Last one:

"Each commodity has its idiosyncrasies. Thus, most nickel is sold to stainless steel makers, who fabricate five main groups of product: martensitic, ferritic, austenitic, duplex and precipitation hardening steels. Certain grades of stainless steel, such as martensitic and ferritic, do not use nickel; the most corrosion resistant products, such as 316 or 18/8 use 18% chromium, 8% nickel and 2% molybdenum.

Nickel prices have been smashed up where mills have increasingly marketed stainless steel grades without nickel (effectively, substitution). There have also been supply side issues: when nickel prices exceed a certain level, large deposits of low grade nickel ores in Indonesia become economic."

http://www.mineweb.net/mineweb/view/...

I refer to it as a nasty circle. Substitutes are used when Ni. prices are high and substitutes are cheap to make, process, or simply buy. When Ni drops and becomes affordable again it then becomes the product of choice when really there are no substitutions for the product you may ultimately want or the quality you demand. Up and down things will go and move until all supply demand balances occur.