Abstract
A new technique is proposed for the ceramic lining of a pipe inner surface by means of a thermit reaction under the influence of a centrifugal force (“Centrifugal-Thermit Process”). The technique is characterized by a large amount of the reaction heat and the centrifugal force applied to the reaction products. In the present work, the effect of the centrifugal force and the characteristics of the thermit reaction in the process are investigated to assess its potential and limitation.
With the increase of the centrifugal force, the compressive strength and the apparent porosity of the products were improved. The compression-shear stress and thermal shock resistances were not necessarily improved. The metal and ceramic layers were uniformly partitioned and a dense ceramic layer was obtained under the centrifugal effect of about 200G. However, small cracks were observed in the ceramic layer.
The propagation rate of the thermit reaction was inversely proportional to the thermit powder density. When the technique is applied to a hollow body, the reaction propagated along the inner surface first and into the layer of the reactant subsequently. It is concluded that the Centrifugal-Thermit process proceeds along the inner surface of the hollow body first and then into the layer in the radial direction resulting in the ceramic lining of homogeneous quality.
