未热解厚热障涂层的隔热能力和黏接强度

Thermal insulation capability and adhesion strength of unpyrolyzed thick thermal barrier coatings

对比研究使用未热解粉末制备的厚热障涂层(UPTTBC)和传统TBC、厚TBC(TTBC)及密集垂直裂纹(DVC)TTBC 4种涂层的隔热能力和黏接强度。采用降温法测试涂层的隔热能力;根据ASTM C633标准,采用拉拔试验检测涂层的黏接强度。结果显示,UPTTBC和DVC TTBC的黏接强度分别比TTBC高35%和25%。这可能是由于UPTTBC结构中存在亚微米尺度的未熔化区域,起到了阻止裂纹扩展的作用。此外,隔热测试的结果表明,DVCTTBC涂层的隔热能力最差,为0.28℃/μm,而UPTTBC涂层的隔热能力最强,为0.40℃/μm。由于UPTTBCs显微组织中存在亚微米区域,使涂层展现出优越的隔热能力。相反,DVCTTBC因其致密的结构,具有最低的隔热能力。

Thermal insulation capability and adhesion strength of thick thermal barrier coatings(TBC)produced by unpyrolyzed powder(UPTTBC)were compared with those of the conventional TBC,thick TBC(TTBC),and dense vertically cracked(DVC)TTBC.Thermal insulation capability was evaluated using temperature drop.The adhesion strengths of the coatings were also measured by pull-off test method according to ASTM C633.The results indicated that the adhesion strength of UPTTBC and DVC TTBC was 35% and 25% higher than that of the TTBC,respectively.This could imply that the non-melted areas with sub-micron dimensions in UPTTBC structure,act as a trap and prevent the cracks propagation.In addition,the results of thermal insulation tests showed that DVC TTBC coatings had the lowest thermal insulation capability with temperature drop rate of 0.28℃/μm and UPTTBC coatings had the highest insulation capability with temperature drop rate of 0.40℃/μm.Due to the presence of sub-micron zones in the microstructure of UPTTBCs,the coatings exhibited superior thermal insulation capability.In contrary,the DVC TTBC showed the lowest thermal insulation capability because of its dense structure.