| Advanced erosion resistant carbonitride cermets -> Monitor Keywords |
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Advanced erosion resistant carbonitride cermetsRelated Patent Categories: Specialized Metallurgical Processes, Compositions For Use Therein, Consolidated Metal Powder Compositions, And Loose Metal Particulate Mixtures, Compositions, Consolidated Metal Powder Compositions, With Nonmetal Constituent - Silicon(si) Considered A Metal (e.g., Cermet, Etc.), Carbide Containing, With Another Nonmetal, Nonmetal Is Boron(b) Or Nitrogen(n)Advanced erosion resistant carbonitride cermets description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070163382, Advanced erosion resistant carbonitride cermets. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] This application claims the benefit of U.S. Provisional application 60/471,994 filed May 20, 2003. FIELD OF INVENTION [0002] The present invention is broadly concerned with cermets, particularly cermet compositions comprising a metal carbonitride. These cermets are suitable for high temperature applications wherein materials with superior erosion and corrosion resistance are required. BACKGROUND OF INVENTION [0003] Erosion resistant materials find use in many applications wherein surfaces are subject to eroding forces. For example, refinery process vessel walls and internals exposed to aggressive fluids containing hard, solid particles such as catalyst particles in various chemical and petroleum environments are subject to both erosion and corrosion. The protection of these vessels and internals against erosion and corrosion induced material degradation especially at high temperatures is a technological challenge. Refractory liners are used currently for components requiring protection against the most severe erosion and corrosion such as the inside walls of internal cyclones used to separate solid particles from fluid streams, for instance, the internal cyclones in fluid catalytic cracking units (FCCU) for separating catalyst particles from the process fluid. The state-of-the-art in erosion resistant materials is chemically bonded castable alumina refractories. These castable alumina refractories are applied to the surfaces in need of protection and upon heat curing hardens and adheres to the surface via metal-anchors or metal-reinforcements. It also readily bonds to other refractory surfaces. The typical chemical composition of one commercially available refractory is 80.0% Al.sub.2O.sub.3, 7.2% SiO.sub.2, 1.0% Fe.sub.2O.sub.3, 4.8% MgO/CaO, 4.5% P.sub.2O.sub.5 in wt %. The life span of the state-of-the-art refractory liners is significantly limited by excessive mechanical attrition of the liner from the high velocity solid particle impingement, mechanical cracking and spallation. Therefore there is a need for materials with superior erosion and corrosion resistance properties for high temperature applications. The cermet compositions of the instant invention satisfy this need. [0004] Ceramic-metal composites are called cermets. Cermets of adequate chemical stability suitably designed for high hardness and fracture toughness can provide an order of magnitude higher erosion resistance over refractory materials known in the art. Cermets generally comprise a ceramic phase and a binder phase and are commonly produced using powder metallurgy techniques where metal and ceramic powders are mixed, pressed and sintered at high temperatures to form dense compacts. [0005] The present invention includes new and improved cermet compositions. [0006] The present invention also includes cermet compositions suitable for use at high temperatures. [0007] Furthermore, the present invention includes an improved method for protecting metal surfaces against erosion and corrosion under high temperature conditions. [0008] These and other objects will become apparent from the detailed description which follows. SUMMARY OF INVENTION [0009] The invention includes a cermet composition represented by the formula (PQ)(RS) comprising: a ceramic phase (PQ) and a binder phase (RS) wherein, P is a metal selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Mn and mixtures thereof, Q is carbonitride, R is a metal selected from the group consisting of Fe, Ni, Co, Mn and mixtures thereof, S comprises at least one element selected from Cr, Al, Si and Y. BRIEF DESCRIPTION OF THE FIGURES [0010] FIG. 1 is a scanning electron microscope (SEM) image of TiC.sub.0.7N.sub.0.3 cermet made using 30 vol % 304 stainless steel (304SS) binder illustrating the Ti(C,N) ceramic phase particles dispersed in binder and the reprecipitation of new phase M.sub.2(C,N) where M is mainly Cr, Fe, and Ti and M(C,N) carbonitride where M is mainly Ti and Ta. Also shown in the micrograph is the formation of M(C,N) rim around the Ti(C,N) ceramic. [0011] FIG. 2 is a transmission electron microscope (TEM) image of the same cermet shown in FIG. 1. [0012] FIG. 3 is a SEM image of a TiC.sub.0.3N.sub.0.7 cermet made using 25 vol % Haynes.RTM. 556 alloy binder illustrating Ti(C,N) ceramic phase particles dispersed in binder and the reprecipitation of new phase M.sub.2(C,N) where M is mainly Cr, Fe, and T.sub.1 and M.sub.2(C,N) where M is mainly Mo, Nb, Cr, and Ti. [0013] FIG. 4 is a transmission electron microscope (TEM) image of the same cermet shown in FIG. 3. [0014] FIG. 5 is a graph showing the thickness (am) of oxide layer as a measure of oxidation resistance of titanium carbonitride cermets of the instant invention made using 30 vol % binder exposed to air at 800.degree. C. for 65 hours. The oxidation resistance of titanium carbide and nitride cermets are also shown for comparison. DETAILED DESCRIPTION OF THE INVENTION [0015] One component of the cermet composition represented by the formula (PQ)(RS) is the ceramic phase denoted as (PQ). In the ceramic phase (PQ), P is a metal selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Mn and mixtures thereof. Q is carbonitride. Thus the ceramic phase (PQ) in the carbonitride cermet composition is a metal carbonitride. The molar ratio of P to Q in (PQ) can vary in the range of 1:3 to 3:1. Preferably in the range of 1:2 to 2:1. As non-limiting illustrative examples, when P=Ti, (PQ) can be Ti(C,N) wherein P:Q is 1:1. When P=Cr then (PQ) can be Cr.sub.2(C,N) wherein P:Q is 2:1. The ceramic phase imparts hardness to the carbonitride cermet and erosion resistance at temperatures up to about 1000.degree. C. Continue reading about Advanced erosion resistant carbonitride cermets... Full patent description for Advanced erosion resistant carbonitride cermets Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Advanced erosion resistant carbonitride cermets patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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