This study focused on improvement of electroless plating methods by use of particular bath additives. The techniques developed here can enable us to plate very thin layers selectively on a nonconductive substrate and thus create metallized features on a nanoscale. Through the development of such bottom-up techniques this work contributes a key technology to achieving self-assembled nanocircuits. The use of additives in an electroless plating environment can modify the barriers to nucleation (or seeding) and growth. Two additives, namely 3-mercapto-1-propanesulfonic Acid (MPS) and 1,3-propanedisulfonic acid (PDS), notably increased the selectivity of electroless metallization on chemically modified surfaces, which can be used to create patterned structures. More specifically, the additives increased the growth rate of metal on an aminosilane-coated surface relative to an uncoated surface. This work includes an examination of metal layer thickness and conductivity in addition to selectivity. The layer thickness was determined through the use of atomic force microscopy on surfaces that exhibited conductivity. The conductivity of the surface metal was determined through a measurement on a four-point probe measurement. In this series of experiments, the disulfonate-containing additive PDS provided the highest nucleation density, highest conductivity and the best selectivity ratio. The palladium metal deposit on the PDS-treated surface was nearly uniform in height and its conductivity approached the bulk conductivity of palladium with a metal height of less than 30 nm. MPS-treated surfaces also provided increased nucleation density when used during the seeding step, but the resulting conductivity was less than that of the PDS treated samples. We recommend the use of PDS as an effective electroless plating additive for use in palladium electroless plating processes.

No description available.

A 2 cm ostectomy was performed on 10 pairs of canine cadaveric humeri proximal to the supratrochlear foramen. Stabilization was with a double plate construct (DB-PLATE) (n=10) or external skeletal fixator with intramedullary pin tie-in configuration (ESF-IMP) (n=10). Cyclic testing was performed. Axial compressive load to failure testing followed. Data analyzed included dynamic stiffness, stiffness and yield load. No constructs failed during cyclic testing or lost stiffness over time, although mean dynamic stiffness was greater for DB-PLATE compared to ESF-IMP. Mean stiffness of DB-PLATE in load-toailure testing was not significantly different than ESF-IMP. Yield force of DB-PLATE was significantly higher than ESF-IMP. These results suggest that both DB-PLATE and ESF-IMP would be appropriate fixation techniques for stabilization of comminuted supracondylar humeral fractures in dogs with appropriate exercise restriction. Double plate fixation may be preferable when prolonged healing or inadequate post-operative restraint was anticipated because it was stronger in destructive testing.

No description available.

No description available.

No description available.

The object of this investigation was to study the properties of copper electrodeposits on carbon, to compare the various methods of electrodeposition as to adhesion to the carbon, nature of the interface, polishability, solderability, effect of the carbon surface, effect of temperature of plating, and to determine a suitable etching solution for the electrodeposited copper. The carbon samples that were used were approximately three-eighths of an inch in diameter and three inches long. Each sample was plated with copper from copper cyanide, copper strike, and copper sulfate plating solutions. The thicknesses of the electrodeposits from the cyanide copper plating solution were 0.0005, 0.001, and 0.002 inches. The temperature of the copper cyanide plating solution was varied from 49 to 70°C for the tests. The surfaces of the carbon rods that were used were smooth, rough, and very rough, relative only to one another. The forces required to break the adhesion between the copper electrodeposits and the carbon rods were determined as a function of the thickness of the electrodeposits, temperature of the copper cyanide plating solution, nature of the carbon surface, and the particular plating solution used. Also the polishability and solderability of the copper electrodeposits were determined, The force required to break the adhesion between the copper electrodeposit and the carbon red increased from 76 to 265 pounds per square inch for electrodeposit thickness increasing from 0.0005 to 0.002 inches. The force required to break the adhesion between the copper electrodeposit and the carbon rod varied from 220 pounds per square inch for a plating temperature of 60°C, to 249 pounds per square inch for a plating temperature of 70°C, and to 274 pounds per square inch for a plating temperature of 49°C. The force required to break the adhesion between the copper electrodeposit and the carbon rod was 220 pound per square inch for the smooth surface of the carbon, 18o pounds per square inch for the rough carbon surface, and 235 pounds per square inch for the very rough carbon surface. The force required to break the adhesion between the copper electrodeposit and the carbon surface was 220 per square inch for the copper cyanide solution, 326 pound per square inch for the copper strike solution, and 100 pounds per square inch for the copper sulfate solution. The copper deposited from the copper cyanide solution polished to a bright shine and was easily soldered for the adhesion tests. The interface between the copper electro-deposit and the carbon red plainly showed the that electro-deposits filled the irregular voids on the carbon surface, the etchant best suited for use with the copper electro-deposits was determined to be the solution composed of potassium bichromate, sodium chloride, concentrated sulfuric acid, and distilled water. / B.S.

