Microstructure and Properties of Cold-Sprayed Iron Coatings

Cold-sprayed pure iron coatings were applied to titanium substrates to determine the structural and functional properties of as-sprayed material and post-spray annealed coatings. Microhardness testing and quantitative image analysis (QIA) were used to analyze the annealing kinetics in the 450 to 750°C temperature range. Sintering/annealing of the coating reduces the porosity content and improves the soft magnetic behavior based on B-H magnetic loop testing, although the cold-sprayed and annealed material does not approach the magnetic performance of annealed bulk (wrought) iron. Tensile tests were performed on small specimens machined from the thick coatings. The strength and ductility of as-sprayed material are quite low, but increasing mechanical properties are observed as a function of annealing temperature up to 850°C as shown by Weibull statistical analysis.

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.