Method of Forming a Particulate Magnetic Layer
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-04
A particulate magnetic layer is formed containing at least a binder, magnetic particles and a fixed quantity of phosphoric acid controlling the porosity of the layer. For forming the magnetic layer, a mixture containing at least a hardenable binder, such as an epoxide phenolic resin, a solvent, magnetic particles, and, based on the composition of the binder used, up to 0.7 percent by weight phosphoric acid (the optimum rate ranging from 0.06 to 0.4 percent), is applied to a substrate, such as a disk, and subsequently dried and cured. Finally, the layer surface is polished. The porosity of the layer is directly proportional to the acid concentration. As the porosity of the layer and its lubricant retention are correlated, the latter can be generated as a function of the quantity of acid added.