Abstract: A method for depositing synthetic diamond film on a substrate, including the following steps: pre-stressing the substrate to obtain a pre-deposition stress across a surface thereof; depositing the diamond film on the pre-stressed substrate surface; and cooling the film and substrate, and relieving the pre-deposition stress during the cooling. When the substrate has a higher coefficient of thermal expansion than the diamond film, the pre-stress is a compressional stress. When the substrate has a lower coefficient of thermal expansion than diamond film, the pre-stress is a tensile stress.

Abstract: Precision measuring instruments having highly parallel and wear-resistant contact members and a method for fabricating these contact areas are disclosed. The measuring instruments preferably include two contact members each having diamond coated ceramic substrates. The method for diamond coating the contact members of the measuring instruments includes, for each contact member, preparing a ceramic substrate to high tolerance so that it has two surfaces which are parallel within 0.25 microns, diamond coating one surface of the substrate by any one of several chemical vapor deposition (CVD) techniques, and metalizing the other surface of the substrate for affixing it to the contact member of the measuring instrument. The metalized surface of the substrate is preferably affixed to the contact members of the measuring instrument by brazing, gluing or welding. Preferred embodiments of the measuring instruments with diamond coated contact areas include calipers and micrometers.

Abstract: The invention provides a process for recovering abrasive grains from vitreous bonded materials by boiling the material in an aqueous solution of an alkali metal base.

Abstract: A radiation monitoring system and method characterized by the use of paired active and passive radiation detectors to monitor exposure to a radiation field. The active detector provides an output representative of radiation exposure on a real time basis while the passive detector is readable on a delayed basis after exposure to radiation for a period of time to provide an output representative of radiation exposure over said period of time. Respective readers are provided for extracting the radiation exposure information from the detectors, as is a processor which determines a quantity of radiation exposure from the radiation information extracted from the detectors. The processor corrects radiation exposure data derived from one of the detectors using radiation exposure data derived from the other of the detectors.

Abstract: A barrier comprising:a) between about 75 w/o and about 95 w/o alumina-silica refractory grain, andb) between about 2 w/o and about 10 w/o of a sealant selected from the group consisting of zinc borate; sulfur; R1 Al.sub.x/2 Si.sub.y/2 O.sub.z/2 and R2 Si.sub.b/2 S.sub.c/2 C.sub.d/2 O.sub.e/2 H.sub.f/2 wherein:i) R1 is selected from the group consisting of Na, K, and Li, and mixtures thereof,ii) x,y and z are integers between 0 and 16,iii) R2 is selected from the group consisting of Ca, Sr and Mg, and mixtures thereof, andiv) b,c,d,e and f are integers between about 0 and 16.

Abstract: The reliability of a braze joint formed between a diamond film and a tungsten carbide body is increased by use of a vanadium containing braze. The braze joint exhibits an average shear strength greater than about 40,000 pounds per square inch, (276 MPa) and the braze exhibits a contact angle with the diamond film of less than about 15.degree..

Abstract: A sintered silicon nitride ceramic comprising between about 0.6 mol % and about 3.2 mol % rare earth as rare earth oxide, and between about 85 w/o and about 95 w/o beta silicon nitride grains, wherein at least about 20% of the beta silicon nitride grains have a thickness of greater than about 1 micron.

Abstract: A waterwall heat transfer system has a tube block secured to a tube assembly. The tube assembly includes a plurality of parallel tubes connected together by a membrane. The tube block has a base section and a plurality of spaced ridges extending upward from the base section, the upper surface of at least one of the spaced ridges defining a generally horizontal surface. The ridges are spaced to define channels therebetween with the height of at least one of the ridges selected to provide a seat for the membrane of the assembly.

Abstract: Alpha alumina abrasive grits with grain boundaries modified with at least one of yttria and a rare earth metal oxide, and one or more oxides selected from the oxides of magnesium and/or transition elements, perform at enhanced levels if at least the yttria and/or rare earth metal oxide modifiers are present within the body of the grit in concentrations at least as high as their concentrations at the surface of the grit.

Abstract: A hydrogen torch comprising concentric inner and outer fluid delivery tubes wherein the outer tube comprises silica and the inner tube comprises silicon carbide. One end of the inner tube is connected to a third tube comprised of silica which has an inlet in fluid connection with a hydrogen supply line. The outer tube is in fluid connection with an oxygen supply line. A reverse ball joint connection is used to join the tubes and defines an annulus between the inner and outer tubes through which the oxygen can flow and be isolated from the hydrogen flowing within the inner tube.

