Stability of ultradispersed diamond and carbon nanotube suspensions in water and aqueous electrolytes for the fabrication of composite electrochemical coatings

We have studied the stability of ultradispersed diamond and carbon nanotube suspensions in water and aqueous solutions of various salt electrolytes. The results demonstrate that, in the course of coagulation and sedimentation, the particles in suspension become separated into size fractions and form agglomerates several orders of magnitude greater in size than the parent particles, and that the dependence of the suspension concentration on storage time has a linear portion. The sedimentation process in the electrolyte solution-based suspensions proceeds until an almost zero concentration of fine particles is reached. We have determined the settling time of the particles in the suspensions, which determines their stability, and evaluated the porosity of particle conglomerates. The feasibility of suspension redispersion after sedimentation has been examined. Resonication of the suspensions has been shown to restore the particle concentration and size.