Hello,
Can we "define" a maximum hours for appearing rust in "salt spray"test for each coating?
e.g. "maximum duration for nickel plated steel is 100 hours , in salt spray" ?
Not easy to identify the maximum accelerated corrosion test a plating able to withstand without undergo the test. However, you may establish your own 'standard' of this longest time.
Say, for NiNiCr plating you produce, can withstand max 100hrs SST, this could be the reference for you, but not other platers or NiNiCr process.
Standards (ASTM, ISO, JIS) that available can give you a brief idea how long a particular plating condition SHOULD withstand a period of SST or CASS Test. However, that is not a 'maximum', many ppl can do much more better than wat suggested by the Standards. check it out. Good luck.