Mixed powder for powder metallurgy, method for producing same, and method for producing sintered compact of iron-based powder formulation

According to the present invention, a machining-improving powder is a crystalline layered alkali silicate heat-treated at a temperature range of 400-1100°C, and the mixture constituting the machining-improving powder is set such that an iron-based powder takes up 0.01-1.0 mass% in relation to the total amount of alloy powder and machining-improving powder. As a result, not only can sintering of a compact be performed in a sintering furnace without having any negative effects on the environment inside the furnace, but it is also possible to attain a mixed powder for powder metallurgy by which it is possible to obtain a sintered compact having both exceptional lathing properties and exceptional drilling properties.