Electrochemical Corrosion of InP in Saturated CaCl sub 2.

Anodic and cathodic reactions at n- and p- type InP electrodes in saturated CaCl sub 2 have been studied by rotating ring- disk and coulometric methods, using illumination where the processes are carrier limited. Likely products were voltammetrically investigated for identification and calibration. In(III) and protons were quantitatively detected in the anodic reactions at 3 and 1 Faradays of electrons (holes), respectively, per mole of InP corroded. In this medium the InP surface can be stable to reduction and thus cathodization produces only hydrogen and hydroxide, the latter at 1 Faraday / mole by amperometric titration. InP dissolves freely on anodization in this 5.6M CaCl sub 2 medium, and its passivation behavior was studied as a function of CaCl sub 2 concentration. A transition to a film growth condition occurs over a narrow range around 1. 4M.