部分稳定氧化锆陶瓷的凝胶注模成型工艺_英文_

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口腔托槽用ZTA陶瓷材料的凝胶注模成型工艺的研究

口腔托槽用ZTA陶瓷材料的凝胶注模成型工艺的研究

口腔托槽用 ZTA陶瓷材料的凝胶注模成型工艺的研究由于氧化铝陶瓷材料具有脆性比较大,易断裂的弱点,使其优良的性能得不到充分的发挥,为口腔医师和患者带来了不必要的麻烦。

氧化锆陶瓷材料是一种生物惰性材料,它化学性质稳定、色泽逼真、生物相容性好,并且有着优异的韧性、强度等力学性能。

这些优异性大大解决了陶瓷材料在口腔硬组织修复领域中的不足,使得陶瓷材料在口腔医学中得到了充分的应用。

实验利用正交试验设计方法来设计实验,通过凝胶注模成型制备牙科托槽用ZTA陶瓷,以Al2O3、ZrO2粉体固含量、CMC用量、AA用量、APS用量为四个影响因素,设计一个“四因素三水平”的正交试验,有效试验次数为9次。

将9组不同配比的浆料在一定温度下凝胶、干燥,并在同一烧结制度下进行煅烧,制备出9个不同配方的ZTA陶瓷试样。

对得到的陶瓷试样进行XRD和SEM扫描,分析陶瓷的晶相组成与表面形貌。

结合陶瓷材料的抗弯强度、断裂韧性、相对致密度、线收缩率等测试结果,探究四个因素对ZTA陶瓷性能的影响,总结得到最优水平组合。

实验药品主要原料包括原料名称分子式纯度氧化铝Al2O399.9%氧化锆ZrO2分析纯丙烯酸C3H4O2分析纯羧甲基纤维素可变分析纯过硫酸铵(NH4)2S2O8分析纯柠檬酸三铵C6H5O7(NH4)3分析纯氧化镁MgO分析纯二氧化钛TiO2分析纯硅脂295-3分析纯技术路线按照实验设计,本实验选用CMC加入量、AA加入量、APS加入量、Al2O3、ZrO2粉体固含量为四个影响因素,根据前期实验探索得到的结果,每个因素选取三个水平,正交实验设计方案见表。

正交试验设计试验号CMC(g)APS(g)AA(ml)Al2O3+ZrO2(g)10.80.87100+30 20.817.5105+31.5 30.8 1.28110+33 40.850.87.5110+33 50.8518100+30 60.85 1.27105+31.5 70.90.88105+31.580.917110+33 90.9 1.27.5100+30将不同配比的Al2O3、ZrO2粉体、CMC、AA、APS经球磨机高速球磨,充分混合,注模,干燥固化成型,烧结,得到牙齿托槽用ZTA陶瓷材料。

陶瓷凝胶注模成型

陶瓷凝胶注模成型

凝胶注模成型工艺研究夏培(天津大学材料科学与工程学院,教育部先进陶瓷与加工重点实验室,天津300072)摘要:凝胶注模成型是一种优于传统成型工艺的先进陶瓷成型方法,为净尺寸高性能复杂形状陶瓷的制备提供了有效的技术途径。

本文对陶瓷凝胶注模成型的原理、工艺、成型体系、特点等进行了简单的概论介绍,综述了目前凝胶注模成型的研究现状、存在的问题和应用情况并展望了发展趋势。

关键词:凝胶注模;研究现状;问题与展望Study on the gel-castingXIA Pei(Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, college of Material Science and Engineering, Tianjin University, Tianjin300072, Tianjin, China)Abstract: Gel-casting process is an advanced manufacturing technology for ceramic forming, which is superior to the traditional one, and has provided an effective approach to prepare high performance net size ceramics with complicated shapes. The principles,procedures,forming system and character of gel-casting are simply discussed in this paper, moreover, the present research process,problems as well as applications are also included. Finally, the tendency of this technology is forecasted in a dialectical way.Key words: gel-casting; present research; problems and prospects1.引言随着当代科学技术的发展,国防、工业等技术领域对结构材料的要求越来越高,耐高温、耐腐蚀、高硬度和综合力学性能好的结构材料的开发和研究已经变得十分重要。

陶瓷注射成型技术

陶瓷注射成型技术
▪ 练泥机转速:练泥时因螺杆转速太快而引起高的剪切力会导致喂料中陶瓷 粉末对挤出机料筒的磨损而引入杂质,转速太慢则不能产生适当的剪切力 而造成粘结剂粘度太低,使得混炼均匀变得很困难,从而引发后续的缺陷。 故需要将转速同喂料匹配,使喂料在粘度适当的条件下进行混炼。
▪ 练泥时间:时间过短则练泥混合效果不好,时间过长则练泥混合效率不高
1) 粉末应专门配制,以求高的极限填充密度和低的成本; 2) 2) 粉末不结块团聚; 3) 3) 粉末外形主要为球形; 4) 4) 粉末间有足够的摩擦力以避开粘结剂脱出后坯件变
形或塌陷,在大多数情况下,自然坡度角应大于55°; 5) 5) 为利于快速烧结,应具有小的平均粒度,一般要
求小于1μm; 6) 6) 粉末本身致密,无内孔隙; 7) 7) 粉末的表面清洁,不会与粘结剂发生化学反应。
立式注射成型机
注射成型机构组成
▪ 可塑化机构(注射机构) ▪ 合模机构(包括模具) ▪ 油压机构 ▪ 电气掌握机构
注射成型模具
注射成型制备氧化锆坯体
注射成型制备氧化锆坯体
注射成型过程中缺陷的掌握
▪ 在注射成型过程中缺陷的掌握基本可从两个方面考 虑:一方面是成型温度、压力和时间三者关系设定; 另一方面是填充时喂料在模腔中的流淌。由于CIM 产品大多数是外形简洁、精度要求高的小尺寸零件, 混料在模腔的流淌就牵涉到模具设计问题,包括进 料口位置、流道的长度、排气孔的位置等,都需对 混料流淌性质、模腔内温度和残余应力分布等参数 有清楚了解。现行计算机充模过程动态模拟,正为 注射成型这一步供应理论指导。
孔洞缺陷
▪ 孔洞,指在生坯的横截面上可以发现的孔隙。 有的是一个近圆形的小孔,有的就进展为几 乎贯穿生坯坯体的中心通孔,这是常见的缺 陷.

