摘 要

TiB陶瓷作为一种由TiB₂和Ti人工合成得到的一种新型陶瓷具有高强度和高硬度的特点，同时为了得到Ti金属的高韧性以及塑性，本实验决定采用Ti金属与TiB₂制成TiB-Ti梯度材料，使其同时具备多种优良性能，可以广泛应用于航空航天等行业。但是同时由于梯度材料的不同组分的差异会导致每层的最佳烧结温度不同，如果整体进行一次烧结会导致某些梯度的组分难以达到最好的性能。不仅如此，复杂形状的梯度材料制备起来也非常困难，需要专业设备以及工具进行精密设计后才能制备出来。

本实验选择325目TiB₂陶瓷黑色粉末以及350目金属钛粉作为原材料，利用一种新型的离心喷涂技术以及特制的离心喷涂机器完成了管状TiB-Ti梯度材料的研究。研究发现，混合料的分散剂的种类及添加量，pH值以及粘接剂含量，以及离心球磨时间等都会对料浆的流动特性造成影响，从而影响离心喷涂镀层的成型效果，并研究出与特制设备最为匹配的最佳工艺条件。实验使用的粘结剂为1wt%的聚乙烯醇PVA，分散剂为1wt%的六偏磷酸钠SHMP，实验所用pH值为11、使用的喷枪压力为0.5MPa。经过研究发现，基于此工艺条件，TiB₂-Ti混合料浆可以均匀的喷涂于Ti环模具上，保持其梯度设计，从而方便我们完成烧结工作，得到完好的管状烧结材料。本次实验目的为探究TiB₂梯度材料的离心成型方法和效果。根据放电等离子烧结我们发现在1200℃到1450℃范围内进行烧结会使得不同组分的TiB-Ti符合梯度材料可以实现致密化烧结，本次实验设置浓度梯度：钛环（100%钛），Ti75%-TiB25%,Ti50%-TiB50%，Ti25%-TiB75%,以及纯TiB，实验中TiB换算为等量的Ti和TiB₂，按照反应公式Ti TiB₂=2TiB进行换算。如此便可以实现由Ti金属侧向TiB陶瓷侧的浓度梯度。而梯度材料的弹性模量与弯曲强度的大小会随着材料的厚度增加而增大。最终从喷涂完成后的管状样品中取出1cm厚的小样进行测试。

基于上述工艺研究我们完成了喷涂工作并填充好氮化硼最后在1450℃下烧结制成了管状TiB-Ti梯度材料，通过排水法计算得到致密度98.6%，得到的样品可以从断面看到明显的分层梯度现象。本次实验为管状梯度材料的制备提供了一种有效的方法。

关键词：管状TiB-Ti梯度材料 离心成型

Abstract

As a new type of ceramic synthesized by TiB₂ and Ti, TiB ceramics have high strength and hardness,In order to obtain the high toughness and plasticity of Ti metal,In this experiment, Ti metal and TiB₂ were used to make TiB-Ti gradient material, so that it has a variety of excellent properties at the same time, so it can be widely used in aerospace and other industries, But at the same time, because of the difference of different components of gradient materials, the optimal sintering temperature of each layer will be different. If the whole sintering is carried out once, it will be difficult for some gradient components to achieve the best performance. Moreover, the preparation of gradient materials with complex shapes is also very difficult, which requires professional equipment and tools for precise design.

In this experiment, 325 mesh TiB₂ ceramic black powder and 350 mesh titanium powder were selected as raw materials, and a new centrifugal spraying technology and a special centrifugal spraying machine were used to complete the study of tubular TiB-Ti gradient materials. It was found that the type and amount of dispersant, pH value and adhesive content of the mixture, as well as the centrifugal ball grinding time, would all have an impact on the flow characteristics of the slurry, thus affecting the molding effect of centrifugal spraying coating

