The production of CrSiW systems is restricted due to the significantly diverging melting points as well as the high oxygen affinity of every individual element. Powder metallurgical productions offer considerable advantages such as an implementation of the process under inert atmosphere to avoid oxidations. This paper will analyze the impacts of two different W particle size modifications (3 and 0.8 µm) on the diffusion and porosity of hot pressed CrSiW by varying the temperature, pressure, and sintering time. Two mixtures of 60Cr10Si30W (wt.%) are prepared by means of high energy milling. Concerning the sintering mechanisms, the corresponding interface reactions, which take place at the W particle boundaries, are of particular interest. It is the aim of this paper to investigate the diffusion between Cr and W, since these elements tend to form two solid solutions due to a miscibility gap in the binary phase diagram of Cr-W for 20 ≤ W ≤ 98 (wt.%).