摘要:

ABSTRACTThe various means for developing the maximum covering power of enamels are very important. This investigation brings out the marked effect on the opacity of different clays used for suspending cover enamels. This may be equivalent to at least 5% in the reflectance, as measured by the reflectometer. Where suspension and opacity are both important, a blend of clays may be used, one of which may have excellent suspension while the other imparts opacity to the enamel.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1936.tb19796.x

出版商:Blackwell Publishing Ltd    

年代:1936

数据来源: WILEY

摘要:

ABSTRACTThe influence of alumina on the behavior of simple fluoride glasses is investigated. Analytical melting studies indicate that the fluorine may be liberated by at least three typical mechanisms. X‐ray diffraction studies reveal influences of alumina on crystallizatio

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1936.tb19797.x

出版商:Blackwell Publishing Ltd    

年代:1936

数据来源: WILEY

摘要:

ABSTRACTA method for determining the moisture content at which a plastic body becomes elastic is given. Results of tests made on an earthenware body indicate the transition to have taken place at approximately 12.8% water content. With decreased water content of the body the yield values decreased, the deformation per unit stress beyond the yield value pressures decreased, the total deformation at ultimate failure decreased, and the ultimate failure pressures increased.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1936.tb19798.x

出版商:Blackwell Publishing Ltd    

年代:1936

数据来源: WILEY

摘要:

AbstractThe influence of the glaze composition upon glaze fit and mechanical strength has been studied on a series of commercial and twelve experimental glazes. The latter have a RO constant of 0.3 K2O, 0.7 CaO, 0.4 to 0.7 Al2O3, and 2.4 to 5.6 SiO2. The coefficient of thermal expansion was determined by calculation. Glazes high in fluxes (feldspar and whiting) appear to be unfavorable to high strength and good glaze fit.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1936.tb19799.x

出版商:Blackwell Publishing Ltd    

年代:1936

数据来源: WILEY

摘要:

AbstractWhen a wide range of temperatures is considered, difficulty is encountered in accurately representing the thermal conductivity of any material, the temperature‐conductivity function of which is not a straight‐line relation. This difficulty can be obviated by use of the “true” conductivity function as defined herein.The use of the “true” conductivity function confers the additional advantage that it makes possible a graphical method for the calculation of heat transmission through compound structures, under conditions of equilibrium heat flow. Though this is still a trial‐and‐error process, from the theoretical viewpoint it is more sound and from the practical angle more easily usable than the arithmetical method generally employed heretofore. The new method is illustrated by the solution of a

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1936.tb19800.x

出版商:Blackwell Publishing Ltd    

年代:1936

数据来源: WILEY

摘要:

AbstractThis paper points out that, to convert temperature values recorded in the literature to the present International Temperature Scale, a correction must be applied which is calculated from the constants that define the particular scale upon which the recorded values are expressed. Applying the same corrections to all previous scales leads, in many cases, to values which depart from the present scale more than the values actually recorded.Examples are given showing the proper method of converting temperature values based on Wien's Law to the International Scale.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1936.tb19801.x

出版商:Blackwell Publishing Ltd    

年代:1936

数据来源: WILEY

摘要:

AbstractA method has been devised for studying the physical properties of the fused enamel containing the mill additions by firing it onto a split‐steel ring and studying the changes in the radius of the ring and stresses produced due to the difference in the coefficient of thermal expansion of the enamel and the stee

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1936.tb19802.x

出版商:Blackwell Publishing Ltd    

年代:1936

数据来源: WILEY

摘要:

AbstractThe classical method for the analysis of glass sand, based on fusion of the pulverized material with sodium carbonate, dehydration of the silica with HCl, and determination of the other components from the filtrate, while accurate, requires considerable time. The method outlined by the writer, using HNO3and HF, gives satisfactory results and requires only about one‐fourth the tim

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1936.tb19803.x

出版商:Blackwell Publishing Ltd    

年代:1936

数据来源: WILEY

摘要:

AbstractExperiments designed to test the theories of gripping and electrochemical displacement as factors in the adherence of enamels to metals were performed. Rough surfaces on chromium, the stainless steels, and nickel produced no better adherence than smooth surfaces. Rough and smooth surfaces on iron enameledin vacuoand in nitrogen gave extremely poor adherence. Gripping action apparently functions on enameled noble metals.Poor adherence on chromium, a metal higher than cobalt in the electrochemical series, and good adherence on copper, a metal below cobalt in the series, tend to show that electrolytic reactions, if they do occur, are not the fundamental cause of adherence. Enamels fired on ironin vacuoor in nitrogen are given the most advantageous conditions for electrolytic reactions to take place, yet the adherence in these cases is extremely poor.Gripping action or electrolytic reactions could not function properly on oxidizable alloys and metals due to oxide layers which formed under the glass layer in firing. The importance of oxygen in enameling metals is emphasized by these experiments.A brief review of the work of Pfeil, Castro and Portevin, and Mathewson, Spire, and Milligan on the constitution of iron scale is given. It is shown that metallic iron particles may exist in ferrous‐oxide scale as true primary dendrites, as rounded grains of residual α‐iron from the base, and as minute specks or thin layers of secondary α‐iron.Microscopic study of iron‐enamel contact zones showed no true dendrites of iron to be present. In underfired enamels was found the α‐iron phase from the initial scale, but in the scale underlying this enamel both residual α‐iron phase and secondary α‐iron were found. In normally fired enamels only detached surface iron produced by slow oxidation of the iron base surface was found. The iron surface and the detached surface iron particles after proper etching showed a film of ferrous phase approximately 3 × 10‐5inch thick between the glass and metal. This film of ferrous phase is believed to be the medium which bonds the enamel and iron together.Microscopic study also showed the effect of an increased diffusion of oxygen as the enamel became richer in iron oxide. Cobalt oxide in the enamel is believed to promote solution of ferrous phase and also to act as an oxygen carrier through the molten glass layer.A description of the six stages in the complete firing of cobalt ground‐coat enamels on iron is given and also the reactions wh

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1936.tb19804.x

出版商:Blackwell Publishing Ltd    

年代:1936

数据来源: WILEY

摘要:

AbstractSince the effect on thermal expansion of clay, feldspar, and silica, when introduced as mill additions to a sheet‐iron ground‐coat enamel, has not hitherto been clearly shown, thermal‐expansion studies were made on a two‐frit ground‐coat enamel for sheet iron, varying the amounts of clay, feldspar, and silica within reasonable limits of mill additions.It is common practice to use a combination of a hard and a soft frit ground coat to give greater flexibility in firing and operation, but it is not known whether the two frits form a single glass upon firing to give an expansion dependent upon the relative amounts of each frit present. Thermal‐expansion tests, therefore, were also made on enamels containing varying proportions of high‐ and low‐expansion frits.Results were obtained by the use of the interferometer, and the rod method of making specimens as used by Andrews and Smith1was compared to the plate method described in this paper. Through the use of these two methods of preparing the samples, a comparison of the relative solubility of the mill additions in the ground‐coat

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1936.tb19805.x

出版商:Blackwell Publishing Ltd    

年代:1936

数据来源: WILEY