THE THERMAL EXPANSION OF SHEET-IRON GROUND-COAT ENAMELS*

The thermal expansions of sheet-iron ground-coat enamels were determined by use of the interferometer. The results showed that the calculated expansions based on the factors of Mayer and Havas were close to the actual expansions. It was also shown that variations of borax, feldspar, and quartz resulted in a fairly uniform change in the expansion. It was possible to interpolate between values for these constituents. The softening of the enamels in the interferometer test proved to be a characteristic change depending on the fusibility of the enamel. These data showed promise as a test for fusibility.     

PORCELAIN ENAMELING CHARACTERISTICS OF SOME COMMON FERROUS METALS *

The experimental evidence gathered during the investigation of seven ferrous metals shows that there is a relationship between the hydrogen behavior and enameling characteristics of these metals. This relationship can best be explained on the basis of diffusibility of atomic hydrogen through these metals and is in no way affected by the total carbon content or by the stabilization of the carbon through the formation of carbides other than iron carbide. These added metallic elements may decrease the diffusibility of hydrogen through steel in two ways, namely, (1) they may have a poisoning or reverse catalytic effect on hydrogen diffusion or (2) they may “plug the gaps” in the crystal lattice and by so doing render the metal impenetrable to atomic hydrogen diffusion.     

CHARACTERISTICS OF IRON AND STEEL FOR PORCELAIN ENAMELING *

The chemical and physical requirements of porcelain enameling sheets are presented. It is explained why the most satisfactory base metal for enameling purposes is one low in carbon, manganese, sulfur, phosphorus, and silicon. Thermal expansion curves and pertinent photomicrographs are shown.     

RELATION OF ENAMELING IRON PREPARATION AND ACCESSORY CONDITIONS TO COPPERHEAD-TYPE DEFECTS*

The tendency of blue ground-coat enamels to copperhead is shown to be related to residual iron salts formed on the surfaces of enameling iron sheets in sulfuric acid pickling. Ferrous sulfate generated in the pickling oxidizes and hydrolyzes readily into compounds which are not soluble in cyanide neutralizer. These effects may be retarded by keeping the solutions between the sulfuric acid and the neutralizer slightly acid and by minimizing the time in these solutions and the exposure to air in transferring between them. The determination of these conditions and the establishment of satisfactory procedures in the production process are described. Some accessory conditions which affect copperheading are also included.     

STUDY OF METALLOGRAPHIC CHARACTERISTICS AND ENAMELING QUALITIES OF CERTAIN CAST IRONS *

The enameling properties of three different irons are described and their analyses are given. Photomicrographs are shown, depicting the structure of each iron near the surface before and after enameling. Structural changes during enameling are described and discussed as to their possible influence on enameling properties. It is shown that one iron anneals perfectly during enameling with no apparent surface alteration, another anneals perfectly but shows surface decarburization; the third sample does not anneal perfectly. Sample No. 1 enamels better than either No. 2 or No. 3.     

EFFECT OF COMPOSITION AND TEMPERATURE ON SOLUBILITY OF IRON OXIDE IN GROUND-COAT ENAMEL GLASS*

The solubility of iron oxide in ground-coat enamel glasses at various temperatures was studied by adding varying amounts of ferric oxide to the milled enamel and giving the mixture a heat-treatment to acquire uniformity without devitrification at the desired temperature. The iron oxide solubility was obtained by finding the breaking point in the curve for iron oxide versus index of refraction. The frit solubilities were obtained at 1400°, 1600°, 1800°, and 2000°F. with variations in Na₂O, B₂O₃, A1₂O₃, CaF₂, CaO, F₂, SiO₂, COO, NiO, MnO₂, BaO, and MoO₃. Data are given on a number of commercial frits.     

