Method for accurate measurement on nitric acid content of chemical corrosion solution for titanium alloy

Abstract

The invention provides a method for accurate measurement on nitric acid content of a chemical corrosion solution for titanium alloy. With the presence of high concentration sulfuric acid, NO<3-> is reduced into NO through ferrous sulfate, and the excessive ferrous sulfate is titrated through potassium permanganate standard solution; a Gaikeli funnel is used during the experiment, carbon dioxide produced by sodium bicarbonate ensures complete exhausting of air from an erlenmeyer flask, and carbon dioxide constantly produced during the reaction protects the solution and prevents the entry of external air, so as to ensure sufficient reduction of the solution while preventing the interference from oxygen in the air. The above points show that the experiment method saves time, and can eliminate the influence of metal impurities and other weak-acid or weak-base salt solutions; the end point mutation is obvious during solution titration, so as to measure more accurate nitric acid content.

Description

technical field [0001] The invention belongs to the technical field of chemical analysis, in particular to a method for accurately measuring the content of nitric acid in a titanium alloy chemical corrosion solution. Background technique [0002] The main components of titanium alloy chemical corrosion solution are nitric acid and hydrofluoric acid, which are used in chemical milling, dust removal, coloring and surface pre-corrosion of titanium alloy. [0003] At present, the determination of nitric acid content in the national standard and navigation mark mainly includes acid-base titration and redox capacity method. The methods that can be queried involve steps such as sample separation, fractionation, redox, titration, etc., and the commonly used methods have the following limitations: acid-base titration can only be applied to solutions that do not contain metal impurities and other weak acid and weak base salts ;The determination of nitric acid content in mixed acid ca...

AI Technical Summary

Problems solved by technology

The methods that can be queried involve steps such as sample separation, fractionation, redox, titration, etc., and the commonly used methods have the following limitations: acid-base titration can only be applied to solutions that do not contain metal impurities and other weak acid and weak base salts ;The determination of nitric acid content in mixed acid can only be calculated by indirect method; when applying redox method, due to the interference of oxygen in the air, the determination accuracy of nitric acid content is low; redox titration in related standards also needs special Instrument—Potentiometric Titrator

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