Chamber pressure

About: Chamber pressure is a research topic. Over the lifetime, 2988 publications have been published within this topic receiving 30725 citations.

Surface treatment of metals at low pressure

Abstract: A method of surface hardening metals (in particular stainless steel) comprises heating the component in a chamber to a temperature of less than 550 DEG C, at a pressure of less than 10mTorr (eg 7.5m Torr) containing an element which reacts with the surface of the metal and being in ionized form by use of a plasma in the presence of a gas or gas mixture. This mixture may contain carbon (eg acetylene) or nitrogen containing gases eg nitrogen or a gas containing both carbon and nitrogen. The gas is ionized by a low pressure d.c. negative workpiece bias or r.f. plasma system so that carbon, nitrogen (or both) enter the surface of the metal. An electron emission source, which may be a negatively biased, heated tungsten filament, may provide plasma enhancement independently of workpiece voltage and chamber pressure parameters. In addition, an earthed hot tungsten filament may provide additional substrate heating conventional nitriding may be carried out as a pre-treatment and the method is particularly suitable for treating steels. An apparatus for carrying out the method is also disclosed (see Fig). Hard diffusion layers with superior combinations of wear, fatigue and/or corrosion resistance are produced depending on gas mixture, at a low temperature (as low as 270 DEG C). The range of materials which can be treated by this technique, without the need for post-finishing (either by heat treatment or machining operations), is superior to that achievable by any other single plasma diffusion process.

Coaxial Dump Combustor Investigations

Abstract: : An experimental investigation was conducted involving coaxial dump combustors with two different types of flameholders (annular and Y) installed at the dump station in an attempt to correlate combustor performance with previous non-reacting flowfield results. Flameholder blockage, combustor length, exit area ratio, inlet temperature, and chamber pressure were varied for both all injection and premixed fuel conditions. Lean blowout limits, combustion efficiency, combustor total pressure drop, and wall static pressure distributions were obtained from these runs using JP-4 fuel. In addition, a limited amount of surface heating patterns and combustion oscillation data were obtained.

Characterization of an aluminum etching process in an inductively coupled discharge using measurements of discharge impedance and current and voltage sensors

Abstract: The rf characteristics of a BCl3/Cl2 discharge used to etch aluminum films for semiconductor interconnect applications have been studied in a transformer coupled plasma™ (TCP™) etching system. The impedance (both real and imaginary parts) of the discharge was obtained as a function of process condition by studying the capacitor positions of the matching network attached to the TCP plasma source. By correcting for the contribution of the excitation coil, estimates were made of the plasma resistance and reactance as a function of generator power and chamber pressure. In addition, measurements of rf current and voltage were made using IV probes incorporated into the match as a function of TCP power measured at the generator, pressure, and total gas flow. It was found that the rf current and voltage at the input to the coil were both linearly dependent on power, inversely dependent on total pressure and virtually independent of total gas flow. The current–voltage measurements were correlated with measurements...

Induction period for ignition of fuel sprays at high temperatures and pressures

Abstract: An experimental study of the induction period for ignition of fuel sprays with particular consideration of its dependence upon temperature and pressure is reported. Emphasis in the study was placed upon conditions of thermodynamically supercritical state for the fuel. The tests were performed in a stainless steel cylindrical chamber located in an oven, both provided with quartz windows for optical insight in axial direction of the radially injected spray. Spray formation and igniton were observed by high-speed schlieren cinematography concomitantly with measurements of chamber pressure and the displacement of the injector needle. The induction period was evaluated as the time interval between the rise in the displacement transducer signal and the instant when pressure attained three percent of its peak value.