Green shrinkage seen in: (A) Phosphate bonded investment., (B) Ethyl silicate bonded investment., (C) Gypsum bonded investment., (D) All of the above.
Answer is B. • Green shrinkage:
-Occurs during heating of silicate investments.
-Occurs due to loss of alcohol & water during phase(168ºC) to form a concentrated, hard gel.
This also leads to volumetric contraction of the mould