Showing papers on "Carbide published in 1969"
TL;DR: In this paper, the binding energy shifts of Cl s electrons in Group 4b, 5b and 6b carbides and of core electrons in Ti and V compounds are discussed and compared with X-ray spectroscopic investigations and energy band calculations.
502 citations
190 citations
TL;DR: In this article, pyrolytic polycrystalline β-silicon carbide was irradiated to 2.0 to 4.2 × 1021nvt (E > 0.18 MeV) at temperatures between 460 and 1040 °C.
123 citations
Patent•
23 Jun 1969TL;DR: In this paper, strong, hard, impact-resistant bodies comprising tungsten carbide bonded with from 3 to 25% by weight of heterogeneous cobalt-tungsten solid-solution alloy, useful as cutting tools, are prepared by heating an intimately mixed cobalt/tungsten carbide powder to a temperature above 1000* C and consolidating the powder to density of at least 98% of its theoretical density.
Abstract: Strong, hard, impact-resistant bodies comprising tungsten carbide bonded with from 3 to 25% by weight of heterogeneous cobalt-tungsten solid-solution alloy, useful as cutting tools, are prepared by heating an intimately mixed cobalt/tungsten carbide powder to a temperature above 1000* C and consolidating the powder to a density of at least 98% of its theoretical density, having either. 1. MIXED A CARBON-RICH AND A CARBON-DEFICIENT POWDER TOGETHER PRIOR TO CONSOLIDATION TO PRODUCE A NON-HOMOGENEOUS BINDER; 2. ADDED FREE CARBON TO A CARBON-DEFICIENT POWDER TO PRODUCE LOCAL AREAS WHERE TUNGSTEN IS REMOVED FROM THE BINDER ALLOY AS TUNGSTEN CARBIDE; OR 3. ALLOWED A PORTION OF THE CARBON IN THE TUNGSTEN CARBIDE TO OXIDIZE DURING CONSOLIDATION TO PRODUCE AREAS IN THE BINDER PHASE WHICH ARE THEN CARBON DEFICIENT AND HIGH IN TUNGSTEN.
105 citations
TL;DR: The vanadium LII,III x-ray emission and absorption spectra (λ∼24 A) from pure metal, oxides, nitride, carbide, and boride have been investigated using a plane-crystal vacuum spectrometer with electron beam excitation and flow-proportional detection as discussed by the authors.
Abstract: The vanadium LII,III x‐ray emission and absorption spectra (λ∼24 A) from pure metal, oxides, nitride, carbide, and boride have been investigated using a plane‐crystal vacuum spectrometer with electron beam excitation and flow‐proportional detection. Emission spectra were studied over a wide range of accelerating voltages and takeoff angles, showing that satellite emission and self‐absorption effects can cause gross distortion in band shapes. A replica of the LII,III absorption spectrum can be constructed solely from emission spectra afflicted with widely different amounts of self‐absorption. The LII,III emission spectra from the oxides and nitride exhibit an anamalous crossover transition from the 2p level of the anion to the LII and LIII levels of vanadium. This transition appears to be related to the degree of anion‐cation orbital overlap and to the electrical properties of the material. Energy shifts of emission bands and absorption edges indicate the charge flow from vanadium to anion in the oxides and nitride. The LIII edges are used to estimate the width of the forbidden gap in V2O5. Oxygen K emission from the oxides exhibits a peculiar dependence on the dispersing crystal used and is also influenced by satellite emission and self‐absorption.
88 citations
TL;DR: The catalytic decomposition of carbon monoxide on iron surfaces at 550°C has been studied by optical methods, internal friction measurements, X-ray diffraction and electron microscopy.
70 citations
58 citations
Patent•
19 Jun 1969
TL;DR: Hard, dense, composite ceramic bodies of boron carbide, silicon carbide and silicon, particularly useful as ceramic armor, are produced by forming a mixture of granular borons carbides and a temporary binder into a desired shape and setting the binder to obtain a coherent green body which is siliconized by heating it, in an inert atmosphere and in contact with a controlled amount of silicon, to a temperature above the melting point of silicon and in the range of about 1500-2200 DEG C, whereupon the molten silicon infiltrates the body and reacts with
Abstract: Hard, dense, composite ceramic bodies of boron carbide, silicon carbide and silicon, particularly useful as ceramic armor, are produced by forming a mixture of granular boron carbide and a temporary binder into a desired shape and setting the binder to obtain a coherent green body which is siliconized by heating it, in an inert atmosphere and in contact with a controlled amount of silicon, to a temperature above the melting point of silicon and in the range of about 1500-2200 DEG C, whereupon the molten silicon infiltrates the body and reacts with some of the boron carbide thereof.
