Chapter 23 Alloys Chemistry, The Central Science, 11th edition Theodore L. Brown; H. Eugene LeMay, Jr.; and Bruce E. Bursten Chapter 23 Alloys © 2009, Prentice-Hall, Inc.

Physical Properties of Metals Conduct heat and electricity. Are malleable (can be pressed or hammered into sheets). Are ductile (can be drawn into wire). Are packed so atoms can slip past each other. So metals aren’t as brittle as other solids. © 2009, Prentice-Hall, Inc.

Electron-Sea Model Metals can be thought of as cations suspended in “sea” of valence electrons. Attractions hold electrons near cations, but not so tightly as to impede their flow. © 2009, Prentice-Hall, Inc.

Electron-Sea Model This explains many of the properties of metals, like Conductivity of heat and electricity; Deformation. © 2009, Prentice-Hall, Inc.

Alloys Alloys are mixtures of elements that have properties characteristic of metals. Many of the ordinary uses of metals involve alloys. © 2009, Prentice-Hall, Inc.

Substitutional Alloys Components of alloys are dispersed uniformly— In substitutional alloys, solute particles take the place of solvent metal atoms. The particles in these alloys are quite close in size, of comparable radius. © 2009, Prentice-Hall, Inc.

Substitutional Alloys Density of substitutional alloys typically lies between those of the component metals Alloy remains malleable and ductile. e.g. brass – Some Cu substitutes for Zn © 2009, Prentice-Hall, Inc.

Interstitial Alloys In interstitial alloys, solute particles find their way into the holes between solvent metal atoms. In this type of alloy the solute particles are smaller than the solvent particles. © 2009, Prentice-Hall, Inc.

Interstitial Alloys The interstitial atoms make the lattice more rigid, decreasing malleability and ductility. e.g. steel, where carbon is the interstitial atom © 2009, Prentice-Hall, Inc.