Interface vs Interphase

piq706

My colleagues do not agree on the use of interface for liquid-liquid separation processes despite of being the right word as it is defined in English dictionaries. They reckon that 'interphase' is a common word for these issues in many scientific papers.
I would like to know what is the most appropriate use or if there is a former example with other couple of words where official definition does not suit with the common use.
Thanks in advance.