JPS58139322A - Porcelain composition used for magnetic head fastener - Google Patents

Abstract

PURPOSE:To restrain chipping while processing, and to enhance thermal shock resistance and mechanical strength, by changing a proportion of a specified porcelain component to select freely heat expansion coefficient within a specified range. CONSTITUTION:As porcelain composn., 20-75wt% TiO2; 20-78wt% MgO; 0.01- 10wt% ZnO; and at least one of BaO, SrO, CaO, SiO2, Nb2O3, Al2O3, SnO2, ZrO2, Cr2O3, and Fe2O3 amounting to <=20wt% are contained in 100wt% composn., and it is sintered. Its heat expansion coefficient can be selected freely within (80-120)X10<-7>/ deg.C by changing proportion of each component, as a result, bore distribution is improved chipping can be restrained in mechanical working, and heat expansion coefft., thermal shock resistance, and mechanical strength can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is characterized in that the thermal expansion coefficient of porcelain is 80X120~1σ7℃-
In addition, alumina, forsterite, steatite porcelain, etc. have been conventionally used as porcelain for magnetic head stoppers due to their mechanical strength, hardness, and heat resistance.

However, the biggest drawback of these is that it is extremely difficult to change the coefficient of thermal expansion in the same component system. For this reason, when used in combination with a ferrite element or even a glass element, it is extremely difficult to select one because these elements have different coefficients of thermal expansion. In addition, the main application is to bring both the magnetic head and the head stopper porcelain into contact with a magnetic tape to magnetize the magnetic tape, and in this case, the magnetic head and the head stopper porcelain do not have the same degree of abrasion. A gap is created between the ferrite and the magnetic tape, which adversely affects the magnetization of the magnetic tape. Furthermore, if a bore with a bore diameter of 60 μm or more is present in this porcelain fastener, the surface of the magnetic tape will be damaged.

To solve these problems, it is possible to freely change the desired thermal expansion coefficient from the material side, and it has strong thermal shock resistance, as well as high mechanical strength and Vickers hardness, and has the same level of abrasion resistance as magnetic heads. The objective is to develop a porcelain material for a magnetic head stopper with a small bore.

In particular, recently the hot press method and HI P (Hot Iso
Polycrystalline ferrite manufactured using the static pressing method or single crystal ferrite manufactured using the single crystal manufacturing method is used as a porcelain for fasteners such as magnetic heads for electronic computers and video tape recorders, with excellent mechanical strength and heat resistance. There is a strong demand for an element body with good poling, hardness, ceramic pore distribution, etc., and a thermal expansion coefficient in the range of 60 to 120 x 10°C.

Currently, as a publicly known document regarding porcelain for magnetic head fasteners that has solved some of these drawbacks, there is
Publication No. 28, Special Publication No. 51-42606, Special Publication No. 5
There are Japanese Patent Publication No. 2-30162 and Japanese Patent Publication No. 62-29766. However, since the bore distribution of the magnetic tapes disclosed in Japanese Patent Publication No. 51-15528 to Japanese Patent Publication No. 52-29766 has not been improved, there are many bores with a bore diameter of 60 μm or more, which damage the magnetic tape surface. Furthermore, when the atmosphere in the furnace changes from an oxidizing atmosphere to a neutral or reducing atmosphere during firing, TiO2 is reduced and color unevenness occurs inside the porcelain. Although there are other methods that have solved these drawbacks, they have the disadvantage that chipping is likely to occur during machining and precision machining is difficult.

The present invention eliminates the conventional drawbacks, is extremely stable in the firing atmosphere, has very few chippings during precision mechanical processing, and has excellent thermal shock resistance, mechanical strength, and hardness during rapid heating and cooling. The present invention provides a composition for a new porcelain body for a magnetic head stopper, which has all the conditions necessary for a porcelain for a magnetic head stopper, such as , bore distribution, etc.

That is, the ceramic composition for a magnetic head stopper according to the present invention has T 102 :20-7'5% by weight, MgO:
20-78% by weight, ZnO: 0, 01-10
weight%.

BaO, SrO, CaO, 5i02. Nb2O6, At
203゜SnO2, ZrO2, Cr2O3, Fe2o3
It is characterized by being formed by sintering a composition in which one or more of the above have a composition range of 20% by weight or less, and the total is 100% by weight.

By changing the component ratio within the above range, the thermal expansion coefficient value can be freely selected within the range of 80 to 120 x 10''℃-1. It has very little occurrence, no color unevenness due to changes in the firing atmosphere, high mechanical strength, good bore distribution, wear resistance comparable to that of ferrite, and good thermal shock properties. - Glass - When combined with porcelain for fasteners, it is stable without any cracks and has high reproducibility.

