BSAS喷涂粉体制备工艺及其对涂层性能的影响

采用不同工艺制备BSAS(BaO-SrO-Al_2O_3-SiO_2)喷涂粉体。研究喷涂粉体特性及其对等离子喷涂工艺制备的环境障涂层结构和性能的影响。结果表明:粉体造粒工艺制备的BSAS喷涂粉体颗粒不均匀,流动性差。制备的涂层粗糙,孔隙率高,结合强度为24.1MPa;造粒烧结工艺制备的BSAS喷涂粉体表面圆滑,流动性好,沉积效率高。制备的涂层结构均匀,少孔隙,无裂纹,结合强度达到29.8MPa,涂层中BSAS相保留率最高,达到53.2%;熔融破碎工艺制备的BSAS粉体呈致密不规则块状,虽然流动性好沉积效率高,制备的涂层光滑且孔隙极少,但微裂纹较多,结合强度仅为14.2MPa,粉体经喷涂后发生相结构重组,BSAS相保留率为20.5%,对涂层的高温性能不利。分析认为,造粒烧结工艺制备BSAS粉体具有工艺过程简化、粉体质量好、相稳定性高等优点,更适合于等离子喷涂的要求。

Preparation of BSAS Pow ders and Its Effect on Properties of Coatings

BSAS (BaO‐SrO‐Al2 O3‐SiO2 ) powders were prepared by different methods .The character‐istics of the pow ders ,their effect on the structures and properties of the plasma‐sprayed environmen‐tal barrier coatings (EBC) were analyzed .The results show that BSAS powders prepared by powder granulation process have uneven particles and poor fluidity ,and the coatings prepared by this method have rough surface and high porosity structure with bonding strength of 24 .1MPa .BSAS powders prepared by agglomerate sintered method have smooth surface ,good fluidity and high deposition effi‐ciency ,while the coating prepared has an uniform structure with few pores and no cracks with the bonding strength up to 29 .8MPa and BSAS phase retention rate is 53 .2% after spraying ,which is the highest among the three kinds of powders .BSAS particles prepared by fused crushed method are dense and irregular ,good liquidity and high deposition efficiency ,and the coatings prepared by this powders are smooth with very few pores ,but there are lots of micro‐cracks ,and the bonding strength is only 14 .2MPa .The coating phase is restructured after spraying ,and the BSAS phase retention rate is 20 .5% ,w hich can decrease the properties of the coatings at high temperatures .Results show that the agglomerate sintered method simplifies the preparing process of the spraying pow ders ,and by this method ,BSAS powders of excellent quality and high phase stability can be produced .Compared with other methods ,BSAS powders prepared by agglomerate sintered method is more suitable for plasma spraying .