水力机械胶粘耐磨涂层的制备与性能的研究

【作者】 张微；

【导师】 何莉萍； 唐绍裘；

【作者基本信息】 湖南大学 ， 材料科学与工程， 2002， 硕士

【摘要】 论文综述了耐磨涂层的研究概况，介绍了采用接枝聚合法制备具有互穿聚合物网络的聚氨酯（PU）改性环氧树脂（EP）胶粘剂，并对水力机械胶粘耐磨涂层的制备技术及性能进行了详细研究。 水力机械胶粘耐磨涂层的特点在于由三层组成：富锌环氧底部涂层、环氧云铁中间涂层及耐磨表面涂层，并且耐磨表面涂层采用聚氨酯改性环氧树脂为胶粘剂，添加硬质耐磨的陶瓷骨料，其抗冲蚀磨损性能尤其突出。在制备底部涂层的过程中，分别研究了涂层的防蚀机理，及锌粉含量、磷铁粉含量和硅烷偶联剂处理金属表面对涂层性能的影响。研究得出：当锌粉占干膜的80wt％，磷铁粉和环氧溶液的质量比为0.25，金属基体表面经过KH-550型硅烷偶，联剂处理时，富锌涂层具有优良的防蚀性能。在制备中间涂层的过程中，采用正交实验法获得涂层的优化配方，并对涂层的防蚀机理、固化机理、固化动力学及热裂解过程进行了研究。结果表明：选择鳞片状云母氧化铁能有效地防止金属基体腐蚀；采用低分子聚酰胺（LMPA）固化E-44环氧树脂时，固化反应主要为环氧基团与胺基间的反应，其表观活化能为75.2kJ/mol；固化剂用量在一定范围内用得越多，固化越完全，体系柔性及抗冲击性增加，但耐腐蚀性能降低；此外，固化反应也与固化温度有关，温度越高，固化越完全，120℃时几乎完全固化，且在50～80℃范围内不宜快速升温。在制备表面涂层过程中，分析探讨了改性环氧胶粘剂的改性原理及固化机理，骨料的含量、骨料级配及涂层厚度对涂层耐磨性能的影响及涂层的磨损机理。得出：当PU/EP的质量比为0.3时，改性胶粘剂的性能较好；当固化剂LMPA用量为改性胶粘剂中EP的50wt％时，常温下涂层表干时间为4小时，实干时间为3～5天；当骨料含量为25wt％，粗颗粒含量为20wt％，涂层厚度在130～180μm时，耐磨表面涂层的耐冲蚀磨损性能是A₃钢基体的1.5～2倍。 论文同时研究了由三层涂层组成的水力机械胶粘耐磨涂层的耐磨防腐性能。结果指出，与同类产品相比，涂层具有更好的耐冲蚀磨损性能。研究涂层之间及涂层与基体之间的界面结合性能发现：底部涂层与基体间的相互吸附、涂层间的相互扩散、偶联剂的共价键连接及机械互锁，均能使涂层与涂层之间、底层与基体之间在界面处形成牢固结合，有利于提高其抗冲蚀磨损性能。测试具有不同涂层层数的试样的阳极极化曲线，结果表明：随涂刷层数增加，涂层具有很好的耐蚀性能，可更好地保护基材。水力机械胶粘耐磨涂层己成功地应用于湘潭炼铁厂的水轮机叶片上，使原本3个月就需检修一次的水轮机经半年后仍然正常运作，有效地提高了水轮机的耐冲蚀磨损性能，并延长了其使用寿命。更多还原

【Abstract】 This paper firstly gave a brief overview on the past and the future of the abrasion resistant coatings, and then the major work focused on the preparation of the epoxy resin / polyurethane (EP/PU) IPN using the graft co-polymerization method and on the investigation on its related abrasion resistant coatings used for components serving in hydraulic engines.The characteristics of abrasion resistant coatings used for components serving in hydraulic engines were that them included three layers of coatings: a zinc-riched epoxy primer, an epoxy micaceous iron mica intermediate coating and a top layer of abrasion resistant coating, and the top layer with the modified epoxy resin binder and the rigid ceramic aggregate had good erosion wear resistance. For the primer, the corrosion resistant mechanism and the effects of the fraction of zinc powder in weight, the amounts of ferrophosphorous powder and the silane coupling agent on the primer were studied. It was found that the zinc-riched primer had excellent corrosion resistant property when the fraction of zinc powder was of 80wt% in weight, the ratio between ferrophosphorous and the epoxy mucus was 0.25. and the metal substrate was treated by KH-550 type silane coupling agent. For the intermediate coating, optimal composition of the coating was obtained by the orthogonal method. In addition, the corrosion resistant mechanism, the curing mechanism, the curing kinetics, and the thermal cracking process of this coating were investigated in depth. The results showed that the scale-like structure of micaceous iron mica prevented the substrate from corrosion effectively. It was also found that the curing reaction was the reaction between the epoxy and amine groups when the EP was cured by the polyamide (LMPA) with low molecular weight. The surface activation for the reaction was 75.2 kJ/mol. The toughness and the impact resistance improved, but the corrosion resistance reduced with the increase of the content of LMPA with in a specific range. On the other hand, the curing degree depended on the temperature. Theresults indicated that the higher the temperature, the higher curing degree would be, and the coating completely cured at 120 . For the top layer (abrasion resistant coating), the modification mechanism of modified epoxy, the curing mechanism, the wear mechanism, and the effects of the aggregate content, the aggregate size, and the coating thickness on the erosive wear resistant property of the abrasion resistant coating were investigated. The results showed that the modified epoxy resin with excellent properties was prepared when the ration of PU/EP was 0.3, and the drying time in the air was about 3~5 days at room temperature with the ratio of LMPA/EP 50wt%. It was also found that the abrasive resistant property of the coating was about 2 times of the As steel under the proper conditions.The abrasion and corrosion resistance of the fabricated coatings were studied in the present work. The erosive wear resistance of the coatings was better than those of the others reported in the literature. The results indicated that the good erosive wear resistance of the fabricated coatings was resulted from the absorption between the primer and the substrate, the diffusion between the three layers, the strong covalent bond coherence of the SA, and the mechanical interlocking. The anodic polarization curves of the top layer, the top layer + the intermediate layer, and the top layer + the intermediate layer + the primer layer showed that these coatings protected the substrate effectively with the increase of the number of the layers. The coatings have been used to improve the erosion wear resistance of the water-wheel machines successfully.更多还原