Detailed properties of iron oxide solid propellant catalyst

Hematite represents the most common burning rate modifier used in propellant production. The effect of burning rate fine tuning is obtained even for amounts ranging below 1 wt% of the total composition. Different studies have evidenced a role in ammonium perchlorate dissociation while few data are available regarding its capability to enhance binder decomposition. The acceptance of such ingredient in an industrial environment is based mostly on the verification of few parameters relevant to catalytic action (namely, particle size, specific surface area). The complexity of the iron oxide panorama shows a wide set of features neglected in standard quality check but important for a detailed characterization. Such properties assist in defining a unique fingerprint of the material and can be used for detailed identification of batch-to-batch reproducibility, for new supplier qualification, or for improvement of basic knowledge. The present paper is an extract of a detailed characterization activity performed on different lots of nominally identical propellant-grade hematite. A subset of results is proposed to show some peculiar properties of the ingredients and some characterization methodologies specifically employed for the scope.