凝胶注模成型制备Sialon陶瓷的研究进展

凝胶注模成型制备Sialon陶瓷的研究进展

凝胶注模成型制备Sialon陶瓷的研究进展Sialon陶瓷是一类兼具氧化物陶瓷和非氧化物陶瓷优点的新型陶瓷材料。

它具有高硬度、高抗磨损性、耐高温性和耐腐蚀性等良好性能,因此在各种领域得到了广泛应用。

凝胶注模成型(Gel Casting)是制备Sialon陶瓷的重要方法之一。

本文将对凝胶注模成型制备Sialon陶瓷的研究进展进行综述。

一、Sialon陶瓷的特点Sialon陶瓷是一种典型的复合材料,由Si(硅)、Al(铝)、O(氧)和N(氮)等多种元素组成,其中氮元素的含量较高。

Sialon陶瓷的晶体结构可分为β-Sialon、α-Sialon和O-Sialon三种,其中β-Sialon陶瓷是目前应用最广泛的一种。

相比传统陶瓷材料,Sialon陶瓷具有以下特点:1.高硬度和抗磨损性:Sialon陶瓷的硬度可达到HRA90以上,具有良好的抗磨损性能。

2.耐高温性:Sialon陶瓷具有良好的耐高温性能,热稳定性佳,可在高温下长期稳定使用。

3.耐腐蚀性:Sialon陶瓷对许多强酸、强碱和腐蚀性气体具有较好的耐腐蚀性能。

4.绝缘性能:Sialon陶瓷具有优异的绝缘性能,可用于制作高压绝缘件。

5.低密度:Sialon陶瓷的密度相对较低,易于加工和制造。

二、凝胶注模成型制备方法凝胶注模成型(Gel Casting)技术是一种非常有效的制备复杂形状Ceramic Matrix Composites(CMCs)的方法。

与传统的热压法相比,凝胶注模成型具有以下优势:1.成本低:凝胶注模成型没用高成本的设备,且原材料成本较低,因此制备成本相对较低。

2.制品复杂性高:该技术可用于制备复杂形状的陶瓷制品。

3.精度高:通过凝胶注模成型制备的陶瓷制品尺寸和形状精度高。

1.原材料混合:将SiC、α-Al2O3、AlN和氧化硅(SiO2)等原材料按照一定比例混合,并加入含有十四酸钠(SDS)的溶液中,搅拌均匀。

2.凝胶形成:在混合物中缓慢稀释乙醇,同时加入硝酸,使混合物凝胶化。

氧化锆陶瓷制作工艺流程

氧化锆陶瓷制作工艺流程

氧化锆陶瓷制作工艺流程英文回答:The process of manufacturing zirconia ceramics involves several steps. First, zirconia powder is prepared bymilling zirconium oxide and stabilizers such as yttrium oxide or magnesium oxide. This powder is then mixed with binders and additives to form a slurry.Next, the slurry is shaped into the desired form using various techniques such as slip casting, injection molding, or pressing. Slip casting involves pouring the slurry into a mold and allowing it to solidify. Injection molding uses a machine to inject the slurry into a mold under high pressure. Pressing involves compressing the slurry into a mold using a hydraulic press.Once the green body is formed, it undergoes a drying process to remove the moisture from the ceramic. This can be done by air drying or using a kiln. After drying, thegreen body is ready for sintering.Sintering is the key step in the manufacturing process. The green body is heated to a high temperature, typically around 1500-1600°C, in a controlled atmosphere. Thi s causes the zirconia particles to bond together and form a dense ceramic structure. The sintering process also helps to eliminate any remaining binders and additives.After sintering, the zirconia ceramic may undergo additional processing steps such as polishing or machining to achieve the desired shape and surface finish. Finally, the ceramic is inspected for quality and any defects or imperfections are addressed.中文回答:制作氧化锆陶瓷的工艺流程包括几个步骤。

