A composition comprising particles A and particles B, each of the particles A and B comprising a core, the core of the particles A being a soft magnetic iron based core wherein the iron content is 95% by weight or more, the remainder being any material or element other than silicon (Si), wherein the surface of each core of the particles A and B is coated with a phosphorus-containing insulating layer A1 respectively B1, and wherein the particles A having the insulating coating layer A1 are provided with a further layer A2 on top of the layer A1, the layer A2 being formed from a compound of formula (I), or a reaction product therof : M(OR 1 ) x (R 2 ) y Formula (I) wherein M is selected from Si, Ti, Al, or Zr; preferably Si or Ti, and more preferably Si, R 1 is a straight or branched alkyl group having 4 or less, preferably 3 or less carbon atoms, preferably an ethyl group or a methyl group; R 2 is an organic group optionally containing a funtional group, and x + y are integers denoting the number of groups OR 1 and R 2 , respectively, and are if M is Si, Zr or Ti, x is chosen from 1, 2 and 3, and y is chosen from 1, 2 and 3, with the proviso that (x+y)=4; and if M is Al, then x is chosen from 1 and 2, and y is chosen from 1 and 2, with the proviso that (x+y)=3; and wherein the particles A further comprise particles C that are adhered to the layer A2 or which are incorporated into the layer A2, the particles C being particles of a material having Mohs hardness of 3.5 or less; characterized in that: - the core of the particles B is formed from an Fe-Si alloy wherein the amount of Si is from 4.0 to 7.0 % by weight, the remainder being formed by Fe and unavoidable impurities in an amount of 0.2% by weight or less, - the core particles of the particles A have an apparent density of 3.2-3.7 g/ml as classified by dry sieving, - and wherein the weight ratio of particles A and B (A:B) is from 80:20 to 60:40. wherein the surface of each core of the particles A and B is coated with a phosphorus-containing insulating layer A1 respectively B1, and wherein the particles A having the insulating coating layer A1 are provided with a further layer A2 on top of the layer A1, the layer A2 being formed from a compound of formula (I), or a reaction product therof : M(OR 1 ) x (R 2 ) y Formula (I) wherein M is selected from Si, Ti, Al, or Zr; preferably Si or Ti, and more preferably Si, R 1 is a straight or branched alkyl group having 4 or less, preferably 3 or less carbon atoms, preferably an ethyl group or a methyl group; R 2 is an organic group optionally containing a funtional group, and x + y are integers denoting the number of groups OR 1 and R 2 , respectively, and are if M is Si, Zr or Ti, x is chosen from 1, 2 and 3, and y is chosen from 1, 2 and 3, with the proviso that (x+y)=4; and if M is Al, then x is chosen from 1 and 2, and y is chosen from 1 and 2, with the proviso that (x+y)=3; and wherein the particles A further comprise particles C that are adhered to the layer A2 or which are incorporated into the layer A2, the particles C being particles of a material having Mohs hardness of 3.5 or less; characterized in that: - the core of the particles B is formed from an Fe-Si alloy wherein the amount of Si is from 4.0 to 7.0 % by weight, the remainder being formed by Fe and unavoidable impurities in an amount of 0.2% by weight or less, - the core particles of the particles A have an apparent density of 3.2-3.7 g/ml as classified by dry sieving, - and wherein the weight ratio of particles A and B (A:B) is from 80:20 to 60:40. - the core of the particles B is formed from an Fe-Si alloy wherein the amount of Si is from 4.0 to 7.0 % by weight, the remainder being formed by Fe and unavoidable impurities in an amount of 0.2% by weight or less, - the core particles of the particles A have an apparent density of 3.2-3.7 g/ml as classified by dry sieving, - and wherein the weight ratio of particles A and B (A:B) is from 80:20 to 60:40. <EOS>