目的 分析喷距对钛涂层显微结构和性能的影响。 方法 采用低温超音速火焰喷涂工艺,在不同的喷距下制备钛涂层,分析钛涂层的显微组织、相结构及显微硬度,探讨涂层受喷距影响的机制。 结果低温超音速火焰喷涂钛涂层的表面粗糙度较高,涂层的孔隙率随喷距的增加呈先减小、后增大的趋势,当喷距为 150 mm 时,涂层的孔隙率最小。 钛涂层没有发生明显的氧化,粒子主要以固态形式沉积。结论 当喷距为 150 mm 时,粒子在焰流中加热较为充分,同时具有较高的飞行速度,粒子的扁平化程度高,因此涂层具有较高的致密度。

Objective To study the effects of spray distance on the microstructure and property of Ti coatings. Methods Ti coatings were prepared at different spray distances by Low Temperature HVOF process. The microstructure, phase structure and microhardness of the coatings were analyzed. Besides, the influence mechanism of spray distance on Ti coatings was discussed. Results The results showed that LT-HVOF Ti coatings had relatively high surface roughness, and the porosity of the coatings first decreased and then increased with the increase of spray distances, and the minimum porosity of the coating was 0. 70% at the spray distance of 150 mm; no obvious oxidation was observed in Ti coatings; the splats deposited on the substrate were mainly in its solid state. Conclusion When the spray distance was 150 mm, Ti particles were sufficiently heated in plume and had a high in-flight velocity, so Ti splats were well flattened to form dense Ti coating.