49 citations
TL;DR: In this article, the microstructural changes which occur during the liquid-phase sintering of the alloys NbC-22 wt.% Fe and Ni-Ni alloy were investigated and the effect of temperature on grain growth was measured and activation energies of the growth rates were determined.
Abstract: An investigation has been made of the microstructural changes which occur during the liquid-phase sintering of the alloys NbC-22 wt.% Fe andNbC-22 wt.% Ni. It was found that the growth of the carbide grains, dispersed in either of the liquid metals, is consistent with the theoretical equation, derived by Wagner, for a solution/ precipitation growth process controlled by the diffusion of the solid constituent through the liquid. The same growth behaviour has been observed earlier in a similar alloy of NbC in cobalt. The effect of temperature on grain growth was measured and “activation energies” of the growth rates were determined.
43 citations
TL;DR: In this paper, the growth of 2H silicon carbide showing temperature profile along susceptor as an affecting factor is discussed, along with the effect of temperature profile on susceptor temperature.
Abstract: Crystal growth of 2H silicon carbide showing temperature profile along susceptor as affecting factor
34 citations
TL;DR: In this paper, the first stage of tempering of high-carbon martensites results in the precipitation of the metastable epsilon carbide; in low-carbon steels, it is generally considered that the carbide does not form during tempering and only cementite is observed.
TL;DR: In this article, the particle coarsening followed a time-dependent relationship where the square of the mean carbide particle edge size is linear with time for the temperatures investigated (600-680°C).
Abstract: This paper describes a study of particle coarsening in an isothermally transformed Fe-2·0% V-0·2% C alloy steel which makes use of the background metallography of an earlier paper (Schwartz, Davenport and Ralph 1968). The method used to obtain the particle size distributions has been described previously (Schwartz and Ralph 1969). The particle coarsening followed a time-dependent relationship where the square of the mean carbide particle edge size is linear with time for the temperatures investigated (600–680°C). This is in qualitative agreement with the theoretical predictions of a coarsening process whose rate is controlled by mass transfer at the particle/matrix interfaces.
TL;DR: In this paper, the authors applied homogeneous nucleation theory to uranium carbide to describe bubble formation and swelling and concluded that at temperatures less than 700 °C and for burn-ups less than 5 × 1020 fissions/cm3, bubble formation is unlikely.
Patent•
28 Feb 1969TL;DR: Refractory carbides, particularly tungsten carbide, are reclaimed from cemented carbides by treating the carbide with molten zinc and subsequently distilling the zinc from the mass as mentioned in this paper.
Abstract: Refractory carbides, particularly tungsten carbide, are reclaimed from cemented carbides by treating the cemented carbide with molten zinc and subsequently distilling the zinc from the mass. The zinc forms an alloy with the cementing agent, usually cobalt, thereby dissolving the carbide-cementing agent bond and permitting recovery of a mixture of the carbide and the cementing agent in a form that can be reused in preparation of cemented carbides.
Patent•
04 Jun 1969TL;DR: Anisodimensional tungsten carbide platelets having a maximum dimension of from 0.1 to 50 microns and a minimum dimension of less than one-third the maximum dimension are prepared by heating an intimately mixed uniformly fine cobalt/tungsten carbonide powder to a temperature above 1,300* C as mentioned in this paper.
Abstract: Anisodimensional tungsten carbide platelets having a maximum dimension of from 0.1 to 50 microns and a minimum dimension of less than one-third the maximum dimension are prepared by heating an intimately mixed uniformly fine cobalt/tungsten carbide powder to a temperature above 1,300* C. and recrystallizing the tungsten carbide. The platelets are useful in preparing cobalt bonded tungsten carbide cutting tools.
TL;DR: In this paper, the formation of the Group IVA carbide and nitride phases in molybdenum by arc melting simple ternary alloys has been demonstrated.
Abstract: The formation of the Group IVA carbide and nitride phases in molybdenum by arc melting simple ternary alloys has been demonstrated. The threshold solute metal-interstitial atom ratios have been determined for the complete formation of the Group IVA compounds in preference to molybdenum phases. Increasing solubility with increasing temperature, up to 2100 °C, demonstrates that all these alloys show potential precipitation hardening characteristics. In some alloys (chiefly Mo-Ti-C) reversion to Mo2C occurs above 1600 °C.
TL;DR: A new body-centered cubic scandium carbide phase having the approximate composition Sc13C10 has been prepared by high-temperature annealing of arc-melted samples containing small amounts of germanium as mentioned in this paper.
Abstract: A new body-centered cubic scandium carbide phase having the approximate composition Sc13C10 has been prepared by high-temperature annealing of arc-melted samples containing small amounts of germanium. The lattice parameters of this new phase varied from a 0 = 8.514 A to a = 8.530 A suggesting a range of homogeneity. All compositions were found to be superconducting with the transition temperature ranging from 7.0 ° to 8.5 °K. Similar measurements on the previously reported Sc4C3 b.c.c. phase showed no superconducting transition for measurements down to 1 °K.
