| 释义 |
peritectic, a. and n.|pɛrɪˈtɛktɪk|
[ad. G. peritektisch (W. Guertler Metallographie (1912) I. vi. 278), f. Gr. περί around, about + τηκτικ-ός able to dissolve (f. τήκειν to melt): cf. eutectic a. and n.]
A. adj. Of, pertaining to, or designating a reaction that occurs between the solid phase and the liquid phase during the cooling of a mixture, with the formation of a new solid phase; peritectic point, the state at which all three phases coexist in equilibrium, the composition being such that a fall in temperature results in the disappearance of the two phases that exist above that temperature; also, the point representing this state in a constitutional diagram.
1924Jeffries & Archer Sci. of Metals ix. 323 There are different solid phases in equilibrium with the melt above and below the peritectic temperature. During the peritectic reaction there are three phases (two solid and one liquid) in equilibrium, so that the temperature must remain constant until at least one of the phases disappears. 1936Nature 18 Apr. 657/2 Preliminary results from an X-ray study of the peritectic reaction α + liquid → β in the Cu-Zn system prove that the orientations assumed by the β-phase are definitely related to the orientation of the α-phase. 1965Phillips & Williams Inorg. Chem. I. viii. 302 The cases in which there is one or more eutectic or peritectic points..reflect rather an unfavourable interaction between A and B which may well be caused by size differences in the atom. 1967A. H. Cottrell Introd. Metall. xv. 230 The composition at r..is the peritectic composition and the isothermal line pq marks the peritectic temperature. Just above this temperature there is no β-phase in any alloy; just below, all alloys from p to q contain some β. The silver-platinum system has a simple peritectic diagram. 1968B. Bayly Introd. Petrol. 330 If we knew that all Hawaiian rocks were generated from one homogeneous initial magma pool, we would conclude that there was necessarily a peritectic relation. 1973J. G. Tweeddale Materials Technol. I. vi. 163 The reverse type of change to a eutectic reaction called a peritectic reaction can occur in many materials—this cannot be used to induce supersaturation but may be a means for producing a stable solid solution structure.
B. n. A peritectic point or temperature.
1929Jrnl. Iron & Steel Inst. CXIX. 337 In carbon steels, between the temperature of freezing and that of the peritectic, iron containing a maximum of 0·07 per cent. of carbon is the only solid to separate. 1975Nature 20 Nov. 220/2 Any model of the igneous processes which produced the eucrites must account for this preferential generation of liquids at peritectic A (Fig. 1).
Hence periˈtectically adv., by a peritectic reaction.
1935G. E. Doan Princ. Physical Metall. iv. 158 At 1500° the melt and δ crystals react peritectically to form γ-iron solid-solution crystals. 1967A. H. Cottrell Introd. Metall. xv. 233 Fig. 15.12 shows an example in which the γ primary solution also forms peritectically. |