Cvd, Incorporated

Tevtech LLC

James C MacDonald

Lee E Burns

Alexander Teverovsky

Raymond L Taylor

Jeffery L Kirsch

Jitendra Singh Goela

Michael A Pickering

Lee Erich Burns

Parul V Purohit

A method and apparatus for producing a coating or a near net shaped monolithic ceramic part by chemical vapor deposition, where the resultant coatings or parts consume less deposit material and require less machining. Mandrel substrates are closely designed for producing a specific, near net shaped final part, including negative relief features. Several of the mandrel substrates are mounted through centers in a spaced relationship on one or more rotable shafts as tooling for a chemical vapor deposition furnace. The tooling is installed in a chemical vapor deposition furnace so that the shafts are oriented perpendicular and the substrate planar surfaces are parallel to the flow pattern of reactant gases through the furnace. The shafts are rotated during the deposition process so that the mandrel substrates each receive a uniformly distributed ceramic deposit in the near net shape of the final part.

Chemical vapor deposition of near net shape monolithic ceramic parts

The surface of a zinc selenide substrate is ground to curve in the opposite direction from that which occurs due to the bimetallic effect when zinc sulfide is deposited on a flat substrate by the chemical vapor deposition process. The bowing of the interface that occurs upon cooling of the hot laminate when the surface of the substrate is flat before deposition is compensated for by the pre-figured bowing. A distortion free window for the transmission of infra-red radiation is provided by this invention.

Process for an improved laminate of ZnSe and ZnS

A method and device are provided for reducing the loss of CVD manufactured parts due to cracking caused by mechanical stresses resulting from the mismatch of the coefficient of thermal expansion between the chemical vapor deposed part and the mandrel plate. The method and device provide a removable mandrel support which is removed after the chemical vapor deposition but prior to the cooling of the CVD part and the mandrel plates. This permits the CVD part to contract upon cooling without mechanical restriction, thus reduce cracking caused by contraction of the CVD part against a mold which does not contract substantially.

Method of producing domes of ZNS and ZNSE via a chemical vapor

A process and apparatus for the manufacture of chemical vapor deposition deposited structures which comprises supplying a solid zinc metal continuously to a heated retort at a controlled rate. The retort is a body of refractory material having a top and a bottom and a traverse cross section which decreases from the top to the bottom of the retort. The zinc is melted, vaporized, and conveyed to a chemical vapor deposition zone defined by a number of heated mandrel plates where it is reacted with either hydrogen sulfide or hydrogen selenide to form a chemical vapor deposited structure. The process and apparatus provide for improved control over the evaporation rate of zinc and a reduction in the furnace volume needed to melt and vaporize the zinc.

Process and apparatus for supplying zinc vapor continuously to a

A process and apparatus for the manufacture of chemical vapor deposited silicon carbide which comprises conveying the reaction gases to a triangular chemical vapor deposition cell where material is deposited by chemical vapor deposition. The triangular cell provides a large surface area for deposition while occupying a minimum amount of the furnace floor surface area. The triangular cell has the added benefit in that deposited silicon carbide is of negligible thickness at the edges thereby permitting easy separation of material with a minimum of post deposition machining.

Triangular deposition chamber for a vapor deposition system

Process for an improved laminated of ZnSe and ZnS

An improved method of forming a ZnS layer on a ZnSe substrate by chemical vapor deposition of ZnS onto the ZnSe is disclosed in which the ZnS is contacted, prior to the chemical vapor deposition of the ZnS, with H.sub.2 S in the absence of zinc metal vapor to cause reaction of the H.sub.2 S and the surface of the ZnSe substrate.

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Reading, MA, United States of America

James C MacDonald