磁悬浮道岔Zn-Al防护涂层的研究及应用

Zn-Al Protective Coating of Turnout of Maglev and Its Application

目的设计和制备高性能热喷涂Zn-Al合金防护涂层,为其在磁悬浮道岔上的应用提供必要的理论基础,提高磁悬浮道岔的耐蚀性能,延长道岔的使用寿命。方法采用3种丝材火焰喷涂工艺,分别在Q235B钢基体表面制备了Zn-Al合金涂层。通过磁性测量方法、中性盐雾腐蚀试验和划格附着力测试,分析比较这3种工艺条件下制备的Zn-Al合金涂层的厚度、耐蚀性能和附着力。结果热喷涂Zn-Al合金涂层表面光滑,在其他工艺参数不变的情况下,当火焰喷涂距离逐渐减小,喷涂的道数逐渐增加时,热喷涂层的厚度随之增加。当喷涂距离为150 mm、喷涂道数为10时,热喷涂层的厚度最大,为126μm。涂层厚度的增加提高了涂层的耐蚀性能,并且涂层的附着力保持为1级。采用保守计算可知,厚度为126μm的热喷涂Zn-Al涂层的理论防腐寿命可以达到40年。结论热喷涂Zn-Al合金涂层对基体兼具有屏蔽和阴极保护的双重防护作用,保护性能较好,延长了磁悬浮道岔的使用寿命,降低了道岔的维修和维护成本。通过对工艺参数的分析和比较,确定了最佳的热喷涂工艺参数。该工艺条件下制备的热喷涂层结合强度高,耐蚀性能好。

Objective To provide a certain theoretical basis for the design and preparation of high-performance thermal spraying Zn-Al alloy coating and also its application to turnout of maglev vehicle so as to improve the corrosion resistance and extend the working life of the turnout of maglev. Methods The Zn-Al alloy coatings were prepared on Q235B steel substrate by means of 3 kinds of wire flame coating processes in the present work. The thickness, corrosion resistance and adhesion of the prepared coatings were analyzed and measured based on the method of magnetic measurement, neutral salt spray test and adhe- sion test. Results The thermal sprayed Zn-Al alloy coating had a smooth surface. Under the condition of other parameters not changed, the thickness of the coating increased with the gradual decrease of the spraying distance and the increase of the spray- ing times. When spraying distance was 150 mm and spray times was 10, the thickness of coating reached the maximum value 126μm. The increase of the coating thickness improved the corrosion resistance of the coating, and the adhesion of the coating was maintained at level 1. The conservative calculation showed that the theoretical anti-corrosive life of a 126μm thermal sprayed Zn-Al alloy coating might reach 40 years. Conclusion Thermal spraying Zn-Al alloy coating has a great double protec- tive effect on the substrate, i.e. shielding and cathodic protection, which can extend the service life and reduce the maintenance cost for the turnout. Based on the analysis and comparison of the process parameters, the optimum spray parameters have been obtained. The coating made under such conditions shows high strength and good corrosion resistance.