Abstract: In this paper, a pHmicroprobe technique was developed to measure in situ the pHvalue on the cathode/solution interface, and iridium oxide was used as a pHsensitive material which is of a good response behavior in the measured solutions. During electrodeposition process of bioceramic coatings of calcium phosphates, the interfacial pHchange, for example, was first_measured. The experimental results indicated that the pHvalue on the cathode/solution interface first jumped to a maximum, then slowly decreased with the increase of the electrodeposition time. The interfacial pHvalue was increased with the applied current density or cathode overpotential.

Key words: In situ measurement, pH microprobe, Electrode/solution interface