elements  42 B. This embodiment may be used without any adverse effects to the fusion process or the integrity of the hardfacing wear protection coating. 
       FIG. 11  illustrates the cross section of another embodiment of the pre-fusion blank  52  that uses a supplemental braze particle preform  68  with the layered preform coating mat  40  applied to a tubular substrate  14  The layered preform coating mat  40  consists of the base layer preform  32 , hard elements  42 , perforated hard particle preform  34 , and perforated braze particle preform  36 . The cumulative thickness of the perforated hard particle preform  34  and the perforated braze particle preform  36  layers is the same as the thickness of the hard elements  42 . A supplemental braze particle preform  68  is applied over top of the layered preform coating mat  40 . This embodiment may be used without any adverse effects to the fusion process or the integrity of the hardfacing wear protection coating. 
     In the description provided above for the channeled hard facing wear protection coating manufacturing process  28 , manufacturing a hardfacing wear protection that has channels over the entire surface is explained. However, the process can be modified so a highly customized channeled hardfacing wear protection can be manufactured where select areas of the surface can have channels located between the fused hard elements, and remaining areas of the surface can have matrix composite flush to the top of the fused hard elements. In certain applications this selectivity can be advantageous to the performance of a hardfacing wear protection coating by providing preferred areas for fluid circulation resulting in improved cooling, lubrication, and load distribution. 
       FIG. 12  is an illustrated isometric view of an embodiment of a partially channeled radial bearing  100 . In this embodiment the partially channeled radial bearing  100  has a partially channeled hardfacing wear protection  102  that has been applied to the outside of a tubular substrate  104 . The partially channeled hardfacing wear protection  102  has a portion that is channeled hardfacing wear protection  106  and the remaining portion is unchanneled hardfacing wear protection  108 . In this embodiment the profile of the channeled hardfacing wear protection  106  extends only for a portion of the full length and a portion of the circumference of the partially channeled hardfacing wear protection  102 . However, the profile of the channeled hardfacing wear protection  106  can be of any shape, length, size, location, and number as desired and does not have to extend into the ends of the partially channeled hardfacing wear protection  102 . In the channeled hardfacing wear protection  106 , the matrix composite  110 A is recessed back from the tops of the fused hard elements  112 A creating the channels  114  and leaving the fused hard elements  112 A as the sliding contact surfaces in the channeled hardfacing wear protection  106  of the partially channeled radial bearing  100 . The remaining surface is unchanneled hardfacing wear protection  108  where the matrix composite  110 B is flush with the fused hard elements  112 B and both the fused hard elements  112 B and the matrix composite  110 B will be the sliding contact surfaces in the unchanneled hardfacing wear protection  108  of the partially channeled radial bearing  100 . 
       FIG. 13  describes a specific embodiment of a partially channeled hardfacing wear protection manufacturing process  116 . It describes the process for applying a partially channeled hardfacing wear protection coating  102  that has channels  114  in a portion of the entire coating surface to a substrate  104 . The partially channeled hardfacing wear protection manufacturing process  116  is a variation of the channeled hardfacing wear protection manufacturing process  28  with two primary differences. First, in step  118 , a hybrid layered preform coating mat  120  is assembled instead of a layered preform coating mat  40 . Second, in step  122 , a hybrid layered preform coating mat  120  (see  FIG. 14 ) and an unperforated braze particle preform  124  (see  FIGS. 17 and 18 ) are adhered to the substrate instead of just the layered preform coating mat  40 . The unique features of these steps and their results are described below in greater detail. 
       FIG. 14  is an illustrated isometric of an embodiment of a hybrid layered preform coating mat  120 . Many of the features of the hybrid layered preform coating mat  120  are the same as the layered preform coating mat  40  from  FIG. 3 , but there are some distinct differences that allow for the controlled placement of channels  114  in the partially channeled hardfacing wear protection coating  102 . In this specific embodiment, the hybrid layered preform coating mat  120  is made up of several components. There is a base layer preform  126  upon which the next layer is attached. In a specific embodiment the base layer preform  126  is an article made up of fine and/or ultrafine metallic or ceramic particles held together with a fibrillated polymer. 
