Hydrothermal transformation of magnetically orientation-controlled seed layer into orientation-retained dense, continuous film in clear reaction solution

Randomly-oriented and b-axis oriented mordenite seed layers, which were pre-fabricated out of and in a strong 12T magnetic field, were hydrothermally treated in clear reaction solutions with molar ratios of 6Na₂O: Al₂O₃:30SiO₂:xH₂O (x = 1500, and 10000). Crystal growth of the seed particles only slightly occurred in the solution of x = 10000, but occurred in the solutions of x = 1500 and 3500, giving rise to densified films. However, the films treated with x = 1500 were composed of two layers with different morphologies; i.e., the precipitation of crystals from the solution was considered to induce the upper layer in the bilayered films. Homogenized films were formed in the solutions of x = 3500. The initial orientation of the seed layer was retained in the continuous films treated at x = 3500. Thus, dense, continuous mordenite films with random and b-axis orientations were successfully fabricated from random and b-axis oriented seed layers by hydrothermal treatment in the clear reaction solutions at the molar ratio of 6Na₂O:Al₂O₃:30SiO ₂:3500H₂O.