Oxygen in copper

When the oxygen content is higher than 400 Mg/g, precipitates of Cu O become harmful. They decrease the formability of the metal, and therefore drawing to fine wires becomes difficult. 

Copper containing oxygen may not be used in the presence of hydrogen which would reduce the oxygen and create porosity and blisters (hydrogen sickness). For such applications the copper melts are deoxidized with phosphorus. 

The influence of oxygen on the strength of copper is believed to be restricted to small hardening effects only. 

Unalloyed copper of commercial quality can be subdivided in three types 2.1.1. Electrolytical tough pitch copper (ETP) 

The oxygen content of this type of copper normally ranges from 200 yq/q to 500 yq/q. Although the oxygen concentration influences the mechanical qualities to a certain extent, it also suppresses the effect of impurities less noble than copper by converting them into oxides. The result is on 

---

Saha, D., Heffron, J. F., Murphy, K. J., and Becker, J. S., The application of tonnage oxygen in copper smelting, paper presented at Fall Meeting of the Arizona Section of AIME, December 7, 1987. 

Harbison, E. J. and Davidson, J. A., Oxygen in copper smelting, paper presented by Air Products Chemicals, Inc., at the Fall Meeting of the Arizona section of the American Institute of Mining, Metallurgical and Petroleum Engineers, Dec. 1972. 

Figure 9.10 X-ray photoelectron spectroscopy of elemental copper and oxygen in copper coating containing microcapsules.

It should be mentioned that galvanostatic diffusion measurements may also be carried out as has been done by Pastorek and Rapp [39] and by Osterwald and Schwartzlose [40] for oxygen in copper. Recently, Rickert and coworkers have determined the chemical or effective diffusion coefficient in non-stoichiometric compounds. This involves, for example, replacing the gold sink in cell XII by a non-stoichiometric compound which conducts electronically. The cell used by Chu, Rickert and Weppner [32,33]... 

The solubility of oxygen in copper is extremely high and it is markedly dependent on pressure and temperature. The following equations for this relationship are quoted by Fromm and Gebhardt (48) ... 

Table VII-3 Variants in the determination of oxygen in copper by inert gas fusion...

For the determination of oxygen in copper, Dahlmann and Fassel (87) use an auxiliary bath of 80 % platinum and 20 % tin in a 3 to 1 bath to sample ratio the reaction temperature is 1725 to 1775 C. The final concentration of copper in the bath should not exceed 10 %. However this procedure must be regarded as completely obsolete it has, in any case, only been used for the determination of fairly high oxygen concentrations. 

Several variants of vacuum fusion are also available for the determination of oxygen in copper. The parameters used in european joint research work (61)(70) are given in Table VII-4. 

It is known (62) that, in the determination of oxygen in copper by both inert gas and vacuum fusion, carbon monoxide is not the only oxygen containing reaction product formed carbon dioxide is also formed to some extent. 

A study of a different character concerning errors in the vacuum process has been published by Romanova et al. (86). These authors quote the limits of detection for oxygen in copper as about 2 //g/g (1300°C). The reason given for this is the scatter of the blank value due to the volatilization of the metal. 

Table VII-5 Analyses carried out to test the determination of oxygen in copper alloys...

Hydrogen reduction is probably only suitable for the determination of oxygen in copper alloys in special cases. It is limited to alloys containing no alloying components or impurities which form oxides that cannot be reduced with hydrogen. Initial work in this field has been carried out by Hofmann and Schneider (93), who were able to analyse lead bronzes and tin bronzes successfully. 

For the determination of oxygen in copper, triton, helium-3 and helium-4... 

Table VII-18 Results for oxygen in copper (/ g/g) obtained for BCR RM No. 54 by the methods given in Table VII-17 (246)...

F is separated by steam distillation of fluorosilicic acid followed by precipitation of lead chlorofluoride. For helium-3 activation (effective incident energy = 15-18 MeV) no extraction of polonium is required. The results obtained for industrial lead were (0.99 + 0.21) /ig/g (n = 8) for He activation and (0.79 + 0.36) ng/g (n = 8) for He activation. The standard deviations of resp. 21 and 45 % compared to the 10 % obtained when roughly the same analytical technique was applied to the determination of oxygen in copper (213)(245), indicate a less homogeneous distribution of the oxygen in lead. The variance for the He results is significantly... 

Analysis methods for oxygen in copper have been thoroughly studied within BCR. Four reference materials have been certified with oxygen contents of... 

---