. Metallographic etching reagents: I, for copper. ■^W^^S^SB^^^^ <,. c/ Fig. 3.—Structure of hot-rolled copper revealed by progressive etching with dilutenitric acid (i to i). Xjoo Etching period: a, 15 seconds; b, 45 seconds; c, i minute, 45 seconds; d, 2 minutes, 45 seconds lS^S Metallographic Etching Reagents for Copper 647 of the individual crystals. The variation in level of the surface produced by the difference in the rate of solution of adjacent grains in ammonium persulphate is well shown in Fig. 2, c and d. With nitric acid, however, the action occurs so readily that the etching ca
. Metallographic etching reagents: I, for copper. ■^W^^S^SB^^^^ <,. c/ Fig. 3.—Structure of hot-rolled copper revealed by progressive etching with dilutenitric acid (i to i). Xjoo Etching period: a, 15 seconds; b, 45 seconds; c, i minute, 45 seconds; d, 2 minutes, 45 seconds lS^S Metallographic Etching Reagents for Copper 647 of the individual crystals. The variation in level of the surface produced by the difference in the rate of solution of adjacent grains in ammonium persulphate is well shown in Fig. 2, c and d. With nitric acid, however, the action occurs so readily that the etching can not be controlled easily, and a very rough surface results in which most of the evidence revealed by light etching is obliterated. 2. TYPES OF ETCHING For convenience in discussion, the difference in the appearanceof the siu-face of specimens after different methods of etching willwill be referred to as different types of etching, although, as shownbelow, the same etching reagent by proper manipulation may beused for producing more than one type of etched surfac
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Keywords: ., bookcentury1900, bookdecade1920, bookidmetallograph, bookyear1920
