摘要:
A method is described for making a shaped silicon carbide-silicon matrix composite. A confined carbon fiber preform is infiltrated with sufficient molten silicon metal at a temperature in the range of from about 1400.degree. C. to about 1800.degree. C. in an inert atmosphere or vacuum.
摘要:
Cermet compositions having high temperature oxidation resistance, high hardness and high abrasion and wear resistance, and particularly adapted for production of high temperature resistant cermet insulator bodies, comprising a sintered body of particles of a high temperature resistant metal or metal alloy, preferably molybdenum or tungsten particles, dispersed in and bonded to a solid solution formed of aluminum oxide and silicon nitride, and particularly a ternary solid solution formed of a mixture of aluminum oxide, silicon nitride and aluminum nitride. Also disclosed are novel ceramic compositions comprising a sintered solid solution of aluminum oxide, silicon nitride and aluminum nitride.The cermet compositions are designed particularly to provide high temperature resistant refractory coatings on metal substrates, preferably molybdenum or tungsten substrates.
摘要:
This invention relates to ceramic compositions of tungsten and tantalum oxides including 0 to 33 1/3 mole percent of a metal oxide such as hafnia. These ceramics are characterized by melting points greater than about 1400.degree.C and selectively controlled coefficients of thermal expansion of essentially zero to a negative value in the temperature range of 20.degree. to 1000.degree.C.
摘要:
THIS INVENTION PROVIDES A NOVEL ACID CURED FURAN BASED BINDER WHICH IS A LIQUID AT 25*C., WHICH IS USEFUL FOR BINDING SUSTANTIALLY NON-ALKALINE AGGREGATE SUCH AS CARBON AND GRAPHITE, AND WHICH IS CURED AT ROOM TEMPERATURE TO A THERMOSET CONDITION. THE HARD PITCH BINDER COMPRISES 50 TO 75 PERCENT BY WEIGHT HARD PITCH WITH A SOFTENING POINT BETWEEN PLASTICIER WHICH COMPRISES FURFURYL ALCOHOL; FURFURAL; AND A MEMBER SELECTED FROM THE GROUP CONSISTING OF CYCLOHEXANONE, MESITYL OXIDE, AND MIXTURE THEREOF.
摘要:
Disclosed is a refined and alloyed martensite-free cast steel abrasive material and method of making the same. The abrasive material is either shot or grit and has a composition which includes carbon in about the range of 0.60 to 1.20 percent by weight, silicon in about the range of from 0.30 to 1.50 percent by weight, sulphur in about the range of from 0.0 to 0.1 percent by weight with the remainder substantially all iron, trace elements and impurities. The substantially martensite-free micro-structure is characterized by the presence of one or more of the group consisting of lower bainite, upper bainite, pearlite or ferrite and mixtures thereof, thus providing a more ductile abrasive particle of improved wear resistance.
摘要:
An abrasion resistant composition comprising between 40 and 60 percent by volume of boron carbide in particulate form, dispersed in a matrix of molybdenum disilicide.
摘要:
Process for dispersing fibers in a refractory metal compound phase comprising coating fibers, e.g. graphite fibers, with a mixture of a refractory metal compound of extremely small particle size, e.g. NbC of 0.02 micron size, and sufficient binder, e.g. polymerizable furfuryl alcohol and maleic anhydride, to form a slurry, forming the coated fibers to the desired shape and heating the formed coated fibers at high temperatures in the range of about 40% to about 98% of the melting point of the refractory compound, e.g. about 3,000*C, to form a composite. The article produced by the above process is characterized by low thermal expansion values.
摘要:
DENSE COMPOSITIONS HAVING A GRAIN SIZE SMALLER THAN 10 MICRONS AND CONTAINING FROM 10 TO 80 VOLUME PERCENT OF A WEAR-RESISTANT MATERIAL SELECTED FROM THE GROUP CONSISTING OF (A) ALUMINUM NITRIDE, (B) TANTALUM NITRIDE, (C) MIXTURES OF (A) AND (B), AND (D) A REFRACTORY OXIDE OF AN ELEMENT SELECTED FROM THE GROUP CONSISTING OF MAGNESIUM, ZIRCONIUM, HAFNIUM, TITANIUM, CHROMIUM, BERYLLIUM, ZINC, CALCIUM, THORIUM, BARIUM, STRONTIUM, SILICON, THE RARE EARTH METALS, AND MIXTURES THEREOF; 15 TO 80 VOLUME PERCENT OF A METALLINE SELECTED FROM THE GROUP CONSISTING OF TITANIUM CARBIDE, TITANIUM NITRIDE, ZIRCONIUM CARBIDE, ZIRCONIUM NITRIDE, TANTALUM CARBIDE, NIOBIUM CARBIDE, NIOBIUM NITRIDE, AND MIXTURES THEREOF; AND 5 TO 35 VOLUME PERCENT OF AN INTERMETALLIC SELECTED FROM THE GROUP CONSISTING OF MOLYBDENUM NICKELIDE, TANTALUM NICKELIDE, ZIRCONIUM, NICKELIDE, NIUBIUM NICKELIDE, COBALT, ALUMINIDE, COBALT TITANIDE, IRON ALUMINIDE, IRON TITANIDE, NICKEL ALUMINIDE, NICKEL TITANIDE, TUNGSTEN ALUMINIDE, MOLYBDENUM ALUMINIDE, NIOBIUM ALUMINIDE, TANTALUM ALUMINIDE, TITANIUM ALUMINIDE, ZIRCONIUM ALUMINIDE, AND MIXTURES THEREOF ARE (1) EFFECTIVE FOR CUTTING TOOLS FOR HIGH SPEED MACHINING AND (2) RESISTANT TO OXIDATION.
摘要:
A composite having high strength and impact resistance comprising from 30 to 90 percent by volume of a glassy material from the group consisting of the following approximate formulations given in approximate percentages by weight: 4% SiO2, 3% A12O3, 10% B2O3, 83% PbO; and 28.7% SiO2, 9.1% CaO, 11.77% Na2O, 26.3% B2O3, 5.3% ZnO, 17.2% BaO, and 3.1% F2; and having from 10 to 70 percent by volume of stainless steel fibers, boron fibers, or graphite fibers.