     Over the base layer preform  126  is a second layer containing hard elements  128 , a depressed perforated hard particle preform  130 , and a perforated braze particle preform inlay  132 . The hard elements  128  can be made from tungsten carbide, polycrystalline diamond solid, or a similar hard composite and can be in any one of a number of shapes (e.g., round, square, rectangular, hexagon, etc.) and may have flat, rounded, curved, ridged, or rippled bottoms. They are typically, but not limited to, applied in a pattern such that the spacing between them is even and cover the area that will become the wear protected area. 
     Between the hard elements  128  and adjacent to the base layer preform  126  is the depressed perforated hard particle preform  130  that contains one or more depressions  134 .  FIG. 15  is an illustrated isometric of a specific embodiment of the depressed perforated hard particle preform  130  from  FIG. 14 , but without the perforated braze particle preform inlay  132 . The depressed perforated hard particle preform  130  consists of a hard particle preform  136  that contains one or more depressions  134 . The dimensions and locations of the depressions  134  in the depressed perforated hard particle preform  130  correlate with the dimensions and locations where channels  114  between the fused hard elements  112 A (see  FIG. 12 ) are desired in the channeled hardfacing wear protection  106  on a partially channeled hardfacing wear protection coating  102 . The areas outside the depressions  134  correlate with the unchanneled hard facing wear protection  108  of  FIG. 12 . The areas outside the depression  134  contain perforations  138  that, in a specific embodiment, may have the same pattern as the hard elements  128  in the hybrid layered preform coating mat  120  from  FIG. 14 . In this area, the thickness  140  of the hard particle preform  136  may be approximately the same as the thickness of the hard elements  28 . The depressions  134  contain perforations  142  that also have the same pattern as the hard elements  128  in the hybrid layered preform coating mat  120  from  FIG. 14 . In this area, the thickness  144  of the hard particle preform  136  may be approximately the same as the thickness of the resulting fused matrix composite  110 A in the bottom of the channels  114  from  FIG. 12 . In a specific embodiment, the depressed perforated hard particle preform  130  may be an article made up of fine and/or ultrafine hard particles held together with a fibrillated polymer. The hard particles can be, but not limited to, spherical or crushed tungsten carbide, thermally stable polycrystalline diamond, cubic boron nitride, or a similar hard material. An adhesive may be used to secure the hard elements  128  and the depressed hard particle preform  130  to the base layer preform  126 . 
     Referring to  FIG. 14 , in the depressions  134  of the depressed perforated hard particle preform  130 , and between the hard elements  128  is located the perforated braze particle preform inlay  132 .  FIG. 16  is an illustrated isometric of a specific embodiment of the perforated braze particle preform inlay  132 . The perforated braze particle preform inlay  132  consists of a braze particle preform  148  that contains perforations  146  that, in a specific embodiment, may have the same pattern as the perforations  142  in the depressions  134  of the depressed perforated hard particle preform  130 . The dimensions and locations of the perforated braze particle preform inlay  132  in the depressed perforated hard particle preform  130  may, in a specific embodiment, correlate with the dimensions and locations where channels  114  between the fused hard elements  112 A are desired in the channeled hardfacing wear protection  106  on a partially channeled hardfacing wear protection  102  (see  FIG. 12 ). The thickness of the perforated braze particle preform inlay  132  may or may not be the same thickness as the depth of the channels  114  in the channeled hardfacing wear protection  106 . In a specific embodiment, the perforated braze particle preform inlay  132  may consist of fine and/or ultrafine braze particles held together with a fibrillated polymer. 
       FIG. 17  is a sectional view along line A-A of  FIG. 14  of the hybrid layered preform coating mat  120  in  FIG. 14  that illustrates a cross-section of the hybrid layered preform coating mat  120  that does not contain a depression  134  in the depressed perforated hard particle preform  130 . In this cross section, the hard elements  128  are arrayed in the perforations of the depressed perforated hard particle preform  130  and are located on the base layer preform  126 . The thickness of the depressed perforated hard particle preform  130  in this cross section is approximately the same as the thickness of the hard elements  128 . 