The binder used in this experiment is PVA of 1wt%, the dispersant is SHMP of 1wt%, the pH value used in this experiment is 11, and the pressure of the spray gun used is 0.5MPa. According to the research results, based on this process condition, tib2-ti mixture slurry can be uniformly sprayed on the Ti ring mold to maintain its gradient design, so as to facilitate us to complete the sintering work and obtain intact tubular sintering material. The purpose of this experiment is to explore the centrifugal molding method and effect of TiB₂ gradient materials, According to discharge plasma sintering, we found that sintering in the range of 1200 ℃ to 1450 ℃ would enable densification and sintering of TiB-Ti compliant gradient materials of different components.Concentration gradient was set in this experiment: titanium ring (100% titanium), Ti75%- TiB25%,Ti50%- TiB50%, Ti25%- TiB75%, and pure TiB. In the experiment, TiB was converted into equal amount of Ti and TiB₂, which was converted according to the reaction formula Ti TiB₂=TiB.

In this way, the concentration gradient from Ti metal side to TiB ceramic side can be achieved. The elastic modulus and bending strength of gradient materials increase with the increase of material thickness. Finally, a 1cm thick sample was taken from the tubular sample after spraying and tested. It was found that the bending strength was as high as 1130MPa and the elastic modulus reached 250GPa.

Based on the above process studies, we finished the spraying work and filled the boron nitride. Finally, the tubular TiB-Ti gradient material was sintered at 1450 degrees Celsius, and the resulting density was calculated by the drainage method to get 98.6%. The obtained sample showed obvious stratification gradient phenomenon from the section. This experiment provides an effective method for the preparation of tubular gradient materials.

Key Words：ubular TiB-Ti gradient ;material was centrifuged

目录

第1章 绪论 6

1.1功能梯度材料的制备 6

1.1.1功能梯度材料的制备方法 7

1.1.2功能梯度材料的性能评价 8

1.2 TiB-Ti梯度材料研究进展 9

1.3 TiB-Ti梯度材料研究现状 9

1.4 离心成型研究现状 9

1.5本文研究目的及主要内容 10

第2章 TiB-Ti梯度材料的离心成型 11

2.1原材料及处理 11

2.1.1原材料性质 11

2.1.2原材料的混合 12

2.2均匀TiB2/Ti复合料的制备 12

2.2.1分散剂对TiB₂/Ti复合料浆的影响 12

2.2.2 pH值对料浆的性质的影响 16

2.2.3粘结剂对料浆流变性的影响 16

2.3 TiB₂/Ti混合料浆的离心成型过程 18

2.3.1喷涂压力 19

2.3.2离心成型 19

2.3.3干燥条件对成型效果的影响 20

2.3.4喷涂距离对喷涂效果的影响 21

第3章 TiB-Ti梯度材料的结构和性能 23

3.1 TiB-Ti梯度材料的结构 23

3.1.1 TiB-Ti梯度材料的相组成 23

3.1.2 TiB-Ti梯度材料的微观形貌 23

3.2 TiB-Ti梯度材料的力学性能及结构特点分析 24

3.2.1 硬度 24

3.2.2 致密度计算 25

第4章 结论与展望 26

4.1 结论 26

4.2 展望 27

参考文献 28

致谢 30

第1章 绪论

针对当今各种工作环境对复杂形状的梯度材料的需求以及特殊梯度材料制备的困难的问题，本实验探究了一种管状的TiB-Ti梯度材料的制备方法。并对其力学性能进行了测试。

1.1功能梯度材料的制备

由于科技的进步与发展，目前许多行业都对工程材料的性能有着越来越高的要求，普通的金属材料或者陶瓷及其复合物都已经无法满足日益苛刻的工作环境，像航空航天行业的发动机构件大多数都是在高温高强度环境下长时间工作，所以我们需要研发出更加抗高温抗腐蚀的工程材料以满足类似这种恶劣的环境。

研究人员们尝试将金属和耐高温的陶瓷材料进行复合化得到复合新材料来满足日益苛刻的工艺条件，但是均匀的复合新材料属于性能均一，有各向同性。其性能并不能满足工艺要求，所以我们尝试在金属钛上进行涂敷一层耐高温陶瓷进行改性，但是由于这种梯度材料由于两种材料性能差异过大，在两种材料的接触表面的性能不能连续变化就，所以导致复合梯度材料在使用中容易产生剥落，本次实验目的为了解决上述复合梯度材料的问题进行了探究与研发。