9 3 g sr350 silicone resin ge silicones and about 45 3 g melox 5y ysz magnesium elektron inc about 8 yttria content about 0 5 micron average particle size these ingredients were placed in a nalgene bottle along with several u00bc inch diameter zirconia milling media and mixed on a paint shaker for about 20 minutes the cement paste was prepared by hand mixing about 20 g of the primer material with about 50 g of zy 8 fused ysz muscle shoals minerals inc about 25 microns average particle size about 270 mesh the substrates used were about 1 inch diameter disks of inconel 718 or rene n5 superalloys nicraly bondcoats or porous ysz tbc were plasma sprayed atop the superalloy base for most of the substrates in applying the cement paste to the substrates the substrates were first press fitted into about a 1 inch diameter hole in a teflon mold the top surface of each of the substrates remained beneath the teflon surface creating a gap of about 20 to 50 mil after the primer material was painted on the cement paste was troweled into this gap and a razor blade was used to create a uniformly thick cement layer atop each of the substrates alternatively the porous ysz tbc was grit blasted out from the center of each of the substrates leaving about a 1 mm or larger ring of tbc on the outer rim after the primer material was painted on the cement paste was troweled into these voided areas a razor blade was again wiped across each of the substrates to create a smooth cement layer of uniform thickness about a 2 hour drying of the as prepared specimens at about 25 degrees.