几种粘土原料性能及其应用

系统地测试并研究了皮库山粘土、王府山粘土及铜井粘土的主要理化性能及工艺性能。结果表明：前二者可作为结合粘土用于建筑陶瓷。后者可塑性稍低,但也可代替长石、石英或用作部分粘土制造建筑陶瓷。     

DEVELOPMENT AND PRELIMINARY STUDIES OF PINITE*

A deposit of a soft talclike rock, called “pinite,” composed of hydrous aluminum silicates, has been found recently in South American Canyon on the east side of the Humboldt Range near Rochester, Nevada. Prospecting and development of the deposit have consisted of trenching, open-cut work, and the subsequent removal of sufficient tonnage to show a large zone of uniform material. Pinite inverts readily to mullite, and firing is accompanied by a permanent expansion. Thermal-expansion curves show an absence of free silica. Pinite has a high specific gravity, it fires extremely hard and white, and the fired product is highly resistant to certain types of fluxes and to abrasion. Refractories have been produced and placed in selected applications. The results obtained from tests with pinite indicate a superiority over other refractories in certain types of service. Products have been made by the stiff-mud and casting processes, Pinite refractories have been used in rotary enamel smelting furnaces and in the cold zone and cooler linings of rotary cement, lime, and magnesite kilns.     

COMPOSITIONS AND PROPERTIES OF SOME HIGH-TITANIA CERAMICS*

The compositions are given for high-titania ceramic bodies which mature at cone 10. One series contains calcium titanium silicate as an essential flux, and the other series contains alkali-free titania glasses. Electrical measurements cover the range of 60, 1000, and 1,000,000 cycles for both power factor and dielectric constant. Detailed consideration is given to the type of electrodes used. The properties covering dielectric strength, temperature coefficient of capacity, effect of humidity, and thermal expansion are given for one composition. An X-ray diffraction pattern of this body shows the formation of rutile crystals.     

SOME EXPERIMENTS WITH ZIRCON AND ZIRCONIA REFRACTORIES*

This is a record of the results of five years' research on refractory uses for a chemically purified grade of zircon and electrically fmed zirconia of high purity. The products investigated included semi-permanent foundry molds, refractory brick and cements, ladle nozzles, and crucibles. Electric firing and a small oil-fired tunnel kiln are described. Sintered zircon grog was found superior to electrically fused grog. Zircon brick made with 50% grog, using 20% milled zircon for the permanent bond and fired at 1600°C for an hour, showed no firing shrinkage, very slight volume change, and high compressive strength at 1600°C. They were extremely resistant to spalling but did not resist basic slags or metallic oxides very well a t high temperature. Zircon-bonded magnesite brick were more refractory than ordinary magnesite, more resistant to spalling, and had about the same slag resistance magnesite. Zirconia was more refractory than zircon and had better slag resistance. Lime-bonded zirconia crucibles of good spalling resistance were made, but the cost was higher than that of zircon. The effects of various binders are discussed.     

SOME PARTICULATE CHARACTERISTICS OF COMMERCIAL FLINT AND FELDSPAR *

The particle-size variations of eleven shipments of commercial flint and of fifteen shipments of feldspar have been investigated as a possible cause of production variations in electrical porcelain. A correlation of sieve data with specific surface calculations based on sedimentation determinations was made on six grades of commercial flint. The Andreasen pipette sedimentation method was used for all tests except those in which the hydrometer method was employed for comparison purposes. Either of these sedimentation methods had adequate accuracy to control particle size. The percentage remaining on the 325-mesh sieve, however, could not be correlated with the specific surface values. Particle-size distribution was determined for each sample. To facilitate comparisons, specific surface values were calculated from a plot of the distribution data on log-probability graph paper. The investigation included the effect of various liquid suspending media and electrolytes on the settling characteristics of flint and feldspar. Neither flint nor feldspar could be adequately dispersed in non-polar liquids. Feldspar apparently has surface-active characteristics that permit it to be flocculated or deflocculated, depending on the nature of the ions present in solution. An anomalous peptizability of some feldspar samples in the particle-size range below 3 microns is discussed.     

MICROSCOPIC AND X-RAY INVESTIGATION OF SOME STEATITE BODIES*

Microscopic, and X-ray examinations of a series of steatite compositions reveal that the body having the best dielectric properties Also has the simplest and most homogeneous physical structure. It is believed that the attainment of similar physical structures in other ceramic bodies will lead to improvements in dielectric properties. This empirical finding is in accordance with present theories of conduction in crystals. It depends on the contribution to conductivity and dielectric loss made by imperfections of crystal structure. However, even in homogeneous materials, alkaline earth ions tend to cause less conduction under like conditions than alkali ions, and there are high-dielectric constant materials like the titanates which, though homogeneous and pure, have a high loss.     

