CS226806B1 - Glass-crystal solder for soldering ferrite elements of magnetic heads - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to glass-crystalline solder for setting ferrite magnetic parts of heads, in particular to form slits of magnetic heads precisely defined geometrically and magnetic widths.

Description

The invention relates to a glassy crystalline solder for setting ferrite parts of magnetic heads, in particular for generating slots of magnetic heads of precisely defined geometric and magnetic widths.

Known glass and glass crystalline solders are known in which the brazing temperatures of the ferrite portions are in the range of 500 to 900 ° C, for example according to U.S. Pat. V. Britain 1,016,937, Pat. U.S. 3,681,044, U.S. Pat. U.S. Pat. No. 3,639,976, U.S. Pat. U.S. Pat. No. 3,954,434, U.S. Pat. V. Britain 1,310,575, Pat. Great Britain 1,320,971.

The disadvantage of glass solders is that, when the magnetic head is operationally used, the glass material is crumbled as the recording material moves due to different glass and ferrite hardnesses. Furthermore, during the construction the diffusion of the glass components into the ferrite occurs and thus the magnetic width of the slit increases compared to the geometric width.

In contrast, glassy crystalline solders usually exhibit higher hardness than glassy solders.

In both cases, however, it is necessary that the coefficient of thermal expansion of the glass or glassy crystalline solder is equal to the coefficient of thermal expansion of the ferrite. Furthermore, the strength of the joint affects the ability of the solder to adhere to the ferrite surface in the slot.

In a number of cases, all of these properties of the known compositions of glass and vitreous crystalline solders do not guarantee.

The glass-crystalline solder according to the invention is based on the above-mentioned requirements, which consists in a content by weight of 65 to 75 lead oxide PbO, 7 to 15 zinc oxide ZnO, 15 to 19 boron oxide BgOg, 1 to 2 iron oxide FegOO. optionally 0.2 to 1 nickel oxide NiO or 0.2 to 1 manganese dioxide ItoOg or 0.1 to 3 titanium dioxide TiO ₂ «

Glasses containing ferric oxide, nickel oxide, titanium dioxide, Fe ₂ Op NiO, TiO ₂ are suitable for building Fe-Zn-Ni ferrites, Glasses containing Fe ₂ O 4, MnO ₂ ,

TiO ₂ for Fe-Zn-Mn ferrite building. These glasses crystallize after melting, i.e. melting and flowing into the ferrite crevice, the crystalline phase consisting predominantly of PbO.2ZNO.B2Q3 in the first case and 4 PbO.BZnO.SBgO4 in the second case and a number of other crystalline phases, for example NiO , FegO .ZnO ^, ^ FejjO .MnOg, PbO.TiO ₂ at a lower concentration.

Table 1 shows exemplary compositions of glassy crystalline solder according to the invention.

Table 1

7o b ^ 0-300 * ¹⁰ L ° S 1¾ td W Průin. microhardness [MPa] At load 0.98 N ozna- čení Weight PbO ZnO ^B Γ 2 ° 3 FegO ^ NiO Mn0 ₂ Ti0 ₂ glassy state crystalline state 1 67.5 14.0 16.5 1.6 0.4 - - 8.53 376 394 3 310 3 490 2 67.5 14.0 16.5 l _ř 6 - 0.4 - 8.37 367 390 3 380 3 590 3 70.0 8.0 18.0 1.6 0.4 - 2,0 9.05 380 397 3 580 4 280 4 70.0 8.0 18.0 1.6 0.4 2,0 8.89 372 399 3 700 4 650

The graph shows the linear thermal expansion curves of glasses 1, 2, 3 and 4 compared to Fe-Zn-Ni ferrite.

The melting point of the crystallized solder is higher than the glass solders as shown in Table 2.

Table 2

Designation soldering temperature PcJ at extreme angle ^u <g> = 90 ° The melting point of the crystallized solder, read at 90 ° 1 500 660

thus, the glassy crystalline solder can be used for the so-called two-stage fusing, i.e. first fusing ferrites in the slot with glassy crystalline solder and then low-melting solder, e.g. composition 10 zinc oxide ZnO, 70 brazing other parts of the magnetic head.

Glassy crystalline solder 1 was melted from a batch containing, in parts by weight, 104.3 of Pb4 O4, 22.0 zinc oxide ZnO, 44.1 boric acid H3BO3, 2.6 iron oxide FegO4, 0.6 nickel oxide NiO in corundum crucible.

The glass was melted at 1200 ° C, after melting the glass was poured into a block.

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After cooling, the fibers 0.2 to 0.2 were withdrawn in a special furnace from the reheated glass

0.4 mm and made two. parts of the Jeři tu., flowing into the crevice. In this case, the fiber was laid on the joint of two ferrites, the width of the slit being defined by spacers.

The solder according to the invention is suitable for setting ferrite parts of magnetic heads of strictly defined geometric and magnetic widths.

Claims (4)

A glassy crystalline solder for setting ferrite parts of magnetic heads, characterized in that it contains, by weight, 60 to 80 lead oxide, 5 to 20 zinc oxide, 13 to 22 boron oxide and 1 to 4 iron oxide. 2. A glassy crystalline solder according to claim 1, characterized in that it contains, by weight, 0.1 to 2 nickel oxide. 3. A glassy crystalline solder according to claim 1, characterized in that it contains 0.1 to 2 manganese dioxide by weight. Glassy crystalline solder according to one of Claims 1 to 3, characterized in that it contains 0.1 to 4 titanium dioxide by weight.