HU190776B - Wear-resisting details - Google Patents

Abstract

The invention relates to the ceramic industry, metallurgy and mechanical engineering. The aim of the invention is the extension of the service life of parts subject to wear as well as the extensive avoidance of damaging grinding and reduction of the milling time during grinding processes in the ceramic industry and metallurgy. The invention has for its object to provide high-wear parts with high abrasion resistance, relatively high density and low production costs. The object is achieved in that the titanium parts consist of 0.5 to 15 atomic percent dissolved oxygen and 0.03 to 7.5 atomic percent dissolved nitrogen, suitably the ratio of oxygen to nitrogen 2: 1. Possible fields of application of the invention are wear-resistant parts in machines and devices, in particular mixing and grinding units, for example for grinding bodies and linings for ball mills.

Description

BACKGROUND OF THE INVENTION The present invention relates to a wear-resistant component, particularly for mixing and grinding equipment, which can be used in the ceramic industry, in the metallurgical industry, and in the field of mechanical engineering under corrosive conditions.

Grinding bodies or grinding drums made of carbide, steel, porcelain, Hint stone, agate, various plastics or titanium are well known in the industry. However, they are quite costly to produce and have the disadvantage that they are contaminated by abrasion due to wear.

Grinding balls containing up to about 97% by weight of titanium oxide and plasticizer or binder such as bentonite or cellulose ether are known (Palatzky, Techn. Keramik, VEB Verlag Technik, Berlin 1954). The disadvantage of such grinding balls is that they have low abrasion resistance and thus require quite frequent replacement. However, these balls also have the disadvantage that their chewed particles contaminate the ground, making processing difficult and impairing the usability of the articles made of it.

A further disadvantage of the above grinding bodies is that they also have a relatively low density (approximately 4 gcm '), which results in a relatively long grinding time.

When 2-10% by weight of lead compound is added to said titanium oxide, the abrasion resistance is almost doubled (1 in German Patent No. 1072,179). However, the abrasion resistance achieved in this way is still relatively low and the use of lead may pose further problems in using the powder.

The purpose of the present invention is to provide wear-resistant components that are long-lasting, prevent dirt from entering the grinding mill and provide reduced grinding time and are thus well suited for the ceramic industry and the metallurgical milling process.

The object of the present invention is solved by the components being made of titanium or titanium-based alloy containing from 0.5 to 15, preferably from 2 to 10, percent of dissolved oxygen and 0.03 to 7.5, preferably from 1 to 6, percent of dissolved nitrogen. contain. The ratio of dissolved oxygen to nitrogen is preferably 2: 1.

When making cylindrical grinding bodies from the alloy according to the invention, it is expedient to perform in-line grinding to round off the roll edges prior to use, with up to 100 hours of filling with clean water.

The components of the invention are very useful in the processing of special ceramic materials sensitive to texture and dirt, such as semiconductors, capacitors and piezoelectric materials.

A further advantage of the present invention is that it is possible to obtain a more uniform particle spectrum during grinding with grinding bodies made of such an alloy than conventionally, and to improve the homogeneity obtained during sintering. This is especially important for ceramic varistors, so that the proper shape and current paths are well formed and local overheating is avoided.

The present invention saves energy by increasing the amount of solids involved in the milling process and reducing the amount of dewatering slurry required.

Further details of the invention will be illustrated by way of example in the drawings. In the drawing it is

Figure 1 shows electrical parameters obtainable using the grinding bodies according to the invention, a

Figure 2 shows the results obtained using conventional agate balls.

Example 1

For cylindrical grinders, titanium was used as a wear-resistant base material with 6 atomic percent dissolved oxygen and 3 atomic percent dissolved nitrogen. Compared to known TiO ₂ -based mills, the life span has been doubled, but the milling time has been shortened by about 20%. Compared to agate balls, with the same wear resistance, the grinding time was reduced by 5 to 8 times and the goods were significantly lower.

Example 2

ZnO-based metal oxide resistors were prepared. In addition to ZnO, the feedstock contained CoO, MnO, Bi ₂ O ₃ , Cr ₂ O ₃ and possibly other metal oxides in a total amount of 1-20 mol%. The product was made using standard ceramic technology. Grinding is carried out in drum mills using the grinding bodies according to the invention, and the same batch composition is milled using agate balls for comparison. The resulting slurry was dewatered using known techniques; the dewatered material was pressed into bodies and sintered at a temperature of 1100 to 1300 ° C. The sintered bodies may be provided with electrodes, such as silver electrodes, by means of screen printing, by various contact methods. Figures 1 and 2 show better electrical parameters achieved using the grinding bodies according to the invention. The results of Figure 2 were achieved with agate balls but with a factor of 5-8 longer milling time. It is well recognized that with the use of the new grinding bodies, low residual I _R currents, high non-linearity values and low V _c varistor voltages can be achieved at very short grinding times.

Example 3

Cold conductor material was prepared. composition of La _x Ba _y Sr _z Ti, was

190,776 where x = 0.001-0.004 y = 0.5-1 z ~ 0-0.5

After weighing and mixing the raw materials, the materials were calcined in bulk at 1000-1200 'Con. The calcined material was ground in water in plastic drums or in a drum lined with an alloy according to the invention for 1 to 10 hours using the same grinding bodies with water. Following the usual drying and shaping procedures used in the ceramic industry, the bodies were shrunk and electrodes provided at temperatures between 1300 and 1450 ° C. Resistance values of 10 to 30 ohms can be achieved with the discs produced in this way, having a diameter of 10-12 mm and a height of 3-5 mm. Such low resistance values have so far only been available with agate balls under the same conditions.

Claims (4)

An abrasion-resistant component, particularly for mixing and grinding equipment, characterized in that it consists of titanium ⁵ or titanium-based alloy containing from 0.5 to 15 atomic percent dissolved oxygen and 0.03 to 7.5 atomic percent dissolved nitrogen. An embodiment of a component according to claim 1, characterized in that it contains 2 to 10 atomic percent dissolved oxygen. An embodiment of a component according to claim 1 or 2, characterized in that it contains from 1 to 6 atomic percent dissolved nitrogen. 4. An embodiment of a component according to any one of claims 1 to 3, characterized in that the ratio of dissolved oxygen to nitrogen is 2: 1.