Iron-based sintered alloy valve seat for internal combustion engine

Provided is an iron-based sintered alloy valve seat having excellent wear resistance. As an iron-based sintered alloy valve seat for an internal combustion engine, Si-Cr-Ni-Fe-based Mo-based intermetallic compound particles having a hardness of 700-1300 HV in terms of Vickers hardness and having a composition containing, in mass%, 1.5-3.5% of Si, 7.0-9.0% of Cr, 35.0-45.0% of Mo, 5.0-20.0% of Ni, and the balance of Fe and inevitable impurities are dispersed in a matrix phase as hard particles. The matrix part comprising the matrix phase, the hard particles, the solid lubricant particles and the like has a composition containing, in mass%, 0.5-2.0% of C, 0.2-2.0% of Si, 5% or less of Mn, 0.5-15% of Cr, 3-20% of Mo, 1-10% of Ni, 0-5% of V, 0-10% of W, 0-2% of S, and 0-5% of Cu, with the remainder comprising Fe and unavoidable impurities. As a result, it is possible to produce a valve seat which can prevent the occurrence of fragmentation and defects of hard particles even in a Co-free composition, can prevent a