【作者】 李伟；

【导师】 王永涛；

【作者基本信息】 北京化工大学 ， 机械工程， 2020， 硕士

【摘要】 在面对传统金属打印设备和打印耗材昂贵、受限于金属材料、生产成本高等问题时,提出了金属浆料3D(three-dimensional)打印的方案,该设备有结构简单,成本低,无需加热等诸多优势。并利用金属镍粉作为打印材料制备多孔结构催化剂代替昂贵的金属铂,与商用泡沫镍相比,在电解水时的电流密度更大,实现了制备高性能电解水催化剂工艺上的新突破。本课题利用浆料3D打印技术制备金属催化剂,降低了打印设备的成本,扩大了材料的选择性。以镍及镍合金粉末作为实验材料,聚乙烯醇(PVA)水溶液作为粘结剂。通过3D打印技术制备多孔金属镍催化剂并对其制备工艺进行研究,研究的内容包括多孔金属的制备,脱脂与烧结对孔隙的影响;探索了不同方式制备和合金催化剂在电解水制氢性能。具体内容如下:1、本文选用实验室改进后的3D打印机作为实验设备,镍及镍合金粉末与质量分数为10%的PVA溶液混合成的金属浆料作为打印材料。通过对金属粉末与PVA溶液相关性质的测试,得出当镍粉与PVA溶液的质量比为15:2时,此时浆料的密度为3.7214g/cm3,粘度为1265pa.s。金属浆料能够连续的挤出,并得到了挤出压力与挤出速度之间的关系,且打印制备的成型效果佳。2、在对粘结剂通过TG-DSC测试之后,设置并优化了坯体的脱脂工艺参数,脱脂时间短。探究了多个升温速率对烧结制品质量的影响,得出以5℃/min升温速率是合适的结论。并且找到烧结的坯体在高温环境中容易被氧化的原因,即在脱脂与烧结之前,都必须抽真空将炉内的空气排除干净。3、通过对烧结温度的改变,可以改变坯体中金属的接触面和改变金属颗粒的形貌。这对烧结后的金属制品的拉伸强度、密度和收缩率有着重要的作用效果。探究了在设置的几个烧结温度与3D打印制品质量的关系。结果表明,金属制品的拉伸强度、密度和收缩率都随着烧结温度的升高而增大。4、在催化剂性能测试中,以粉末烧结制备的镍催化剂性能都优于商用泡沫镍。其中,又以3D打印制备的多孔镍最好,其电流密度约为74.17mA/cm2,是泡沫镍电流密度的7倍。说明3D打印制备的多孔金属镍催化剂在电解水制氢有着极大的优势。在镍粉中加入铜粉混合形成合金粉末并以3D打印技术制备多孔结构催化剂,其性能在纯镍的基础上又有3倍的增长。更多还原

【Abstract】 Faced with the problems of expensive traditional metal printing equipment and printing consumables,limited by metal materials and high production cost,a three-dimensional printing scheme of metal paste is proposed.The equipment has many advantages,such as simple structure,low cost and no heating.In addition,nickel powder was used as printing material to prepare porous catalysts instead of platinum.Compared with commercial nickel foam,the current density during water electrolysis was higher,which made a new breakthrough in the process of preparing high-performance electrolysis water catalyst.This topic USES paste 3D printing technology to prepare metal catalyst,which reduces the cost of printing equipment and expands the selectivity of materials.Nickel and nickel alloy powder were used as experimental materials and polyvinyl alcohol(PVA)aqueous solution was used as binder.The preparation technology of porous metal Nickel catalyst was studied by 3D printing technology,including the preparation of porous metal,the influence of degreasing and sintering on porosity.Different preparation methods and properties of alloy catalysts for hydrogen production by electrolysis of water were explored.The details are as follows:1.In this paper,the improved 3D printer in the laboratory was selected as the experimental equipment,and the metal paste of nickel and nickel alloy powder mixed with PVA solution with a mass fraction of 10%was used as the printing material.By testing the properties of metal powder and PVA solution,it is concluded that when the mass ratio of nickel powder to PVA solution is 15:2,the density of paste is 3.7214g/cm3 and the viscosity is 1265pa.s.The metal paste can be extruded continuously and the relationship between extrusion pressure and extrusion speed is obtained.2.After the binder was tested by TG-DSC,the degreasing process parameters of the blank body were set and optimized,and the degreasing time was short.The influence of several heating rates on the quality of sintered products was investigated,and it was concluded that 5℃/min was appropriate.In addition,the reason why the sintered green body is easy to be oxidized in high temperature environment is found,that is,before degreasing and sintering,the empty space in the furnace must be vacuumed to eliminate it.3.The contact surface of metal and the morphology of metal particles can be changed by changing the sintering temperature.This has an important effect on the tensile strength,density and shrinkage of sintered metal products.The relationship between the sintering temperature set and the quality of 3D printed products was explored.The results show that the tensile strength,density and shrinkage of metal products increase with the increase of sintering temperature.4.The properties of nickel catalyst prepared by powder sintering are better than that of commercial nickel foam.Among them,the porous nickel prepared by 3D printing is the best,and its current density is about 74.17mA/cm2,which is 7 times that of foamy nickel.This indicates that the porous nickel catalyst prepared by 3D printing has great advantages in electrolysis of water to produce hydrogen.Copper powder was added into nickel powder to form alloy powder and 3D printing technology was used to prepare porous catalyst.更多还原