自反应火焰喷涂梯度过渡陶瓷涂层研究

Gradient transition ceramic coatings prepared by reactive flame spraying

以Ti-B4C-C和Ni-Al自粘结复合粉为自蔓延反应喷涂体系,采用反应火焰喷涂技术,在金属表面制备了Ti(Cx,Ny)-TiB2-NimAln梯度过渡涂层.整个涂层以Ti(C0.7,N0.3)、TiC、TiN和TiB2构成陶瓷主结构,NimAln金属间化合物作为过渡相连续分布其中,涂层具有沿厚度方向宏观连续分布和微观成分突变的特征,并存在孔隙与夹杂,呈典型的多相非均质结构.涂层经梯度过渡后,与基体的结合强度由14.38 MPa增加到30.27 MPa,抗热震性能由2次增加到16次,孔隙率由原来的32%降至19%,显微硬度由底层的Hv545增加到表层的Hv1253.涂层耐磨损性能是45号钢的14倍.

Taking Ti - B4 C - C and Ni - Al self-meh composite powders as the reactive flame spraying system, Ti（ Cx ,Ny） -TiB2 -NimAln gradient transition coatings were prepared on the metal substrate by the technology of reactive flame spraying. The results show that the phases of Ti（ C0.7, N0.3 ） , TiC, TiN and TiB2 form the main ceramic structure of the coatings. NimAln intermetallie composite continuously distributes in the frame as transition phase. The coatings take on the characteristics of macro continuous distribution and micro mutation along the vertical orientation, and there are also some pores and inclusion in the coatings. The coatings have typical multiphase heterogeneous structure. By gradient transition, the adhesive strength of the coatings to the substrate increases from 14. 38 MPa to 30. 27 MPa, the number of heat shock resistance increases from 2 to 16, and the porosity decreases from 32% to 19%. The micro-hardness of the surface of the coatings is Hv0.2 1253, that of the bottom of the coatings is Hv0.2 545,and the average micro-hardness of the coatings is Hv0.2 835. The property of wear resistance is 14 times of that of 45^# steel.