| 摘要 |
<p>Al or Al base alloys are electro-brightened in an aq. soln. contg. at least one carbonate, hydrogen carbonate or sesquicarbonate of the alkali metals and ammonia and at least one mono, di or tribasic orthophosphate of the alkali metals and ammonia, the soln. pH measured by a glass electrode at 70 degrees C being 9-10.7. The reaction products and depleted soln. are continuously dispersed from the surface of the component at a rate to allow the current density to increase automatically by a factor of 2-4. The disposal of the reaction products and depleted soln. may be achieved by vigorous relative agitation between the soln. and component and the soln. is maintained at 80 degrees C to the b.pt. Specular reflectivities >80% are achieved over a wide range of alloy compsn., current density up to 15 A/dm2 may be used with treatment times of 3-45 mins. and there is no "running in" period when using a fresh bath of electrolyte.</p> |
