摘 要

为提高Ni60粉末喷涂层的性能，常采用重熔工艺对涂层性能进行改良。本文以Q235为基板，采用氧-乙炔火焰喷涂方法，制备Ni60粉末喷涂层，再将制备的Ni基涂层样品置于空气电阻炉中重熔处理，温度设为960℃、1020℃和1050℃三组，分别保温10min。然后对比研究重熔后与未重熔的Ni60涂层的外貌特征、金相组织结构及涂层的硬度，通过分析总结试验数据，获得最佳重熔温度和火焰喷涂工艺方法。

研究表明，氧-乙炔火焰制备的Ni基涂层表面比较粗糙，涂层结构主要由半熔融颗粒物堆叠而成，孔隙率高，涂层硬度较低；经重熔后，Ni60涂层的性能均有提高，且涂层孔隙率降低，致密度提高，晶粒更均匀细小，硬度明显提高。在Ni60涂层的重熔处理中，以1050℃重熔得到的涂层性能最佳。

本文特色在于，通过在不同重熔温度的加热，来了解Ni60粉末涂层的结构性能，进而确定较佳重熔温度，即按照材料的工艺-组织性能-工艺的方法，来完成课题任务。该研究方法对两步法制备Ni基合金喷涂层及改善能具有参考价值。

关键字：镍基涂层；氧-乙炔火焰喷涂；炉中加热重熔；组织性能

Abstract

In order to improve the performance of Ni60 powder coating, the coating performance was improved by remelting process. This paper on Q235 substrate, by using an oxy - acetylene flame spraying method prepared Ni60 powder coating, and remelting processing in the preparation of Ni based coating sample placed in the air resistance furnace, temperature is set as the 960 ℃, 1020 ℃ and 1050 ℃ , respectively holding for 10min. Then, the surface characteristics, microstructure and hardness of Ni60 coating after remelting and non re melting were compared and studied. The optimal remelting temperature and flame spraying process were obtained by analyzing and summarizing the experimental data.

Studies have shown that the oxygen - acetylene flame preparation of Ni based coating surface is rough, coating structure is mainly composed of a semi molten particles stacking and, high porosity, coating hardness lower; after remelting, Ni60 coatings performance are all improved and decrease the coating porosity, the density increased, more uniform grain small hardness was increased. In the remelting process of Ni60 coating, the coating performance is best at 1050 ℃.

The characteristic of this paper is that through in different melting temperature of heating, to understand the structure and properties of powders of Ni60, and then determine the better remelting temperature, namely according to the material and process organization performance - process method to complete the task. This research method has reference value for the preparation of Ni based alloy coating and the improvement of the two step method.

Key Words:nickel based coating;oxygen acetylene flame spraying;Reheating furnace remelting; microstructure

目录

第一章 绪论.................................................................1

1.1 表面工程技术..........................................................1

1.2 涂层制备技术..........................................................1

1.3 热喷涂技术............................................................1

1.3.1 热喷涂简介........................................................1

1.3.2 热喷涂工艺流程....................................................1

1.3.3 氧-乙炔火焰喷涂...................................................2

1.4 二步法制备涂层的重熔方法..............................................3

1.5 镍基自熔性粉末........................................................3

1.6 本课题的研究内容及意义................................................4

第二章 实验材料和方法.......................................................5

2.1 实验材料..............................................................5

2.2 喷涂的相关设备和喷涂参数..............................................5

2.3 金相样品制备、显微组织观察............................................7

2.4 显微组织观察和硬度测定试..............................................7

第三章 Ni60合金涂层的组织结构和性能.........................................9

3.1 Ni60喷涂层的组织特征..................................................9

3.2 Ni60喷涂层重熔后的组织结构特征........................................9

3.2.1 涂层960℃重熔后的组织结构分析.....................................9

3.2.2 涂层1020℃重熔后的组织结构分析...................................10

3.2.3 涂层1050℃重熔后的组织结构分析...................................11

3.3 本章小结.............................................................12

第四章 Ni60涂层的显微硬度测定及分析........................................13

4.1 Ni60喷涂层的显微硬度分析.............................................13

4.2 Ni60喷涂层重熔后的显微硬度分析.......................................13

4.3 本章小结.............................................................15

第五章 结论及展望..........................................................16

5.1 结论.................................................................16

5.2 展望.................................................................16

参考文献...................................................................17

致谢.......................................................................18

第一章 绪论