BOND STRENGTH MEASUREMENT BETWEEN GLASS FIBRES AND EPOXY RESIN AT ELEVATED TEMPERATURES USING THE PULL-OUT AND PUSH-OUT TECHNIQUES

Pull-out and push-out measurements were performed on glass fibres in an epoxy resin to determine the dependence of bond strength on test temperature and on fibre surface treatment. A comparative analysis of the two techniques was carried out to elucidate elementary processes of polymer-fibre debonding and to determine energy values for adhesional bonds. Differences in bond strength values for pull-out and push-out tests were attributed to failure mechanisms that were either interface-controlled or matrix-controlled. Evidence for the different failure mechanisms characteristic of the two test techniques was provided by an estimation of failure parameters, such as the activation energy for debonding. Failure mechanisms also were manifest in AFM images, showing differences in topography and roughness that depended on fibre surface treatment, test geometry, and test temperature.     

SOME EXPERIMENTS ON CRYSTAL GROWTH AND SOLUTION IN GLASSES*

Experiments, which included the development of methods of measuring the linear rates of crystal growth and crystal solution and a study of surface crystallization, were conducted on commercial-type glasses. A method of studying interdiffusion of two glasses of similar composition is described but no conclusions were reached. It was found that (a) the rate of crystal growth is constant until the crystallization zones from the opposite surfaces meet and (b) the curve of crystal solution is continuous with that of crystal growth as the temperature is raised above the liquidus temperature. The results indicate that dust in the atmosphere is a major contributing factor promoting surface devitrification.     

REACTIVITY AND MECHANISTIC STUDIES OF BASE-CATALYZED REACTION OF SOME DIHYDROXAMIC ACIDS

Kinetics and mechanism of the alkaline hydrolysis of two dihydroxamic acids, oxalo and malonodihydroxamic acids, have been studied in 25% (v/v) DMSO at 75°C. The solvent, salt, temperature, and solvent isotopic effects have been examined. Correlation of reaction rate with the acidity function (H-) and these effects indicate a pathway involving the rate-limiting formation of a tetrahedral intermediate that decomposes to give products.     

REACTIVITY AND MECHANISTIC STUDIES OF BASE-CATALYZED REACTION OF SOME DIHYDROXAMIC ACIDS

Kinetics and mechanism of the alkaline hydrolysis of two dihydroxamic acids, oxalo and malonodihydroxamic acids, have been studied in 25% (v/v) DMSO at 75°C. The solvent, salt, temperature, and solvent isotopic effects have been examined. Correlation of reaction rate with the acidity function (H–) and these effects indicate a pathway involving the rate-limiting formation of a tetrahedral intermediate that decomposes to give products.     

OXIDATION-REDUCTION EQUILIBRIA IN GLASS BETWEEN IRON AND SELENIUM IN SEVERAL FURNACE ATMOSPHERES*

This study has been limited to the reactions between iron and selenium in soda-lime and potash-soda-lime glasses melted in atmospheres of air, nitrogen, and carbon monoxide. Glasses containing selenium and iron, together and singly, were melted in the several atmospheres. and their spectral absorption curves between 350 and 1000 mμ were obtained. An analysis of these curves shows that under neutral or slightly oxidizing conditions selenites react with ferrous iron as follows: This reaction leads to an increase in red and brown and a decrease in blue colors. The decolorizing action of selenium may be explained by this reaction because the colorless selenite ion oxidizes the more colored ferrous ion to the less colored ferric ion, arid the increase in the red elemental selenium color physically compensates as a complimentary color for the remaining unoxidized ferrous ion. The results show that it is not necessary to postulate the formation of ferrous selenium to explain the color changes. The results also show that under reducing conditions the principal reaction is      

分子内敏化鎓盐的合成及光敏性研究

二芳基碘鎓盐和三芳基硫鎓盐是阳离子聚合的光引发剂和光敏产酸物,但他们在300nm以上的光吸收很低,限制了对紫外光的利用效率。为解决此问题,本文合成了一些新的碘鎓盐和硫鎓盐,并用凝胶时间方法考察了它们的光引发效率。实验结果表明,2-苯硫基甲基,2′,4′-二甲基二苯碘鎓盐和9-蒽丙基,二苯基硫鎓盐具有特别高的光引发效率,这归之于光照时这些鎓盐发生了分子内电荷转移反应,即发生了分子内敏化。9-蒽丙基二苯硫鎓盐分子中的蒽基(An)是电子给体也是敏化基团,光照时可发生如下反应: