以甲基纤维素作分散剂制备高分散超细银粉

Preparation of highly dispersed ultrafine silver powders using methylcellulose as dispersant

以AgNO3为原料,抗坏血酸为还原剂,甲基纤维素为分散剂,采用化学液相还原法制备超细银粉,研究温度、分散剂用量、pH值等对银粉分散性、粒度和形貌的影响。结果表明,反应温度对银粉形貌有很大的影响,当温度为25和30℃时,银粉为不规则的类球形;当温度为40、50和60℃时,银粉均为树枝状。分散剂用量越大,银粉的分散性越好。pH值对银粉粒度有很大的影响,随pH值增加,银粉粒度逐渐减小,当pH值从2增加至10时,所得银粉粒度分别为2.26和0.053μm。最佳工艺为:温度为25℃,pH值为2,分散剂与抗坏血酸质量比为0.02,所得银粉分散性良好,平均粒度为2.21μm。

Ultrafine silver powders were prepared from silver nitrate by chemical reduction method with ascorbic acid as reducing agent, methylcellulose as dispersant. The effects of the pH value, temperature, dispersant dosage on the dispersibility, mean particle size and morphology of the ultrafine silver powders were studied. The results show that the reaction temperature has a great effect on the morphology of the ultrafine silver powders. Spherical-like silver powders can be prepared when the temperature is 25 ℃ and 30 ℃, dendritic silver powders can be prepared when the temperature is 40 ℃, 50 ℃ and 60 ℃, respectively. The dosage of dispersant has a great effect on dispersibility of ultrafine silver powders. Silver powder has better dispersibility with increasing dosage of dispersant. The pH value has a great effect on the particle size of silver powder, and the size of silver powder decreases with increasing the dosages of dispersant pH value. When pH value is 2 and 10, the particle size of silver powder is 2.26 and 0.053 μm, respectively. Ultrafine silver powders with better dispersibility and mean particle size of 2.21 /am can be obtained in the condition of the reaction temperature of 25 ℃, pH value of 2, the mass ratio of dispersant and ascorbic acid of 0.02.