Abstract: Molybdenum composites containing silicon and boron for environmental resistance are combined so as to minimize the silicon solid solution in the molybdenum phase. The composites include ratios of molybdenum, silicon, and boron to form three phase mixtures of molybdenum, A15 (Mo3Si), and T2 (Mo5SiB2) or molybdenum, SiO2, and T2 (Mo5SiB2). Beneficial additives, including manganese and strontium aluminosilicate, are included to improve the composite's properties. Manufacturing processes to produce these composites as either powders or solid parts are included.