Metallurgy Commons^™

Imperfections In A Silicon Crystal Studied By The X-Ray And Density Method, Pierre Borgeaud

Masters Theses

"The study of imperfections in several crystals of silicon was conducted by the x-ray and density method"--Abstract, page 2.

A Thermodynamic Study Of The System Pbo-Pbs, John P. Hager

Masters Theses

"An experimental investigation was conducted in order to determine the thermodynamic and kinetic behavior of the system PbO-PbS.

The thermodynamic behavior of the system PbO-PbS was studied by measuring the P_SO₂ in argon-SO₂ mixtures equilibrated with various PbO-PbS mixtures in a recirculating-type equilibrium apparatus, and analyzing the condensed phases by means of X-ray diffraction.

The effect of temperature and PbO/PbS ratio on the rate of SO₂ evolution was investigated in order to determine the reaction mechanisms involved in the approach to equilibrium.

A sodium hydroxide, hydrogen peroxide titration technique was employed in the analysis of SO_{2 …}

Preparation Of Casting Slips Containing Ferrous Powders And Alginates, Robert Eugene Newcomer

Masters Theses

"The preparation of casting slips containing ferrous powders dispersed by alginates was studied and an attempt was made to determine the mechanism by which suspension was attained. The colloidal aspects of preparing ceramic casting slips are discussed and an analogy is drawn to preparation of metallic slips suspended by alginates.

Sodium and ammonium alginates were used to suspend stainless steel and iron powders. The effect of NaOH, HC1, and various phosphate additions on the properties of slips and algin solutions was considered.

It was found that colloidal concepts can not be applied to explain observed behavior in the system studied. …

A Thermodynamic Study Of The Germanium Sulphides, Satya Prakash Jain

Masters Theses

"The experimental determination of some of the thermodynamic properties of germanium sulphide phases was conducted by a hydrogen reduction technique. The equilibrium H₂S/H₂ ratios were determined as a function of temperature for the two phase equilibria GeS₂-GeS and GeS-Ge. A Tutwiler analysis technique was used to analyze the equilibrated gas mixture for hydrogen sulphide content.

A detailed description is given for the process and the apparatus used in performing the experiments for equilibration of H₂S/H₂ gas mixture. The methods used for the preparation of germanium sulphide phases are also discussed.

The investigation …

A Thermodynamic Study Of Germanium Sulfides, Sham Lal Malhotra

Masters Theses

"The vapour pressure of germanium monosulfide (liquid) was determined by a boiling point method. An expression for the vapour pressure as a function of temperature was obtained and the heat of vapourization calculated. Using the heat of sublimation data obtained by other investigators, the heat of fusion was calculated.

The thermodynamic properties, change of standard free energy (Δ F°) heat content (Δ H°) and entropy (Δ S°); of germanium disulfide were determined by using an indirect method. The equilibrium H₂S/H₂O ratios are determined for the reaction:

GeS₂ (s) + 2H₂O(g) = GeO_{2 …}

A Dissolution Rate Study In Hydrofluoric Acid Of Titanium And The Alpha Solid Solutions Of Oxygen In Titanium, John L. Ratliff

Masters Theses

"The dissolution mechanism of titanium in hydrofluoric acid was studied by collecting the hydrogen evolved during the dissolution reaction. A concentration range of 0.05 N to 0.50 N and a temperature range of 15°C to 45°C were employed for the determination. Values of the reaction order and energy of activation were determined for both pure titanium and the alpha solid solutions of oxygen in titanium and found to be the same within experimental limits. This indicated that the reaction giving rise to hydrogen evolution on the surfaces of both pure titanium and the TiO_x alloys was the same. The …

The Effect Of Rare Earth Additions On Low Alloy Steel, Sukh Dev Sehgal

Masters Theses

"Rare earth metals have for some years been used as an inoculant in nonferrous foundry practice and lately in the production of nodular iron. It has been reported that addition of rare earth metal to certain grades of stainless steel so improve the hot malleability that reduction of large size ingots in the blooming mill is now possible. It has been reported that considerable improvement in soundness and mechanical properties of steel castings and wrought products have been attained as a result of small additions of rare earth metals and oxides. In practically all investigations, it has been reported that …

Mechanization Of First Stage Graphitization In Fe- C-Si- Alloys, Dildar S. Gill

Masters Theses

"The purpose of this investigation was to study the mechanism of first stage graphitization in iron-carbon-silicon alloys in the light of results obtained by Taub, and to propose a new mechanism of graphitization. The results of preliminary experiments confirmed the findings of Taub as regards the precipitation of secondary carbides. Therefore, it was decided to extend the investigation so as to include the study of growth of secondary carbides. In order to know the chief factor responsible for the growth of secondary carbides, the activation energy was calculated. Another factor which was investigated was the site of graphite nuclei formation”--Purpose …

X-Ray Diffraction Study Of The Metal Powder Compacts, Rajendra Sharan

Masters Theses

"Various theories have been put forward about the mechanism of compacting and sintering processes. None of these theories are confirmed. The reason is that most of these theories are based on observations on metallographic specimens, which is not a particularly good tool for such a study. Little data using xray diffraction analysis is available and there seems to be a great need of making a thorough investigation in this direction.

The main object of this investigation is to study xray diffraction patterns of green compacts of aluminum, nickel and copper powders pressed under different compacting pressures to see if any …

The Vapor Pressures Of Pbo-Sb₂O₃-Sio₂ Mixtures., John Henry Smith

Masters Theses

"The removal of antimony is one of the important steps in the production of pure lead. The process of removing antimony from impure lead bullion is called "lead softening". The most common method used is to blow air into a bath of impure molten lead. The impurities, primarily antimony, arsenic and tin, if present, are oxidized and form a slag or "dross" which floats on the surface of the lead bath. A considerable amount of lead is oxidized in this step and joins the other oxidized compounds in the dross. This dross is skimmed from the bath of molten lead …

The Effect Of Heating Chill Cast Eutectics, Robert Lewis Dreshfield

Masters Theses

"This investigation is the result of the author's specific interest in two phase systems. In the past, considerable work has been done investigating the alteration of eutectoid structures; however, eutectic structures have been neglected to a great extent. Tammann did some work on the subject in 1937 as did Brown and Guy in more recent times. In both of the above cases the eutectic structure was altered by cold working and subsequent heating of the alloy.

Tammann also noted that eutectics chill cast in liquid air display a vastly different structure than those cast under equilibrium conditions and that there …

Lattice Constants, Thermal Expansion Coefficients And Perfection Of The Phase Tio, Hsiung Wei Li

Masters Theses

"TiO is one of the intermediate phases in the titanium - oxygen system with a crystal structure of the sodium chloride type. The phase extends from about 22 to 29 weight or about 46 to 55 atomic percent oxygen. A comprehensive survey of the physical properties of the phase has been made in previous investigations (see review of literature), but only impure titanium was available at that time. Therefore, some revision of the measurements had to be made. Also, neither the thermal expansion coefficients nor the temperature at which the lattice constants were measured were reported.

For precision determination of …

Methods To Improve The Metallurgy Of Bolivian Tin Ores, Oscar Davila-Michel

Masters Theses

"Tin is a rare element; among the base metals it is one of the rarest. Although it was one of the first metals used by man and has been used since prehistoric time, the ore-dressing and metallurgical methods of tin are inefficient and very wasteful.

The only tin deposits of importance in the Americas are located in Bolivia, South America, and it is in Bolivia that the problems of tin metallurgy are greatest. More than 50% of the tin that is mined in Bolivia is lost in the tailing dumps of the beneficiation plants. In a country where the export …

Influence Of Some Metals On The Rate Of Corrosion And Deposition Of Titanium In Molten Salt Baths, Yu-Pu Huang

Masters Theses

"2. The purpose of this investigation. The substances obtained by corrosion of titanium in fused salts, if leached with water and dried, are composed of three kinds of products, namely of black, gray and yellowish ones. The black product was identified by X-ray diffraction as titanium-oxygen alloy with 9-10% by weight oxygen which later was used as coating material instead of the titanium sheet for deposition experiments described previously. The yellowish product was identified as rutile. The grayish product was also rutile but containing some titanium powder. Of these three products only the black one possessed the ability to deposit …

Separation Of Iron-Tin Alloys Using Gas-Solid Reactions, Carl Richard Bieling

Masters Theses

"For years it has been a problem to the tin smelting, plating, and detinning industries to be able to separate iron from tin once they were associated together as described above. Due to the lack of a tin smelter in the United States in the past, and the abundance of tin scrap available, which had little value either for the iron content or the tin content in their untreated state, most interest was concentrated on seeking methods of separating this tin scrap into its two useful components, iron and tin, rather than deal with the problems of smelting tin from …

An Investigation Of The Dissolution Of Hafnium-Free Zirconium In Hydrofluoric Acid And The Effect Of Fluoride Additions, Alfred S. Neiman

Masters Theses

"Hafnium-free zirconium has assumed great importance in commercial use in recent years. When economical methods were developed in 1950 to remove hafnium from Zr, a metal was produced which not only exhibited good corrosion resistance and desirable physical properties, but also had a very low absorption cross section for thermal neutrons. Such a metal could obviously be utilized to advantage as a structural material for nuclear reactors. This application is the most important one for Zr at present.

Good corrosion resistance to most mineral acids is one of the outstanding non-nuclear properties of Zr. Hf-free Zr has good corrosion resistance …

Statistical Analysis Of X-40 (Stellite-31) Production Blends., Edward P. Patterson

Masters Theses

"An investigation was undertaken to statistically analyze the data obtained on X-40 (Stellite 31) production blends which were tested to the requirements of AMS 5382. For our purpose a blend is one or more furnace heats, the shot of which has been thoroughly mixed to produce greater uniformity of product. The mixed shot is charged to the arc furnaces and cast into parts, and test specimens. A great range of test results have been obtained in testing blends, and it was felt that a statistical analysis of a few of the variables might yield information which could be applied toward …

Determination Of Lattice Constants, And Thermal Expansion Coefficients Of Ti₂O₃ And Of Its Solid Solutions With Ti, Tatsuhiko Ejima

Masters Theses

"For the determination of the precise lattice constants of Ti₂O₃, it is very important to use a Ti₂O₃ as pure as possible.

Due to the formation of solid solution with titanium or oxygen, ranging from 32.5 to. 34.5% O₂ by weight in the Ti-O binary system, it is very difficult to get a pure Ti₂O₃ (33.8% O₂ by weight) in the laboratory.

To determine the precise lattice constants of pure Ti₂O₃, therefore, the extrapolation method was used.

This method computes the respective constants for pure Ti₂O₃ from the values obtained With Ti₂O₃-Ti solid solutions by extrapolation. To carry out such …

A Study Of The Deleading Of Zinc Sulfide Concentrates, Larry Leroy Gidley

Masters Theses

"The object of this research was to study the basic principles and optimum conditions for the deleading of commercial zinc sulfide concentrates by sublimation of the lead in the form of a sulfide. Present commercial practice conducts this sublimation in hearth roasters. This research considered only the variables affecting sublimation of the lead sulfide, not the types of applicable equipment, or other possible processes. However, the laboratory conditions were at least partially similar to those that could be obtained in commercial practice"--Object, page 1.

A Study Of Titanium Diffusion Coatings By X-Ray Fluorescent Methods, Alan Bernard Burgess

Masters Theses

"As the only previous determinations of the chemical composition of the titanium coatings had been analyses of the average composition of the entire coating, the determination of the variation in chemical composition throughout the coating was suggested. From this information, it was proposed that a better insight might be gained as to the extent and mechanism of diffusion in the coatings. It was also hoped to correlate the results with concurrent work being done on the phases present in the titanium coatings. From this correlation, it might be possible to show which phases are responsible for the desirable properties of …

Deposition Of Titanium By Gaseous Reaction, Louis John Reitsma Jr.

Masters Theses

"Previous investigations undertaken at the Missouri School of Mines and Metallurgy on the deposition of titanium involved the use of fused salt baths, aqueous solutions, and cementation processes. The fused salt baths produced satisfactory coatings on small metal parts. Some difficulty was encountered however, when the coating of large articles was attempted.

For this reason, it was decided to investigate the possibility of titanium deposition by the reaction of a volatile titanium compound with a metal surface. Two different compounds were proposed for investigation, (1) a lower chloride of titanium and (2) an iodide of titanium. The reaction with the …

The Preparation Of Titanium Tetrachloride From Rutile, Nalin Sen

Masters Theses

"In recent years, considerable interest has been shown in the manufacture of titanium metal because of its outstanding properties both physical and chemical. The commercial process for the preparation of metallic titanium, known as the Kroll process, consists essentially of the reduction of titanium tetrachloride with magnesium in an inert atmosphere to produce titanium metal with magnesium chloride as a by-product.

Since, titanium tetrachloride is the basic compound from which to prepare metallic titanium by the Kroll process, much thought has been given to the preparation of titanium tetrachloride from titanium ores such as rutile or ilmenite.

The present work …

A Study Of The Structure Of Titanium Diffusion Coatings On Iron And Steel, Pao-Jen Chao

Masters Theses

"The Problem of the Thesis: A series of experiments have been made in the Metallurgical. Engineering Department of the Missouri School of Mines and Metallurgy for the investigation of titanium diffusion coatings. The technique of applying the titanium diffusion coatings on iron and steel is still in the experimental stage. A few of the physical properties and chemical compositions of such coatings have been determined, but the structures have not yet been extensively studied. As the correlations of the structures and the desirable properties are valuable for improving the quality or titanium diffusion coatings on iron and steel, an investigation …

Deposition Of Metallic Coatings From Fused Salt Baths, Andrew Hessler Larson

Masters Theses

"This thesis is the result of an investigation undertaken to study some of the important factors affecting the deposition of metallic diffusion coatings on other metals immersed in a fused salt bath….

There are many methods which have been devised to obtain diffusion coatings on various metals. One which is quite well known and used commercially is the process of “chromizing” which produces a diffusion layer if chromium on another metal. One method of “chromizing” consists of immersing the specimen to be coated in a mixed chloride fused bath containing chromium metal flakes. Another method consists of packing a low …

Effect Of Carbon Content In Steels Upon The Deposition Of Titanium From A Fused Salt Bath, Reinhard Paul Abendroth

Masters Theses

"STATEMENT OF PROBLEM Previous work done at the Missouri School of Mines and Metallurgy on the deposition of titanium upon various metals, especially iron and steel, bas shown that titanium can be deposited upon ingot iron and. low carbon steels with comparitive ease. Difficulty was encountered in attempts to deposit titanium upon steels of higher carbon content and upon cast irons.

For this reason, it was decided to investigate more thoroughly the relationship between the carbon content of various steels and the quality of titanium coatings deposited on these steels. Once this relationship had been established, a suitable theoretical explanation …

Corrosion Products Of Titanium In Fused Salt Baths, Kai-Chai Chiou

Masters Theses

"Titanium is gaining great interest in the modern metal industry because of its natural abundance and its desirable physical and chemical properties. Among them, its excellent corrosion resistance, such as the resistance to normal atmosphere attack, humid and saline atmosphere attack, sea water attack, and nitric acid attack, is the most prominent characteristic being welcomed by the engineers. The usefulness of titanium would be greatly increased if it were possible to plate titanium on other metals, thus increasing the corrosion resistance of these other metals.

Much concern, at present, has been given to the possibilities of the electrodeposition of titanium …

Mechanism And Measurement Of First Stage Graphitization In White Cast Iron, David S. Gould

Masters Theses

"The original object of this thesis was to ascertain if coercive force measurements could be used for the determination of degree of malleablization in malleable iron. Since first stage graphitization was involved, it was only natural that an interest in the mechanism of first stage graphitization developed. The investigation which resulted from this interest was done primarily for the edification of the author, however it was subsequently deemed of enough importance to be included in this thesis. For this reason the thesis may appear at times to deviate from the original objective"--Preface, page iii.

The Lattice Constant And Coefficient Of Expansion Of Chromium, Chao-Ching Weng

Masters Theses

"The most important use of chromium, other than as an alloying element in the manufacture of stainless steel, is for electroplating; to form a coating on other metals for corrosion prevention in order to procure longer life, and to achieve a decorative effect.

The physical properties of chromium are important in the effectiveness of its uses, and its lattice constant, as well as coefficient of thermal expansion, seem worthy of exact determination.

A number of research workers, over a span of thirty years, have spent considerable effort in determining the aforementioned constants. However, their results do not check, and the …

The Effect Of Impeller Speed And Air-Volume On The Flotation Rate With Respect To Particle Size, William Edward Horst

Masters Theses

"Today the ore being mined is low grade and the mineralization has become very complex. In order to concentrate a complex ore, the requirement of grinding the ore very fine is imposed. The process of flotation was developed to concentrate the finely ground ore particles; however, the finer size fractions of the ore still present a concentrating problem.

The fact has been established that the flotation rate which is the recovery that can be attained during a given time interval varies with particle size. The flotation rate increases with an increase in particle size until the maximum flotation rate is …

X-Ray Studies Of Zirconium Cyanonitride, John T. Ballass

Masters Theses

"The purpose of this research was to study, by means of x-ray and metallographic analysis, a material reported to be zirconium cyanonitride.

The x-ray analysis had a three fold purpose, the determination of the symmetry of the constituents, the number of phases present, and the crystal structure type. Metallography was used to confirm some of the results obtained by x-ray analysis establishing certain definite phase relationships present in the microstructure.

The sample investigated contained three principal elements namely zirconium, nitrogen, and carbon. On the basis of constitution this work is a contribution toward the development of the three component equilibrum …