Prodn. of absorbent finish on solar energy panels

摘要

The process consists of (a) cleaning the metal surface and treating with dil. sodium stearate soln; (b) drying to leave a thin coating on the surface; (c) placing across the secondary ends of a transformer with terminals of longitudinal spacer shape; and (d) passing a current of 25 A per m/cu.m. of section for 30 secs. to raise the temp. to 550-650 deg.C. - Combustion of the sodium stearate film produces a blue colouration which is highly absorbent of solar heat radiation.