Fabrication and Structural Properties of LaNb1‐xAsxO4 Ceramics

Lanthanum niobate substituted with arsenic was synthesized by three methods: solid state reaction from binary oxides and two different methods combining co‐precipitation and solid‐state reaction. In the first of the combined methods LaNb1‐xAsxO4 was synthesized from LaAsO4, obtained from co‐precipitation method, and lanthanum and niobium oxides. In the second LaNbO4 was first synthesized from binary oxides and then mixed with LaAsO4 and fired in the second step to obtain the final material. Single phase materials could not be synthesized via solid‐state synthesis, whilst it was possible with both of the combined methods. Structural parameters of the materials obtained with both methods were similar what shows that they do not relate to the synthesis method. Ceramics obtained with both combined methods were dense, however, the density of the ceramics formed from LaAsO4 and LaNbO4 was higher. The LaNb1‐xAsxO4 ceramics were synthesized by the means of combined co‐precipitation and solid‐state reaction methods. The solid state synthesis method (method no. 1) was unable to produce single phase materials with high As‐content. For higher amount of As, the co‐precipitation method is needed (methods 2, 3). Obtained materials exhibit similar structural parameters, what suggest that they do not relate to the method of synthesis, however the most dense pellets were obtained by the third one.