ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15465.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Thermal‐expansion, stress‐temperature, and thermal‐shock tests were conducted on glassed low‐alloy and plain‐carbon steels. The addition of alloying elements increases the hardenability and strength of the steels but lowers the austenite‐to‐ferrite transformation temperature, thus decreasing the residual compressive stress in the glass coating and therefore its resistance to thermal shock. It is shown thatD1, the calculated hardenability index, may be correlated with certain physical properties of the glass‐s

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15466.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

A better insight into the initial stages of densification during the hot‐pressing of ceramics can be obtained by performing the experiments at low temperatures. The parameters which have been examined are pressure, temperature, and the particle size of the alumina used. The results obtained preclude plastic flow as the predominant mechanism responsible for the large increases in density observed initially. Particle rearrangement by boundary sliding is suggested as the process responsible for the initial increase in compact densit

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15467.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Mixtures of beryllium and boron powders were reacted under argon at elevated temperatures. X‐ray single‐crystal and powder diffraction analyses, chemical analyses, and Knoop micro‐hardness measurements were made. Melting‐point ranges were established for compounds of reasonable purity. One compound was identified. Beryllium diboride (BeB2) had a hexagonal unit cell. Its hardness was 3180 ± 100 (Hk100) and its melting point was greater than 1970°C. Beryllium hexaboride (“BeB6”) had a tetragonal unit cell, a hardness of 2577 ± 75 (Hk100), and a melting point between 2020°) and 2120°C. An anisotropic unknown phase existed whose Be: B ratio was between 6:1 and 2:1 and whose hardness ranged between 623 and 917 (Hk25), depending on orientation. A eutectic between beryllium and this unknown phase was observ

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15468.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

The glassforming region in the system was roughly outlined and liquidus data were obtained for the three joins LiPO3‐BPO4, Li4P2O7‐BPO4, and Li3PO4‐Li2B4O7. Compatibility relations for the ternary subsystems Li4P2O7‐BPO4‐P2O5and Li2O‐Li3PO4‐Li2B8O13were established. Two ternary compounds with the probable compositions 22Li2O ‐ 11B2O3‐ 13P2O5and 2Li2O 3B2O3

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15469.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Lithium fluoride single crystals which had been annealed in various gases, abraded with papers of different grits, etched, polished, and coated with metals before testing were deformed in compression. Another series of tests was performed in which the specimens were deformed while immersed in mineral, fatty, dicarboxylic, and tricarboxylic acids and in xanthates, Aero‐floats, amines, water, and bases. Attempts to correlate the observed mechanical properties and the environment or surface condition were partly successful. The appearance of the stress lines and the fracture characteristics of these crystals were also investigate

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15470.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Basal‐, prism‐, and rhombohedral‐plane specimens cut and polished from flame‐grown sapphire boules developed fine surface textures during heat‐treatment in the range 1700° to 1900°C. Microscopic examinations of such surfaces revealed low‐angle grain boundaries, dislocations, and other crystal imperfections. Thermally etched textures apparently were generated by three overlapping processes, namely annealing, etching, and decoration. Thermal etching gave evidence of high‐temperature relaxation of residual strain energy introduced at low temperature (analogous to cold work in metals), including that introduced by fracture, microindentation, and cutting and polishing during surf

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15471.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Samples of Ca2SiO4were prepared by three different methods. These samples were examined by differential thermal analysis, high‐temperature X‐ray diffraction, and air quenching of pellets. It was found that the β modification, during cooling, converted completely and rapidly to the γ modification and “dusted” only if it had been heated above 1420†± 10† C. If the sample was not heated above this critical temperature, a mixture of the β and γ forms always resulted at room temperature. The addition of 0.5 weight % of CaO, SiO2, Al203, Fe203, or MgO had no effect on the sequence of phases for samples cooled from above the critical temperature. When, however, these same samples were cooled from below 1410†C, the final room‐temperature product was not the same for all samples. On the other hand, the additional 0.5% of Na20, K2O, Cr2O3, or B203prevented the formation of the β modification regardless of the temperature from which the sample was cooled. The critical heating temperature correlated with the transformation temperature for the α‐α inversion. A theory relating this inversion to the completeness of the β→

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15472.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Published work in the literature indicates that small amounts of platinum bring about phase separation in sodium phosphate melts which can be recognized in electron micrographs. The influence of 0.0038, 0.0076, 0.038, and 0.15% platinum on the constitution of and phase separation in sodium phosphate glasses with n, the number average chain length, varying from 3 to 9 has been investigated using both paper chromatographic and electron microscopic techniques. The results indicate that platinum nucleation apparently has no effect on the distribution of polyphosphates in the glasses studied, although electron micrographs show phase separation. The significance of the results in relation to immiscibility phenomena is discussed.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15473.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15474.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY