Using TiO2 G5, which has a very hig

使用具有非常高的表面积（〜370m2 / g）的TiO 2 G5，获得了致密化的增加。将G5粉末与60 wt％的H2O（根据理论计算覆盖粉末整个表面所需的量）混合，得到的CS_G1样品（图4b）具有半透明，牢固的表面以及锋利且规则的边缘。CS_G1甚至在切割后也不会崩溃，相对密度等于68％。使用过量的去离子水（CS_G2）获得了相似的结果。由于G5悬浮液（参数3.1）显示的自然pH值为7.0，即接近TiO2的等电点[36]，因此在CS_G1和CS_G2（表1）的相同CSP条件下使用60进行了进一步测试wt％的1 M乙酸溶液（pH = 3.0）代替去离子水，即降低pH使其接近P25和DT51。<br>被排除在去离子水中影响烧结性能。根据这些结果，起始粉末的比表面积似乎是通过CSP烧结TiO2的关键参数。纳米颗粒的高表面积以及因此<br>在烧结过程中趋于降低的较大表面能（较大的颗粒曲率角）提供了促进致密化的强大驱动力。

Using TiO2 G5, which has a very high surface area (˜370 m2/g), an increase in densification was obtained. Mixing G5 powder with a 60 wt% of H2O, the amount needed to cover the entire surface of the powder according to theoretical calculations, sample CS_G1 (Fig. 4b) was obtained with a translucent, well-consolidated surface and with sharp and regular edges. CS_G1 didn’t crumble even after cutting and the relative density was equal to 68%. Similar results were obtained using an excess of deionized H2O (CS_G2). Since a natural pH of 7.0 was shown by the G5 suspension (par. 3.1), i.e. close to the isoelectric point of TiO2 [36], a further test was performed in the same CSP condition of CS_G1 and CS_G2 (Table 1) using 60 wt% of 1 M acetic acid solution (pH = 3.0) instead of deionized water, i.e. lowering the pH close to that of P25 and DT51. As a relative density equal to 68% was again obtained, powder coagulation<br>was excluded to affect the sintering behaviour in deionized water. According to these results, the specific surface area of the starting powder appears to be the key parameter for sintering TiO2 by CSP. The high surface area of the nanoparticles and, consequently, the greater surface<br>energy (greater particle curvature angle) which tends to decrease during sintering, provides a strong driving force that promotes the densification.

使用具有非常高的表面积（∮370m2/g）的TiO2 G5，可以增加致密化。将G5粉末与60 wt%的H2O（覆盖粉末整个表面所需的量）混合。根据理论计算，样品CS U G1（图4b）具有半透明、固结良好的表面和锐利规则的边缘。切割后CS-G1仍不破碎，相对密度为68%。使用过量去离子水（CS_G2）也得到了类似的结果。因为G5悬浮液显示自然pH值为7.0（标准。3.1），即接近TiO2的等电点【36】，使用60 wt%的1 M乙酸溶液（pH=3.0）代替去离子水，在相同的CSP条件下（CS G1和CS G2）（表1）进行进一步试验，即将pH降低到接近P25和DT51的水平。当再次获得相当于68%的相对密度时，粉末凝固<br>排除了对去离子水中烧结行为的影响。结果表明，起始粉末的比表面积是CSP烧结TiO2的关键参数。纳米粒子的高比表面积，因此，更大的表面<br>能量（较大的颗粒曲率角）在烧结过程中趋于减少，提供了一个强大的驱动力，促进了致密化。<br>