This Small Business Innovation Research (SBIR) Phase I investigates the feasibility of Thermal Forming Combustion Synthesis (TFCS) of coatings. TFCS will combine two established materials processing techniques - thermal spray forming and Self-propagating High-temperature Synthesis (SHS) -as a novel method for synthesizing advanced coating materials in-situ to produce structural, wear and/or corrosion resistant coatings on the surfaces of substrates using simple, low-cost, starting materials. The technique is also applicable for the production of thin-walled freestanding structures. Layered deposits of Ni-Al and MoO3-AlxSi materials will be thermally sprayed onto 'model' steel and graphite substrates in both flat coupon and cylindrical configurations. The microstructures of the 'as-sprayed' layers will be characterized to determine porosity, contact area etc., prior to initiation of an SHS combustion synthesis within the layers and studies of the reaction mechanisms during combustion. The composition, microstructure, porosity level, and basic mechanical properties of the resulting deposits will be characterized using metallography, X-ray diffraction, SEM and microhardness testing. The critical sprayed layer thicknesses required for both the Ni-Al and MoO3-AlxSi material systems will be determined and compared to theoretical predictions. Economic (thermal spray forming + SHS reaction) production of coatings would have significant commercial applications, particularly for the in-situ coating of parts where cost is the primary concern, such that conventional approaches, including the thermal spraying of more costly 'engineered' composite powders is not an option. In addition, the SHS component of the investigation will enable compositional and microstructural variations to be achieved within reacted coatings, which could not be readily obtained by other methods. The approach may enable thin-walled tubes of novel structures and compositions to be produced, for use as catalyst supports, filters and in fuel cells etc. Once proven, the thermal spray forming + in-situ SHS synthesis of coatings promises to be a new, economical, coating process.
