New compounds and phase equilibria in the Zr–Ti–P system

Highlights: ► The interaction between components in the Zr–Ti–P system was analyzed; isothermal section diagram at 1070 K was constructed. ► The crystal structure of ZrTiP0.68 is Zn3Cu-type, with homogenous in the range Zr1.0−1.5Ti1.0−0.5P0.68. ► From single-crystal methods the structure of Zr0.93Ti0.07P0.93 was determined to belong to the WC-type structure. - Abstract: The interaction between components in the Zr–Ti–P system in the range of up to 67 at.% P was analyzed and the isothermal section diagram at 1070 K was constructed from X-ray structural and EDS analysis. Solid substitutional solutions based on the binary phosphides M3P with the Ti3P-type structure (Ti3.0−2.3Zr0−0.7P and Zr3.0−2.5Ti0−0.5P) were found. The phosphide (Ti,Zr)2P with the Co2Si-type structure is homogeneous at the Zr1.2−0.6Ti0.8−1.4P composition. From powder X-ray diffraction methods, the crystal structure of ZrTiP0.68 was shown to be of the Zn3Cu-type (space group P-6, a = 0.47600(1), c = 0.30038(1) nm, RI = 0.0444); HfTiP0.68 is isostructural. These compounds are homogenous in the range Zr1.0−1.5Ti1.0−0.5P0.68 and Hf0.9−1.2Ti1.1−0.8P0.68. From single-crystal methods, the structure of Zr0.93Ti0.07P0.93 was determined to belong to the WC-type structure (space group P-6m2, a = 0.3004(2), c = 0.3117(3) nm, RF = 0.0228).