Method and apparatus for direct use of low pressure vapor from liquid or

Abstract

Methods and apparatus for selectively depositing a layer of material from a gas phase to produce a part comprising a plurality of deposited layers. The apparatus includes a computer controlling a directed energy beam, such as a laser, to direct the laser energy into an unheated chamber substantially containing the gas phase to preferably produce photodecomposition or thermal decomposition of the gas phase and selectively deposit material within the boundaries of the desired cross-sectional regions of the part. At least one component of the gas phase is a vapor which condenses at a temperature above the ambient temperature of the chamber. Each such component can exist at a partial pressure no higher than its equilibrium vapor pressure at the chamber ambient temperature. For each cross section, the aim of the laser beam is scanned over a target area and the beam is switched on to deposit material within the boundaries of the cross-section. Each subsequent layer is joined to the immediately preceding layer to produce a part comprising a plurality of joined layers. A catalytic environment can be created proximate or upon the target area to ensure that initial nucleation and renucleation layers are receptive to substantially rapid and uniform growth of decomposed gas phase material at the target location. The catalyst can be placed on the initial substrate layer and/or upon successive layers as the layers are being deposited on the outer surface of the evolving part.