       FIG. 18  is a sectional view along line B-B of  FIG. 14  of the hybrid layered preform coating mat  120  in  FIG. 14  that illustrates a cross-section of the hybrid layered preform coating mat  120  that does contain a depression  134  in the depressed perforated hard particle preform  130 . Like the section in  FIG. 17 , the hard elements  128  are arrayed in the perforations of the depressed perforated hard particle preform  130  and are located on the base layer preform  126 . In the areas outside the depression  134 , the thickness of the depressed perforated hard particle preform  130  is approximately the same as the thickness of the hard elements  128 . In the depression  134 , however, the thickness of the depressed perforated hard particle preform  130  is the same as the thickness of the fused matrix material  110 A (see  FIG. 12 ) required in the bottom of the channels  114  in the channeled hardfacing wear protection  106  on a partially channeled hardfacing wear protection coating  102 . Within the depression  134 , and around the hard elements  128  in the depression  134  is the perforated braze particle preform inlay  132 . In this embodiment, the perforated braze particle preform inlay  132  is the same thickness as the depth of the depression  134  so the perforated braze particle preform inlay  132  is flush with the tops of the hard elements  128 . 
     Once the hybrid layered preform coating mat  120  has been assembled per step  118  of  FIG. 13 , it must be assembled onto a substrate with an unperforated braze particle preform  124  per step  122  of  FIG. 13  to make a hybrid pre-fusion blank  150 .  FIG. 19  is an illustrated isometric view of the hybrid layered preform coating mat  120  from  FIGS. 14-16  and an unperforated braze particle preform  124  applied to a tubular substrate  152  to manufacture the radial bearing in  FIG. 12 . The hybrid layered preform coating mat  120  is oriented such that the base layer perform  126  is adjacent to the cylindrical surface of the tubular substrate  152 , and, in the case of a tubular substrate  152 , the ends of the hybrid layered preform coating mat  120  meet up at its ends when wrapped around the tubular substrate  152 .  FIGS. 17 and 18  show that the perforated braze particle preform inlay  132  is positioned into the depression  134  in the depressed perforated hard particle preform  130 . The hybrid layered preform coating mat  120  is positioned such that the depression  134  in the depressed perforated hard particle preform  130  is in the location and orientation where channels  114  (see  FIG. 12 ) are desired in the channeled hardfacing wear protection  106  on the partially channeled hardfacing wear protection coating  102  when it is fused. The hybrid layered preform coating mat  120  can be adhered to the tubular substrate  152  with, but not limited to, adhesive. 
     Next, as shown in  FIGS. 19 and 20 , unperforated braze particle preform  124  is applied over the top of the hybrid layered preform coating mat  120 . In a preferred embodiment, the supplemental braze particle preform  124  is shaped and positioned such that it does not cover over the perforated braze particle preform inlay  132  as shown in  FIG. 18 . However, according to non-illustrated embodiments of this disclosure, a portion of the unperforated braze particle preform  124  can be applied over the perforated braze particle preform inlay  132  if the amount of braze in the perforated braze particle preform inlay  134  is not enough to fully and properly infiltrate and fuse the base layer preform  126 , depressed perforated hard particle preform  130 , and hard elements  128  in the depression  134 . 
       FIG. 20  is an illustrated detail section view of the hybrid pre-fusion blank  150 . The detail section view is taken perpendicular to the axis of the tubular substrate  152  midway through the perforated braze particle preform inlay  132  of the hybrid layered preform coating mat  120  and shows the cross section at the edge of a perforated braze particle preform inlay  132  and a depression  134  in the depressed perforated hard particle preform  130 . The detail view shows the perforated braze particle preform inlay  132  in the depression  134  of the depressed perforated hard particle preform  130 . The hard elements  128  are positioned in the perforations of the perforated braze particle preform inlay  132  and the depressed perforated hard particle preform  130 . The base layer preform  126  is positioned under the depressed perforated hard particle preform  130  and hard elements  128  and is adjacent to the tubular substrate  152 . Finally, the unperforated braze particle preform  124  is adhered over the surface of the hybrid layered preform coating mat  120 . 