一种氧化锆陶瓷的注射成型制备方法

一种氧化锆陶瓷的注射成型制备方法

一种氧化锆陶瓷的注射成型制备方法注射成型是一种常用的陶瓷制备方法,可以制备出复杂形状和高精度的陶瓷产品。

下面是一种氧化锆陶瓷的注射成型制备方法,包括以下50条步骤,并附有详细描述:1. 准备原料:氧化锆陶瓷的主要成分是氧化锆粉末,需要准备高纯度的氧化锆粉末材料。

2. 通过研磨和筛分处理氧化锆粉末,以确保粒径均一。

3. 往氧化锆粉末中添加适量的有机增塑剂,以增加其可塑性和流动性。

4. 在加入增塑剂的氧化锆粉末中加入一定量的有机溶剂,使用超声或机械搅拌的方法将其混合均匀,形成可注射的糊状物料。

5. 放置混合后的糊状物料静置,以使其中的泡沫自行消除,提高糊状物料的流动性。

6. 将糊状物料装入注射机的料筒中。

7. 在注射机的注射头中装配适当的模具,以便注射成型时可以形成所需形状的陶瓷产品。

8. 将注射机的料筒与模具连接,确保糊状物料能够流入模具中。

9. 启动注射机,并调整注射速度和注射压力,以确保糊状物料能够均匀地填充整个模具。

10. 注射完成后,等待糊状物料在模具中发生固化反应。

11. 取出固化后的陶瓷产品,可选择进行表面处理和调整尺寸。

12. 将固化后的陶瓷产品进行烘烤,以去除其中的有机成分。

13. 烘烤完成后,将陶瓷产品进行烧结处理,以提高其密度和力学性能。

14. 根据需要,可以进行陶瓷产品的磨削、抛光和涂层处理,以提高其表面光滑度和耐磨性。

15. 进一步测试和检验陶瓷产品的物理和化学性能,以确保其符合设计要求。

16. 针对不合格的陶瓷产品,可以选择进行返工或重新制备。

17. 对合格的陶瓷产品进行包装和储存,以便运输和使用。

18. 根据需要,可以进行陶瓷产品的装配和组装,以形成成品。

19. 在注射成型过程中,可以添加一定量的增塑剂,以提高糊状物料的可塑性和流动性。

20. 同样,也可以加入适量的抗结团剂,以防止糊状物料在注射成型过程中过度固化和凝胶化。

21. 注射成型的糊状物料常常需要在一定的温度范围内进行处理,以保持其流动性和可塑性。

凝胶注模成型制备Sialon陶瓷的研究进展

凝胶注模成型制备Sialon陶瓷的研究进展

凝胶注模成型制备Sialon陶瓷的研究进展作者:吴泱银锐明来源:《佛山陶瓷》2020年第03期摘要:本文系统阐述了凝胶注模成型制备Sialon陶瓷的研究与进展,根据凝胶来源分成非水基凝胶注模体系和水基凝胶注模体系,介绍它们的工艺过程和原理。

最后提出了凝胶注模成型制备Sialon陶瓷目前应当注意的问题,并展望了它的前景。

关键词:凝胶注模成型;Sialon;研究与进展1 前言Sialon陶瓷是一种在1970年代初发现的Si-Al-O-N四元结构材料[1、2],分子式为Si6-zAlzOzN8-z,因其优异的耐磨性、耐热冲击性、硬度、强度、韧性、耐热性和化学稳定性而广泛用于交通运输、冶金、航空航天、化工机械和医药领域。

它被认为是最有前景的结构材料之一[3]。

根据Sialon中O和Al固溶体的不同条件,单相Sialon陶瓷可分为α'-Sialon,β'-Sialon,X-Sialon,O'-Sialon,AlN多晶型物。

在所有单相Sialon陶瓷中,β'-Sialon是最稳定的固溶体,具有与β-Si3N4相近的结构,并且其物理性质与Si3N4相似。

相比Si3N4陶瓷,Sialon陶瓷更容易烧结。

同时,β'-Sialon含有大量的Al2O3,因此其化学性质类似于Al2O3[4]。

β'-Sialon具有比Si3N4更好的抗热震性和抗氧化性。

此外,它与熔融金属具有良好的混溶性[5]。

目前来看,Sialon陶瓷的成形方法有很多,可通过压制、注射、凝胶注模等方法成型[6]。

其中,凝膠注模成型是一种新型的、被广泛应用的成型方法。

在1990年代初期,美国橡树岭国家实验室开发了一种新的陶瓷成型技术,被命名为凝胶注模成型技术[7、8]。

该技术将聚合物单体的交联聚合反应应用于陶瓷成型工艺,以使粉末原位固化,从而获得稳定且近净尺寸形状的陶瓷体。

凝胶注模成型技术具有适用范围广、工艺易于控制、生坯强度高、生坯和烧结体均匀性好等优点,是重要的陶瓷成型技术之一[9、10]。

凝胶注模成型制备Sialon陶瓷的研究进展

凝胶注模成型制备Sialon陶瓷的研究进展

凝胶注模成型制备Sialon陶瓷的研究进展凝胶注模成型技术是一种新型的制备陶瓷材料的方法,具有高效、精准、环保等多种优点。

在该工艺中,采用凝胶作为原料,通过注模成型、干燥、烧结等工艺过程制备出陶瓷制品。

Sialon陶瓷是一种刚玉-硅氮化物复合材料,具有高强度、高硬度、高耐磨性以及高温稳定性等特点,被广泛应用于航空、汽车、机械等领域。

本文将回顾凝胶注模成型制备Sialon陶瓷的研究进展。

1.凝胶注模成型技术的优势(1)高生产效率。

凝胶注模成型工艺中,使用凝胶作为原料,可以通过注射成型、干燥和烧结等工艺步骤制备出高质量的陶瓷制品。

相比传统的推压成型、滚压成型等方法,凝胶注模成型技术可以节约成本、节约时间,提高生产效率。

(2)高制品质量。

凝胶注模成型工艺中,凝胶具有非常高的均一性和稳定性,通过注塑成型可以制备出具有高精度、高质量的陶瓷制品。

同时,该工艺中可以控制注塑成型的环境条件,可以避免其他制备方法中容易出现的杂质、气泡等问题,从而在制品质量上优于传统的制备方法。

(3)高环保。

凝胶注模成型工艺中,采用凝胶作为原料,不需要使用传统制备陶瓷材料时需要的大量有害化学品,可以降低对环境的污染和对工人健康的危害。

(1)制备方法研究。

根据不同的制备方法,可以将凝胶注模成型技术应用于Sialon 陶瓷的制备。

如使用聚乙烯吡咯烷酮(PVP)为增塑剂,采用凝胶注模成型技术制备出了氮化硅和氮化铝的Sialon陶瓷复合材料;采用聚乙烯醇(PVA)为胶粘剂,加入苯乙烯为增塑剂,成功地制备出了具有高硬度、高耐磨性和高强度的Sialon陶瓷。

(2)材料性能研究。

凝胶注模成型技术制备的Sialon陶瓷,相比传统方法制备的陶瓷,具有更好的机械性能和高温稳定性。

例如,在1000°C下,使用凝胶注模成型技术制备的Sialon陶瓷的抗折强度可以达到580 MPa以上,而传统制备方法制备的Sialon陶瓷则仅为340 MPa左右。

