Fractal aggregates of particles

Recent work to understand aggregation of particles using the concept of fractal is reviewed. We introduce all the tools issued from the theory of fractals, and which are useful for our study. Then we define and detail the two main models: the particle-cluster process where individual particles come to stick on large clusters, and the cluster-cluster process where clusters diffuse and stick when they collide. The important parameters of these models are varied and their influence on the resulting geometrical disordered structure is discussed. All along the paper, the connections with existing experiments are given.