Metal Finishing Guide Book

2011-2012 Surface Finishing Guidebook

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the flask until excess of KMn04 is destroyed and the solution clears. Add 10 ml of a vanadate solution and boil gently until the solution is a clear light bluish- green, which indicates that excess of H202 has been destroyed. Cool to the room temperature. Transfer the solution to a 100-ml volumetric flask and dilute to about 80 ml with water. Add 10 ml of a molybdate solution, dilute to mark and mix. The color of the phosphorus complex develops within 5 minutes and is sta- ble for at least 1 hour. The recommended concentration range is 0.1–1.2 mg of phosphorus in 100 ml of solution. Measure the absorbance of the sample, reference and calibration solu- tions at 470 nm. Plot the photometric readings of the calibration solutions against mg of phosphorus per 100 ml of solution. Convert the photometric reading of the test solution to mg of phosphorus by means the calibration curve. Calculation: P%= (mg (P) x 250 x 100 x 1g A x B x 1000 (mg (P) x 25 = A x B Where: A- ml of the sample, used for photometry. B- g of the sample (into 250 ml). The tables 1, 2 show that the proposed methods can be applied successfully for the simple and precision determination of phosphorus in electroless nickel deposits without a significant systematic error. REFERENCES 1. Fredericka A. Lovenheim, "Modern Electroplating", Third edition, 1974, p.721. 2. Ponomarev A., "Methods of chemical analysis of minerals", Vol. 2., Moscow, 1955, p.163-164. 3. Teplouchov V., "Express analysis of steels", Third edition, 1971, p.154-157. 4. ASTM, " Annual book of ASTM Standards", 1985, Method E156, p. 432- 433. BIO Dr. Vera Persits was granted her M.Sc. in chemistry from Rostov State University in 1971, earning her Ph.D. in analytical chemistry from Leningrad (currently Saint Petersburg) state university in 1982. The theme of the doctorate was "Investigation of Process of Electro-ther- mal Atomization and Their Utilization for the Elaboration of Methods for the Determination of Zinc, Cadmium, Lead, Tin, Bismuth and Antimony in Steels and Alloys." Dr. Vera Persits authored and co-authored 20 articles and has two patents in analytical chemistry. Since 1992, Dr. Persits has worked at IAI as a chemistry engineer in the field of plating. 146

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