氮化铝陶瓷的湿法成型工艺 |
添加时间:2018/11/16 16:02:51 浏览次数: |
氮化铝陶瓷的湿法成型工艺
Wet forming process of aluminum nitride ceramics
氮化铝陶瓷具有优良的绝缘性、导热性、耐高温性、耐腐蚀性以及与硅的热膨胀系数相匹配等优点,成为新一代大规模集成电路、半导体模块电路及大功率器件的理想散热和封装材料。成型工艺是陶瓷制备的关键技术,是提高产品性能和降低生产成本的重要环节之一。
Aluminum nitride ceramics have excellent insulation, thermal conductivity, high temperature resistance, corrosion resistance and the matching of thermal expansion coefficient of silicon and so on. It has become an ideal heat dissipation and packaging material for a new generation of large-scale integrated circuits, semiconductor module circuits and high-power devices. Molding technology is the key technology of ceramic preparation, and it is one of the important links to improve product performance and reduce production cost.
随着工业技术的高速发展,传统的成型方法已难以满足人们对陶瓷材料在性能和形状方面的要求。陶瓷的湿法成型近年来成为研究的重点,因为湿法成型具有工艺简单、生产效率高、成本低和可制备复杂形状制品等优点,易于工业化推广。
With the rapid development of industrial technology, traditional molding methods have been unable to meet the requirements of ceramic materials in terms of performance and shape. Wet molding of ceramics has become the focus of research in recent years, because the wet molding has the advantages of simple process, high production efficiency, low cost and preparation of complex shape products. It is easy to be popularized in industrialization.
湿法成型包括流延成型、注浆成型、注射成型和注凝成型等。
Wet forming includes tape casting, injection molding, injection molding and injection molding.
1.氮化铝陶瓷的流延成型
Casting of 1. aluminum nitride ceramics
料浆均匀流到或涂到支撑板上,或用刀片均匀的刷到支撑面上,形成浆膜,经干燥形成一定厚度的均匀的素坯膜的一种料浆成型方法。流延成型工艺包括浆料制备、流延成型、干燥及基带脱离等过程。
The slurry is uniformly flowing to or coated on the supporting plate, or the blade is evenly brushed to the support surface to form a slurry, and a slurry forming method is formed to form a uniform plain film of a certain thickness by drying. Tape casting process includes slurry preparation, tape casting, drying and baseband detachment.
溶剂和分散剂
Solvent and dispersant
高固相含量的流延浆料是流延成型制备高性能氮化铝陶瓷的关键因素之一。溶剂和分散剂是高固相含量的流延浆料的关键。溶剂必须满足以下条件:
High solid content casting tape is one of the key factors to produce high performance AlN Ceramics by tape casting. Solvents and dispersants are the key to casting slurry with high solid content. The solvent must meet the following conditions:
(1)必须与其他添加成分相溶,如分散剂、粘结剂和增塑剂等;
(1) it must be dissolved with other additives such as dispersants, adhesives and plasticizers.
(2)化学性质稳定,不与粉料发生化学反应;
(2) the chemical property is stable and does not react with the powder.
(3)对粉料颗粒的润湿性能好;
(3) the wettability of powder particles is good.
(4)易于挥发与烧除;
(4) easy to volatilize and burn out;
(5)使用安全、卫生且对环境污染小。
(5) It is safe, hygienic and has little environmental pollution.
常用有机溶剂与水的物理性质
The physical properties of common organic solvents and water
粘结剂和增塑剂
Adhesives and plasticizers
在流延浆料中加入粘结剂与增塑剂主要是为了提高薄片的强度和改善薄片的韧性及延展性。流延薄片在室温下自然干燥时,溶剂不断挥发,粘结剂则能自身固化成三维网络结构防止薄片中的颗粒沉降,并且赋予薄片一定的强度。增塑剂的引入保证了薄片的柔韧性,同时降低了粘结剂在室温和较低温度时的玻璃化转变温度。
The addition of binder and plasticizer in tape casting is mainly aimed at improving the strength of the sheet and improving the toughness and ductility of the sheet. When the strip is naturally dried at room temperature, the solvent volatilizes continuously. The binder can solidify into a three-dimensional network structure to prevent the particles from settling in the sheet, and gives a certain strength to the thin sheet. The introduction of plasticizers ensures the flexibility of the lamellae while reducing the glass transition temperature of the binder at room temperature and lower temperature.
流延成型的工艺特点:
The technological characteristics of the casting process:
优点:设备不太复杂,工艺稳定,可连续生产,效率高,自动化程度高,坯膜性能均一且易于控制, 适于制造各种超薄形陶瓷器件,氧化铝陶瓷基片等。
Advantages: the equipment is not too complex, the process is stable, the production is continuous, the efficiency is high, the degree of automation is high, the performance of the billet film is uniform and easy to be controlled. It is suitable for the manufacture of various ultrathin ceramic devices, alumina ceramic substrate and so on.
缺点:坯体密度小,收缩性高。
Shortcomings: the density of the body is small, and the shrinkage is high.
