Method of preparing Ag-based oxide contact materials with directionally arranged reinforcing particles

A preparation method of a particle directional arrangement reinforced Ag-based oxide contact material comprising steps of:

• a) preparing mixed solution containing Ag+ and reinforcing phase metal ion, adding co-precipitator while stirring, obtaining precipitate, washing and roasting the precipitate, and obtaining evenly dispersed composite powders, wherein the proportion of the Ag+ and reinforcing phase metal ion is obtained by calculating constituents of the composite powders to be prepared;
• the co-precipitator is a precipitant that can precipitate the solution of Ag+ and reinforcing phase metal ion, and the precipitate can be decomposed to metal oxide after roasting, wherein the co-precipitator should be in sufficient amount so as to completely precipitate the solution of Ag+ and reinforcing phase metal ion;
• b) granulating the composite powders obtained in step a) by high energy ball milling, sieving the powder, reprocessing the powder that fail to be sieved, and sieving again;
• c) mixing the powders granulated in step (b) and Ag matrix in a powder mixing machine, wherein the weight ratio of the granulated powders and the Ag matrix is calculated according to the material to be prepared;
• d) pressing the powders obtained in step c) by cold isostatic pressing to obtain a green body;
• e) sintering the green body obtained by cold isostatic pressing;
• f) hot-pressing the sintered body;
• and
• g) hot-extruding the hot-pressed sintered body, and obtaining the Ag-based oxide contact material with directionally arranged reinforcing particles, wherein in step a) the stirring speed is between 80 revolutions per minute and 120 revolutions per minute;
• the reaction time is between 2 and 4 hours;
• the roasting temperature is between 300° C. and 500° C. and the roasting time is between 1 hour and 5 hours.

A preparation method of a particle directional arrangement reinforced Ag-based oxide contact material comprising steps of:

• a) preparing mixed solution containing Ag+ and reinforcing phase metal ion, adding co-precipitator while stirring, obtaining precipitate, washing and roasting the precipitate, and obtaining evenly dispersed composite powders, wherein the proportion of the Ag+ and reinforcing phase metal ion is obtained by calculating constituents of the composite powders to be prepared;
• the co-precipitator is a precipitant that can precipitate the solution of Ag+ and reinforcing phase metal ion, and the precipitate can be decomposed to metal oxide after roasting, wherein the co-precipitator should be in sufficient amount so as to completely precipitate the solution of Ag+ and reinforcing phase metal ion;
• b) granulating the composite powders obtained in step a) by high energy ball milling, sieving the powder, reprocessing the powder that fail to be sieved, and sieving again;
• c) mixing the powders granulated in step (b) and Ag matrix in a powder mixing machine, wherein the weight ratio of the granulated powders and the Ag matrix is calculated according to the material to be prepared;
• d) pressing the powders obtained in step c) by cold isostatic pressing to obtain a green body;
• e) sintering the green body obtained by cold isostatic pressing;
• f) hot-pressing the sintered body;
• and
• g) hot-extruding the hot-pressed sintered body, and obtaining the Ag-based oxide contact material with directionally arranged reinforcing particles, wherein in step b) a rotating speed of ball mill is between 180 revolutions per minute and 350 revolutions per minute;
• ball milling time is between 5 and 15 hours;
• ball-to-powder weight ratio is between 10 and 20;
• the number of sieving meshes is between 100 and 400.