     The hybrid pre-fusion blank  150  is then processed per step  140  of  FIG. 13 , which is identical to step  46  of  FIG. 2  and is described previously in this disclosure. The resulting article is a fused substrate  100  per  FIG. 12  with a partially channeled hardfacing wear protection coating  102  having a channeled hardfacing wear protection  106  and unchanneled hardfacing wear protection  108 .  FIG. 21  is an illustrated detail section view of the cross section of a fused substrate  100  per  FIG. 12 . The detail section view is taken in the same plane and location as the detail section view of  FIG. 20 , but after fusion has been completed. Referring to  FIGS. 20 and 21 , during the fusion process, the base layer preform  126  has had the polymer burnt off and been infiltrated with the braze from the perforated braze particle preform inlay  132  and the unperforated braze particle preform  124  to form a fused base layer  109  that has fused with the fused hard elements  112 A and  112 B, the fused matrix composite  110 A and  110 B, and with the surface of the tubular substrate  104 . The fine and/or ultrafine metallic particles from the base layer preform  126  may or may not have partially or fully alloyed with the braze depending on the alloy used for the base layer preform  126 . The depressed perforated hard particle preform  130  has had the polymer burnt off and has also been infiltrated with braze from the perforated braze particle preform inlay  132  and the unperforated braze particle preform  124  to form a fused matrix composite  110 A and  110 B that has fused to the fused base layer  109  and to the sides of the hard elements  112 A and  112 B. The fused hard elements  112 A and  112 B and the fine and/or ultrafine hard particles from the depressed perforated hard particle preform  130  preferentially remain intact. The perforated braze particle preform inlay  132  and the unperforated braze particle preform  124  that existed on the hybrid pre-fusion blank  150  is now gone after having the polymer burnt off and the braze particles melted and infiltrated into the layers below. This results in the fused matrix composite  110 A being recessed from the top of the fused hard elements  112 A where the depression  134  was in the depressed perforated hard particle preform  130 , which creates a channel  114  between the hard elements  112 A when the perforated braze particle preform inlay  132  is melted away. Outside the area of the depression  134  in the depressed perforated hard particle preform  130  the fused matrix composite  110 B is flush with the top of the fused hard elements  112 B and no channels being formed when the unperforated braze particle preform  124  is melted away. 
     Those skilled in the art will understand that the ability to specifically place and orient channels in the hardfacing is defined by the placement of the depression  134  in the depressed perforated hard particle preform  130 , and placement of the perforated braze particle preform inlay  132  in the depression  134  of the hybrid layered preform coating mat  120 . This can be done with a single depression or multiple depressions which allows the creation of any channel pattern desired. 
     Those skilled in the art recognize that a number of methods can be used to create the required perforated patterns in the perforated hard particle preform  34 , perforated braze particle preform  36 , depressed perforated hard particle preform  130 , and perforated braze particle preform inlay  132  to locate the hard elements  42 , or hard elements  128  including, but not limited to, punching using punches, or cutting using a blade, a laser, or a water jet. Preferentially, creation of perforations in the perforated hard particle preform  34  and perforated braze particle preform  36 , or depressed perforated hard particle preform  130 , and perforated braze particle preform inlay  132  is performed after material for the preforms have been adhered together.  FIG. 22  is a side view of one embodiment of an illustration of a multilayer preform  200 . The multilayer preform  200  may be made up of a hard particle preform  202  and a braze particle preform  204 . The hard particle preform  202  and the braze particle preform  204  are milled to their desired thicknesses and then are adhered together using an adhesive into multilayer preform  200 . Perforating the multilayer preform  200  will result in matching perforations in both the hard particle preform  202  and the braze particle preform  204 , simplifying the manufacturing process. 
