| 释义 |
eutectic, a. and n.|juːˈtɛktɪk|
[ad. Gr. εὔτηκτος easily melting (f. εὐ- eu- + τήκ-ειν to melt) + -ic.]
A. adj. That is a eutectic; of or pertaining to a eutectic or its liquefaction or solidification; eutectic point, the melting-point of a eutectic, or the point representing it in a constitutional diagram.
1884F. Guthrie in Phil. Mag. 5th Ser. XVII. 462 The main argument..hinges upon the existence of compound bodies, whose chief characteristic is the lowness of their temperatures of fusion. This property..may be called Eutexia, the bodies possessing it eutectic bodies or eutectics (εὖ τήκειν)... It will, however, perhaps be better to make the term more useful by limiting its application. I shall use it..for bodies made up of two or more constituents..in such proportion to one another as to give to the resultant compound body..a lower temperature of liquefaction than that given by any other proportion. 1885Nature 5 Nov. 21/1 When metals do unite in atomic ratios the alloy produced is never eutectic, i.e., having a minimum solidifying-point. Thus pure cast-iron is..an eutectic alloy of carbon and iron. 1902[see B. n. below]. 1910Encycl. Brit. I. 705/2 The two sloping lines cutting at the eutectic point are the freezing-point curves of alloys. 1911Ibid. XXI. 330/1 This mixture, which is known as the eutectic mixture, has the lowest melting-point of any which can be formed from these minerals. 1950Engineering 16 June 672/2 Fusible plugs of eutectic alloys. 1967A. H. Cottrell Introd. Metallurgy xvi. 253 This is the ternary eutectic point at which the liquid is in equilibrium with all three solids A, B and C.
B. n.
1. A mixture which is distinguished from other mixtures of the same constituents in different proportions by having a single temperature at which it melts and freezes, this temperature being lower than the freezing-point of any of the constituents or of any other mixture of them. Also fig.
1884[see A. adj. above]. 1884Asclepiad Oct. App. 3 Eutexia..applies to compound bodies in chemistry ‘whose chief characteristic is the lowness of their temperature of fusion.’ They are henceforth to be called eutectics. 1885Athenæum 28 Mar. 412/3 The temperature of liquefaction of a eutectic substance is lower than the temperature of either, or any, of the metallic constituents of an alloy. 1902Encycl. Brit. XXVIII. 569/2 The eutectic F[reezing] P[point] is of longer duration, but still at the same temperature. For an alloy of the composition of the eutectic itself there is no arrest until the eutectic temperature is reached. 1923Glazebrook Dict. Applied Physics V. ii. 454/2 This most fusible alloy of a system is termed the ‘eutectic’ and its microscopic appearance is often characterised by fine laminations. 1926Auden in Oxford Poetry 1 Love mutual has reached its first eutectic. 1948Glasstone Physical Chem. (ed. 2) x. 750 Only a pure substance, or a mixture having the composition of the eutectic, melts sharply at a definite temperature. 1954Proc. Prehistoric Soc. XX. 76 It is probably true that speculum is not very far removed from the eutectic of copper and tin. 1958Van Nostrand's Sci. Encycl. (ed. 3), Eutectic... By a similar usage in petrology, a eutectic is a discrete mixture of two or more minerals, in definite proportions, which have simultaneously crystallized from the mutual solution of their constituents.
2. A eutectic point.
1940Glasstone Physical Chem. x. 740 The temperature at which the first minute drops of liquid appear..is the eutectic for the given system. 1967A. H. Cottrell Introd. Metallurgy xiv. 210 Such a singular point of phase equilibrium is known as a eutectic or peritectic. |