Materials Science and Engineering Commons^™

A Survey Of The Influence Of Selected Sulfides On The Thermal Decomposition Rate Of Zinc Sulfate, L. G. Twidwell

Masters Theses

"The influence which ZnS, CdS, Cu₂S, PbS, and FeS has on the thermal decomposition rate of ZnSO₄ was studied by measuring the SO₂ gas evolved per unit of time for various ZnSO₄-MeS mixtures at 600°C, and analyzing the solid phases by means of X-ray diffraction patterns.

The SO₂ gas evolved upon heating the pellets was analyzed as a function of time by absorbing the gas in a solution of distilled water, H₂O₂, and NaOH, and measuring the time required for the SO₂ to neutralize the NaOH. The gas …

Preliminary Investigation Of The Effects Of Seeding Fusion Cast Refractories, Thomas Spencer Montgomery

Masters Theses

"The crystallization process in a zirconia-alumina- silica melt of high viscosity was studied, A system was used of the same composition found in commercial electrocast glass tank refractories. Artificial nucleation was tried in an attempt to control the process of crystallization; the method involved the addition of suitable "seeding" material.

It was found that introduction of nucleation agents consisting of the major component oxides of the system had noted effect upon the course of crystallization. Preferred orientation normally found in unseeded electrocast refractories was diminished with the addition of zirconia grains and amplified with particles of tabular alumina.

Results obtained …

A Study Of The Chemical Kinetics, Activation Energy And Difference Effect On Beryllium Dissolving In Mineral Acids, Daniel Santhamurthi Gnanamuthu

Masters Theses

"The rate of dissolution of polycrystalline beryllium was studied in hydrofluoric, hydrochloric and sulfuric acids. Two samples of beryllium containing different amounts of beryllium oxide were used. The experiments were performed at temperatures ranging from 20 to 50°C, and at various acid concentrations. The kinetics of these heterogeneous processes conformed to a reaction order of approximately one in all the cases. Since the conditions of the surface were complex during dissolution, these might complicate the reaction. This might be due to the oxide layer, which is present as impurity.

The difference effect was determined at various acid concentrations at 25°C …

A Study Of Several Commercial Steels In The Red Short Range, Jorge Alberto Espana

Masters Theses

"The red short phenomenon present in steel, was studied by means of torsion tests at temperatures between 800 and 1200⁰C. Cold drawn bars of different compositions of steels were tested, and the number of turns to failure and maximum twisting torque were plotted versus temperature.

All the steels tested, exhibited to have a certain degree of red shortness. By comparing the curves and the respective chemical analyses, the detrimental effect of sulphur and lead and the beneficial effect of manganese, was established.

Microscopic examinations revealed the intergranular nature of the cracks in the red short range. Sulphur and oxide distribution …

The Effect Of The Rolling Load On The Micro-Structure Of Low Carbon Sheet Steel, Jerry Lee Cadden

Masters Theses

"A Stanat 315, two high-four high, combination rolling mill is used to cold roll annealed, low carbon steel strips. A method of measuring the rolling load was presented. The method consisted of constructing a load cell using SR-4 strain gages attached to a steel column. The load cell was placed under the hold down screw of the rolling mill and a known load was applied. The stresses from this load were transferred to the mill housing where another SR-4 strain gage was located. The strain in the mill housing was recorded at the corresponding applied load. During rolling, the strain …

A Weight Loss Technique For The Determination Of Phase Boundaries, Robert Lee Benner

Masters Theses

"An apparatus has been designed and constructed that would continuously record the weight loss of a sample in a flowing inert atmosphere, at a constant temperature.

A technique has been developed to determine the phase boundaries of a binary phase diagram.

Alloys of the magnesium-nickel, cadmium-antimony, copper-cadmium, copper-zinc, and magnesium-zirconium systems were subjected to investigation to verify the operation and resolve a number of limitations of the equipment.

These investigations disclosed that the apparatus gave the best results with alloys having vapor pressures in the range between 1 and 35 millimeters of mercury"--Abstract, page 2.

Isothermal Decomposition Of Austenite (In 1.4% Tungsten Steel) At Subcritical Temperatures, Samir Moustafa Riad

Masters Theses

"An experimental investigation was conducted in order to study the relationship between temperature, time and the decomposition of austenite in Tungsten steel of a given composition - and to plot the T-T-T Diagram for this steel.

The steel was prepared, homogenized and cut into identical specimens for further heat treatment and metallographic inspection. Precautions were taken to prevent these specimens from decarburizing during any heat treatment.

This experimental work may be divided into three main parts:-

I. Determination of the critical temperature range; i.e. the range of temperature Ae₁ and Ae₃ above which austenite is stable and below …

Electron Microscope Study Of The Systems Cadmium-Cadmium Chloride And Lead-Lead Chloride, Dennis O'Neill

Masters Theses

"The nature of the dispersed phase in the cadmium-cadmium chloride and lead-lead, chloride systems were investigated with the electron microscope.

Preliminary experiments on preparing and examining the dispersed phase showed that it was most feasible to study the material by electron-microscopic examination of replicas made from the surfaces of the fractured materials. Melting apparatus and methods were chosen so that samples of the melts could be easily quenched to different temperatures and so that the samples could be easily fractured with a minimum of surface contamination. Of the conventional replicating techniques tried, that of carbon replicas pre-shadowed with chromium was …

A Vacuum Induction Furnace For Pyrometric Cone Equivalent Determinations, Robert E. Farris

Masters Theses

"Various furnaces which are commonly used for P.C.E. determinations were compared from a literature review. The inadequacies of these furnaces were noted and a furnace was designed, constructed, and evaluated in an effort to minimize or eliminate some of the indicated problems. For this furnace heat is developed in opposed cones (susceptors), which are fabricated from 0.005” molybdenum sheet, by induced (induction) currents from a 10 KW vacuum tube generator. The furnace components are enveloped by a pyrex cylinder in which a vacuum (approximately 1 to 5 micron pressure absolute) is maintained during operation"--Abstract, page ii.

A Study Of The Difference Effects On Alpha Solid Solutions Of Oxygen In Titanium Dissolving In Hydrofluoric Acid, Kuo-Chin Chuang

Masters Theses

"Alpha solid solutions of oxygen in titanium dissolving in hydrofluoric acid exhibited a positive difference effect with k values of 5.7, being independent of the concentration of HF, within the compositional range studied 0 to 5 w/o oxygen. This indicates that various TiO_x alloys are polarizable to the same extent by the same strength of anodic current in hydrofluoric acid.

The difference effect observed on TiO_x alloys dissolving in HF-HCl revealed that the effect is dependent on the oxygen content of the solid solution as well as on the concentration of HCl. The presence of HCl results in …

A Resistivity Study Of Hot Short Ferrous Alloys, Harold Alfred Koelling

Masters Theses

"Resistivity measurements were performed at elevated temperatures on four special ferrous alloys and one commercial iron. The alloys were pure iron, iron with .023 per cent sulfur, iron with .33 copper, iron with .32 copper and .024 sulfur. Other elements were held to the minimum amounts possible in order to determine the actual effects of sulfur and copper. The commercial alloy was Armco Iron.

Measurements of resistivity versus temperature were taken at slow heating rates to determine if the iron sulphide liquid film formed in the grain boundaries of red-short steels had any effect on the electrical resistivity"--Abstract, page 7.

A Preferred Orientation Study Of Sheet Formed By Rolling Copper, Nickel, Titanium And Tungsten Metal Powders, Martin Franklin Marchbanks

Masters Theses

"Pole figure scans of strip rolled from copper, nickel, titanium, and tungsten metal powders were made on samples taken across the width of the strip, and with various amounts of surface material removed, to determine if any preferred orientation existed. No preferred orientation was found in any of the samples examined.

The method used was a modification of the Schultz technique, using the Norelco Pole Figure Fixture, whose geometry and operation is described, in conjunction with the Norelco diffractometer.

Defocusing resulting during the run of a pole figure is discussed and a method for reducing this defocusing is described.

The …

The Effects Of Sulphur And Copper On Hot-Workability Of Pure Iron, Hung-Chi Chao

Masters Theses

"The independent effects of sulphur, copper and their combinations on the hot-workability of pure iron free from other elements was studied, with special emphasis on the red-short phenomenon. Electrolytic pure iron with the addition of 0.023 cent sulphur, 0.33 per cent copper and 0.024 per cent sulphur plus 0.032 per cent copper along with a heat of only electrolytic pure iron was melted under vacuum, and cast under helium pressure. The specimens machined from the forged bars were tested at various temperatures by the hot twist-test and by the constant energy single blow drop forging test to evaluate the hot-workability …

A Dissolution Rate Study Of Beryllium In Hydrofluoric Acid, Donald Lee Mathis

Masters Theses

"Beryllium was shown to react stoichiometrically with HF, HCl, and H₂SO₄ acids in accordance with a plus two valence. These reactions were investigated by the hydrogen evolution method.

Dissolution rates were determined in five concentrations, 0.01, 0.05, 0.10, 0.50, and 0,75 N, of HF acid at 10, 20, 30, 40 and 50°C, This was accomplished by the hydrogen evolution method and the results were based on the tested stoichiometry. Beryllium has a high dissolution rate in HF acid, which approximates the following under similar conditions: 10 times Al, 4 times Ti, and 1.5 times Zr. A kinetic …

High Temperature Oxidation Of Nickel, Virgil R. Friebel

Masters Theses

"Using a sensitive volumetric technique, a study was made of the kinetics of oxidation of nickel at 1200° C. and 1300° C. Three purities of nickel were used for the investigation which was limited to the initial three hours of reaction.

The rate of oxidation of nickel followed the parabolic rate law after an initial period of deviation which lasted up to 40 minutes. No direct correlation was found between the oxide thickness and the end of the period of deviation from the parabolic rate law.

The purity of the nickel was found to have a marked effect on the …

The Constitution Of Magnesium-Rich Magnesium-Zirconium Alloys, Kenneth Allen Fowler

Masters Theses

"The magnesium-zirconium system has been studied to 0.8 per cent zirconium which represents the limit of solubility of zirconium in liquid magnesium at 950°C. Alloys have been prepared by two methods of alloy additions, and the results compared. Microstructural studies have been made of the alloys in the cast, extruded, and heat-treated conditions. The limit of solid solubility has been determined on the basis of resistivity and temperature coefficient of resistivity measurements, as well as by metallographic examination, with good agreement. A secondary structure resulting from precipitation of a second phase within cored regions of the alloy has been studied …

The Effect Of The Rare Earth Elements On The Hot Workability Of Ingot Iron, L. A. Neumeier

Masters Theses

"The effect of mischmetal and rare earth oxides on the hot workability of ingot iron in the hot-short region was studied. Thirteen heats were melted in air in a basic-lined induction furnace. All heats were thoroughly deoxidized with aluminum prior to the rare earth additions. Mischmetal was added in amounts of 0.1, 0.3 and 0.5 per cent. Rare earth oxides were added in amounts of 0.1 and 0.2 per cent. Temperatures were maintained at approximately 2900°F and holding intervals between mischmetal additions and pouring at two minutes. Bars were hot rolled and swaged for hot twisting in the hot-short region. …

Segregation Method As Possible Process To Beneficiate Oxidized Lead Ores, Jose Molfino Tomasio

Masters Theses

"In this investigation it has been demonstrated that the Segregation Process has merit for treating oxidized lead ores.

The process comprises heating the crushed ore with salt and coal at about 750° C. to produce metallic lead attached to the carbon particles, which then is recovered by conventional flotation methods.

The quantities of sodium chloride and coal required for the best segregation of lead obtained in this work was 1.0 percent of coal and 1.0 percent of salt by weight.

Good segregation was obtained by using salt and coal as fine as 65 or 48 mesh. Segregation varied with the …

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 …

Some Properties Of Chrome-Magnesite Mixtures And Calcium Aluminate Cement-Magnesite Mixtures, Edward Charles Duderstadt

Masters Theses

"The knowledge of the physical and chemical properties of refractories is of great importance in determining their usefulness and application. The thermal expansion of refractories is of particular importance in that it affects the thermal stability of the product. A high coefficient of thermal expansion leads to greater spalling and destruction of the bricks in use. It is, therefore, desirable to develop compositions having low coefficients of thermal expansion. This investigation was undertaken (1) to determine some of the properties of chromite-magnesite refractory mixtures in an attempt to determine the optimum composition of these mixtures, the specific properties including thermal …