Converting Star Wars Technologies to Material ProcessingDr. Glenn Whichard - UTRON Inc.
UTRON, Inc. personnel began developing new gun launch technologies under the Reagan Strategic Defense Initiative in the 1980s. Methods to accelerate projectiles, such as the electric light gas gun, combustion light gas gun, ram cannon, rail gun and electrothermal/electrochemical ignition systems were invented. When the Cold War ended defense funding for these programs was cut significantly. UTRON, Inc. turned its attention from defense to applying these high acceleration technologies for commercial processes and products.
UTRON has been particularly active in the replacement of solid propellant with gasses as in the Electric Light Gas Gun which launches projectiles as fast as 7 km / sec. Commercial Spin-offs from this technology are being developed in four areas of material engineering. Polymer Coating, Impact Bonding, Consolidation of Powders, and Fine Metal Powder production (nano materials).
In the area of "Consolidation of Powders" a technique referred to as CDDC (Combustion Driven Dynamic Consolidation) has been developed. Generally the gasses combusted are hydrogen and oxygen. The technique allows control of 1) Pressure rise rate, 2) Pressure Peak, 3) Duration, 4) Energy, and 5) Temperature. While still highly developmental, Aluminum powder has been consolidated to 98% of theoretical density at ambient temperature. Forming pressures as high as 500 kpsi are reached. It is hoped this technique will permit production of near net shapes from unusual alloys.
For impact bonding (coating) UTRON is developing a technique called PHAST (Pulsed High Acceleration Spray Technique). This technique developes a high pressure gas charge within a barrel. When the barrel is opened a pressure front moves back as pressure is released. Powder is fed and ignition (by capacitor discharge) of a plasma jet is timed to propel the powder outward at maximum velocity (> 2000 m/sec). With this velocity coating can be formed below the melting point of the coating materials which means low oxide contents. Currently the major limitation of the process is the relatively long time required to recharge capacitors, limiting the pulse rate. This should not be difficult to overcome, however. A variant of the process feeds solid fine wire instead of powder in front of the plasma jet. Results are similar but velocities are somewhat lower (1260 m / sec).
In the area of atomization a molten metal stream is fed in front of a plasma jet similar to that described above. The charge is dispersed into a collection chamber for the atomized powder. The atomizer is typically run with inert (Argon) gasseous atmosphere at about 40 pulses / sec. Highly spherical fully dense particles are formed with a broad distribution of sizes from 3 nanometers up to 5 micrometers (pure copper example). Currently the process can produce about 3 Kg of powder in 18 minutes. Development will be aimed at increasing the yield of nanoparticles from the process.