Examination of Cr-Cr₃Si-NbC & Cr-(Cr,Mo)₃Si alloys for industrial applications

Refractory metal silicides have many desirable properties such as a high melting point, good corrosion resistance, low densities, and low wear rates. Previous investigators have produced Cr-Cr3Si-NbC alloys via a powder metallurgy route with Vickers hardness values ranging between 956 +/- 75 and 1338 +/- 111 and corrosion rates in aerated boiling 70% sulfuric acid of 50 +/-1.5 to 121 +/- 4.5 mpy. However, these alloys exhibit a fracture toughness of 3 to 6.6 MPa-m1/2. Other investigators demonstrated that the fracture toughness of the Cr-Cr3Si alloys was improved to 8 MPa-m1/2 with the addition of molybdenum. A series of Cr-Cr3Si-NbC and Cr-(CrMo)3Si-NbC alloys have been created in an attempt to improve wear resistance, corrosion resistance, hardness and fracture toughness. This new alloy series had NbC additions of 0, 5, 10 and 15-volume %. The alloys were created via a powder metallurgy route. Elemental Cr, Mo, Si and NbC were mechanically alloyed and then hot pressed to produce the alloys --Abstract, page iii