论文总字数：20472字

摘 要

市场上出售的碳化硅粉体大多数粒度分布范围比较宽泛并且形状各式各样，有呈球状的、有呈片状的、有带棱角的。不同领域的需求不同，在多孔陶瓷领域往往需要对碳化硅粉体进行分级及表面球形化处理。该文的主要目的就是找出碳化硅粉体的分级及表面球形化的方法，确定缩小碳化硅粒度分布范围和使球形度变好的工艺流程。

分散是分级的基础。本文起始探讨了磁力搅拌、超声搅拌、先超声后磁力搅拌各自对颗粒分散的影响，尔后试验了不同浓度分散剂PEI的质量百分比对分散的影响。选取恰当的实验操作得到粒径变窄的分级粉体，然后使用3D共聚焦显微镜分析粉体的形貌。在整形实验中分别研究了氧化腐蚀和氢氧化钠腐蚀对碳化硅粉体的作用，探索了氧化温度与溶液温度、浓度和反应时间对球形化的影响。

通过严谨的实验，获得了较为理想的分级效果和球形化颗粒，给出了碳化硅粉体分级和表面整形的工艺参数，即碳化硅质量分数为5%、分散剂PEI质量分数为1%的料浆先超声搅拌75min后磁力搅拌10min，静置23min,得到的颗粒均匀度最好。利用3D共聚焦显微镜观察，得出氢氧化钠在100℃下腐蚀5h球形度最佳的结论。

关键词： 碳化硅粉末 分级 颗粒整形 NaOH腐蚀

Study on Classification and Surface Spheroidization of SiC Powder

Abstract

Most of the silicon carbide powders sold on the market have a wide range of particle size distributions and various shapes, which are spherical, flaky, and angular. Different needs in different fields, in the field of porous ceramics often need to grade and surface spheronization of silicon carbide powder. The main purpose of this paper is to study the method of grading and surface spheronization of silicon carbide powder, and to find out the process flow for narrowing the size distribution of silicon carbide and improving the sphericity.

Dispersion is the basis of classification. In this paper, the effects of magnetic stirring, ultrasonic agitation, and magnetic stirring on the dispersion of particles were initially investigated, and the influence of the mass percentage of dispersing agent PEI on the dispersion was tested. The appropriate experimental procedure was used to obtain a grading powder with narrow particle size, and then the morphology of the powder was analyzed using a 3D confocal microscope. The effects of oxidation corrosion and sodium hydroxide corrosion on silicon carbide powders were investigated in plastic experiments, and the effects of oxidation temperature and solution temperature and concentration on spheronization were explored.

Through rigorous experiments, the ideal classification effect and spheroidized particles were obtained, and the technological parameters of classification and spheroidization of silicon carbide powder were given. That is, the mass fraction of silicon carbide is 5%, and the material propeller with a mass fraction of Polyethylene imine of 1% is magnetically stirred for 75 minutes and then stirred for 10 minutes, and allowed to stand for 23 minutes to obtain the best particle uniformity.By 3D confocal microscope, it was found that sodium hydroxide had the best sphericity at 100°C for 5 hours.

Key words: Silicon carbide particles ; Grading; Particle plasticing;NaOH corrosion

目录

摘要 I

Abstract II

第一章 文献综述 1

1.1引言 1

1.2碳化硅的结构与性能 1

1.2.1碳化硅的结构 1

1.2.2碳化硅化合物的性质 2

1.3碳化硅粉体的分级方法 4

1.3.1干法分级技术原理及设备 4

1.3.2湿法分级技术原理及设备 5

1.4碳化硅粉体表面球形化工艺 9

1.4.1球磨整形 9

1.4.2氧化腐蚀 10

1.4.3酸碱腐蚀 11

1.5本论文研究的意义及主要内容 11

1.5.1课题研究的目的和意义 11

1.5.2课题实验的主要内容 12

第二章 实验 13

2.1实验原料与设备 13

2.2实验过程 13

2.3实验结果表征与测试 15

2.3.1分散效果表征 15

2.3.2 热重分析和差示扫描量热法（TG-DSC） 15

2.3.3 3D共聚焦显微镜 15

第三章 结论与分析 16

3.1碳化硅原料分析 16

3.2影响分散的因素 17

3.2.1搅拌时间对分散的影响 18

3.2.2分散剂PEI浓度对分散的影响 20

3.3分级颗粒分析 21

3.4影响颗粒表面球形化的因素 24

3.4.1氧化温度对颗粒氧化腐蚀的影响 24

3.4.2NaOH溶液温度对颗粒腐蚀的影响 25

3.4.3NaOH溶液浓度对颗粒腐蚀的影响 26

3.4.4NaOH溶液腐蚀时间对颗粒腐蚀的影响 27

3.5整形后颗粒的分析 28

第四章 总结 31

参考文献 32

致谢 34

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