       FIGS. 23A and 23B  show a preferred method of manufacturing a perforated multilayer preform  206 .  FIG. 23A  illustrates a top view of multilayer preform  200 . Alternating cuts  208  are made through both the hard particle preform  202  and the braze particle preform  204  layers of multilayer preform  200  at the same time. The alternating cuts  208  are all the same length and are equally spaced within each column. Each column is evenly spaced and is offset from the column beside it such that the center of each cut aligns with the web between each alternating cut  208  in the next column. This alternating cut  208  pattern results in multilayer preform  200  that can be expanded and the alternating cuts  208  will spread open to create perforations.  FIG. 23B  illustrates the perforated multilayer preform  206  that has cavities  212  created by expanding the multilayer preform  200  from  FIG. 23A . The cavities  212  have a stretched rhombus shape and a hard element  42  or hard element  128  may be manufactured to tightly fit the dimensions of the cavity  212  for use when using the perforated multilayer preform  206  in a layered preform coating mat  40  or a hybrid layered preform coating mat  120 . This method simplifies the cutting of perforations in the perforated multilayer preform  206  and reduces the amount of waste that occurs. 
     Another method of perforating a multilayer preform  200  involves using punches to shear through the multilayer preform  200 . In a preferred embodiment of a punch style method of perforating the multilayer preform  200 , the hard elements  42  or hard elements  128  themselves can act as the punch to create the perforation in the multilayer preform  200  and result in the hard elements  42  or hard elements  128  positioned in the perforation in the same action.  FIG. 24  shows an embodiment of a hard element  214  that includes raised edges  216  on its face  218  around its perimeter  220  that may be used for this method. The purpose of the raised edges  216  will become evident in the descriptions for  FIG. 25  and  FIG. 26 . 
       FIG. 25  shows a cross sectional view of a method that uses hard elements  214  themselves to act as the punch to displace a matching profile of the multilayer preform  200  that may be made up of the hard particle preform  202  and the braze particle preform  204 . The multilayer preform  200  is placed over a die plate  222  that has a series of receptacles  224 , with each receptacle  224  closely matching the dimensions of the hard element  214  and the receptacles  224  arrayed in the desired pattern for the hard elements  214 . The hard elements  214  are then placed over the multilayer preform  200  with the sharp edges  216  on their faces  218  oriented against the multilayer preform  200 . The hard elements  214  are also positioned such that they are each located over a matching receptacle  224  in the die plate  222 . Force  226  is then applied to each hard element  214  to push them down against the multilayer preform  200 , shearing the multilayer preform  200  to the mating hard element  214  shape and resulting in the perforation of the multilayer preform  200 . 
       FIG. 26  shows a cross sectional view of the hard elements  214  pushed into the now perforated multilayer preform  228  and the displaced multilayer preform  230  pushed into the receptacles  224  in the die plate  222 . The hard elements  214  and perforated multilayer preform  228  is then separated from the die plate  222  and can be used for assembly of the layered preform coating mat  40  or hybrid layered preform coating mat  120  as described previously. The displaced multilayer preforms  230  can be removed from the die plate  222  and be recycled. Pressing of the hard elements  214  into the multilayer preform  200  can be performed individually, or as multiples, and can use any various means including but not limited to, presses or rollers. The receptacles  224  in the die plate  222  may or may not also have raised edges around their perimeter to assist with the shearing of the multilayer preform  200 . The hard elements  214  can be of any shape, including but not limited to, square, rectangular, round, oval, or a polygon. The hard elements  214  may have raised edges  216  on one or both faces  218  or may not have raised edges on either face. The hard elements  214  may or may not be positioned prior to pressing into the multilayer preform  200  using a template that matches the pattern on the die plate  222  to ensure aligned positioning of the hard elements  214  over the receptacles  224  in the die plate  222 . The multilayer preform  200  may be oriented such that the braze particle preform  204  is adjacent to the hard elements  214  prior to their shearing through the multilayer preform  200  or the hard particle preform  202  may be adjacent to the hard elements  214  prior to their shearing through the multilayer preform  200 . 