Patent•
18 Dec 1969
TL;DR: In this paper, a heat treatable, temper resistant, chromium-containing, carbidic tool steel having a total carbon content of at least about 6 percent by weight is provided comprising about 25 to 75 percent by volume of primary carbide grains of essentially titanium carbide distributed through a heat-treatable steel matrix containing by weight about 6 to 12% chromium, about 0.6 to 1.2% carbon, the total tungsten and molybdenum content not exceeding about 5%, 0 to 2% vanadium, 0 to 3% nickel,
Abstract: A heat treatable, temper resistant, chromium-containing, carbidic tool steel having a total carbon content of at least about 6 percent by weight is provided comprising about 25 to 75 percent by volume of primary carbide grains of essentially titanium carbide distributed through a heat treatable steel matrix containing by weight about 6 to 12% chromium, about 0.6 to 1.2% carbon, about 0.5 to 5% molybdenum, 0 to 5% tungsten, the total tungsten and molybdenum content not exceeding about 5%, 0 to 2% vanadium, 0 to 3% nickel, 0 to 5% cobalt, 0 to 1.5% silicon, 0 to 2% manganese and the balance essentially iron, the ratio by weight of chromium to carbon in the steel matrix ranging from about 7:1 to 25:1, the steel matrix surrounding the primary carbide grains being characterized by a microstructure comprising an austenitic decomposition product.
TL;DR: The ternary system Ce-C-N is complex. as discussed by the authors showed evidence of substitutional replacement of C22− by N3−, with a significant composition range.
Patent•
08 Aug 1969
TL;DR: Piston Rings, including pressure and oil control rings, have been used for internal COMBUSTION engine control as discussed by the authors, and have been shown to be very hard and resistant to scuffing.
Abstract: PISTON RINGS, INCLUDING COMPRESSION AND OIL CONTROL RINGS, FOR INTERNAL COMBUSTION ENGINE PISTONS, HAIVNG A BEARING FACE OF AN ALLOY IS COMPOSED OF REFRACTORY A PLASMA JET STREAM. THE ALLOY IS COMPOSED OF REFRACTORY METAL CARGIDES SUCH AS TUNGSTEN CARBIDE IN SOLID SOLUTION WITH ANOTHER METAL, SUCH AS COBALT, TO PROVIDE A HARD WEAR PHASE WITH THE CARBIDE PARTICLES RELATIVELY FREE FROM SHARP EDGES AND CORNERS AND A SOMEWHAT SOFTER MATRIX PHASE COMPOSED OF METALS SUCH AS NICKEL, CHROMIUM, BORON, AND ALUMINUM. THE ALUMINUM SHOULD BE PRESENT IN A MINOR AMOUNT SUCH THAT EVER MINOR SCUFFING OF ENGINE CYLINDERS IS AVOIDED. THE COATING IS VERY HARD AND REFRACTOR, POSSESSES A HIGHER TENSILE STRENGTH THAN HERETOFORE USED PISTON RING FACINGS, DOES NOT SCUFF, HAS IMPROVED ABRASIVE WEAR RESISTANCE, AND OPERATES COMPATIBLY WITH THE ENGINE CYLINDERS. THE CARBIDES IN THE COATING WILL NOT PULL OUT IN OPERATION OF THE RING BECAUSE THEY ARE IN SOLID SOLUTION AND DO NOT HAVE A SHARP PARTICULATE FORM. THE NICKEL, CHROMIUM AND BORON IN THE ALLOY PROVIDE BINDERS IMPROVING THE MECHANICAL STRENGTH OF THE COATING AND THE HARDNESS OF THE MATRIX.
Patent•
03 Mar 1969TL;DR: In this article, the authors present a comparison of different types of dense compositions for cutting steel and casting IRON and show that they are effective tools for cutting STEEL and cast IRON, and useful as OXIDATION RESISTant MATERIALS of CONSTRUCTION.
Abstract: DENSE COMPOSITIONS HAVING A GRAIN SIZE SMALLER THAN 10 MICRONS AND CONTAINING FROM 20 TO 80 VOLUME PERCENT ALUMINA; 10 TO 78 VOLUME PERCENT OF A METALLINE SELECTED FROM THE GROUP CONSISTING OF TITANIUM CARBIDE, TITANIUM NITRIDE, ZIRCONIUM AND CARBIDE, ZIRCONIUM NITRIDE, NIOBIUM CARBIDE, NIOBIUM NITRIDE, TANTALUM CARBIDE, TANTALUM NITRIDE, AND MIXTURES THEREOF; AND 2 TO 30 VOLUME PERCENT OF AN INTERMETALLIC SELECTED FROM THE GROUP CONSISTING OF IRON ALUMINIDE, IRON TITANIDE, COBALT ALUMINIDE, COBALT TITANIDE, NICKEL ALUMINIDE, NICKEL TITANIDE, TUNGSTEN ALUMINIDE, MOLYBDENUM ALUMINIDE, NIOBIUM ALUMINIDE, TANTALUM ALUMINIDE, TITANIUM ALUMINIDE, ZIRCONIUM ALUMINIDE, AND MIXTURES THEREOF, ARE (1) EFFECTIVE TOOLS FOR CUTTING STEEL AND CAST IRON AND (2) USEFUL AS OXIDATION RESISTANT MATERIALS OF CONSTRUCTION.
