Showing papers by "Cabot Corporation published in 1990"

Method of making powders and products of tantalum and niobium

Abstract: A powder of tantalum, niobium, or an alloy thereof, having an oxygen content less than about 300 ppm, and the production thereof without exposure to a temperature greater than about 0.7 T H . A powder metallurgy formed product of tantalum, niobium, or an alloy thereof, having an oxygen content less than about 300 ppm, and the production thereof without exposure to a temperature greater than about 0.7 T H .

Carbon blacks and rubber compositions containing the carbon blacks

Abstract: Carbon blacks having a N 2 SA of from at least about 150 m 2 /g to about 180 m 2 /g, a DBP of about 125 cc/100 g or less, a Dmode of 70 nm or less, a N 2 SA/I 2 No. ratio of 0.85 to 0.98 and a ΔDBP less than 210 cc/100 g which, when incorporated into rubber compositions, impart increased abrasion resistance, heterogenous abrasion resistance and grip performance properties. Also disclosed are rubber composition incorporating the novel carbon blacks.

Treadwear/hysteresis carbon blacks

Abstract: Improved treadwear/hysteresis carbon blacks having a CTAB of 120-160 m2 /g, a N2 SA of 125-180 m2 /g, a CDBP of 95-120 cc/100 g, a DBP of 110-145 cc/100 g, a Tint/CTAB ratio of 0.80-1.10, a ΔD50 of 70-100 nm and a ΔD50/Dmode ratio of 0.80-1.05. Also disclosed are rubber compositions containing the carbon blacks which exhibit superior treadwear/hysteresis performance properties.

Method of abrading

Abstract: A method of abrading a tire tread compound to measure its irregular wear characteristics, includes the steps of abrading each of a plurality of sample wheels in rotating engagement with a respective abrasive member. An outer layer of each sample wheel is made of a tire tread compound to be abraded. The velocity of the sample wheels relative to the velocity of the abrasive members defines a first slip value. Each sample wheel is abraded in rotating engagement with a plurality of abrasive members at the first slip value. The loss of the tire tread compound of each sample wheel at the first slip value is then measured. Each sample wheel is then abraded in rotating engagement with a plurality of respective abrasive members at a second slip value. The loss of the tire tread compound of each sample member at the second slip value is then measured. Each sample wheel is then abraded in rotating engagement with a plurality of respective abrasive members at a third slip value. The loss of the tire tread compound due to abrasion at the third slip value is then measured. The second slip value causes a higher level of abrasion severity than the first slip value. The third slip value in turn causes a higher level of abrasion severity than the second slip value. The irregular wear characteristics of the tire tread compound is measured based on the loss of the compound due to abrasion at each of the different slip values.

Carbon black having a high specific surface area

Abstract: Carbon blacks having stable surface area and structure which, when incorporated into rubber compositions, impart increased abrasion resistance and lower hysteresis. Also disclosed are rubber composition incorporating the novel carbon blacks.

Sealing system for hermetic microchip packages

Abstract: A sealable hermetic microchip package includes a vent therein that permits gas to escape during the sealing operation, but then itself is sealed at the completion of the sealing operation to render the package hermetic. The venting of gas from the interior of the package avoids the buildup of internal pressure during the sealing operation that can introduce bubbles and other faults into the sealing material. The vent may be a channel in the sealing surface of the lid of the package that is initially open, and then fills with the seal material as it flows to effect the seal. The vent may also be a hole in the lid that is sealed by the flow of a bead of the seal material. An equivalent approach to venting provided that the lid be mounted on standoffs that flow during sealing to permit the lid to settle onto the base of the package.