凝胶注模成型工艺流程

凝胶注模成型工艺流程

凝胶注模成型工艺流程英文回答:Gel injection molding is a manufacturing process that involves injecting a liquid gel material into a mold cavity, allowing it to solidify and take the shape of the mold.This process is commonly used for producing various products, such as medical devices, automotive components, and consumer goods.The gel material used in this process is typically atwo-component system consisting of a base material and a curing agent. These two components are mixed together in a controlled ratio to initiate the curing process. Themixture is then injected into the mold cavity under high pressure.Once the gel material is injected into the mold, it undergoes a curing process, which can be either thermal or chemical. In thermal curing, the mold is heated to aspecific temperature, which accelerates the curing reaction. In chemical curing, a catalyst is added to the gel material to initiate the curing process.After the gel material has solidified and taken the shape of the mold, the mold is opened, and the molded partis ejected. The part may undergo additional post-processing steps, such as trimming, polishing, or surface treatment,to achieve the desired final product.Gel injection molding offers several advantages over other molding processes. Firstly, it allows for the production of complex shapes and intricate details withhigh precision. The gel material can flow easily into thin and narrow sections of the mold, resulting in parts with excellent dimensional accuracy.Additionally, gel injection molding enables the production of parts with unique properties, such as softness, flexibility, and transparency. By adjusting the composition of the gel material, manufacturers can tailor the mechanical and physical properties of the molded partsto meet specific requirements.中文回答:凝胶注模成型是一种制造工艺,涉及将液体凝胶材料注入模具腔中,使其凝固并成型。

凝胶注模成型制备Sialon陶瓷的研究进展

凝胶注模成型制备Sialon陶瓷的研究进展

凝胶注模成型制备Sialon陶瓷的研究进展【摘要】凝胶注模成型是一种常用于陶瓷制备的先进技术,本文通过对Sialon陶瓷的研究进展进行总结和分析。

首先介绍了凝胶注模成型技术的基本原理和优势,然后对Sialon陶瓷材料的特性进行了详细分析。

接着探讨了凝胶注模成型制备Sialon陶瓷的工艺优势,以及研究方法和研究成果。

最后展望了未来凝胶注模成型制备Sialon陶瓷的研究方向,指出了当前研究中存在的挑战和机遇。

本文旨在为进一步开展凝胶注模成型制备Sialon陶瓷的研究提供参考和指导,推动该领域的发展和应用。

【关键词】凝胶注模成型,Sialon陶瓷,研究进展,技术简介,材料特性分析,工艺优势,研究方法,研究成果,研究展望1. 引言1.1 凝胶注模成型制备Sialon陶瓷的研究进展凝胶注模成型(Gelcasting)是一种先进的陶瓷成型技术,通过在溶胶凝胶体系中添加陶瓷粉末和适量的增塑剂、分散剂等,形成可流动的陶瓷浆料,再在模具中固化成形,最终得到具有高密度和复杂形状的陶瓷制品。

Sialon陶瓷是一类具有良好耐磨性、高温稳定性和化学惰性的陶瓷材料,被广泛应用于陶瓷刀具、航空航天等领域。

凝胶注模成型制备Sialon陶瓷的研究进展近年来备受关注。

通过优化凝胶注模成型工艺参数,如浆料配方、固化条件等,可以实现对Sialon陶瓷制品微观结构和性能的精确控制。

结合先进的材料表征技术,对凝胶注模成型制备的Sialon陶瓷进行深入分析,揭示其结构特征和性能优势,为其在工程应用中的进一步推广与应用提供了重要的理论基础。

凝胶注模成型制备Sialon陶瓷的研究进展不仅促进了陶瓷材料制备技术的发展,也为提高Sialon陶瓷制品的质量和性能提供了重要参考。

随着相关研究的深入推进,凝胶注模成型技术在Sialon陶瓷领域的应用前景将更加广阔,为实现Sialon陶瓷的产业化应用奠定坚实基础。

2. 正文2.1 凝胶注模成型技术简介凝胶注模成型技术是一种将悬浮在溶剂中的陶瓷粉料注入模具,并通过冷凝或凝胶化使其固化成形的方法。

注凝成型制备氧化锆陶瓷工艺设计

注凝成型制备氧化锆陶瓷工艺设计

注凝成型制备氧化锆陶瓷工艺设计文档下载说明Download tips: This document is carefully compiled by this editor. I hope that after you download it, it can help you solve practical problems. The document 注凝成型制备氧化锆陶瓷工艺设计can be customized and modified after downloading, please adjust and use it according to actual needs, thank you! In addition, this shop provides you with various types of practical materials, such as educational essays, diary appreciation, sentence excerpts, ancient poems, classic articles, topic composition, work summary, word parsing, copy excerpts, other materials and so on, want to knowdifferent data formats and writing methods, please pay attention!氧化锆陶瓷是一种在高温下具有优异性能的陶瓷材料,常用于制备高温工具、陶瓷零件等。

设计注凝成型制备氧化锆陶瓷的工艺需要考虑多个因素,包括原料选择、工艺流程、设备条件等。

以下是一个简要的设计方案,供参考。

1. 原料选择。

主要原料。

氧化锆粉末(ZrO2),通常选择粒径细致、纯度高的氧化锆粉末。

添加剂。

常用的添加剂包括稳定剂(如氧化钙、氧化镁)、结合剂(如聚乙烯醇)、助燃剂等,用于调节氧化锆陶瓷的性能和工艺性。

凝胶注模成型亚毫米级氧化锆陶瓷微珠的工艺研究

凝胶注模成型亚毫米级氧化锆陶瓷微珠的工艺研究

凝胶注模成型亚毫米级氧化锆陶瓷微珠的工艺研究
凝胶注模成型是一种常用的氧化锆陶瓷微珠制备工艺,其工艺研究可分为以下几个方面:
1. 生物源材料制备:首先准备氧化锆粉末,可以选择不同的合成方法,如溶胶-凝胶法、水热法等。

