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Electrode potential and polarographic studies have been made on solutions of zirconium and hafnium ions in molten normalLiCl‐normalKCl eutectic at 450°–550°C. Anodic dissolution of Zr at 450°C yielded Zr(IV), but at 550°C, chiefly Zr(II). Only Hf (IV) was observed over this range. Apparent standard electrode potentials were (mole fraction scale, Pt(II)/Pt(0) reference) normalZr)(II/normalZr)(0;−1.77normalv at 550°C normalZr)(IV/normalZr)(0;−1.86normalv at 450°C normalHf)(IV/normalHf)(0;−1.88normalv at 450°C;−1.92normalv at 550°C

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The various electrochemical techniques for predicting galvanic corrosion behavior of metals are described. Each method is evaluated on the basis of practicality using specific galvanic couples as examples. The paper describes some serious shortcomings of the existing techniques and warns of the dangers of their improper use.

The electrochemical behavior of the nickel hydroxide electrode in binary aqueous alkali hydroxide solutions was investigated in the temperature range −40°–60°C. Maxima were observed in the electrode capacity vs. temperature curve for each electrolyte. The nature of the interaction of the alkali metal ion has a marked effect on the charge acceptance of the electrode. At the higher temperatures, the charge acceptance is greatest with the normalLiOH‐H2O electrolyte. At the lower temperatures, the charge acceptance is greatest with the normalRbOH‐H2O and normalCsOH‐H2O electrolytes. The results correlate with the variation in solution properties at these temperatures.

ASTM Subcommittee G01.11 on Electrochemical Measurements in Corrosion Testing has conducted round-robin testing on the reproducibility of cyclic potentiodynamic polarization measurements for determining susceptibility to localized corrosion. This work was used in the development of a practice that provides a standard experimental procedure for conducting these tests. This paper presents the experimental procedure and results of the round-robin tests with statistical analysis of the data. The reproducibility of the measurements and sources of error are discussed.

'The methods of potentiometry and polarography have been used to study the Ti(I1) and 'Ti(I1I) ions in solution in the LiCI-KC1 eutectic a t 450 "C and 550 "C. Solutions of Ti(I1) were prepared by anodic dissolution of T i metal, and Ti The technological importance of titanium inetal has led to its study a t elevated temperatures and in molten salt systems. Disproportionation equilibria in alkali halide melts were studied by YiIellgren and Opie (I) and Kreye and Kellogg (2) by direct analysis, and by Flengas (3) and Smirnov (4) using potential measurements in molten KC1-NaC1 mixtures. These studies showed the iinportance of the lower states Ti(I1) and Ti(II1) in these systems.Redox potential ineasurements of the Ti(III)/Ti(II) couple in the LiC1-KC1 eutectic melt were carried out by Menzies et al. (5) and by Smirnov (6). Although both groups used essentially the same technique, their values differ by 0.6 V a t 500 OC. Bockris et al.(7) studied solutions of titanium chlorides in the same melt polarographically. At 400 OC they obtained the polarographic wave for the reduction of Ti(II1) to Ti(II), but no wave for the Ti(I1)-Ti(0) reduction was seen a t potentials less negative than that for decomposition of the melt. However, under the same conditions Okada (8) has obtained polarogra~ns for both of these reduction processes. The object of this work was to make a further investigation of the redox potentials of the titanium system in the LiCl-KC1 eutectic melt in which the lower oxidation states of titanium were prepared in situ. Our approach was by way of anodic dissolution of the metal, rather than by direct addition of titanium chloride as had been done previously. In addition to the metal, three oxidation states are of importance: Ti(II), Ti(III), and Ti(1V). The last of these is volatile as the chloride and was not investigated.Electrode potentials in this work are referred to the cells Ti I Ti(II),Cl glass P t (I I), C2 [A]

An X-ray powder diffraction analysis has been performed on several samples from the naturally occuring patina of the Statue of Liberty. This work, which was conducted as a service to the National Park Service as part of the restoration activities for the Statue, was performed to assess the impact of acid deposition on the phase composition of the patina. Samples of the patina that were obtained from various locations on the copper skin of the Statue were found to consist primarily of the basic copper sulfate known as brochantite or CuSO4·3Cu(OH)2. Another less stable form of basic copper sulfate CuSO4·2Cu(OH)2 known as antlerite was also observed in samples taken from areas that are more exposed to the incoming weather in New York harbor. The presence of antlerite supports the contention that acid deposition is promoting undesirable changes in the phase composition of the patina. Analyses were also performed on patina samples that were taken from pieces of the Statue's copper skin that had been removed in the years 1905 and 1980. X-ray powder diffraction of the corrosion product on the 1905 sample showed that it consisted primarily of the stable brochantite phase, while the 1980 sample displayed both copper chlorides as well as the less stable antlerite. Both samples also contained cuprite (Cu2O) which appears to have formed prior to either of the sulfates.