1. A method of joining members to be joined by use of an Au\u2014Sn brazing material, said method comprising the steps of:
applying a gold plating of 0.05 \u03bcm to 3 \u03bcm in thickness onto joint surfaces of the members to be joined, prior to a joining of the members; and performing a joining of the members, at a temperature ranging from 300\xb0 C. to 320\xb0 C., under an inert atmosphere of nitrogen, hydrogen or vacuum, with an Au\u2014Sn brazing material consisting of an Sn content of 23 wt % to 25 wt % and the balance being Au;
adjusting a thickness of the Au\u2014Sn brazing material so that the following relationships hold among a composition and the thickness of the Au\u2014Sn brazing material and the thickness of a gold plating; and
adjusting the Sn content of a joint after joining to be 20.65 wt % to 23.5 wt %; thereby providing joints having either a eutectic structure or a structure containing an Sn rich phase in a eutectic structures:
At 22 wt % of Sn
y \u2266 0.0480 x
At 23 wt % of Sn
y \u2266 0.0825 x
At 24 wt % of Sn
0.0152 x \u2266 y \u2266 0.1163 x
At 25 wt % of Sn
0.0452 x \u2266 y \u2266 0.1492 x
where x is the thickness of the brazing material in \u03bcm, and y is the thickness of the gold plating in \u03bcm, and where 0.05 \u2266 y \u2266 3.
2. The method of claim 1 wherein composition and thickness of the Au\u2014Sn brazing material are adjusted so that the Sn content of a joint formed by the joining is from 21 wt % to 23 wt %.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of printing catalyst on an electrolyte membrane, comprising:
manufacturing an ink for the catalyst;
injecting the ink toward the electrolyte membrane through an injecting hole;
applying ultrasonic energy to the injected ink by using a vibrator provided between the injecting hole and the electrolyte membrane; and
coating the catalyst on the electrolyte membrane by dispersing the ink comprising the catalyst uniformly while applying the ultrasonic energy, the dispersed ink contacting the electrolyte membrane in a predetermined pattern.
2. The method of claim 1, further comprising vaporizing solvent of the ink by heating the injected ink.
3. The method of claim 2, wherein the solvent of the ink is vaporized by heating the ink to a temperature of about 50 to about 100 \xb0 C.
4. The method of claim 1, wherein the predetermined pattern comprises:
a plurality of first direction lines parallel with each other; and
a plurality of second direction lines crossing the first direction lines at a predetermined angle being formed with respect to the first direction lines.
5. The method of claim 4, wherein the first direction lines are parallel with a flow of fluid and the second direction lines are vertical to the first direction lines.
6. The method of claim 5, wherein a distance between the adjacent second direction lines increases or is constant along the flow of the fluid.
7. The method of claim 5, wherein thicknesses of the plurality of second direction lines decrease or are constant along the flow of the fluid.
8. The method of claim 1, wherein the ultrasonic energy has frequency in a range of about 20 kHz to about 40 kHZ.
9. The method of claim 1, wherein frequency of the ultrasonic energy is determined based on types of the catalyst and solvent.
10. The method of claim 1, wherein the predetermined pattern includes a plurality of direction lines, and
wherein a density of the plurality of direction lines positioned at an upstream of the flow of the fluid is greater than that of the plurality of direction lines positioned at a downstream of the flow of the flow.