Ceramic material, varistor, and method for producing the ceramic material and the varistor

A ceramic material comprising:

• ZnO as main constituent;
• Y as a first additive;
• second additives comprising Cr and optionally at least one additional compound containing a metal element, wherein the metal element is selected from the group consisting of Bi, Co, Mn, Ni and Sb;
• Si4+ as a first dopant;
• and
• second dopants comprising Ba2+ and optionally at least one additional compound containing a metal cation from Al3+ or B3+,
• wherein a corresponds to a molar proportion of Bi calculated as Bi2O3, b corresponds to a molar proportion of Y calculated as Y2O3, c corresponds to a molar proportion of Al calculated as Al2O3, d corresponds to a molar proportion of Ba calculated as BaO, e corresponds to a molar proportion of B calculated as B2O3, f corresponds to a molar proportion of Si calculated as SiO2, g corresponds to a molar proportion of Ni calculated as NiO, h corresponds to a molar proportion of Co calculated as Co3O4, i corresponds to a molar proportion of Cr calculated as Cr2O3, j corresponds to a molar proportion of Sb calculated as Sb2O3, and k corresponds to a molar proportion of Mn calculated as Mn3O4,
• wherein the molar proportions mentioned above are based on 100 mol% of ZnO,
• wherein:
• 0.5 mol %≤b≤3.0 mol %,
• 0 mol %<d<0.1 mol %, and
• 0 mol %<f<0.1 mol %,
• 0.0 mol %<i≤0.3 mol %,
• wherein:
• 0.1 mol %≤a≤0.99 mol % when Bi is present,
• 0 mol %<c<0.1 mol % when Al3+ is present,
• 0 mol %<e<0.1 mol % when B3+ is present,
• 0.7 mol %≤g≤1.5 mol % when Ni is present,
• 0.3 mol %≤h≤0.8 mol % when Co is present,
• 1.1 mol %≤j≤1.9 mol % when Sb is present, and
• 0.2 mol %≤k≤0.4 mol % when Mn is present.