摘要:
A method for selective controlled etching of a material particularly by sequentially switching between two (2) or more modes of radiofrequency waves and/or by distance from a source of the microwaves. The modes and/or distance are selected depending upon the surface of the material to be etched. The etching is rapidly conducted at 0.5 mtorr to 10 torr, preferably using microwave plasma etching.
摘要:
Shaped ceramic articles can be obtained by screen printing the desired shapes from a dimensionally stable dispersion of a precursor of the ceramic onto a surface, drying the screen printed shapes so obtained and firing them to generate the shaped ceramic articles.
摘要:
Output variations of individual channels of radiation detector arrays and particularly the outer channels of the scintillator crystal array are reduced by modifying the reflectivity of the surfaces of the individual crystal elements according to the output. This is accomplished by creating a specific difference in the reflectivity of the internal channel reflectors compared to the external reflector material to enhance or reduce the output of specific channels to achieve a balance in the outputs. The specific difference in reflectivity may be obtained by using different color pigments, different color cements and various colored foils, for example.
摘要:
Sol-gel alumina that is dried but unfired can be explosively comminuted by feeding the dried gel into a furnace held at temperatures above those at which vaporizable materials are eliminated from the particles of gel. At suitably elevated temperatures the firing is sufficient to form fully densified alpha alumina particles of a size suitable for direct use as abrasive grits.
摘要:
A mandrel for use in a diamond deposition process for generating free standing diamond films has a segmented surface forming a plurality of surfaces for deposition of diamond. The segmented surface is formed of a plurality of mesa segments on a common supporting base surfaces for the mesas. The mesa segments are preferably removably attached to the common base by any suitable means such as by bolts through the mandrel substrate which extend into the mesa segments. The mesa segments may vary in shape, size, and number, thus permitting different shaped diamond films to be made simultaneously from the same run if desired. The provided arrangement increases yield by reducing losses due to premature lifting of the diamond film during deposition, due to violent lifting after deposition upon cooling of the mandrel, and due to cracking.
摘要:
A method for depositing a substance includes the following steps: producing a vapor containing constituents of the substance; providing a rotating mandrel assembly that includes a mandrel, having a deposition surface exposed to the vapor so that the substance is deposited on the deposition surface, and a base having a plurality of radiator fins extending therefrom; interleaving a plurality of receptor fins with the radiator fins; and providing heat exchange to the receptor fins to cool the mandrel during deposition of the substance on the deposition surface of the mandrel.
摘要:
At least the surface region of a cutting tool substrate made of tungsten carbide in a cobalt matrix is carburized to chemically passivate the cobalt prior to deposition of diamond film on it. The passivation improves adhesion by preventing reaction of the cobalt with the diamond in the course of the deposition process.
摘要:
A process comprising the steps of: a) providing a fiber preform comprising a non-oxide ceramic fiber with at least one coating, the coating comprising a coating element selected from the group consisting of carbon, nitrogen, aluminum and titanium, and the fiber having a degradation temperature of between 1400.degree. C. and 1450.degree. C., b) impregnating the preform with a slurry comprising silicon carbide particles and between 0.1 wt % and 3 wt % added carbon c) providing a cover mix comprising: i) an alloy comprising a metallic infiltrant and the coating element, and ii) a resin, d) placing the cover mix on at least a portion of the surface of the porous silicon carbide body, e) heating the cover mix to a temperature between 1410.degree. C. and 1450.degree. C. to melt the alloy, and f) infiltrating the fiber preform with the melted alloy for a time period of between 15 minutes and 240 minutes, to produce a ceramic fiber reinforced ceramic composite.
摘要:
There is provided an improved kiln furniture assembly: wherein the improvement comprises vertical posts comprising: i) a vertically disposed channel, and ii) a spacer block (13a) vertically separating the upper and lower horizontal beams which extend from the same post, wherein at least a portion of the spacer block or the horizontal beam is positioned within the vertically disposed channel.