在选择合适的方法后,
制备出粒径适宜的氧化锆粉末,作为成型的原料。

2. 注模模具设计制作:根据所需的微珠尺寸和形状,设计并制作合适的注模模具。

通常采用精密机械加工方法制造出模具,以确保微珠的尺寸和形状精度。

3. 凝胶注模成型工艺参数优化:在进行凝胶注模成型过程中,需要优化一系列工艺参数,如注模温度、注模压力、注胶速度等。

通过对这些工艺参数的优化,可以获得合适的成型质量和良好的一致性。

4. 烧结过程优化:完成凝胶注模成型后,需要进行烧结过程。

在烧结过程中,需要调整烧结温度和时间,以获得高密度、致密均匀的氧化锆陶瓷微珠。

5. 表面处理:为了提高氧化锆陶瓷微珠的表面光洁度和稳定性,可以进行表面处理。

常用的表面处理方法包括研磨、抛光、涂层等,通过这些方法可以得到表面平整光滑的氧化锆陶瓷微珠。

综上所述,凝胶注模成型工艺研究涉及到原材料制备、模具设计制作、工艺参数优化、烧结过程优化和表面处理等方面,通
过对这些方面的研究和优化,可以获得高质量的亚毫米级氧化锆陶瓷微珠。

凝胶注膜成型

凝胶注膜成型

溶剂
+ 有机 单体
+ 交联

无机粉体+分散剂 预混液
研磨 混合
脱气
脱模
固化
机加工
干燥
排胶
注膜
.
烧结
料浆 催化剂+引发剂
★ 凝胶注膜成型工艺的基本原理
Gelcasting工艺的基本原理是在低粘度高 固相含量的料浆中加入有机单体,在催化剂和 引发剂的作用下,使料浆中的有机单体交联聚 合成三维网状结构,从而使料浆原位固化成型。 然后再进行脱模、干燥、去除有机物、烧结, 即可得到所需的陶瓷零件。
近年Gelcasting已经用生产各种陶瓷制品,从单 一组分到复合组分,从简单的片状、管状、到复杂的 叶片、齿轮、涡轮转子,从结构陶瓷到功能陶瓷。
今后,该工艺的应用还应进一步拓展,从非金属 粉末要逐步推广到金属领域,其尺寸范围要进一步扩 大,目前主要应用于微米级颗粒成型和较粗的耐火材 料成型,纳米颗粒的应用相对较少,细、密、匀、纯 是性能优良材料的必要条件,因此研究纳米级颗粒注
.
★ 凝胶注膜成型工艺的发பைடு நூலகம்趋势
凝胶注模成型工艺自问世以来,得到了迅猛发 展,其应用前景极为广阔,值得进一步研究开发,其 今后的发展方向主要有以下几个方面。 ① 应用领域的拓展 ② 环境友好型凝胶体系的开发 ③ 合理的凝胶固化方法的研究 ④ 与激光选区烧结成型技术联用 ⑤ 热可逆凝胶注模成型的发展
凝胶注膜成型工艺
.
主要内容
★ 凝胶注膜成型工艺简介 ★ 凝胶注膜成型工艺特点 ★ 凝胶注膜成型工艺流程图 ★ 凝胶注膜成型工艺的基本原理 ★ 凝胶注膜成型工艺的发展趋势 ★ 参考文献
.
★ 凝胶注膜成型工艺简介

凝胶注模成型制备Sialon陶瓷的研究进展

凝胶注模成型制备Sialon陶瓷的研究进展

凝胶注模成型制备Sialon陶瓷的研究进展引言Sialon陶瓷是一种具有优良性能的先进陶瓷材料,具有优异的耐磨、耐腐蚀、耐高温等特点,因此在陶瓷制品的领域中具有广泛的应用前景。

凝胶注模成型是一种先进的陶瓷成型方法,能够制备高质量、复杂形状的陶瓷制品。

近年来,凝胶注模成型制备Sialon陶瓷的研究成果逐渐增多,取得了一系列令人瞩目的进展,本文将对此进行综述。

一、Sialon陶瓷的特点Sialon陶瓷是由氧化铝(Al2O3)、氮化硅(Si3N4)和氮化铝(AlN)等原料经过高温反应烧结而成的陶瓷材料。

Sialon陶瓷具有以下特点:1. 高硬度:Sialon陶瓷的硬度高于普通金属材料,具有优异的耐磨性能。

2. 良好的耐热性:Sialon陶瓷能够在高温环境下保持较好的物理和化学性能。

3. 耐腐蚀性:Sialon陶瓷能够在酸碱等恶劣环境中保持稳定,不易受腐蚀。

4. 机械性能优异:Sialon陶瓷具有良好的抗拉强度和弹性模量,具有较高的机械稳定性。

二、凝胶注模成型技术凝胶注模成型是一种制备复杂形状陶瓷制品的先进成型技术,其主要步骤包括:1. 凝胶制备:通过将适量的陶瓷粉末与有机物混合,并在特定条件下形成凝胶。

