Phosphate fluoride pretreatment

Mason et al. [13] used indicator dyes to determine the effect of pretreatment on the surface acidity of Ti-6,4. They found that surfaces treated with a basic etchant left a basic surface with an isoelectric point between 7.3 and 9.2. A phosphate-fluoride etch left the surface acidic with an isoelectric point between 5.4 and 7.3. 

Fig. 1. Trace bromate determination using matrix elimination and preconcentration. See text for details. Peaks 1, fluoride 1.0 mg/1 2, unknown 3, chlorite, 0.01 mg/1 4, bromate 0.005 mg/1 5, chloride, 200 mg/1 6, nitrite 0.1 mg/1 7, bromide, 0.01 mg/1 8, chlorate, 0.01 mg/l 9, nitrate, 10.0 mg/l 10, o-phosphate, 0.1 mg/l 11, sulfate, 200 mg/l. Sample B was pretreated with OnGuard II Ag, H cartridges. Samples also contained 200 mg/l bicarbonate.

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