Lead print III

Lead print III

Material Name: Steel
Recipe No.: 12066
Primary Chemical Element in Material: Fe
Sample Type: Bulk
Uses: Lead segregation
Etchant Name: Lead print III
Type (Macro/Micro): Macro
Etching Method: Chemical
Etchant (Electrolyte) Composition: Three solutions are required:
Printing solution: 25 g tartaric acid, 100 g ammonium nitrate, 250 ml water. Saturation of resulting solution with H2S.
Developing solution: Water saturated with H2S. Clearing solution: 10% aqueous ammonium persulfate or tartaric acid solution saturated with H2S.
Procedure (Condition): The ground billet disc is first etched with an aqueous solution of 50% HNO3, washed and dried. Gelatin paper is soaked in the printing solution and then placed on the surface of the disc. The back of the paper is kept moist with the printing solution. After 2 to 3 min, the paper is removed and placed in the developing solution. Intense black staining due to dissolved iron is observed. Some of this black stain is removed in the developing solution and the balance in the clearing solution. After clearing, the print is washed in clean developing solution to counter fading. The print is then washed in water, rinsed with alcohol, and dried.
Note: Northcott and McLean used a lead print method developed by Ledloy. Ltd.
Reference: George F. Vander Voort, Metallography, Principles and Practice, ASM International, 1999, pp. 52-56.