Abstract: A method of making a diamond film on a graphite substrate is disclosed, which comprises the steps of forming a layer of carbon-containing compound on a surface of the graphite substrate and controlling said compound to be rich or lean in carbon with respect to the stoichiometric carbon content in the compound to adjust the adherence of a diamond layer to be deposited on said layer of carbon-containing compound; and depositing a synthetic diamond layer on said layer of carbon-containing compound.

Abstract: The reliability of a braze joint formed between a diamond film and a tungsten carbide body is increased by use of a vandium containing braze. The braze joint exhibits an average shear strength greater than about 40,000 pounds per square inch, (276 MPa) and the braze exhibits a contact angle with the diamond film of less than about 15.degree..

Abstract: A sintered silicon nitride ceramic comprising between about 0.6 mol % and about 3.2 mol % rare earth as rare earth oxide, and between about 85 w/o and about 95 w/o beta silicon nitride grains, wherein at least about 20% of the beta silicon nitride grains have a thickness of greater than about 1 micron.

Abstract: Seeded sol-gel alumina abrasive grits with improved grinding performance incorporating alkali metal oxides selected from rubidium and cesium oxides.

Abstract: An annular seal for use in a heat exchanger connection comprising a tube and at least one annular seal, wherein the annular seal is compression seated upon the outside diameter of the tube.

Abstract: A ceramic material comprising:(a) between about 50 and about 80 v/o of an electrically insulating ceramic having a resistivity of at least about 10 E+10 ohm-cm;(b) between about 10 and about 45 v/o of a semiconductive material having a resistivity of between about 1 and about 10 E+8 ohm-cm;(c) between about 5 and about 25 v/o of a metallic conductor having a resistivity of less than about 10 E-2 ohm-cm; and(d) between about 0.5 and about 20 v/o of a resistivity-enhancing compound selected from the group consisting of metallic oxides, metallic oxynitrides, rare earth oxides, rare earth oxynitrides, and mixtures thereof.

Abstract: A method for producing free-standing diamond film having a surface area of at least 1000 square millimeters includes the following steps: providing a substrate; depositing, on the substrate, by chemical vapor deposition, a first layer of diamond over a surface area of at least 1000 square millimeters, and to a first thickness, the first layer being deposited at a first deposition rate; depositing, on the first layer, a second layer of diamond, over a surface area of at least 1000 square millimeters, and to a second thickness, the second layer being deposited at a second deposition rate; and releasing the diamond from the substrate; the second deposition rate being as lest twice as high as the first deposition rate, and the first thickness being sufficiently thick to prevent the released diamond from bowing by more than a given distance.

Abstract: A dosimeter product that simplifies the process of dosimetry in medical diagnosis, therapy and other fields where high precision is needed. The dosimeter product is obtained by a unique training method which stabilizes the sensitivity of the dosimeter. Stability in sensitivity is established by a combination of high temperature cyclical annealing and low temperature furnace annealing. After the sensitivity of the dosimeters is stabilized, the dosimeters are then calibrated by generating for every dosimeter within a group element correction coefficients (ECCs) that compensate for the differences in sensitivity among the group of the dosimeters, bringing the sensitivity of each dosimeter to the sensitivity of the mean of the population. The result is a group of precalibrated dosimeters with stable sensitivity that are ready to use with established correction factors for individual TL response differences.

Abstract: A sintered silicon nitride ceramic having an L10 value of at least 50 million stress cycles in ASTM test STP 771 under 6.9 GPa applied contact stress.

Abstract: A combination measuring and ablation laser apparatus is provided which generally includes an ablating laser, a profilometer laser, an automatic feedback control unit and electro-mechanical positioning apparatus. The combination measuring and ablation laser apparatus can have a single multi-mode laser having an ablating mode and a measuring mode and a positioning means for positioning the laser between ablating and measuring modes. In operation, the profilometer laser measures the thickness of a diamond sample and compares it to the desired thickness. Where the measured thickness is too large, the feedback control unit activates the ablating laser for a predetermined time interval to smoothen any irregularities which may be contributing to the diamond sample thickness. At the end of the time interval, the portion is remeasured by the profilometer laser to determine if it conforms to the desired thickness.