KR20040056533A - Metalizing composition for coating alumina ceramic and method of metalizing alumina ceramic - Google Patents

Abstract

PURPOSE: Provided are a metallizing composition for coating an alumina ceramic, which can reduce the cost and improve productivity and has an excellent adhesive strength, and a method for metallizing the alumina ceramic by using the composition. CONSTITUTION: The metallizing composition for coating the alumina ceramic comprises: 63-89.55wt% of molybdenum, 7-9.95wt% of manganese, and 0.5-30wt% of silicon dioxide. And the method for metallizing the alumina ceramic contains the steps of: spreading the metallizing composition on an alumina sintered body; and heat-treating the alumina sintered body at 1300-1400deg.C.

Description

Metalizing composition for alumina ceramic coating and metallizing method of alumina ceramic using the same {METALIZING COMPOSITION FOR COATING ALUMINA CERAMIC AND METHOD OF METALIZING ALUMINA CERAMIC}

The present invention relates to a metallizing composition for alumina ceramic coating and a metallizing method of alumina ceramic using the same.

Conventional metallizing method is to apply a paste of a mixed powder of high melting point metal such as molybdenum (Mo), tungsten (W) and manganese (Mn) to the surface of the alumina sintered body, and to heat it in a humidified nitrogen atmosphere. This is a method of forming a high melting point metal on the surface of an alumina sintered compact. This method has the disadvantage of having to be sintered at a high temperature of 1500 to 1700 ° C. in a non-oxidizing atmosphere.

In order to solve the disadvantage of sintering at high temperature, metallization is performed with a paste made by adding a glass phase containing a large number of alumina, silica, calcium oxide, magnesium oxide, and manganese oxide to a high melting point metal. As a method, Japanese Patent Laid-Open No. 57-13518, in which aluminum oxide-silicon oxide-calcium carbonate-magnesium oxide was added to tungsten, prepared by adding aluminum oxide, tantalum oxide, silicon oxide, calcium oxide, and magnesium oxide to tungsten. Japanese Patent Laid-Open No. 63-64942 using a paste, and Japanese Patent Laid-Open No. 2-30688 in which aluminum oxide-manganese oxide-silicon oxide and silicon oxide-calcium oxide-manganese oxide are added to molybdenum or tungsten are proposed. .

However, in order to manufacture the glass phase used in the above-described method, a number of processes such as mixing and pulverizing various kinds of raw materials, melting of the pulverized oxide, and crushing the molten glass phase are required. There is a very high disadvantage.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention relates to a metallizing composition for alumina ceramic coating which can economically coat a metal layer on the surface of an alumina ceramic.

Another object of the present invention relates to a metallizing method of alumina ceramic using the composition.

1 is a schematic view of the alumina ceramic specimen used in the embodiment of the present invention.

FIG. 2 is a schematic representation of an experimental tool made using the alumina ceramic specimen shown in FIG. 1 used to measure tensile strength in an embodiment of the present invention. FIG.

In order to achieve the above object, the present invention is molybdenum 63 to 89.55% by weight; Manganese 7-9.95 wt%; And it provides a metallizing composition for alumina ceramic metal coating comprising 0.5 to 30% by weight of silicon dioxide.

The present invention also applies a metallizing composition comprising 63 to 89.55 wt% molybdenum, 7 to 9.95 wt% manganese, and 0.5 to 30 wt% silicon dioxide to the alumina ceramic sintered body; It provides a metallizing method of the alumina ceramic comprising a step of heat-treating the alumina ceramic sintered body coated with the metallizing composition at 1300 to 1400 ℃.

Hereinafter, the present invention will be described in more detail.

The metallizing composition for alumina ceramic coating of the present invention comprises 63 to 89.55 wt% molybdenum, 7 to 9.95 wt% manganese and 0.5 to 30 wt% silicon dioxide. That is, the metallizing composition of the present invention uses a smaller amount of 7 to 9.95% by weight, compared to about 10 to 30% by weight of manganese in the metallizing composition using Mo-Mn.

If the content of the silicon dioxide is less than 0.5% by weight does not form a liquid phase between the manganese oxide and silicon dioxide can not form a metallizing layer at a temperature of 1300 to 1400 ℃, the amount of silicon dioxide is more than 30% by weight This results in the formation of very low melting liquid phases, making it impossible to use metallized specimens at high temperatures.

The metallizing composition may also include a vehicle to have a viscosity that facilitates coating, and such a vehicle may be any material known in the art, and the representative name is Organic Vehicle Type 424. ) Can be used.

The metallizing method of the alumina ceramic of this invention using the said metallizing composition apply | coats the said metallizing composition to an alumina ceramic sintered compact.

The obtained alumina ceramic sintered body is heat-treated at 1300-1400 degreeC low temperature.

When the metallizing temperature is lower than 1300 ° C., the liquid phase of manganese oxide and silicon dioxide is not formed, and thus the liquid phase in the paste cannot move to the alumina sintered body to form a metallizing layer having sufficient strength. This phenomenon is in good agreement with the phenomenon that when the tensile strength of the bonded specimen is measured, the specimen with low strength mainly occurs at the metallization layer and the alumina interface. If the metallizing temperature is higher than 1400 ° C., the liquid phase of manganese oxide and silicon dioxide reacts with the sintered alumina to form a reaction layer, which is not preferable because the reaction layer lowers the tensile strength.

Hereinafter, the Example and comparative example of this invention are described. However, the following examples are only one preferred embodiment of the present invention and the present invention is not limited to the following examples.

(Example 1)

0.5 wt% silicon dioxide in a mixed powder of molybdenum metal powder (average particle size: 0.7 microns), 89.88 wt% of manganese metal powder (average particle size: 10 microns), using a 90 micron, 325 mesh stainless steel sieve % Was added and the organic vehicle 424 vehicle was added to prepare a metallizing composition.

The composition was applied to the A surface of the alumina ceramic specimen 1 having an inner diameter d of 10.4 mm, an outer diameter D of 29.4 mm, and a height h of 14.5 mm shown in FIG. 1, and then dried.

Subsequently, the specimen was heat-treated at 1300 ° C. for 30 minutes at a heating rate of 6 ° C./min while blowing a mixed gas of 1.75 liters / minute of nitrogen gas and 1.25 liters / minute of hydrogen gas at a dew point of 25 ° C. The composition prepared a metallized alumina ceramic specimen.

The metallized alumina ceramic specimens were washed with acetone and caustic soda solution and then nickel plated by nickel electroless plating to coat the nickel layer on the surface.

Subsequently, as shown in FIG. 2, the obtained ceramic specimens (1, 1 ° C. were brazed for 20 minutes.

(Example 2)

The same procedure as in Example 1 was carried out except that 88.2 wt% molybdenum metal powder, 9.8 wt% manganese metal powder, and 2.0 wt% silicon dioxide were mixed.

(Example 3)

The same procedure as in Example 1 was carried out except that 85.5 wt% molybdenum metal powder, 9.5 wt% manganese metal powder, and 5.0 wt% silicon dioxide were mixed.

(Example 4)

The same process as in Example 1 was carried out except that 81.0 wt% molybdenum metal powder, 9.0 wt% manganese metal powder, and 10.0 wt% silicon dioxide were mixed.

(Example 5)

The same process as in Example 1 was carried out except that 76.5 wt% molybdenum metal powder, 8.5 wt% manganese metal powder, and 15.0 wt% silicon dioxide were mixed.

(Example 6)

The same procedure as in Example 1 was carried out except that 63.0 wt% molybdenum metal powder, 7.0 wt% manganese metal powder, and 30.0 wt% silicon dioxide were mixed.

The bonding strength of the alumina ceramic specimens prepared in Examples 1 to 6 was measured using a tensile strength jig to tension the crosshead speed to 0.5 mm / min using a universal testing machine to determine the maximum load when the specimen was broken. It was calculated by dividing the junction area, and the results are shown in Table 1.

Paste Composition (wt%) Metallizing Temperature and Time Plane of destruction Folding strength (kg / mm ² ) Mo Mn SiO ₂ Example 1 89.55 9.95 0.5 1300 ℃, 30 minutes Alumina 5.81 Example 2 88.2 9.8 2.0 1300 ℃, 30 minutes Alumina 6.03 Example 3 85.5 9.5 5.0 1300 ℃, 30 minutes Alumina 4.47 Example 4 81.0 9.0 10.0 1300 ℃, 30 minutes Alumina 6.53 Example 5 76.5 8.5 15.0 1300 ℃, 30 minutes Alumina 4.64 Example 6 63.0 7.0 30.0 1300 ℃, 30 minutes Alumina 6.59

As shown in Table 1, when the metal and alumina were joined by a paste containing 0.5% to 30% by weight of silicon dioxide mixed with 9: 1 molybdenum and manganese, the bonding strength between the metal and the ceramic was 4.47 to 6.59 kg. A high value of / mm ² and fracture occurred mainly on the alumina side.

(Example 7)

The same process as in Example 1 was carried out except that the metallizing temperature was changed to 1400 ° C.

(Example 8)

It carried out similarly to Example 2 except having changed the metallizing temperature to 1400 degreeC.

(Example 9)

It carried out similarly to Example 3 except having changed the metallizing temperature to 1400 degreeC.

(Example 10)

The same process as in Example 4 was carried out except that the metallizing temperature was changed to 1400 ° C.

(Example 11)

The same procedure as in Example 5 was carried out except that the metallizing temperature was changed to 1400 ° C.

(Comparative Example 1)

The same process as in Example 1 was carried out except that the metallizing temperature was changed to 1500 ° C.

(Comparative Example 2)

85.5% by weight of molybdenum metal powder, 9.5% by weight of manganese metal powder and 5.0% by weight of silicon dioxide were used, except that the metallizing temperature was changed to 1500 ° C.

(Comparative Example 3)

It carried out similarly to Example 3 except having changed the metallizing temperature to 1500 degreeC.

(Comparative Example 4)

It carried out similarly to Example 4 except having changed the metallizing temperature to 1500 degreeC.

Bond strength was measured for the alumina ceramic specimens obtained by the methods of Examples 7 to 11 and Comparative Examples 1 to 4 in the same manner as in Examples 1 to 6, and the results are shown in Table 2 below.

Paste Composition (wt%) Metallizing Temperature and Time Plane of destruction Folding strength (kg / mm ² ) Mo Mn SiO ₂ Comparative Example 1 89.55 9.95 0.5 1500 ° C., 30 minutes Mo interface 3.85 Comparative Example 2 85.5 9.5 5.0 1500 ° C., 30 minutes Mo interface 2.72 Comparative Example 3 81.0 9.0 10.0 1500 ° C., 30 minutes Mo interface 2.64 Comparative Example 4 63.0 7.0 30.0 1300 ℃, 30 minutes Alumina 2.88 Example 7 89.55 9.8 2.0 1300 ℃, 30 minutes Alumina 5.75 Example 8 88.2 9.5 5.0 1300 ℃, 30 minutes Alumina 5.37 Example 9 81.0 9.0 10.0 1300 ℃, 30 minutes Alumina 6.87 Example 10 76.5 8.5 15.0 1300 ℃, 30 minutes Alumina 6.86 Example 11 63.0 7.0 30.0 1300 ℃, 30 minutes Alumina 6.27

As can be seen from the comparative example of Table 2, the bonding strength of the metal-ceramic joint bonded by molybdenum and manganese-added silicon paste was low due to the reaction between the liquid phase and alumina when the metallizing temperature was higher than 1500 ° C. It can be seen that.

As described above, the metallizing composition of the present invention uses a paste in which silicon dioxide is added to a mixture of molybdenum and manganese, thereby lowering the temperature (1300 to 1400) below the conventional molybdenum-manganese paste metallizing temperature (1500 to 1700 ° C). By performing the metallizing at ° C), cost reduction and productivity improvement by shortening the process can be achieved, and also excellent bonding strength can be achieved.

Claims (2)

Molybdenum 63 to 89.55 wt%; Manganese 7-9.95 wt%; And 0.5 to 30% by weight of silicon dioxide Metallizing composition for alumina ceramic metal coating comprising a. Molybdenum 63 to 89.55 wt%; Manganese 7-9.95 wt%; And applying a metallizing composition comprising 0.5 to 30% by weight of silicon dioxide to the alumina sintered body; Heat-treating the alumina sintered body to which the metallizing composition is applied at 1300 to 1400 ° C .; Metallizing method of alumina ceramic comprising a step.