A ceramic material having particular utility as a thermal insulating or thermal barrier coating on metallic substrates is provided. The ceramic material broadly comprises at least one lanthanide sesquioxide and the balance comprising a first oxide selected from the group consisting of zirconia, ceria, and hafnia. The lanthanide sesquioxide has a formula A2O3 where A is selected from the group consisting of La, Pr, Nd, Sm, Eu, Tb, In, Sc, Y, Dy, Ho, Er, Tm, Yb, Lu, and mixtures thereof. The present invention also broadly relates to an article having a metal substrate and a thermal barrier coating as discussed above.