ZrO_2纳米颗粒对Al-12.5%Si合金PEO陶瓷层微观形貌及热防护性能的影响

Effects of ZrO_2 Nano-particles on Properties of PEO Ceramic Coating on Al-12.5%Si Alloy

采用外加ZrO_2纳米颗粒的电解液体系在Al-12.5%Si合金表面制备ZrO_2-Al_2O_3-SiO_2三相PEO陶瓷层。利用SEM和XRD对陶瓷层微观结构和物相进行分析,并对其隔热及热冲击性能进行测试。结果表明:ZrO_2纳米颗粒显著提高了膜层的致密度和结合性,并有效减弱了Si元素对PEO成膜的抑制作用,提高了成膜速率;三相PEO陶瓷层的主要物相为SiO_2及高温稳定相α-Al_2O_3和c-ZrO_2,其独特的微结构和成分致使ZrO_2纳米颗粒改性的陶瓷层具有良好的热防护性能和热冲击性能。

The PEO ceramic coatings containing ZrO2-Al2O3-SiO2 three phases were prepared on Al-12.5%Si alloy in the electrolyte solutions with ZrO2 nano-particles. The microstrucatres and phases of the coatings were analyzed by SEM and XRD, respectively. The heat insulation performances and the thermal shock resistances were also investigated. The results show that the ZrO2 nano-particles can increase the density and binding performance of the coatings significantly, and effectively weaken the inhibition of Si element on PEO process and then improve the growth rate of PEO coatings; the PEO ceramic coatings containing three phases are mainly composed of SiO2 and steady phases such as a-Al2O3 and c-ZrO2, whose special microstructure and composition leads to good heat insulation performances and thermal shock resistances of the ceramic coatings formed in solutions with ZrO2 nano-particles.