S135钻杆材料等离子喷涂Al2O3-TiO2涂层组织与性能

目的选用石油钻井工程中常用的S135钻杆钢作为研究对象,在不破坏S135钢优异力学性能基础上,在S135钢基体上等离子喷涂Al2O3-TiO2涂层,研究喷涂功率对涂层的组织与性能的影响。方法在25、30、42 kW三种喷涂功率下,于S135钻杆材料基体表面制备Al2O3+TiO2涂层,对涂层表面进行SEM形貌观察及XRD物相分析,对端面进行金相组织观察,并测定不同位置的显微硬度,借助于材料表面性能试验仪进行涂层与基体结合强度测定,对不同功率下的喷涂涂层的组织、形貌及性能进行比较。结果在三种功率条件下,涂层由α-Al2O3、γ-Al2O3、Al2TiO5及TiO2组成。随着喷涂功率的增加,涂层中γ-Al2O3、Al2TiO5的含量增加;粘结层中气孔、裂纹等缺陷减少,孔隙率下降。在42 kW喷涂功率下,涂层与基体的结合强度达到92 N。在热喷涂过程中,由于正火作用,靠近喷涂界面的S135基体的晶粒得到细化。涂层表面的硬度都高于粘结层及基体,在喷涂功率为30 kW时,涂层表面的硬度达到1419.6 HV。结论通过改变喷涂功率,可在S135钻杆材料上得到具有较高硬度、与基体结合强度较高的Al2O3-TiO2涂层。

Microstructure and Properties of Plasma Sprayed Al2O3-TiO2 Coatings on S135 Drill Pipe Material

With drill pipe steel S135 as the research object,this paper aims to study the effect of spraying power on the structure and properties of the coating by plasma spraying of Al2O3-TiO2 coating on the steel substrate on the basis of not destroying the excellent mechanical properties of S135 steel.Al2O3+TiO2 coatings were prepared on the surface of S135 drill pipe material under three spraying powers of 25 kW,30 kW and 42 kW respectively.SEM morphology observation and XRD phase analysis of three coatings were carried out.The metallographic structure of the cross-section was observed and the micro-hardness at different positions was measured.The bonding strength between coating and matrix was measured with a material surface performance tester.Microstructure,morphology and properties of sprayed coatings at different spraying powers were compared.The results showed that under the three power conditions,the coating consisted ofα-Al2O3,γ-Al2O3,Al2TiO5 and TiO2.With the increase of spraying power,the content ofγ-Al2O3 and Al2Ti5 in the coating increased,and defects such as pores and cracks in the bonding layer decreased.The bonding strength between the coating and the substrate reached 92 N at 42 kW spraying power.The grain refinement occurred to S135 matrix near the spraying interface during the spraying process due to normalization.Under three power conditions,the hardness of the coating surface was much higher than that of the bonding layer and the matrix.The surface hardness of the coating reached 1419.6 HV when the spraying power was 30 kW.By changing the spraying power,Al2O3-TiO2 coating with high hardness and high bonding strength with the substrate can be obtained on S135 drill pipe material.