No abstract

No abstract

With an organic/inorganic hybrid nature, silicone elastomers are amongst the most versatile engineering materials, exploited in a wide range of applications either as end-products or in manufacturing processes. In many industrial machines, silicone components are exposed to in-service conditions, such as high or low temperatures, contact with functional fluids, mechanical loading, and deformations, which can adversely affect these components and reduce their lifespan, leading to machine failure in turn. The present study investigates the behaviour of a silicone component of a manufacturing equipment and the variations in the part’s properties due to in-service conditions (temperature, exposure to heat transfer fluid, and mechanical deformation) to develop a monitoring tool. An experimental design was employed to study the main and the interaction effects of temperature (22 °C, 180 °C), medium (air, synthetic heat transfer fluid), and strain (0%, 200%) on the silicone component’s properties. Results showed that while the chemistry of the component remains intact, its thermal and in particular mechanical properties are largely influenced by the in-service conditions. Consequently, leading to a physical rather than a chemical failure of the component and limiting its service life. Statistical analysis revealed that high temperature and the exposure to the heat transfer fluid have the most sever effects. Moreover, these two manufacturing parameters were found to have a significant interaction with one another, whose effect cannot not be neglected.

Alumina ceramics of different purities were joined using alumina gel as an interlayer and microwave energy as the heating source. Direct microwave joining of alumina was also accomplished. A comparison between the two joining methods was made. The effect of the gel on joining time and joining temperature was determined. Knoop microhardness was measured across the joint to show the change in the microhardness at the joint region. Joints of hardness as high as that of the bulk were produced when the joining parameters were properly selected. The dielectric properties of the aluminas used in this study were measured. X-ray maps and SEM micrographs were taken for different joints.

No abstract