Please tell in more detail about the environment where your biodegradation experiments are conducted. If in ground/soil - your result would not be a surprise for me.

This has happened due to water evaporation from SBF, which resulted in solution supersaturation by NaCl, which is the major inorganic constituent of SBF. 

I have cut my 3D porous scaffold of particular shape (diameter-6mm, length-6 mim) and immerse it upto 14 days in SBF solution with continuously replacing this solution every 2 days.

Attached image is NACL crystal(confirmed usin EDX) precipitated on my scaffold pore wall,which i got after 14 days of study.

@Dorozkin, Sir, What can be done to avoid this phenomenon?? 

Performing experiments in a closed vessel could be helpful.

Thank you sir for your valuable suggestion.