A Convergence Study to Determine to the Role of Pressure Solution Creep Mechanisms in Driving Cold Sintering in Functional Ceramics

Non-Technical SummaryCold sintering is a recently introduced processing technique that has been demonstrated to be applicable to sintering a broad number of ceramic and ceramic composites. The temperatures that drive densification are an order of magnitude lower than the conventional thermal processes that are used in ceramic manufacturing across the world. The mechanisms enabling these extremely low temperatures use a mechano-chemical process with the use of a transient chemical phase. This investigation considers the theories and geophysical science that drive the formation of sedimentary rock and looks to test its relevance to the cold sintering process that are now being applied to the fabrication of advanced ceramic materials. Through understanding these processes, a broader impact is considered for cold sintering of architectural bricks and tiles. Through a partnership with the United Nations Global Buildings Network and the African MRS, demonstration and education of the cold sintering processes for local brick making in rural areas in Africa will be made. Undergraduate researchers will be involved in this engineering aspect of the project.Technical SummarySedimentary rock densifies over many years with a process known as pressure solution creep. This process involves pressure induced dissolution, transport, and precipitation. Cold sintering is a relatively new introduction to a sustainable manufacturing process. This study will embrace the non-equilibrium geophysics of rock formation and correlate the densification and grain growth process of conventional sintering. Conventional sintering is a process that thermodynamically drives the minimization of excess surface energy at temperatures an order of magnitude higher than the cold sintering process. The proposed study here will experimentally and theoretically test the understanding of the geophysics of the pressure solution creep and consider its applicability to understanding the densification kinetics to cold sintering. There are various sequential processes that enable the low temperature densification including chemo-mechanical dissolution, grain boundary dissolution and precipitation and of which can be the rate limiting step. The proposed study will access these phenomena in model systems to better understand the cold sintering process from a new fundamental perspective and converging material science and geoscience. From a broader impact perspective an investigation will use the cold sintering process to the application of brick formation in rural areas of Africa. This will involve a partnership with both the Global Building Network and the African Materials Research Society.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.