【作者】 赵健；

【导师】 贺文雄；

【作者基本信息】 哈尔滨工业大学 ， 材料加工工程， 2010， 硕士

【摘要】 随着科学技术的发展,工业上对材料性能的要求越来越高,对金属间化合物以及陶瓷相的关注越来越多,它们以优良的性能被广泛应用于各个领域。模具钢由于有耐磨损、耐高温等要求而需进行表面处理。本文主要研究利用激光熔覆和等离子喷涂工艺在钢表面制备Ti-Al以及TiN涂层,达到在提高材料性能的同时降低成本的目的。本文首先采用机械球磨制备Ti-Al和Ti的球磨粉末,再采用DTA、XRD、SEM分析方法研究了球磨粉体的组织结构。结果表明:随着球磨过程的进行,粉末颗粒细化,过程中无金属间化合物形成。然后采用激光熔覆和等离子喷涂工艺在Q235钢基体表面制备Ti-Al涂层和TiN涂层,采用X射线衍射(XRD)和扫描电镜(SEM)对涂层物相和组织分别进行分析,结果表明:激光熔覆涂层与基体形成了冶金结合,而等离子喷涂则为机械结合。球磨粉末熔覆制备的涂层组织更致密,激光熔覆涂层晶粒尺寸随扫描速度的增大而减小。最后对涂层进行硬度、高温稳定性及耐腐蚀性试验,结果表明TiN涂层的硬度最高,在功率为1200W,扫描速度为600mm/min时,其硬度为1013.5HV,大约为基体的9倍。Ti-Al涂层在功率为1000W,扫描速度为600mm/min时,其硬度为949.5HV。等离子喷涂制备Ti-Al涂层硬度最高达到了535.67HV。激光熔覆涂层的硬度随扫描速度的增加而增大。两种工艺制备的涂层均有良好的高温稳定性。激光熔覆的Ti-Al涂层耐腐蚀性最好,在功率1000W,扫描速度为600mm/min时,约为600(kohm)。其它涂层耐腐蚀性由于组织不够致密而变差。更多还原

【Abstract】 With the development of science and technology, the demand of the material properties in industry is higher and higher, intermetallic compound and ceramic phase of more and more concerned with excellent performance has been widely applied in various fields. Die steel with wear-resisting, high temperature resistant requirements needs surface treatment. Ti-Al and TiN coatings were prepared in steel surface by using laser cladding and plasma spraying in order to improve the performance of the material in the lower cost in this paper.Ti-Al powders and pure Ti were prepared by mechanical milling and then were studied by the differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM) in this paper. The results were shown that: with the ball milling time increasing, powders particle size became smaller, however, there was no intermetallic compounds formed in this process.Ti-Al and TiN coatings were preparated in Q235 steel surface by using laser cladding and plasma spraying subsequently, phase and microstructure were studied by XRD and SEM,metallurgical bonding was formed in the coatings which were prepared by laser cladding, and mechanical activation by plasma spraying. Microstructure of the coatings which were prepared by mechanical milling was compact,grain size became low while the scaning speed increased. The hardness test, high temperature stability test and the corrosion test were completed. The result indicated that the hardness of the TiN coating was the highest. The hardness value of it was 1013.5HV with the power of 1200W and the scanning speed of 600mm/min, which was nine times of the matrix. The hardness value of it was 945.5HV with the power of 1000W and the scanning speed of 600mm/min.The highest hardness value of coating on Ti-Al which was prepared by plasma spraying was 535.67HV. The hardness value of laser remelting thermal barrier coatings increased with the scaning speed. The high temperature stability of the coating both of plasma and laser remelting thermal barrier process were excellent.The corrosion resistance on Ti-Al coating was about 600(kohm) with the power of 1000W and the scanning speed of 600mm/min. The corrosion resistance of the other coating was poor due to the porosity of their structure.更多还原