Combustion of Large Monolithic Titanium Particles in Air. II. Characteristics of Condensed Combustion Products

Methods for the collection 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 compositions 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 aerogel round and elongated comet-shaped objects (rarefied openwork particles consisting of chains of nanosized spherules). According to the O/Ti atom ratio, all types of CCP particles are oxide. The mass fraction of aerogel objects in CCPs is 0.52-0.98, and their physical density is about 0.8 g/cm(3). The characteristic sizes of compact spheres are 2-410 mu m, those of aerogel round objects are 11-470 mu m, and the length of aerogel comet-shaped objects can reach 13 mm. The typical sizes of spherules are 25-100 nm. Large compact spheres 200-400 mu m in size typically contain a gaseous bubble and have a density of about 0.9 g/cm(3).