     Those skilled in the art will recognize that each layer of the multilayer preform  200  does not have to cover the full extent of the layer. For example, the hybrid layered preform coating mat  120  uses a depressed perforated hard particle preform  130  with a perforated braze particle inlay  132  located in depression  134  in the depressed perforated hard particle preform  130 .  FIG. 27  illustrates a hybrid multilayer preform  232  that may be used to manufacture a combined depressed perforated hard particle preform  130  and perforated braze particle preform inlay  132  for the hybrid layered preform coating mat  120 . The hybrid multilayer preform  232  has a depressed hard particle preform  234  that contains a depression  236  and the dimensions and location of the depression  236  correlates with where the channels  114  are desired in the partially channeled hard facing wear protection  102 . The thickness of the depressed hard particle preform  234  in the depression  236  may be the same as the desired thickness of the matrix composite  110 A in the channels  114  in the partially channeled hard facing wear protection  106 . The thickness of the rest of the surface area of the depressed hard particle preform  234  is the same as the thickness of the hard elements  112 . A braze particle preform inlay  238  is located in the depression  236  and has the same length and width dimensions as the depression  236 . Though not required, in a preferred embodiment the braze particle preform inlay  238  is the same thickness as the depth of the depression  236 , which results in the top of the braze particle preform inlay  238  even with the top of depressed hard particle preform  234 . The hybrid multilayer preform  232  can be used for but not limited to any of the perforating methods described above. Those skilled in the art will recognize that multiple depressions  236  in the depressed hard particle preform  234  can be used to create the desired pattern for the channels  114  in the channeled hardfacing wear protection  106  of the partially channeled hardfacing wear protection  102 . 
     There are several modifications to the process described above that can be made. 
     In various specific embodiments, the base layer preform  32  or base layer preform  126  may be constituted of fine and/or ultrafine alloy particles held together with a fibrillated polymer per the description above, but the base layer preform  32  or base layer preform  126  may also contain or have its constituents replaced with fine and/or ultrafine braze particles and/or fine and/or ultrafine ceramic particles and/or fine and/or ultrafine hard metal particles held together with a fibrillated polymer. 
     In various specific embodiments, the perforated hard particle preform  34  or depressed perforated hard particle preform  130  may be constituted of fine and/or ultrafine hard metal particles held together with a fibrillated polymer per the description above, but the perforated hard particle preform  34  or depressed perforated hard particle preform  130  may also contain or have its constituents replaced with fine and/or ultrafine alloy particles and/or fine and/or ultrafine ceramic or cermet particles held together with a fibrillated polymer. 
     In various specific embodiments, the hard elements  42 , or hard elements  128  may be tungsten carbide tile, a polycrystalline diamond solid, or any other hard composite material of any shape. 
     In various specific embodiments, the layered preform coating mat  40  or hybrid layered preform coating mat  120  may have other layers added in addition to the ones in the embodiments discussed above. As an example, an additional preform base layer could be added to provide a second transitional stress reducer in the finished coating.  FIG. 28  is a section view of an embodiment of a layered preform coating mat  240  that has a second full base layer preform  242  of other hard particles or ceramic/metallic particles that could be introduced between the base layer preform  244  below it and the hard elements  246  and perforated hard particle preform  248  above it. The perforated braze particle preform  250  remains adjacent to the perforated hard particle preform  248 . The addition of another preform layer does not affect the manufacturing processes described herein. 
     Conversely, to reduce the stresses in the finished coating, the tubular sleeve  14  may already have an initial coating layer applied to it that the layered preform coating mat would be placed over. Those skilled in the art will recognize that the stresses inherent in the coating materials can be excessively high and result in cracking of the coating if not mitigated. One method is to use transition layers in the coating to reduce the stresses between layers and eliminate the risk of cracking. 
     It is to be understood that the inventions disclosed herein are not limited to the exact details of construction, operation, exact materials or embodiments shown and described. Although specific embodiments of the inventions have been described, various modifications, alterations, alternative constructions, and equivalents are also encompassed within the scope of the inventions. For example, while the present inventions have been described in connection with a radial bearing, the present inventions are not so limited but instead are intended to encompass and/or by used in connection with any other composite articles. Although the present inventions may have been described using a particular series of steps, it should be apparent to those skilled in the art that the scope of the present inventions is not limited to the described series of steps. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. It will be evident that additions, subtractions, deletions, and other modifications and changes may be made thereunto without departing from the broader spirit and scope of the inventions as set forth in the claims set forth below. Accordingly, the inventions are therefore to be limited only by the scope of the appended claims. None of the claim language should be interpreted pursuant to 35 U.S.C. 112(f) unless the word “means” is recited in any of the claim language, and then only with respect to any recited “means” limitation.