TiAl/BN复合封严涂层的耐腐蚀性能研究

本研究采用大气等离子与真空等离子喷涂技术制备了Al/BN、Ti Al/BN两种金属和陶瓷复合型多孔涂层,用于航空发动机压气机部位的叶尖可磨耗封严。通过电化学测试和盐雾腐蚀实验对两种涂层的盐雾腐蚀性能进行了研究。结果表明,Ti Al/BN涂层的腐蚀电位明显高于Al/BN涂层(约450m V)。同时,在极化曲线测试过程中发现Ti Al/BN涂层出现了明显的钝化现象。经过960h标准盐雾腐蚀试验后,发现Al/BN涂层发生了较严重的腐蚀,而Ti Al/BN涂层仅发生轻微的腐蚀。腐蚀后涂层的XRD分析表明,Ti Al/BN涂层的腐蚀产物主要为Al(OH)3和Al O,没有发现Ti的腐蚀产物。Ti Al/BN复合涂层中形成的Ti Al合金是该涂层比Al/BN涂层更耐中性盐雾腐蚀的原因。

Salt Spray Corrosion Resistance of TiAl/BN Composite Abradable Coating

In this study, Al/BN and TiAl/BN composite porous coating which were used as abradable gap sealing between blade tip and shroud of aircraft turbine engines were prepared by atmospheric plasma spray and vacuum plasma spray, respectively. Corrosion behaviors of the coatings were investigated via the electrochemical and salt spray corrosion tests. The results indicate that, the potentiodynamic polarization curves of the TiAl/BN coating exhibits typical passivation, and the corrosion potential of TiAl/BN coating is about 450mV higher than that of Al/BN coating. After 960h salt corrosion tests, TiAl/BN coating occurred slight corrosion, by contrast, Al/BN has suffered serious corrosion damage. XRD analysis showed that, the major compositions of the corrosion products of the TiAl/BN coating were Al（OH）3 and AlO, in the absence of Ti. TiAl alloy which was generated during the fabricated process of TiAl/BN coating is the main reason for the superior corrosion resistance of TiAl/BN, compared with Al/BN coating.