Composite powders consist of particle agglomerates of at least 2 different materials. There are various ways to produce such agglomerates, but in the end you usually end up with spherical "raisin rolls" where one material is distributed within another. Basically there are only two variants of how the “raisins” are distributed within the “bun”:

In the first case we talk about bonding phase and bonding phase thickness and in the second case we talk about phase grain contiguity.