Association classes appear in diagrams as three related elements:

• Association class itself (represented by a class icon)
• N-ary association class link (represented by a diamond)
• Association connector (represented by a link between both)

Association classes can connect to as many association end classes (participants) as required. 

The Object Inspector of an association class, association link, and connector contain an additional Association tab. This tab contains the only label property, its value being synchronized with the name of the association class. For the association classes and association end links, the Custom node of the Object Inspector displays additional properties that corresponds to the role of this part of n-ary association (associationClass and associationEnd respectively).  

You can delete each of the association end links or participant classes without destroying the entire n-ary association. However, deleting the association class results in deleting all the components of the n-ary association.