2. 模具设计:设计复杂形状的模具结构,以满足产品的几何要求。

3. 注浆成型:将凝胶注入模具中,使得凝胶在模具中充分充填。

4. 脱脱模:将充填好的凝胶模具进行脱模,得到所需的绿态陶瓷制品。

5. 烧结处理:对绿态陶瓷进行高温烧结处理,使其得到致密的陶瓷制品。

凝胶注模成型技术能够制备复杂形状的陶瓷制品,具有成本低、生产效率高等优点,因此在制备Sialon陶瓷制品的过程中具有广泛的应用前景。

三、凝胶注模成型制备Sialon陶瓷的研究进展1. 凝胶制备工艺凝胶注模成型制备Sialon陶瓷的关键是凝胶的制备工艺。

研究表明,使用聚乙烯醇(PVA)、聚甲基丙烯酸甲酯(PMMA)等有机物作为凝胶添加剂,能够有效改善陶瓷粉末的分散性,提高绿态陶瓷的成型性能。

陶瓷成型工艺 英语

陶瓷成型工艺 英语

陶瓷成型工艺在英语中通常被称为Ceramic forming processes 或Ceramic shaping techniques。

下面是一些常见的陶瓷成型工艺及其英文表达:
1. 压制(Pressing):在固体粉末中施加高压力以形成所需形状。

2. 注射成型(Injection Molding):将陶瓷浆料注入模具中,通过压力使其充满模具并形成所需形状。

3. 挤出(Extrusion):将陶瓷浆料通过模具挤出,形成连续的截面。

4. 滚压(Roller Compaction):通过在陶瓷粉末上施加辊子的压力,使其在模具中形成所需形状。

5. 粘土成型(Clay Forming):使用湿陶瓷粘土,在模具或手工塑造的过程中形成所需形状。

6. 烧结(Sintering):将成型好的陶瓷件置于高温下,使其颗粒结合并形成固体。

7. 热等静压(Hot Isostatic Pressing):在高压和高温环境下对陶瓷进行均匀压实和烧结。

8. 凝胶注模(Gel Casting):将悬浮在溶胶中的陶瓷颗粒注入模具中,通过凝胶状态的溶胶固化形成所需形状。

9. 胶结(Bonding):使用陶瓷粉末或陶瓷涂层将两个
或多个陶瓷件粘合在一起。

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硅酸盐学报· 1620 ·2008年部分稳定氧化锆陶瓷的凝胶注模成型工艺仝建峰,陈大明(北京航空材料研究院,先进复合材料国防科技重点实验室,北京 100095)摘要:用流变学的方法研究了不同条件,如:固相含量、分散剂加入量、烧结助剂、增塑剂等对碱性部分稳定氧化锆(partially stabilized zirconia, PSZ)悬浮体的流变性的影响。

结果表明:分散剂含量对悬浮液的流变性能有明显影响,当PSZ固相体积含量为55%时,分散剂加入量(占固相含量的质量分数)应为0.4%。

当固相体积含量为50%~56%时,氧化锆碱性料浆呈现剪切变稀行为,具有较低的黏度(在剪切速率为10 s–1时,低于50mPa·s)。

氧化锆陶瓷碱性料浆(pH>7)在低的剪切速率(<100s–1)时,表现为剪切变稀。

凝胶注模法生产的PSZ陶瓷坯体的内部结构是均匀的。

关键词:部分稳定氧化锆;凝胶注模;流变特性中图分类号:O373 文献标识码:A 文章编号:0454–5648(2008)11–1620–05PREPARATION OF PARTIALLY STABILIZED ZIRCONIA CERAMIC BY AQUEOUS GELCASTINGTONG Jianfeng,CHEN Daming(The National Key Laboratory of Advanced Composite Materials, Beijing Institute of Aeronautical Materials,Beijing 100095, China, Beijing 81–3 100095, China)Abstract: A partially stabilized zirconia (PSZ) ceramic was prepared by aqueous gelcasting. The effects of the zeta potentials, solid loading, dispersant content and milling time on the PSZ suspension were studied. The dispersant content has a remarkable effect on the rheological properties of the suspension. The appropriate dispersant mass fraction for PSZ aqueous slurry with the solid loading of 55% in volume is 0.4%. All suspensions (50%−56% solid loading) exhibit a shear-thinning behavior and relatively low viscosity (less than 50mPa·s, at a shear rate of 10s–1), which is suitable for casting. The degree of shear thinning and the viscosity at high shear rates increase with the increasing of volume fraction of solid phase. As the milling time is prolonged, the viscosity of the suspension de-creases first, and then a plateau appears and the average diameter remains unchanged. When the milling time is shorter than 20h, the viscosity of the slurry decreases gradually as the time of milling is increased. After 20h milling, the viscosity of the slurry tends to be consistent. Therefore, the ball milling time should be equal to or more than 20h in order to obtain a stable suspension at equilibrium. The appropriate time for casting the slurry (idle time) can be controlled by the amounts of initiator and catalyst added to the slurry as well as by the processing temperature. According to micrographs, the gelcasting green body is homogeneous.Key words: partially stabilized zirconia; gelcasting; rheologic propertyGelcasting is an attractive new ceramic forming proc-ess for making high-quality, complex-shaped ceramic bodies.[1–6] Gelcasting has many distinct advantages compared with conventional ceramic forming processes such as dry pressing, slip casting, tape casting, and injec-tion molding, and it is a near-net-shape forming process. Its products have high green density, low levels of or-ganic additives and machinability in the green state due to a high strength.[7–15]Both non aqueous and aqueous solvents can be used in gelcasting. But aqueous systems are preferred be-cause the use of water as the solvent has many advan-tages, e.g., less departure from traditional ceramic processing and no environmental problems for disposal. In aqueous gelcasting, acrylamide and methylene bis-acrylamide are commonly used to make monomer solu-tions.[11–18]According to previous studies,[1–21 the composition of monomer solution, the amounts of initiator and catalyst added, and the temperature and humidity of the drying atmosphere are important processing parameters to be controlled for optimum gelcasting. In this work, a par收稿日期:2008–04–25。

