Classification of coating particle size

Techniques for precisely controlling the size of particles in a coating solution delivered to a coating apparatus involve continuous classification of coating particle size using a tangential flow filter assembly. The techniques may be particularly useful in the preparation of coating dispersions for manufacture of magnetic recording media. A classification technique makes use of a tangential flow filter assembly that permits delivery of coating particles below a maximum size threshold to a coating path. The filter assembly may be disposed in a circulation path that includes one or more processing devices to reduce the size of coating particles carried by a coating solution. The filter assembly enables coating particles above the maximum size threshold to be recirculated through the circulation path and subjected to repeated processing to reduce particle size to a desired size range.