Abstract
A high-velocity oxyfuel plant was converted to process aluminum oxide. Burner nozzles with different geometries were evaluated for use based on experimental measurements and numeric simulations. Although the modified nozzles promised an improvement in the melting of alumina particles, it was found that some of the melted alumina caked on the inside of the nozzle and fused together into large particles that eventually dislodged, causing a reduction in transfer efficiency. This paper explains how the caking problem was solved by combining the output of a high-velocity oxyfuel gun with that of a combustion flame spraying gun. Tests show that the hybrid solution produces hard alumina coatings with relatively dense microstructure at a transfer efficiency greater than 50%. Paper includes a German-language abstract.
