Shrinkage versus temperature of KNN, (K,Na)-germanate and KNN modified with 0.5, 1, 2 and 4 wt % of (K,Na)-germanate (KNN + 0,5G, KNN + 1G, KNN + 2G, KNN + 4G) powder compacts. Photos of the wetting experiments in a heating-stage microscope at room temperature and at 800 °C are given as insets. (Reprinted with permission from [115]. Copyright 2008 The American Ceramic Society.) Right: microstructure of the KNN + 4G sintered at 1000 °C for 8 h (SEM-BEI). The yellow and red arrows mark the KNN grain and the intergranular germanate phase, respectively. Note the good wetting of the matrix grains and the slightly rounded grain boundaries (Reprinted from [116] with the permission of the author).