Air-fired Ni for ohmic electrode of PTCR

Abstract

The constitution and furing-technology of Ni paste were experimentally investigated. The experimental results show that the contact resistance could be lowered by adding glass powder and Boron powder, respectively used as adhesive and antioxidant when the content of Ni powder is higher than 65 wt%. By firing at 810 °C, Ni paste obtained could form a good ohmic contact to PTC ceramics, as shown by SEM iamges. In addition, we compared the electrical properties of PTCR ceramics measured with various electrodes and found that fired-Ni contact is superior to contacts made by fired-Al and sputtered-Ni.