Patent•
18 Aug 1969
TL;DR: Cemented carbide compositions and shaped bodies produced therefrom containing tungsten carbide or titanium carbide and a binder alloy containing cobalt and nickel and, by weight, about 18 to 20 percent chromium, 0.1 to 1 percent platinum and 0 to 3 percent iron as mentioned in this paper.
Abstract: Cemented carbide compositions and shaped bodies produced therefrom containing tungsten carbide or titanium carbide and a binder alloy containing cobalt and nickel and, by weight, about 18 to 20 percent chromium, 0.1 to 1 percent platinum and 0 to 3 percent iron.
TL;DR: In this paper, the surface of an incandescent tungsten filament in a low pressure flow reactor was decomposed to carbon and hydrogen by a resistance method, and the sticking probability γ was defined as the probability that a room temperature hydrocarbon molecule striking the hot W2C surface would undergo complete decomposition.
Abstract: Hydrocarbons were decomposed on the surface of an incandescent tungsten filament in a low pressure flow reactor. The rate of conversion of tungsten to ditungsten carbide W2C was measured by a resistance method. Carbon accumulation on the outer W2C surface was prevented by rapid inward diffusion. The sticking probability γ was defined as the probability that a room temperature hydrocarbon molecule striking the hot W2C surface would undergo complete decomposition to carbon and hydrogen. The value of γ for different hydrocarbons, measured over a 300-fold range of conversion rates, increased in the order: methane
Patent•
29 Dec 1969
TL;DR: In this article, a small amount of carbon, such as about 0.5 to 3 percent by weight, is added to the composition before hot-pressing to improve the properties of the resulting hot-pressed bodies.
Abstract: Refractory compositions based on aluminum nitride, boron nitride, and at least one refractory boride, nitride, carbide or silicide. A small amount of carbon, such as about 0.5 to 3 percent by weight, is added to the composition before hotpressing. The resultant hot-pressed bodies have improved properties especially in the length of their life when used as aluminum-vaporizing crucibles.
TL;DR: In this article, a study of the fracture mode of samples tensile tested at temperatures to 500°C was carried out and the results showed that the fracture modes fall considerably below what is expected from the constituent properties.
Abstract: Composites of aluminum reinforced with α-silicon carbide whiskers have been fabricated by a powder metallurgical technique. Although reinforcement was achieved, composite properties fall considerably below what is expected from the constituent properties. This is inter preted in terms of voids, fiber breakage, and imperfect fiber orientation and the conclusions are supported by a study of the fracture mode of samples tensile tested at temperatures to 500°C.
Patent•
16 Apr 1969TL;DR: CEMENTED CARBIDE COMPOSITIONS are PREPARED by the production of a sintered Cemented Carbinide COMPACT by CONVENTIONAL LIQUID-PHASE SINTERING TECHNIQUES, FOLLOWED by CHEMICAL REMOVAL OF the METALLIC BINDER and REPLACEMENT by INFILTRATION with a SECOND METALLic BINDer DIFFERENT THAN the original Binder as mentioned in this paper.
Abstract: CEMENTED CARBIDE COMPOSITIONS ARE PREPARED BY THE PRODUCTION OF A SINTERED CEMENTED CARBIDE COMPACT BY CONVENTIONAL LIQUID-PHASE SINTERING TECHNIQUES, FOLLOWED BY CHEMICAL REMOVAL OF THE METALLIC BINDER AND REPLACEMENT BY INFILTRATION WITH A SECOND METALLIC BINDER DIFFERENT THAN THE ORIGINAL BINDER. THE RESULTING COMPOSITIONS ARE FULLY DENSE, HAVE A FINE-GRAINED, HOMOGENEOUS STRUCTURE AND POSSESS THE HIGH HARDNESS NORMALLY ASSOCIATED WITH CEMENTED CARBIDE ALLOYS.
TL;DR: In this paper, the CO-equilibrium pressures of the reaction were determined in the temperature range of 1290-1440°C. The PaC structure has been identified from X-ray powder patterns as being identical to those of the other actinide monocarbides (fcc structure, NaCl-type a0 = 5,0608 ± 0,0002 A).