Progresivní galvanické povlaky pro magnetické materiály na bázi Nd-Fe-B

Abstract

Permanent magnets of the NdFeB type with the best magnetic properties generally have low corrosion resistance and are usually protected by coatings. The aim of the work is to compare and evaluate the corrosion properties of selected coatings and layers on NdFeB magnets. In the theoretical part is presented overview and properties of magnetic materials, especially NdFeB type and their protective coatings made of nickel, zinc and other materials. At the same time, the corrosion properties and the main corrosion tests of the mentioned magnets are described. Within the experimental part, the structures and protective properties of selected coatings (with gold, resin, rubber and passivation) are investigated and evaluated on NdFeB magnets. After the salt mist test, the surfaces were monitored and changes in sample weight were determined. In addition, metallographic assessments were carried out with the thickness measurement of the layers, and after demagnetization, the microanalysis of the magnet composition (Nd(Pr,Dy,Ga)-Fe(Co,Cu)-B + O) and layers (Ni, Cu, Au, Fe).