喷涂工艺对超音速火焰喷涂Al-Cu-Fe-Si准晶合金涂层性能的影响

目的使用活性燃烧高速燃气喷涂(AC-HVAF)方法制备高质量的Al-Cu-Fe-Si准晶涂层,研究喷涂工艺对涂层性能的影响。方法采用气雾化Al-Cu-Fe-Si准晶合金粉末,利用AK02T型AC-HVAF喷涂系统制备Al-Cu-Fe-Si准晶涂层材料。通过X射线衍射及扫描电镜观察分析准晶合金粉末和涂层的组织与结构,通过电化学工作站、显微硬度计和接触角测试仪等手段分析准晶合金涂层的耐蚀性、显微硬度及抗粘性能。结果对气雾化准晶Al-Cu-Fe-Si合金粉末的研究发现,冷却速率显著影响准晶合金粉末的组织,在冷却速率较快的粉末中形成胞状晶组织,准晶I相含量较高。对准晶合金涂层进行热处理,高温退火显著提高了涂层的硬度,950℃退火12 h后,硬度值达到(724±153)HV0.1。分别对准晶合金涂层和基体45~#钢的接触角进行测量,准晶合金涂层的接触角最大为95°,而45~#钢的仅为79°。通过电化学工作站测试比较涂层的耐蚀性,发现在3.5%(质量分数)的Na Cl溶液中,喷涂在45~#钢和5052铝合金基体上的涂层腐蚀电流密度J_(corr)分别为6.8×10~(-6),2.0×10~(-7)A/cm~2。结论不同粒径的气雾化准晶合金粉末的相组成不同,选择合适的粒径是保证铝基准晶合金涂层质量的前提。对涂层进行合适的热处理可以有效地提高涂层的显微硬度,铝基准晶合金涂层的接触角较45~#钢的高,提高了基体的抗粘性。不同基体上制备的准晶合金涂层的耐蚀性有很大差异,5052铝合金基体上的准晶涂层耐蚀性优于喷涂在45~#钢基体上的涂层。

Effect of Spraying Technology on the Properties of AC-HVAF Sprayed Al-Cu-Fe-Si Quasicrystalline Alloy Coating

Objective To prepare Al-Cu-Fe-Si quasicrystalline alloy coatings with high quality by AC-HVAF and investigate the effect of spraying parameters on the coating properties. Methods Al-Cu-Fe-Si quasicrystalline alloy coatings were prepared by AK02T AC-HVAF spraying system using gas-atomized Al-Cu-Fe-Si quasicrystalline alloy powders. The phase and microstructures of gas-atomized alloy powders and coating were analyzed by XRD and SEM. Other properties, such as corrosion resistance, micro-hardness and anti-adhesive, were studied by electrochemical workstation, microhardness tester and contact angle instrument. Results The study on gas-atomized Al-Cu-Fe-Si quasicrystalline alloy powders found that cooling rate had significant influence on the structure of powers and the cellular structure was founded in the finer powder particles with higher cooling rate and the quasic-rystalline content of finer powder particles was higher than that of coarser particles. The microhardness of sprayed quasicrystalline coating increased after annealing at higher temperature during heat treatment. The microhardness reached up to (724±153)HV0. 1 after annealing at 950 ℃ for 12 h. The contact angle between quasicrystalline coating and distilled water at RT reached up to 95°, which was higher than that of 45# steel (79°). The comparison of the corrosion current density for coating by the electrochemical workstation test showed the corrosion current density for coating sprayed on 5052 aluminum substrates was 2. 0×10-7 A/cm2 and for 6. 8×10-6 A/cm2 on 45# steel substrates in 3. 5% NaCl solution. Conclusion Gas-atomized quasicrystalline alloy powders with dif-ferent sizes contain different phases. Selection of proper size of quasicrystalline alloy powders is very important for high quality coat-ings. Annealing process can effectively increase the coating hardness. The contact angle of Al-based quasicrystalline alloy coating is higher than that of 45# steel substrate, which indicates the improvement of anti-adhesive property of substrate. The corrosion re-sistance of coating varies significantly for different coating substrate materials, the coating sprayed on 5052 aluminums substrate has a better corrosion resistance than that on 45# steels substrate.