Method for manufacturing cobalt alloy-based ceramic composite sputtering target
A method for manufacturing a cobalt (Co) alloy-based ceramic composite sputtering target is provided. A cobalt ingot and a chromium (Cr) ingot are melted in vacuum and then nebulized to form a cobalt-chromium (CoCr) alloy powder. Additionally, a ceramic powder and a platinum powder are wetly mixed to form a platinum-ceramic (Pt-ceramic) slurry, in which the ceramic powder is applied onto the platinum powder's surface uniformly. Next, the CoCr alloy powder and the Pt-ceramic slurry are wetly mixed to form a CoCrPt-ceramic slurry. Thereafter, the CoCrPt-ceramic slurry is dried, molded and compressed to form the cobalt alloy-based ceramic composite sputtering target. The resulted cobalt alloy-based ceramic composite sputtering target, which has a fine and dense structure, uniform composition and lower magnetic permeability, is beneficial to a magnetron sputter deposition process, as well as a film sputtering process used in the magnetic recording industry.
1. A method for manufacturing a cobalt (Co) alloy-based ceramic composite sputtering target, comprising:
providing a cobalt-chromium (CoCr) alloy powder, comprising:
performing a vacuum melting process for melting a cobalt ingot and a chromium ingot into a CoCr alloy solution; and
performing a nebulization process for nebulizing the CoCr alloy solution into a CoCr alloy powder;
performing a first wet powder mixing process for allowing a ceramic powder to be uniformly embedded onto a surface of a platinum powder in a solvent, thereby forming a platinum-ceramic (Pt-ceramic) slurry, wherein a purity of the platinum powder is greater than 99.9%, and a hardness of the ceramic powder is greater than a hardness of the platinum powder, and a specific weight of the ceramic powder is smaller than a specific weight of the platinum powder;
performing a second wet powder mixing process for uniformly mixing the CoCr alloy powder and the Pt-ceramic slurry, thereby forming a CoCrPt-ceramic slurry;
performing a drying process onto the CoCrPt-ceramic slurry to form a CoCrPt-ceramic composite powder; and
performing a molding and densification process onto the CoCrPt-ceramic composite powder to form the cobalt alloy-based ceramic composite sputtering target.
2. The method as claimed in claim 1 , wherein the vacuum melting process is performed in a vacuum inductive melting (VIM) furnace.
3. The method as claimed in claim 1 , wherein the vacuum melting process is performed at a temperature between 1650° C. and 1750° C. and a vacuum level of 10 −3 torr.
4. The method as claimed in claim 1 , wherein the nebulization process utilizes high-pressure gas to spray on and nebulize the CoCr alloy solution.
5. The method as claimed in claim 4 , wherein the high-pressure gas is argon or nitrogen and is sprayed on and nebulize the CoCr alloy solution at a pressure between 20 atm (atmosphere) and 30 atm.
6. The method as claimed in claim 1 , wherein an average particle diameter of the CoCr alloy powder is ranged between 10 μm and 40 μm.
7. The method as claimed in claim 1 , wherein, after the nebulization process, the method further comprises:
performing a cooling process for cooling down the CoCr alloy powder nebulized.
8. The method as claimed in claim 7 , wherein the cooling process is a natural cooling process or a cooling process using high-pressure gas for cooling the CoCr alloy powder, and the high-pressure gas is argon or nitrogen and is sprayed on the CoCr alloy powder at a pressure between 20 atm and 30 atm.
9. The method as claimed in claim 1 , wherein the CoCrPt-ceramic composite powder has the ceramic powder within a range from 9 percent by weight (wt %) to 25 wt %, the platinum powder within a range from 5 wt % to 25 wt %, and the CoCr alloy powder within a range from 25 wt % to 75 wt %.
10. The method as claimed in claim 1 , wherein the ceramic powder is formed from a material selected from the group consisting of SiO 2 , TiO 2 , CoO, Cr 2 O 3 , Ta 2 O 5 and combinations thereof.
11. The method as claimed in claim 1 , wherein an average particle of diameter the ceramic powder is ranged between 0.07 μm and 1.0 μm.
12. The method as claimed in claim 1 , wherein the solvent is formed from a material selected from the group consisting of water, alcohol and combinations thereof.
13. The method as claimed in claim 1 , wherein the first wet powder mixing process lasts for 1 hour to 2 hours.
14. The method as claimed in claim 1 , wherein the second wet powder mixing process lasts for 12 hour to 18 hours.
15. The method as claimed in claim 1 , wherein the drying process is a vacuum drying process or an atmospheric drying process.
16. The method as claimed in claim 15 , wherein the vacuum drying process is performed at a temperature between 80° C. and 120° C. and a vacuum level less than 760 torr for 2 hours to 4 hours.
17. The method as claimed in claim 15 , wherein the atmospheric drying process is performed at a temperature between 100° C. and 160° C. for 4 hours to 6 hours.
18. The method as claimed in claim 1 , wherein the molding and densification process is a hot pressing (HP) process or a hot isostatic pressing (HIP) process.
19. The method as claimed in claim 1 , wherein the molding and densification process is performed at a temperature between 900° C. and 1200° C., for 1 hour to 4 hours.
20. The method as claimed in claim 1 , wherein the cobalt alloy-based ceramic composite sputtering target is applied on a film sputtering process used in a magnetic recording medium.