Fatigue life of preceramic soldered and postceramic soldered joints.
This research investigated the fatigue life (ie, the number of cycles of a given stress that can be sustained by a sample prior to catastrophic failure) of metal ceramic soldering. One metal ceramic alloy was joined using four postceramic solders and one preceramic solder. All specimens received appropriate heat treatment simulating ceramic application although no porcelain was applied. Five specimens were fabricated for each solder type, and a 35,000 psi (241.4 MPa) fatigue stress was applied to each solder joint during specimen testing. The test variable was the number of stress cycles required to fail each specimen. The postceramic solders exhibited significantly higher fatigue lives than did the preceramic solder. Scanning electron microscope analysis showed that the preceramic solder not only exhibited a larger grain size, but also showed micropores between these grains.
Abstract The moving parts of any mechanism and machine parts are always subjected to a significant wear due to the development of friction. It is utmost important aspect to address the wear problems in present environment. But the complexity goes on increasing to replace the worn out parts if they are very precision. Technology advancement in surface engineering ensures the minimum surface wear with the introduction of polycrystalline nano nickel coating. In this study, tribological behavior of the nano nickel coating developed through pulsed electro deposition technique has been investigated. The nano structured coated specimen were admitted for pin and disc method of wear testing. The nature of wear has been examined over the surface of the specimen through Atomic Force Microscope (AFM) in order to validate the prior results. The results yielded from pin and disc and AFM registered the negligible deviations.