DE1471433B2 - Process for the production of pressed, especially extruded ceramic materials - Google Patents

Description

Vibrating mill, the addition of a small amount of stearate resulting in a further improvement in the pressing properties. The method according to the invention can also be applied to the pressing of such substances which are only reshaped into ceramic substances during sintering after pressing. Such starting materials are, for example, metal oxides such as Fe ₂ O ₃ , MnO and ZnO, which are transformed into manganese-zinc-ferrite during sintering.

An example of the method according to the invention is given below:

A sintered at about 110o C ⁰ mixture of Fe ₂ O _3, MnO and ZnO is mulled for 6 hours drying in a ball mill with 1.7 weight percent ammonium alginate and 0.3 weight percent zinc stearate. The grist is then mixed in a mixer for 30 minutes with 0.6 percent by weight glycol, 2.3 percent by weight of a wax emulsion and 15 percent by weight water. Antenna rods with a diameter of 10 mm are extruded from this mixture. After drying, the strands are cut to the desired antenna rod length and sintered in a known manner in a continuous furnace at about 1200 ° C. Ammonium alginate has the advantage that there are no undesirable

ίο Residues after sintering in the ceramic Bodies remain.

It turns out that such a process is an important one compared to the process known since then Reduction in manufacturing costs

iS leads without the electrical and magnetic Properties of the antenna rods produced according to the invention are deteriorated.

Claims (4)

About 20 percent by weight of water was added to the patent claims: to convert the inherently non-plastic mix into a plastic mass. This plastic mass will 1. Process for the production of pressed, mixed in turn for about 30 minutes, pelletized and, special extruded ceramic materials, 5 then up to a moisture content of about 0.25% taking to improve their flowability and dried. These granules are sufficient Raw strength the ground and press-ability, without any particular difficulty, too the non-plastic substances to be passed through extrusion with a binding to medium and then to form a compact with sufficient raw strength. Lubricants are provided, thereby ge io This compact is then sintered denotes that the unground, un- subject. plastic substances dry with the binding through »lecture hall for ceramics, glass and enamel«, medium and with a stearate and with 1955, pp. 287 to 290, is the use of this to be ground. Sodium carboxy methyl cellulose in ceramic 2. The method according to claim 1, characterized in that masses are known. This cellulose leaves the indicates that alginate as a binder burns tensile, z. B. during sintering, a considerable will give. Ash residue, which makes usability so 3. The method according to claim 1, characterized in particular placed ceramics to electrical engineering, that about 6 hours when seen dry is extremely impaired, will grind. 20 From this reference it is also known 4. The method according to one of the preceding in the preparation of plastic molding compounds Claims, characterized in that one for earthenware and porcelain in addition to wet mixing Glycol wax emulsion solution as a lubricant also apply a dry mix. While at is admitted. ceramic masses used for earthenware and 25 porcelain production are used, starting substances Find use that already contain a number of additives that give the raw material a very significant amount To impart plasticity, this is the case with oxides The invention relates to a method for the manufacture of ferrite and titanate not the case, position of pressed, in particular extruded, 30 The present invention is the task of zukeramischer Materials, such as barium grounds, a process for the production of pressed, titanate, manganese-zinc-ferrite or the like, with in particular extruded ceramic work improvement for the purpose of compression Their flowability and raw strength create the materials. This should focus on the evaporation ground and non-plastic excess water to be compressed in the mixed material as far as Substances can be mixed with a binding agent and possibly dispensed with. In addition, the press closing be provided with a lubricant. pressure by increasing the flowability of the zu Since these non-plastic ceramic materials pressing ceramic material is reduced especially in electrical engineering z. B. be as Dielek-. trica for ceramic capacitors or as ferro- To solve the above problem Magnetics for electrical coils and the like used 40 sees the invention in a method of the opening paragraph It is also desirable to have the electrical propriety mentioned before that the unground, unplastic such ceramic body to see substances dry with the binder and A stearate is added to the desired intended use and ground with this fit. For example, special emphasis will be placed on. low losses of such ceramic dielectrics 45 It has been shown that especially in the case of or ferromagnetic materials. Use of alginate as a binding agent and the dry In order to meet these requirements, it must be possible to omit the pressing, grinding of this binding agent with the non-plastic process, in particular the type of ceramic powder used for the pressing process, wet grinding and the pressing mixture subjected to it, drying process for this purpose, without being suitable. So you already have the inherently un- 50 the pressing properties compared to the known plastic ceramic mass, so that they are worsened by the pressing process. The flowability is adapted to the process by suitable binding and even improved and the pressure of example lubricants, so-called plasticizers, 'plastically reduced ^{0.5 to 0.3 t / cm 2.} The raw part is made. Ceramic substances are here strength is about 150 compared to 100 kg / cm ² to understand raw materials that are actually 55 when polyvinyl alcohol solution is used, which are not yet ceramics in the actual sense after an expensive wet grinding process, but are starting materials ceramic regrind is added for the ceramic. Forming it dry, as is the case, for example, with the binding agent used for ferrite, is represented by the metal oxides required for fine grinding, in particular for production. In those in vibratory mills, particularly fine and similar to British patent specification 729 538 is carried out, 60 moderately distributed in the powder. This is expressed later that the starting substances are calcined and then in a homogeneous structure of the compacts and a ßend with an equally large amount of water in an increased raw part strength. Furthermore, as a result of the ball mill, it is to be ground. After this good distribution, the flowability of the drying of the ground material to be digested takes place so far that pressing substances are better and consequently the only about 0.5% moisture content in the drying pressure is lower than with powders that are after the neten substance is included. Be prepared according to this previously known procedure,
drive will be an aqueous paraffin wax emulsion The addition of the binder and the dry as a binder, zinc stearate as a lubricant and grinding are advantageously carried out in a ball or