by Chiah Man Fat. / Thesis submitted in: September 1999. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 94-97). / Abstracts in English and Chinese. / Acknowledgements --- p.2 / Abstract --- p.3 / Table of Contents --- p.5 / List of Figures --- p.7 / List of Tables --- p.13 / Chapter Chapter 1 --- Introduction --- p.14 / Chapter 1.1. --- Overview --- p.14 / Chapter 1.2. --- Giant Magnetoresistance (GMR) --- p.15 / Chapter 1.3. --- Application of GMR Materials --- p.20 / Chapter 1.4. --- Preparation Methods --- p.22 / Chapter 1.5. --- This Thesis --- p.23 / Chapter Chapter 2 --- Sample Preparation and Experimental Methods --- p.24 / Chapter 2.1. --- MEVVA Ion Source Implanter --- p.24 / Chapter 2.2. --- The Pulsed Filtered Cathodic Arc Co-deposition System --- p.26 / Chapter 2.3. --- Sample Preparation --- p.29 / Chapter 2.3.1 --- Implantation Condition --- p.29 / Chapter 2.3.2 --- Co-deposition Conditions --- p.31 / Chapter 2.4. --- Characterization methods --- p.32 / Chapter 2.4.1 --- Magnetoresistance Measurement --- p.32 / Chapter 2.4.2 --- Atomic Force Microscopy and Magnetic Force Microscopy --- p.34 / Chapter 2.4.3 --- Rutherford Backscattering Spectroscopy (RBS) --- p.37 / Chapter 2.4.4 --- SQUID Magnetometer --- p.38 / Chapter Chapter 3 --- Characterization of Implanted Samples --- p.39 / Chapter 3.1. --- Introduction --- p.39 / Chapter 3.2. --- Results and Discussion --- p.39 / Chapter 3.2.1 --- Ag Film Thickness Dependence --- p.39 / Chapter 3.2.2 --- Dose Dependence --- p.44 / Chapter 3.2.3 --- Extraction Voltage Dependence --- p.46 / Chapter 3.2.4 --- Annealing Temperature Dependence --- p.49 / Chapter 3.2.5 --- Thicker Layer Formation --- p.56 / Chapter 3.2.6 --- AFM and MFM Measurements --- p.58 / Chapter 3.3. --- Summary --- p.64 / Chapter Chapter 4 --- Characterization of Co-deposited Samples --- p.65 / Chapter 4.1. --- Introduction --- p.65 / Chapter 4.2. --- Results and discussion --- p.65 / Chapter 4.2.1 --- RBS Measurement --- p.65 / Chapter 4.2.2 --- Magnetoresistance Measurement --- p.66 / Chapter 4.2.3 --- AFM Measurement --- p.69 / Chapter 4.2.4 --- MFM Measurement --- p.76 / Chapter 4.3. --- Summary --- p.84 / Chapter Chapter 5 --- Conclusion --- p.85 / Chapter 5.1. --- Main Results of This Work --- p.85 / Chapter 5.2. --- Suggestions on Future Works --- p.87 / Appendix --- p.89 / Reference --- p.94 / Publications --- p.97

ABSTRACT Recent global interests in developing hydrogen economy generate substantial research and development for hydrogen production worldwide. Pd membranes are especially suited for high temperature hydrogen separation and membrane reactor applications. Alloying Pd with Ag not only suppresses hydrogen embrittlement, but also increases the permeability of the alloy membrane. The main objective of this work was to carry out fundamental studies to understand the properties of the porous stainless steel (PSS), morphologies of Pd and Ag deposits on PSS, and the structural changes of the membrane layer upon heat treatment. Both coating and diffusion and co-plating techniques were employed in the study. The Pd-Ag membranes that had sandwiched Ag layers suffered from very low selectivity due to the voids formed because of high diffusion rate of Ag. Alloy membranes with high selectivity can be prepared by applying intermediate annealing after each Ag deposition. On the other hand, the homogeneity of the alloy depended very much on the thickness of the deposited layers and annealing temperature and time. A stable co-plating bath was developed to co-plate Pd and Ag simultaneously. Pd-Ag membranes were prepared from co-plating bath using ultrasound to accelerate the plating rate.

In electrical contacts, thin films of nickel and gold or silver are traditionally plated on top of a copper base plate to provide corrosion resistance and wear protection. Most recently, the rising cost of noble metals and intensified competition in manufacturing technology has driven the industry towards thinner plating layers, which gives rise to questions regarding how interfacial contact and wear is affected by plating thickness and material characteristics. This study uses a combination of finite element analysis and ex-situ wear measurement to determine the effect of gold plating thickness on wear performance under linear reciprocating sliding contact. Correlations between predicted and measured results lead to insight into the stress state within the multi-layer system under contact conditions as well as a wear map for gold platings that can be used to inform future connector designs. The middle layer material, Ni, is relatedly inexpensive, but takes a relatively long time to deposit. Because this deposition time has a direct influence on the cost of manufacturing, it is important to reduce the Ni thickness as well. This project thus determines how different combinations of Ni and Au properties influence wear and subsurface layer exposure, which is critical for determining the makeup of future, low-cost, connector designs.