What exactly is Indium's ability to stabilize non-ferrous metals? I was reading the History section about Indium on Wikipedia when I came across the following sentence: 


  In 1924, indium was found to have a valued ability to stabilize non-ferrous metals, which was the first significant use for the element.


I'm wondering if the ability is to improve crystallinity, structural stability of alloys, resistance to corrosion, or something else.
All I did was click on the reference from the History wikipedia link above for the sentence you were talking about. The sentence comes from a paragraph of a manuscript which is found here: http://pubs.acs.org/doi/abs/10.1021/ed011p270

Note the bolded part, that was what is meant. 

" Its[Indium's] identification as well as its name came from the beautiful indigo-blue line which it so prominently displays in its spectrum. Its commercial development came as the result of the knowledge that it should be a valuable stabilizer of non-ferrous metals much as chromium is a stabilizer of the ferrous metals. "



Above is quote from: 

French, Sidney J. (1934). "A story of indium". Journal of Chemical Education 11 (5): 270. Bibcode:1934JChEd..11..270F. doi:10.1021/ed011p270.