| 摘要 |
In a process for etching aluminium in a sodium hydroxide, sodium nitrate, and sodium aluminate solution, the solution is replenished by adding nitric acid or a nitric acid-sodium nitrate mixture. Until the solution contains an equilibrium concentration of sodium aluminate and hydrated alumina is precipitated out, the solution may be replenished with sodium hydroxide and nitrate. The solution may also contain a foam producing surface active agent e.g. anionic sulphates or sulphonates and non-ionic ethylene oxide condensates. |
