Zirconium pickling

Zirconium is readily attacked by acidic solutions containing fluorides. As Httle as 3 ppm flouride ion in 50% boiling sulfuric acid corrodes zirconium at 1.25 mm/yr. Solutions of ammonium hydrogen fluoride or potassium hydrogen fluoride have been used for pickling and electropolishing zirconium. Commercial pickling is conducted with nitric—hydrofluoric acid mixtures (see Metal surface treatments). 

Uranium-Zirconium Alloy Explosions. An inter-metallic compd, UZr3 (mw 511.69), exists in which a-U and a-Zr have limited solid solubility. According to the ref, this solid soln is designated as the epsilon phase, and has approx lower and upper limits of 41 to 53 wt % Zr. Hence, lesser or greater fractions of finely divided epsilon phase exist in a matrix of a-U. On treatment with nitric acid for the purposes of etching, dissolution or pickling of the U-Zr alloy, the a-U... 

Detailed procedures for pickling are given in ASTM G 2, Test Method for Corrosion Testing of Products of Zirconium, Hafnium, and Their Alloys in Water at 680 F or in Steam at 750 F. 

Effects of Heat Treatment on the Corrosion of Zirconium (Sand-Blasted and Pickled)... 

Zirconium heat exchanger A new direction for pickling operations. Iron Steel Engineering, 52 55. 

Zirconium coils make inroads into pickling tanks. Iron Age, 216 39. 

T.L. Yau. 1988. Zirconium in a sulfuric acid pickling application. Corrosion 88, Paper No. 319, Houston, TX NACE Intemational. 

The chemical conversion of the alurniniiim surface happens in the presence of titanium and fluoride ions in a sulfuric solution. Some treatments use zirconium ions together with titanium ions. The sulfuric add and the fluoride ions pickle the surface and the metal salts are responsible for the passivation of the surface. The titanium and zirconium ions react with the aluminium oxide on the surface and form a mixed oxide layer. Like the deaning process, it can be applied by an immersion or by a spray process. O Figure 37.29 shows the simplified chemical formula for the mixed oxide layer. 

M. L. PiCKLE.siMEK, Anodizing as a Metallographic Technique for Zirconium Base Alloys, L SAEC Report ORNL-2296, Oak Ridge National Laboratory, 1957. 

Lipotin NE Oxy bis zirconium IV tris (bis tridecyl) phosphate wetting agent, metal pickling... 

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