The microstructure characterization of tubular wicks is discussed using an image analysis method, mercury intrusion porosimetry and Arquimedes method. The central objective of this work is to determine the wide convenience of the image analysis technique for wick characterization. It is demonstrate that the image analysis technique is an appropriate tool to determine correlation function, total porosity and pore size distribution in two-dimensional (2-D) binary images of microstructures. The correlation function is used to simulate the 3-D reconstruction of porous structure. The images were obtained from a set of wick samples made of sintered nickel, through scanning electronic microscopy (SEM). A computer program (Imago) was developed and used in the work. The mercury intrusion porosimetry is also used to provide information about the breakthrough diameter of porous material. Results show porosity of about 60% and effective pore size less than 4 μm.
This SAE Aerospace Recommended Practice defines a method for determining the weldability of weld filler metal in continuous coil or cut length form. It is applicable to all solid (non flux-containing) wires. It is intended as a referee method for testing weld filler metals in case of dispute between purchaser and vendor.
This paper will present an overview of waste minimization and wastewater/material recovery practices implemented at Pratt & Whitney's North Haven, CT facility. We will also discuss some of the lessons learned since implementing many of the discussed technologies. Technologies used include process substitution and modification, atmospheric evaporation, ion exchange, electrowinning, and recovery of fume scrubber recirculation water. Processes effected include Woods Nickel Strike, Sulfamate Nickel Plate, Chrome Plate, Cadmium Cyanide Plate, Cadmium Chromate, Chrome Strip, Nickel Strip, Cadmium Strip, and Alkaline/Cyanide Descaling.
The Bosch process has been considered as a means to recover oxygen, from metabolic carbon dioxide through the catalytic production of water. Previous investigations have shown that the oxide formation accounts for the limited activity of the iron catalyst. On the other hand, the maximum water concentrations achievable in the nickel and cobalt systems have been shown to correspond to the carbide formation. This paper presents the results of an experimental study carried out to determine the effectiveness of ruthenium and its alloy with iron as alternative Bosch catalysts. Carbon deposition boundaries over the alloy catalysts are reported.
TWO SPECIALTY APPLICATIONS for electrochemical metallizing have recently proved cost-effective and technologically sound. Aircraft engine manufacturers and maintenance facilities find nickel electrochemical metallizing an excellent way to enhance braze-ability of super alloys on turbine engines and other components. A base nickel deposit permits even brazing at lower temperatures, avoiding heat damage to adjacent honeycomb. Aluminum helicopter rotors present bonding problems, now solved by selective electrochemical anodizing. Leading edges are often covered with a hard alloy shield or a layer of synthetic rubber, bonded to the aluminum base with high-strength adhesives. Selective electrochemical anodizing leading edges of rotors guarantees adhesion vastly superior to direct bonding.
Operating components found in today's high performance aircraft and industrial gas turbines are subject to the most demanding conditions and hostile operating environments imaginable. As such, sophisticated part designs and advanced materials are being utilized to overcome the stringent demands encountered in these engines. Most distressed parts include blades, vanes, shrouds, frames, combustors, etc. These are generally constructed of high strength, heat resistant nickel or cobalt base alloys. Their costs are high, often in the tens of thousands of dollars. When damage occurs, usually thermal fatigue cracking, the part is no longer serviceable and must be repaired or worse - retired and replaced. Weld repair, though satisfactory, has inherent problems. This paper discusses activated diffusion brazing as a viable repair procedure for crack healing.