Behavior of Ultra-Small Colloid Particles
Abstract
The program is an investigation of the growth and agglomeration behavior of ultra-small metal oxide particles such as Al2O3 or BeO particles which are 10 to 10,000A in diameter. Initial work on this program was oriented toward Al2O3 particles. A premixed flat flame at low sub-atmospheric pressures (2-16 torr) was examined as a technique for generating a cloud of Al2O3 particles. Al(CH3)3 and O2 or air were used. Electron microscopy indicated the formation of 50 and 100A diameter particles in the O2 and air systems, respectively. Extinction and scattering techniques for measuring size and concentration in situ in the particle cloud were unsuccessful because the cloud was optically very thin at such low pressures. Particle and gas temperatures were measured by radiation and reversal techniques and were both about 2300 degree K in the second reaction zone, indicating no hot particle-cool vapor problem. Absolute intensity measurements of the continuum radiation being emitted from the hot particles in the burned-gas zone indicated that no growth of the particles was occurring in the burned-gas zone. The measured absorption coefficient of the molten aluminum oxide, 30/mm exponent minus 1 at 1.5 microns, is comparable to that observed for molten sapphire.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1967
- Accession Number
- AD0655906
Entities
People
- Ronald Caruso
- Welby G. Courtney