The casting of ceramic powders can be realized by using distinct techniques, which determine the final characteristics of the products. Although many synthesis and cast techniques have been quoted, the scientific literature shows a need for information about the influence of these processes on the materials surface features, as an example, contaminations originated from the synthesis route. Several authors have already remarked the influence of the contamination, particularly superficial, on the final properties of many ceramic materials. The most used technique for surface impurities removal is based on washings with water. In this work it is drawn a new cleanliness procedure for a ZrO2 powder of national manufacture. Two washing procedures were carried out for comparison: one with deionized water and another with a NH4OH solution at pH = 8.5. The new procedure was established from the electrokinetic characterization results of the ZrO2 dispersion as a function of the pH. In this case, the washings were more efficient affording the cleanliness of the ZrO2 surface. The electrokinetic behavior analysis also revealed that washings introduce significant surface changes.
ceramic processing; ceramic dispersions; surfaces; zirconia; electrokinetic behavior
