Furnace thermal cycle testing of TBC specimens with René N5 substrates and identical APS YSZ top coats revealed significant differences in TBC lifetimes depending on the MCrAlX bond coat composition and deposition method. Figure1 compares the average lifetimes of the TBCs in this study. The TBCs with VPS NiCrAl-1Y bond coats were the most durable and exhibited a 20% improvement in lifetime as compared to TBCs with APS NiCrAl-1Y bond coats. The lifetimes of TBCs with VPS NiCoCrAlYHfSi bond coats were ∼50% lower than TBC lifetimes on VPS NiCrAl-1Y and ∼37% lower than those on APS NiCrAl-1Y. The range of values in Fig. 1 indicates relatively good consistency in coating lifetimes (within the constraints of the specimen amounts).
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