Effect of Transition Metals Oxide Additives on the Properties of Mixed-Alkali Glass for Electric Insulating Coatings on Aluminum

In order to reduce the cost of the thick-film technology of microcircuits and heating elements, as well as toexpand its areas of use, it became necessary to expand the range of materials that, along with ceramics and steel,can also be used as substrates for these products. One of these advanced materials is aluminum. Enamels foraluminum should be subjected to roasting at relatively low temperatures, and therefore contain an increasedamount of alkali metal oxides in their composition, which causes low values of chemical resistance and volumeof electrical resistivity. Electrically insulated coatings on metals are subjected to repeated heating and coolingwhile their produce and use, which promotes the creation of temperature stresses in the coating and leads to theirchipping. Therefore, in order to improve the water resistance and adhesion strength of electrical insulationcoatings on aluminum, CuO, ZrO2 and Bi2O3additives were examined. There was found an increase in waterresistance with a simultaneous increase in the adhesion strength of the enamel coating with an aluminumsubstrate with the addition of not more than 3 pts. wt. of copper oxide (II), up to 1 pts. wt. of zirconium oxide(IV), and up to 4 pts. wt. of bismuth oxide (III) w.r.t. 100 pts. wt. of glass.