In addition, in the above-mentioned components, if MqO is less than 20%, heat resistance properties are poor and mechanical strength is also reduced. Moreover, the occurrence rate of chipping increases. Furthermore, if M (JO) exceeds 78% by weight, sinterability will be poor and mechanical strength will also deteriorate. Also, the incidence of chipping will increase.
If it exceeds 5% by weight, the crystal grain size will become coarse and the mechanical strength will decrease, and furthermore, slight changes in the firing atmosphere will cause uneven coloration. Furthermore, if T 102 is less than 20% by weight, sinterability is poor. Further, if the ZnO content exceeds 10% by weight, the heat resistance properties will be poor, and if it is less than 0.01% by weight, color unevenness will occur inside the porcelain due to subtle changes in the firing atmosphere. Also, Bad.

Cao, 5rO9SiO2, Nb2O6, At2031
When the total amount of one or more of Sn02°ZrO2, Cr2O3, and Fe2O3 exceeds 20% by weight, the occurrence of chipping increases.

As described above, since the porcelain for magnetic head fasteners is embedded in the porcelain (fastener) using adhesive glass as a medium for ferrite elements, thermal expansion coefficient, thermal shock resistance, mechanical strength, bore distribution, etc. Although the relationship with
A porcelain body made of a composition within the scope of the present invention, which is a material that satisfies these conditions, has a coefficient of thermal expansion that can be freely controlled.

Hereinafter, the present invention will be specifically explained with reference to Examples.

For the sample preparation process, industrial raw materials (purity of 98% or more) are used.
TiO, MgO, ZnO, BaCO3, CaCO
3°SrCO3,5i02. Nb2O6, At203.
Using SnO2, ZrO2゜Cr2O3, Fe2O3,
The mixture was wet-mixed using a urethane-lined pot mill to prevent contamination of impurities. As for the order of sample preparation, raw materials were prepared to have the composition ratios shown in Table 1 below, and preliminary firing was carried out at a temperature of 110°C to 1200°C. Also, molding Q
A sample of 50 x 50 x 10 mm was formed using a mechanical press. The main firing is carried out using an electric furnace at a temperature of 13
Firing was performed between 00 and 1400°C. The obtained device exhibited various characteristics as shown in Table 2 below.

(Left below) In this example, the magnesium component was M (JO-use Itaka, MgCO5, MqC121Mq(oH)2.1
Although ZnO was used as the zinc component, good characteristics can also be obtained by using raw materials such as carbonate and oxalate in the present invention component such as Z n CO3.

As is clear from Tables 1 and 2, Examples 1 to 16 are within the scope of the present invention, and Examples 16 to 23 are comparative examples outside the scope. Further, 爲24 is a conventional example of B a O-TiO based porcelain for a magnetic head stopper (having the composition as claimed in Japanese Patent Publication No. 62-29766).

The samples within the scope of the present invention have a significantly low number of chippings during machining, and also have mechanical strength, thermal shock resistance, and bore distribution of 9.
It shows excellent properties such as color unevenness.

Comparative examples outside the range had poor chipping incidence during machining, 1 mechanical strength, 9 color unevenness, etc. In this example, the method for determining thermal shock characteristics is 38
The cracking rate was investigated after dropping a ceramic element (test 3 thick At plate) into a solder bath at 0°C.The number of pieces was 100.
I did an individual test.

The method for measuring the number of chippings is 1o x 10 x 1
The surface material of 0011OI+ was cut in the length direction (1ooWrM) using a diamond high-speed rotary cutter, and the number of chips on the cut surface was counted using an optical microscope equipped with a micrometer. The operating conditions of the cutting machine (diamond cutter N rotation number, sample feeding speed) are kept constant. The number of pieces is 100 pieces tested, and the number of chips is the average value per piece.

As described above, the composition within the scope of the present invention has extremely excellent performance as a magnetic head stopper ceramic material, is extremely stable even in industrial mass production, and has great industrial value. It is something.

Claims (1)

[Claims] TiO2: 20-75% by weight, MgO: 20-78% by weight. ZnO: 0.01-10% by weight, BaO, CaO, Sr
O. SiO2, Nb2o5. At203. SnO2, ZrO
2. For a magnetic head stopper characterized by sintering a composition comprising one or more of Cr2O3゜Fe2O3 in a total amount of 20% by weight or less, and the total amount being 100% by weight. Porcelain composition.