修改稿收到日期:2008–07–03。

基金项目:国家自然科学基金(50672091)资助项目。

第一作者:仝建峰(1972—),男,博士,高级工程师。

Received date:2008–04–25. Approved date: 2008–07–03. First author: TONG Jianfeng (1972–), male, doctor, senior engineer. E-mail: jftong@第36卷第11期2008年11月硅酸盐学报JOURNAL OF THE CHINESE CERAMIC SOCIETYVol. 36,No. 11November,2008仝建峰等:部分稳定氧化锆陶瓷的凝胶注模成型工艺· 1621 ·第36卷第11期tially stabilized zirconia (PSZ) ceramic was prepared by aqueous gelcasting. The effects of the zeta potentials, solid loading, dispersant content and milling time on the PSZ suspension were studied.1 Experimental procedure1.1 GelcastingThe PSZ powder used in the test was commercial grade, produced by Jiangxi Fanmeiya Co., Ltd. in China. Its average size was 0.4μm. The chemical composition in mass of the powder was >94% ZrO2, 5.2% Y2O3, <0.01% SiO2, <0.005% Fe2O3, <0.005% Na2O, <0.005% Al2O3, <0.02% Cl–1. Its average specific surface area was 12m2/g.The essential components of the gelcasting process were the reactive organic monomers: mono-functional acrylamide, C2H3CONH2 (AM), and difunctional, N, N- methylene bisacrylamide, (C2H3CONH)2CH2(MBAM). These monomers were dissolved in deionized water to give a premix solution. The premix solution undergoes free radical initiated vinyl polymerization in the presence of an initiator such as ammonium presulfate, (NH4)S2O8. The reaction is accelerated by heat or by the catalyst N,N,N,N-tetramethylenediamine (TEMED). The result-ing cross-linked polymer is an elastic hydrogel that serves as the binder.[1–6]The gelcasting process flow chart is shown in Fig.1. The monomers were dissolved in deionized water to make solution with a composition of 2.5% (mass fraction according to the mass of PSZ powder solid loading, the same below) AM, 0.125% MBAM. Gelcasting slurriesFig.1 Flow chart of preparing PSZ by gelcasting were prepared by ball-milling the PSZ powder in the monomer solution. 0.4% JA281 (a dispersant produced by Beijing Institute of Aeronautical Materials, Beijing, China) were added to the slurries. In the slurries the solid loading was about 55% (volume fraction, the same be-low), and the total amount of organic monomers was 3.2% for the PSZ powder. Both the initiator, 1% aqueous solution of ammonium persulphate, and the catalyst, 50% aqueous solution of TEMED, were added just before mold casting. After gelling, the disk-shaped samples were demolded and dried in lab atmosphere.1.2 Properties measurementThe zeta potentials at different suspension pH values were measured by a zeta potential meter. The rheological properties of the ceramic slurry were measured by a ro-tary rheometer (Model RV–30, US). The densities of the green bodies were calculated from the volume measured by a mercury displacement method. The dried green body was cut into sample bars with a width of 6mm, a height of 5mm and a length of 36mm. Their room temperature bending strength was examined by the three-point flexure test with a span of 30mm and a cross head speed of 0.5 mm/min. The microscopic morphology was observed by a scanning electron microscope (SEM, Model Jonel–2000).2 Results and discussion2.1 Effects of pH value on zeta potential of PSZsuspensionThe zeta potentials at different pH values of the sus-pensions are shown in Fig.2. After dispersant is added, the isoelectric point (pH iep value) will decrease from 7.5 to 7.0. At lower pH, far from the pH iep value, the PSZ particles have a high positive zeta potential and are col-loidal stable. In the vicinity of the pH iep value, the parti-cles have a low zeta potential that may be either positive (pH<pH iep) or negative (pH>pH iep). The suspensions pre-pared within this region are colloidal unstable, consisting of large agglomerates that are likely to lead to porous gelcast ceramics. At higher pH values, far from the pH iepFig.2 Zeta potentials of PSZ as a function of pH value硅酸盐学报· 1622 ·2008年value, the particles have a high negative zeta potentialand are colloidal stable. The profiles in Fig.2 show thatthe zeta potential is maximized at pH=11, which can pro-vide better colloidal stability.2.2 Rheology characteristic2.2.1 Effect of dispersant on the slurry rheology For the PSZ aqueous slurry with JA281 as dispersant, the effects of dispersant content on the rheology of the slurry are shown in Fig.3. As seen in Fig.3, the viscosity of the slurry has the minimum value at a dispersant mass frac-tion range of 0.35%–0.40%, beyond which the slurry viscosity increases again. Therefore, the appropriate dis-persant concentration for PSZ aqueous slurry is 0.40%.Fig.3 Variation of slurry viscosity with mass fraction ofdispersant JA281It is well known that the dispersant is a polyunsatu- rated ester molecule, and its dispersive capability is not only determined by steric stabilization, but also the stateof the dispersant in the surface of the particles. The three states of dispersant on the surface of the particles are shown in Fig.4.[22] When the state of the dispersant on the surface of the particles is saturated adsorption, the dis-persant capability is good; however, both unsaturated adsorption and over-saturated adsorption are bad for the dispersing of particles in the solvent.Fig.4 The state of dispersant on the surface of the particles2.2.2 Effect of solid loading on the slurry rheologyFigure 5 (a) gives the plots of apparent viscosity versus applied shear rate of stable suspensions after millingFig.5 Rheological behavior of the suspensions with different solid loadings (in volume, the same below) after ballmilling for 24hfor 24h. It can be seen that all suspensions (50%−56% solid loading) exhibit a shear-thinning behavior and rela-tively low viscosity (less than 50mPa·s for 10s–1), and are suitable for casting. Figure 5 (b) shows the plots of the relationship of shear stress versus the applied shear rate of stable suspensions after milling for 24h. It can be seen that the suspensions with 50%−56% solid loading do not possess thixotropy.General concentrated colloidal stable suspensions ex-hibit shear-thinning behavior in steady shearing because of a perturbation of the suspension structure by shear-ing.