Etchants For Zinc And Zinc Alloys

Metallography and Microstructures of Zinc and Its Alloys

Page 1 of 1 Metallography and Microstructures of Zinc and Its Alloys, Metallography and Microstructures, Vol 9, ASM Handbook, ASM International, 2004, p. 933–941

Metallography and Microstructures of Zinc and Its Alloys

Introduction ZINC AND ZINC ALLOY specimen preparation techniques are discussed in this article. Typical structures observed in these specimens are also covered, as is the effect of alloying elements and processes. The etchants used for many of the micrographs included in this article are listed in Table 1. Table 1

Etchants for zinc and zinc alloys

Etchant

Composition

1(a)

200 g CrO3, 15 g Na2SO4, 1000 mL H2O

2(b)

50 g CrO3, 4 g Na2SO4, 1000 mL H2O

3

200 g CrO3 and 1000 mL H2O

4

5 mL HNO3 and 100 mL H2O

5

5 g FeCl3, 10 mL HCl, 240 mL alcohol

6(c)

375 mL H3PO4, and 625 mL ethyl alcohol

7

1 drop HNO3 and 10 mL amyl alcohol (a) For rolled zinc-copper alloys, the Na2SO4 content can be reduced to 7.5 g. If desired, a smoothly etched surface can be obtained by increasing the Na2SO4 to 30 g. (b) This etchant can be prepared by mixing one part (by volume) etchant 1 and three parts H2O. (c) Electrolytic; current density, 0.1 to 0.2 A/cm2 (0.6 to 1.3 A/in.2) for 3 to 8 s

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