阴极等离子电解大面积沉积弥散Pt微粒增韧8YSZ热障涂层

8YSZ thermal barrier coating toughened by Pt particles prepared by cathodic plasma electrolysis deposition

采用大气等离子喷涂(APS)在高温合金表面制备一层Ni Co Cr Al Y粘结层,然后采用阴极等离子电解沉积(CPED)制备一层弥散Pt微粒的8YSZ涂层。通过在电解液中加入陶瓷微珠,促使阴极表面发生均匀的等离子微弧放电,实现了在大面积样品上沉积8YSZ涂层。获得的涂层厚度到达120μm,具有多孔结构,由立方相和四方相8YSZ以及Pt组成。1100℃空气中循环氧化的结果表明,随着涂层中Pt含量的的增加,涂层的抗高温氧化和抗剥落性能得到明显提高。Pt微粒对8YSZ涂层的增韧作用主要为:Pt微粒塑性变形吸收裂纹扩展的能量,钝化裂纹尖端,减小裂纹尺寸,提高涂层的临界断裂应力。

Ni Co Cr Al Y bond-coat was prepared by air plasma spraying( APS) on superalloy surface,then 8YSZ thermal barrier coatings toughened by Pt were deposited on the bond-coat by cathodic plasma electrolysis deposition( CPED). Ceramic balls were put into electrolyte to make arc discharges occurring on cathode uniformly,therefore,depositing 8YSZ coating on large area was achieved. The8 YSZ coating with a thickness of 120 μm possesses porous surface,and the coating is mainly composed of tetragonal and cubic phase of8 YSZ and Pt. The cyclic oxidation tests at 1100 ℃ reveal that the samples' high-temperature oxidation and spallation resistance are improved by increasing the Pt doping amount. The effect of Pt particles on toughening 8YSZ coating can be attributed to Pt particles deforming plastically,absorbing energy for crack growth,blunting crack tip,decreasing crack length and increasing critical fracture stressσcof the coating.