Mmmmm ...
As per 'nodreama' above ....
Also paper gaskets may be used to
reduce the possibility of 'galvanic corrosion' occurring where dissimilar metals may be faced together ie where an aluminium alloy pump might be bolted to a magnesium alloy g'box casing ..... using a paper gasket may also be a method to reduce water or other liquids getting in between mated joins and thereby promoting corrosion or the 'fretting' of the components.