Interaction behavior of nitrogen in liquid niobium

Abstract: The kinetics and mechanism of absorption/desorption of nitrogen in liquid Nb were investigated in the temperature range of 2470 °C to 2670 °C in samples levitated in a N2/Ar stream with various nitrogen partial pressures. The nitrogen solution reaction in liquid Nb was found to be exothermic, with the standard enthalpy and entropy of solution of −236.4 ± 23.3 kJ/mol and −-5.3 ± 8.3 J/K · mol, respectively. Above the threshold flow rate of the N2/Ar stream, the absorption process was determined to be second order with respect to nitrogen concentration, indicating that the rate-controlling step is either the adsorption of nitrogen molecules on the liquid surface or dissociation of adsorbed nitrogen molecules into surface-adsorbed atoms. The desorption process was found to be second order as well. At lower flow rates, however, the absorption rate was found to depend on the gas-phase mass transfer rate. The rate equation for nitrogen absorption in the range of 2470 °C to 2670 °C is given by\(\frac{{dCn}}{{dt}} = 2.290 10^3 exp \left( { - \frac{Q}{{RT}}} \right) \frac{A}{V} (C_{N_e }^2 C_N^2 )\) with the value ofQ calculated to be −327.2 ± 20.6 kJ/mol, while nitrogen desorption at 2670 °C follows the relation\(\frac{{dCn}}{{dt}} = 1.820 x 10^{ - 3} \frac{A}{V} (C_{N_e }^2 C_N^2 )\)

Continuous treatment process for particulate material

Abstract: A process for continuously producing a treating agent contacted particulate material having a bulk density of about 10 lbs./cu. ft. or less comprising contacting the material with a treating agent as the material is being transferred in dense phases from a storage container to a vessel. The material may be heated after contact if necessary.

Apparatus for measuring the non-porous surface area of carbon black

Abstract: An automated method for measuring the non-porous surface area of carbon black is disclosed. The method comprises passing a small sample of a CTAB-carbon black dispersion through a disposable filter to separate the carbon black with adsorbed CTAB from the filtrate containing unadsorbed CTAB. The filtrate next passes through a measuring loop and a high pressure liquid chromatography column to separate the CTAB from the other filtrate components. The CTAB is next sensed by a detector and an integrator calculates the amount of CTAB adsorbed by the carbon black and the non-porous surface area of the carbon black. The integrated apparatus for carrying out this method is also described. Once the carbon black and the CTAB are mixed, there is no further handling of the sample. The system is entirely automated and takes only a few minutes for the CTAB area determination. Measuring temperatures can also be fixed. This results in much more reproducible CTAB numbers for a particular carbon black.

Waessrige colloidale dispersion aus in der gasphase hergestelltem siliciumdioxid, aus einer saeure und aus einem stabilisator, sowie ein verfahren zu ihrer hertellung

Abstract: An aqueous colloidal dispersion of fumed silica, acid and stabilizer, having a fumed silica concentration of at least 40% by weight, a concentration of acid of 0.0025-0.5 of the fumed silica and stabilizer to adjust the pH of dispersion to 7 to 12. The acid used is preferably hydrochloric acid and the stabilizer is preferably an alkali such as ammonium hydroxide. Sulphuric, nitric, phosphoric, acetic or maleic acids are also suitable acids, and sodium hydroxide, potassium hydroxide, lithium hydroxide, triethylamine and dimethylethanol amino are also suitable stabilizers.

Method and apparatus for abrading

Abstract: An abrading apparatus for abrading tire tread compounds has a plurality of test stations (14) and a drive module (16) coupled to the test stations. Each test station (14) has a grindstone (20) and a sample wheel (24), both of which are rotatably driven by the drive module (16). Each sample wheel (24) has an outer layer made of the tire tread compound to be abraded. The sample wheels (24) are engageable with the grindstones (20) to abrade the tire tread compounds against the grindstones. Each test station (14) also has a dust transfer wheel (40) engageable with the sample wheel (24), and a chalk member (44) engageable with the dust transfer wheel (40). The chalk member (44) transfers chalk dust to the dust transfer wheel (40) which, in turn, transfers chalk dust to the sample wheel (24), to dust the interface between the sample wheel (24) and the grindstone (20). The drive module (16) has a gear assembly (78, 88, 90, 92, 94, 98) to change the velocity of the sample wheels (24) relative to the velocity of the grindstones (20), to adjust the slip value and, therefore, the degree of abrasion of the sample wheels (24). The abrading apparatus can be employed to abrade tire tread compounds at different levels of abrasion severity, to predict the irregular wear resistance of the compounds.

Alumina foams and method of producing the same.

Abstract: The present invention relates to alumina oxide particles having an internal foam structure and a method of making the same. The method first creates foam particles of aluminum sulfate in reactor (14) and subsequently, converts the aluminum sulfate to aluminum oxide particles with the same internal foam structure. The aluminum oxide foam particles made by this method have large specific surface areas and pore volumes.