Combustion of large monolithic titanium particles in air. II. Characteristics of condensed combustion products

Methods for the selection and analysis of condensed combustion products (CCPs) of large monolithic titanium particles with a diameter of 350–460 $\mu$m in air at atmospheric pressure are described. Detailed data on the granulometric, morphological, and phase composition of CCPs and the number of particles produced by a single burning mother particle are presented. The following morphological types of CCP particles were identified: compact spheres (combustion residues of mother particles and their fragments) and airgel round and elongated comet-shaped objects (sparse fine particles consisting of chains of nanosized spherules). According to the ratio of O/Ti atoms, all types of CCP particles are oxide particles. The mass fraction of airgel objects in CCPs is 0.52–0.98, and their physical density is about 0.8 g/cm$^3$. The characteristic dimensions of compact spheres are 2–410 $\mu$m, those of airgel round objects are 11–470 $\mu$m, and the length of airgel comet-shaped objects can reach 13 mm. Typical sizes of spherules are 25–100 nm. Large compact spheres 200–400 $\mu$m in size typically have a gaseous bubble and a density of about 0.9 g/cm$^3$.