[8–16] At lower shear rates, the suspension structure is close to equilibrium because the thermal motion domi-nates over the viscous forces. At higher shear rates, the viscous forces affect the suspension structure and shear thinning occurs. At very high shear rates, the viscous forces have a dominant affect and the viscosity can be considered as a measurement of the resistance to flow of a suspension with a completely hydrodynamically con-trolled structure. The degree of shear thinning and the viscosity at higher shear rates increase with the increas-ing of the volume fraction of the solid.2.2.3 Effect of milling time on the slurry rheologyTypical plots of apparent viscosity versus different times仝建峰 等:部分稳定氧化锆陶瓷的凝胶注模成型工艺· 1623 ·第36卷第11期of ball milling for different volume fractions of solid are shown in Fig.6. When the milling time is shorter than 20 h, the viscosity of the slurries decreases gradually with the increase of the milling time. This shows that the absorption of the dispersant on parti-cles cannot reach equilibrium and the suspension is unstable until the ball milling time is equal to or more than 20 h. After 20 h milling, the viscosity of the slurry tends to be consistent. Therefore, the ball milling time should be equal to or more than 20 h to obtain a stable suspension atequilibrium.Fig.6 Effect of milling time on the slurry viscosity of the sus-pensions with different solid loadings2.3 Gelling2.3.1 The effect of initiator, catalyst and temperature on gelling rate In the present study, the initiation of po-lymerization in premixes is determined by changes in solution temperature, since the reaction is exothermic. The process was monitored in terms of idle time, t idle , the time between the addition of the initiator, or the initia-tor/catalyst and the commencement of polymerization. This is equivalent to the time used for casting the slurry during processing. Figure 7 shows the change in tem-perature of a premix solution during gelling and indicates the idle time.Fig.7 Effect of content of the catalyst on the idle timeIni.—Initiator amount; Cat.—Catalyst amount.The idle time can be controlled by the concentration ofthe reagents and the temperature. In this study, the idle time ranged from 5 to 60 min. Figure 7 shows the varia-tion of idle time with the amount of initiator and catalyst, and Fig.8 shows the variation of idle time with initiator and solution temperature. These data show clearly that polymerization is accelerated by an increase in initiator,catalyst or temperature.Fig.8 Effect of contents of the initiator and temperature on theidle time2.3.2 The density and strength of gelcast green bodies The effect of polymer content on the density and strength of the gelcast sample is shown in Fig.9. The maximum density is obtained at a polymer content of ~6% in mass. The green strength, on the other hand, increases more or less linearly with the binder content. The maximum relative density of the green body ob-tained is 58%; at this density, the strength is 46 MPa.Fig.9 Effect of binder content in mass on the density andstrength of green bodies2.3.3 Micrograph of gel-cast green bodies Figure 10 shows the SEM photographs of a dry body. It can be seen that powders are connected by slender polymer chains, which are responsible for the strength of the green body. It can also be seen that the micrographs of the edge and center section were homogeneous.硅酸盐学报· 1624 ·2008年Fig.10 SEM photographs of gelcast green bodies3 Conclusions(1) Aqueous gelcast PSZ slurry has low viscosity at high solid loading.(2) The characteristics of the slurry are connected with the dispersant, solid loading and milling time.(3) The density and strength of gelcast green bodies can be controlled by varying the monomer concentration.(4) The time required for casting the slurry (idle time) can be controlled by the amounts of initiator and catalyst added to the slurry as well as by the processing tempera-ture.(5) The microstructure of the gelcast green is homo-geneous.Reference:[1] JANNEY M A, OMETETE O O. Gelcasting of ceramic powders [P].US Patent, 5145908. 1992–05–12.[2] OMETETE O O, JANNEY M A, STREHLOW R A. Gelcasting–a newceramic forming process [J]. Ceram Bull, 1991, 70(10): 1641–1648. [3] JANNEY M A. Method for molding ceramic powders [P]. US Patent,4894194. 1990–03–15.[4] LANGE F F. V ALAMAKANNI B V. Method of preparing dense ce-ramic product [P]. US Patent, 5188780. 1991–11–13.[5] TIEGS T N,WITTMER D E. Method of preparing a high solids content,low viscosity ceramic slurry [P]. US Patent, 5456877. 1994–09–12. [6] GAUCKLER L J,GRAULE T. Method for forming green ceramics [P].U.S. Patent, 5788891. 1996–11–02.[7] MORISSETTE S L. Chemorheology of aqueous-based alumina-poly(vinyl alcohol) gelcasting suspensions [J]. J Am Ceram Soc, 1999, 82(3): 521–527.[8] YANEZ J A. Shear modulus and yield stress measurement of attractivealumina particle networks in aqueous slurries [J]. J Am Ceram Soc, 1996, 79(11): 2917–1921.[9] HIDDER P C, GRAULE T J, GAUCKLER L J. Citric acid–a dispers-ant for aqueous alumina suspensions [J]. J Am Ceram Soc, 1996, 79(7): 1857–1867.[10] REED J S. Principles of Ceramics Processing [M]. Second Ed. NewYork: John Wiley and Sons, Inc. 1995: 96–97.[11] YOUNG A C, OMETETE O O, JANNEY M A. Gelcasting of alumina[J]. J Am Ceram Soc, 1991, 74(3): 612–616.[12] MARIA J P, KIGGANS J O, TIEGS T N. Gelcasting of sinteredreaction bonded silicon nitride for improved mechanical properties [J].Ceram Eng Sci Proc, 1995, 16(5): 1071–1074.[13] CARISEY T, WERTH A L, BRANDON D G. Control of texture inAl2O3 by gelcasting [J]. J Eur Ceram Soc, 1995, 15(1): 1–8.[14] BASKIN D M, ZIMMERMAN M H, FABER K T. Forming single-pHas a laminates via the gelcasting technique [J]. J Am Ceram Soc, 1991, 74(3): 612–615.[15] DUNCAN J S. Introduction to Colloid and Surface Chemistry [M].London: Bitterworth & Co, 1980: 35–36.[16] MOONEY M. The viscosity of concentrated suspension of sphericalparticles[J]. J Coll Sci, 1956, (6): 162–165.[17] CESARANO Ⅲ J, AKSAY I A. Processing of highly concentratedaqueous α-Al2O3 suspensions with poly (methacrylic acid) polyelec-trolyte [J]. J Am Ceram Soc, 1990, 71(4): 250–254.[18] OVERBEEK H V. On the theory of the stabilization of dispersions byadsorbed macromolecules, I statistics of the change of some configura-tional properties of adsorbed macromolecules on the approach of an impenetrable interface [J]. J Phys Chem, 1971, 75(1): 65–68.[19] OVERBEEK H V. On the theory of the stabilization of dispersions byadsorbed macromolecules, Ⅱ interaction between two flat particles [J]. J Phys Chem, 1971, 75(10): 2094–2097.[20] STRBLE L J, ZUKOSKI C F, MAITLAND G C, et al. Flow andmicrostructure of dense suspension [J]. Mater Res Soc, 1992, 72(4): 123–127.[21] BASKIN D M, ZIMMERMAN M H, FABER K T. Forming sin-gle-phase laminates via the gelcasting technique [J]. J Am Ceram Soc, 1991, 74(3): 612–616.[22] OVERBEEK H V. On the theory of the stabilization of dispersions byadsorbed macromolecules,Ⅱinteraction between two flat particles [J].J Phys Chem, 1971, 75(10): 2094–2097.。

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