A study of the dissolution of titanium in acids with emphasis on hydrofluoric acid

<p>"Titanium is practically a new metal. Although it was discovered by W. Gregor in 1791, the pure metal was not prepared until 1910 by M. A. Hunter, and it is only very recently that tremendous interest has been focused on this new metal, as evidenced by the activities of numerous leading laboratories and pilot plants.</p> <p>The reasons that Ti is gaining increasing attention may be attributed to the natural abundance of Ti ores in reasonable concentration and, what is more important, to its unusual combination of physical and chemical properties. According to F. W. Clark’s classical geochemical data, Ti amounts to 0.629 percent of the earth’s crust and occupies the ninth place in abundance among all of the elements. Among the common metals which may be used structurally, it ranks after aluminum, iron, and magnesium and ahead of copper, lead and zinc. As to properties, Ti has a high strength-weight ratio and a high melting point. It is considered to be a metal that will bridge the gap between steel and aluminum. In addition to its strength and lightness, Ti is characterized by an excellent corrosion resistance. It is not attacked by the atmosphere, and is remarkably resistant to sea water, humid and saline atmospheres, and nitric acid. Undoubtedly such a metal will be welcome to the engineering field.</p> <p>The corrosion data on Ti available in the literature, especially on comparatively pure Ti, are rather limited. Except for two papers which were published while the present research was under way, references concerning the corrosion of Ti are generally qualitative statements. It has been reported, for instance, that Ti is very soluble in hydrofluoric acid, but the extent and mechanism of its dissolution has not yet been fully studied.</p> <p>In view of the importance of this metal as a corrosion-resistant material, and because of the slight knowledge we have concerning its corrosion properties, it seemed worthwhile to investigate more thoroughly the dissolution of Ti in selected reagents. It was with this intent in mind that the present research was carried out.</p> <p>Corrosion tests, as pointed out by Evans, may have two different objects. When carried out in laboratories, they may serve to gain pure scientific understanding of the mechanism of some corrosion process. Alternatively, as field and service tests, they may have an industrial purpose of seeking to discover what material or what protective process will minimize attack. The present research falls within the first category, namely, it is a laboratory investigation of the behavior of Ti when totally immersed in various reagents.</p> <p>The problem was approached by first running a preliminary qualitative test of the reaction of Ti with different common reagents, mostly acids, so that the relative solubility of Ti toward these reagents could be evaluated. Based upon the data thus obtained, the reaction of the reagents which corrode the metal most was given an intensive study. Since Ti is quite corrosion resistant, the metal, as expected, was found to react appreciably with only a few non-oxidizing acids among which hydrofluoric acid was the most outstanding one. In order to investigate the rate and mechanism of the dissolution of Ti, therefore, reaction of the metal with hydrofluoric acid was considered to deserve the most intensive study in the present work"--Abstract, pages 1-3.</p>

Name thesis:degree_name

Ph. D. in Metallurgical Engineering

Grantor

Missouri School of Mines and Metallurgy

Year dc:date.available

2016

Author dc:creator

• Chen, Ping-Chao

• Metallurgy

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/511

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-1513