2.氮化铝陶瓷的注射成型
Injection molding of 2. aluminum nitride ceramics
陶瓷注射成型技术(CIM)是一种制造复杂形状陶瓷零部件的新兴技术,在制备复杂小部件方面有着其不可比拟的独特优势。随着近年来全球范围内电子陶瓷产业化规模的不断扩大,CIM 技术诱人的应用前景更值得期待。该工艺主要包括喂料制备、注射成型、脱脂和烧结。
Ceramic injection molding (CIM) is a new technology for making ceramic parts with complex shapes. It has its unique advantages in the preparation of complex small components. With the expansion of the scale of electronic ceramics in recent years, the application prospect of CIM technology is worth looking forward to. The process mainly includes feeding preparation, injection molding, degreasing and sintering.
粘结剂
binder
粘结剂是氮化铝陶瓷粉末的载体,决定了喂料注射成形的流变性能和注射性能。良好的粘结剂可起到形状维持的作用,且有效减少坯体变形和脱脂缺陷的产生。
The binder is the carrier of aluminum nitride ceramic powder, which determines the rheological and injection properties of the injection molding. Good binder can play the role of shape maintenance, and effectively reduce the deformation and defatting defects of the green body.
陶瓷注射成型粘结剂须具备以下条件:
Ceramic injection molding binder must meet the following requirements:
(1)流动特性好,注射成型黏度适中,且黏度随温度不能波动太大,以减少缺陷产生;
(1) flow characteristics are good, injection molding viscosity is moderate, and viscosity can not fluctuate too much with temperature, so as to reduce defects.
(2)对粉体的润湿性和粘附作用好;
(2) the wettability and adhesion of the powder are good.
(3)具有高导热性和低热膨胀系数。
(3) high thermal conductivity and low thermal expansion coefficient.
(4)一般由多组分有机物组成,单一有机粘结剂很难满足流动性要求。
(4) generally composed of multi component organic matter, single organic binder is difficult to meet the liquidity requirements.
排胶工艺
Sizing process
由于注射成型坯体中有机物含量较高,排胶过快会造成坯体开裂、起泡、分层和变形,因此,如何快速高效排胶成为注射成型的一大难点。排胶工艺包括热排胶和溶剂排胶。起初主要采用热排胶,简单地把有机物烧除,这种方式能耗高、时间长。为了提高排胶效率,一些学者探索了溶剂排胶的工艺。由于粘结剂中石蜡占比重较大,溶剂排胶主要是将坯体中的石蜡溶解,其他粘结剂仍能维持坯体形状。溶剂排胶结合热工艺排胶可以大大缩短排胶时间。
Because of the high content of the organic matter in the injection molding body, the fast sizing of the glue can cause the cracking, foaming, delamination and deformation of the body. Therefore, how to quickly and efficiently drain the glue has become a difficult point in the injection molding. The sizing process includes hot glue and solvent drainage. In the beginning, the main purpose was to remove the organic matter simply by using heat discharge glue. This method has high energy consumption and long time. In order to improve the efficiency of gel discharge, some scholars have explored the technology of solvent discharge. Because the proportion of paraffin wax in the binder is large, the solvent is mainly used to dissolve the paraffin wax in the green body, and other binder can maintain the shape of the green body. The combination of solvent discharge and thermal process can greatly shorten the time of rubber discharging.
注射成型的工艺特点:
The technical characteristics of injection molding:
(1)可近净尺寸成型各种复杂形状,很少(或无需)进行机械加工;
(1) all kinds of complex shapes can be formed in near net dimensions, with little or no mechanical processing.
(2)成型产品生坯密度均匀,且表面光洁度及强度高;
(2) the green density of molded products is uniform, and the surface finish and intensity are high.
(3)成型产品烧结体性能优异且一致性好;
(3) The sintered products have excellent properties and good consistency.
(4)易于实现机械化和自动化生产,生产效率高。
(4) it is easy to realize mechanization and automatic production, and the production efficiency is high.
3.氮化铝陶瓷的注凝成型
The injection molding of 3. aluminum nitride ceramics
该工艺的基本原理是在黏度低、固相含量高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形成三维网状结构,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。
The basic principle of this process is that organic monomers are added to the slurry with low viscosity and high solid content. Under the action of catalyst and initiator, the organic monomer in the slurry is crosslinked together to form a three-dimensional network structure, and the slurry is solidified in situ, and then demoulding, drying, removing organic matter and sintering can be obtained. The required ceramic parts.
注凝成型的工艺特点:
The technological characteristics of injection molding are:
坯体强度高、坯体整体均匀性好、可做近净尺寸成型、适于制备复杂形状陶瓷部件和工业化推广、无排胶困难、成本低等。
The strength of the body is high, the integral uniformity of the body is good, it can be formed near the net size, suitable for the preparation of complex shape ceramic components and industrial popularization, no difficulty in discharging glue and low cost.
目前流延成型和注射成型在制备氮化铝陶瓷方面具有一定优势,随着科学技术的发展以及人们对环境污染的重视,凝胶流延成型和注凝成型必然会取代
Current casting and injection molding have some advantages in the preparation of aluminum nitride ceramics. With the development of science and technology and people's attention to environmental pollution, gel casting and injection molding will inevitably replace it. |
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