Letter | Published:

Surface Hardening of Metals by Spark Discharge


THE local hardening of sparked metal is described by Welsh1 as relying upon transfer from the electrode and/or contamination by the surrounding medium. When discussing these hardening and etching effects in ferrous metals it was mentioned2 that Rawdon3 obtained them even when electrolytic iron was self-sparked in vacuo or in argon. In these cases there would be no transfer, and the only contamination might be from any hydrogen in the electrolytic iron.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Welsh, N. C., Nature, 181, 1005 (1958).

  2. 2

    O'Neill, H., T. Inst. Welding, 9, No. 1, 3 (1946).

  3. 3

    Rawdon, H. S., Trans. Amer. Inst. Min. Met. Eng., 70, 37 (1924); and private discussion (1930).

  4. 4

    Sears, G. W., and Brenner, S. S., Metal Progress, 70, No. 5, 85 (1956).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.