Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

For the investigation of the products of reaction of yttrium oxide with carbon mixed in various proportions, the chemical and X-ray diffraction methods of analysis were combined with the gas chromatographic analysis of the mixture of hydrocarbons and hydrogen formed on the sample decomposition with water. The carboreduction of Y₂O₃ was examined at relatively low temperatures, convenient for obtaining the reaction intermediates in higher yields. At 1 600 °C and pressures of 10^-3 Pa the reduction of a mixture of Y₂O₃ with carbon in a stoichiometric ratio of 1 : 7 yields YC₂ in equilibrium with 20% of Y₂OC phase. At lower carbon contents (down to the Y₂O₃ : C ratio of 1 : 2) tha fraction of the Y₂OC phase increases up to approximately 30%. In addition to Y₂O₃, the reaction mixture contains also Y₂C, Y₂OC and a phase giving propyne on hydrolysis. The presence of traces of C₃ hydrocarbons and small amounts of methane in the product of hydrolysis of the carbide sample prepared by the carbothermal reduction of the oxide can be explained in terms of the occurrence of the Y₁₅C₁₉ phase, probably substituted in part by oxygen, and of the Y₂OC phase. The results are compared with those obtained previously for the Sc₂O₃ + C system.