Proton-fluoride association in sodium perchlorate media

Farrer, Humphrey N.; Rossotti, F. J. C.

doi:10.1016/0022-1902(64)80020-8

Cited by 37 publications

(3 citation statements)

References 14 publications

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“…In Table I, the etch rates and apparent activation energies in the temperature range 30~176 are listed for a selection of solutions made up of various amounts of NH4F and HF. The AEapp values are calculated from relationship [3] Rate ----A exp (AEapp/RT) [3] assuming no change in the pre-exponential factor which includes concentration terms. It is apparent that AEapp tends to increase as the ratio of NH4F to HF is increased.…”

Section: Fig 2 Dependence Of Apparent Activation Energy On the Ratio ...mentioning

confidence: 99%

A Study of the Dissolution of SiO[sub 2] in Acidic Fluoride Solutions

Judge¹

1971

J. Electrochem. Soc.

310

183

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Data are presented on the dissolution rates of SiO2 films in a variety of acidic fluoride solutions. It is shown that the rate of dissolution is linearly dependent on the concentration of HF2− and HF in relatively dilute fluoride solutions. Both reactions have a similar temperature dependence characterized by an activation energy of 9.1 and 8.1 kcal/mole, respectively. The reaction with HF2− is about four to five times as fast as that with HF. Extrapolation to more concentrated solutions suggests that higher polymeric species of the type HxFx+1− may also be active in the dissolution process. Raman data indicates that no single product species is formed although the product spectrum is consistent with the presence of some SiF62− .

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Section: Fig 2 Dependence Of Apparent Activation Energy On the Ratio ...mentioning

confidence: 99%

A Study of the Dissolution of SiO[sub 2] in Acidic Fluoride Solutions

Judge¹

1971

J. Electrochem. Soc.

310

183

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“…Use of the platinum H2/H + electrode for pH measurements on a routine basis is complicated: (i) by the need for a constant partial pressure of hydrogen in the test solution; and, to a lesser extent, (ii) by the possibility of evaporating HF during the hydrogen equilibration period and thus altering the pH. The use of the quinhydrone electrode to measure pH in HF solutions has been described (3)(4)(5). Besides the inconvenience of adding a chemical (quinhydrone) to the test solution, this electrode is subject to interference by the large amounts of ammonium ion present in these "buffered etch" solutions (6); indeed pronounced discoloration and potential drift were found.…”

Section: Electrodesmentioning

confidence: 99%

A Palladium Hydride pH Electrode for Use in Buffered Fluoride Etch Solutions

Jasinski

1974

J. Electrochem. Soc.

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pH measurements can be made in aerated, concentrated, aqueous NH4F‐HF etch solutions with palladium electrodes cathodically charged to palladium hydride. Electrode life and stability in ammonium fluoride, as well as in NH2SO4 , pH 3.6 sodium citrate and in pH 8 ammonium phosphate are enhanced by maximizing the palladium hydride concentration, electrode volume as well as volume to surface ratio. Electrode lifetimes have been measured in the range of 7–14 days for all solutions, times which are significantly longer than have been reported previously in the literature for palladium hydride electrodes.

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“…None of these species are important in HF solutions containing less than 1 m HF (Farrer and Rossotti, 1964). They form by the reactions (McTigue et al, 1985) 2HF Gennick et al (1977) reported the existence of all the above polymeric species in the solid state and X-ray diffraction studies.…”

Section: Hf-h 2 Omentioning

confidence: 96%