Ta/Ti/Ni/Ceramic Multilayered Composites by Combustion Synthesis: Microstructure and Mechanical Properties

Ta/Ti/Ni/ceramic multilayered composites were successfully prepared by combustion synthesis. Laminated composites Ti–Ta–(Ti + 0.65C)–Ni–(Ti + 1.7B)–(Ti + 1.7B)–Ta–Ni-Ti and 3(Ti + 1.7B)–Ta–(5Ti + 3Si)–Ta–(Ti + 1.7B)–Ta–(5Ti + 3Si)–Ta–3(Ti + 1.7B) were combustion synthesized in an Ar atmosphere using (1) metallic foils (Ti, Ta, Ni) and (2) reactive tapes (Ti + 0.65C), (Ti + 1.7B), and (5Ti + 3Si), which, upon combustion, yielded ceramic layers as starting materials. The microstructure, crystal structure, and chemical composition of multilayered composites were characterized by SEM, EDX, and XRD. Their flexural strength was measured at 1100 °C. Upon combustion, Ta foils turned strongly joined with Ti ones due to the development of high temperature in the reactive layers yielding TiCx and TiBy. The formation of a liquid phase between metallic foils and reactive tapes and mutual interdiffusion between melted components during combustion favored strong joining between refractory metallic foils. Good joining between metals and ceramics is reached due to the formation of thin interfacial layers in the form of cermets and eutectic solutions.

Determining the Aging Performance of Vacuum Insulation Panels: Development of a Prediction Model

Vacuum insulation panels (VIPs) are increasingly being explored in building applications. Typically used in industrial processes such as aerospace engineering, cryogenics and refrigerator manufacturing, VIPs have been proven to provide a higher thermal resistance per inch than typical building insulation materials. However, there is speculation on the performance of these panels over an extended period of time due to various factors which gradually cause a reduction in thermal resistance. The purpose of this research project is to identify these variables and how they alter VIP performance over the product’s service life. Based on a thorough literature review, the critical components were interpreted to develop a numerical model which can predict the future performance of VIPs as they age, based on initial material properties. This model is intended to benefit designers and researchers in the construction industry; in understanding the potential for vacuum insulation to contribute to building envelope design. The results of calculation proved to be complementary to experimental results provided by the NRC, (initial calculated conductivities ranged from 4.17x10 The highest calculated conductivity was attributed to the low quality metalized (MF) VIP with a final conductivity after accelerated aging of 5.29 x 10 Some observations included that there is little difference between aluminum and metallic foils in their initial conductivity; however the aluminum foils represented in this report outperformed the chosen metallic foils over time, as they provided smaller gas and water vapour transmission rates. The core material variables with the greatest impact on performance were density and porosity. Some of the simulated panels exceeded the conductivity limit before the end of their service life, while others did not. Therefore the conclusion for VIP performance overall cannot be confirmed, although the development of standards within the industry would ensure high quality material integration within building systems.

Determining the Aging Performance of Vacuum Insulation Panels: Development of a Prediction Model

Vacuum insulation panels (VIPs) are increasingly being explored in building applications. Typically used in industrial processes such as aerospace engineering, cryogenics and refrigerator manufacturing, VIPs have been proven to provide a higher thermal resistance per inch than typical building insulation materials. However, there is speculation on the performance of these panels over an extended period of time due to various factors which gradually cause a reduction in thermal resistance. The purpose of this research project is to identify these variables and how they alter VIP performance over the product’s service life. Based on a thorough literature review, the critical components were interpreted to develop a numerical model which can predict the future performance of VIPs as they age, based on initial material properties. This model is intended to benefit designers and researchers in the construction industry; in understanding the potential for vacuum insulation to contribute to building envelope design. The results of calculation proved to be complementary to experimental results provided by the NRC, (initial calculated conductivities ranged from 4.17x10 The highest calculated conductivity was attributed to the low quality metalized (MF) VIP with a final conductivity after accelerated aging of 5.29 x 10 Some observations included that there is little difference between aluminum and metallic foils in their initial conductivity; however the aluminum foils represented in this report outperformed the chosen metallic foils over time, as they provided smaller gas and water vapour transmission rates. The core material variables with the greatest impact on performance were density and porosity. Some of the simulated panels exceeded the conductivity limit before the end of their service life, while others did not. Therefore the conclusion for VIP performance overall cannot be confirmed, although the development of standards within the industry would ensure high quality material integration within building systems.