ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1952.tb13080.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

The minimum amount of calcia or magnesia required to stabilize zirconia into the cubic form is about 16 mole %. X‐ray diffraction studies show that both calcia and magnesia are in solid solution in cubic zirconia. This solid‐solution phase extends from 16 to 30 mole % in the case of calcia and from 16 to 25 mole % in the case of magnesia. These results are for specimens cooled from 2000°C. After heating at various temperatures between 815° and 1375°C., the calcia‐stabilized zirconia remains cubic, whereas the magnesia‐stabilized zirconia reverts to the monoclinic form. On the basis of the results obtained from X‐ray diffraction and dilatometric measurements, information was obtained on the phase relationships in the systems zirconia‐calcia and zirconia‐magnesia, and some modifications to the previously published phase diagrams of these syst

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1952.tb13081.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

A typical porcelain enamel ground coat containing a small amount of radioactive cobalt as oxide was prepared, applied to sandblasted enameling iron blanks, and fired under conditions selected to give underfired, normally fired, and overfired coatings, respectively. Examination of these specimens revealed that a cobalt‐bearing metallic deposit had been formed at the enamel‐metal interface during firing, and that the enamel layer was depleted in cobalt oxide near the interface. The amounts of such deposit and depletion were found to vary directly with the severity of the firing treatment. The amount of metallic deposit was extremely small, on the order of 0.01μthick if computed as a continuous layer of metallic cobalt in the case of the normally fired speci

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1952.tb13082.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

In the glass SiO271, Na2O 17, CaO 12% with 7.5 parts per hundred of fluorine added to the batch, substitution of up to 6% ZnO for CaO produced a great increase in the opacity; substitution of Al2O3for SiO2or of K2O for Na2O produced much smaller effects, which were dependent on the composition and were inappreciable in the presence of 6% ZnO. Despite the differences in opacity, no differences in fluorine content were detected. No support was found for the belief that Al2O3is essential to the successful opacification of a glass by means of fluorides.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1952.tb13083.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

A procedure for the preparation of the nitrides and carbides of several metals and the preparation of refractory bodies from them is described. The investigation shows that reasonably strong and dense bodies can be prepared from these materials as well as from UO2. Evidence showing the tendency of Be3N2, TaN, and ThN toward instability at high temperatures is presented. Evidence is also given indicating that the hexagonal structure reported by others for TaN is actually that for Ta2N. A lattice for Th2N3is proposed. The melting points of ThN, UN, and UC are determined to be 2630 ± 50°C., 2650 ± 100°C., and 2590 ± 50°C., respect

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1952.tb13084.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

The wetting of alumina‐silica refractories by a soda‐lime‐silica glass at 1200°C. was studied by taking measurements from enlarged photographs of a glass drop on the refractory surface after various time intervals. The values calculated for the contact angles were in agreement with those obtained by direct measurement of the solid‐glass‐air interfaces. A review of the theoretical considerations validating the use of the contact angle as a means of measuring the wetting tendency is presented. The physical conditions which can influence the magnitude of the contact angle are also discussed, as is the method of calculating the contact angle. The rate at which the contact angles decreased indicated that an appreciable difference exists in the tendency of the molten glass to wet the various alumina‐silica refractories. A comparison is made of the wetting behavior of the refracto

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1952.tb13085.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY