| 초록 |
A wide variety of ceramics manufacturing processes is started with ceramics powders which are required for the high quality of the powder properties such as low agglomeration and uniform particle size. Unfortunately, in many years the ceramics powders properties are studied only in aqueous suspension media as known as suspension stabilization. The addition of polymers and dispersant adsorption into the particles' surfaces will help to reduce the agglomeration between the particles and increasing the suspension stability properties. However, once the suspension is dried and heat is applied, the polymers chain which adsorbed on surfaces will drive away from the surfaces of the particles thus increases in the re-agglomeration or re-aggregation of dried powders. According to this concern, we tried to produce high stability and quality of 3Y-TZP powders not only in suspension media but also once after the suspension is dried. In the first step, we modified the 3Y-TZP surfaces with the addition of Ammonium Polyacrylate (APA) and Diammonium Citrate (DAC) in attrition milled and continued by Polyvinylpyrrolidone (PVP) addition. These methods enable us to achieve a suspension with higher stability owing to a combination of steric/electrosteric and depletion stabilizations as shown by FTIR, PSA, and sedimentation test. To confirmed the properties of the suspension in dry condition, the prepared suspensions were dried and re-disperse again in distilled water and analyzed by PSA and sedimentation test. Furthermore, the other dried powders were pressed and sintered at 14500C and characterized by SEM, Archimedes density, and Vickers hardness analysis. Here, we confirm that the depletion stabilization which is generated by PVP addition not only increases the 3Y-TZP properties in suspension media but also after the powders are dried, thus it gives better mechanical properties of the final ceramics products. |
