การเตรียมผงทวิโลหะเงิน - ทองแดงโดยการรีดิวซ์สารประกอบไนเตรตด้วยกลีเซอรอล

• Main Author: พัฒนวงศ์ โชครตนสมบัติ
• Other Authors: เอกสิทธิ์ นิสารัตนพร
• Format: Theses and Dissertations
• Language: Thai
• Published: จุฬาลงกรณ์มหาวิทยาลัย 2011
• Subjects: เงิน; ทองแดง
• Online Access: https://digiverse.chula.ac.th/Info/item/dc:43397
• Institution: Chulalongkorn University

The aim of this study is to synthesize bimetallic Cu-core/Ag-shell powder by glycerol process. The copper powders were produced by reducing Cu(NO₃)₂ with solution of glycerol and NaOH at molar ratio of NaOH:Cu(NO₃)₂ in the range of 0:1 - 5:1, the reaction temperature ranging from 120 - 160°C with constant stirring at 1,000 rpm. The increase of NaOH concentration and reaction temperature gave rise to higher reaction rate resulting in the decrease of both the complete reaction time and powder size. In addition, the more spherical and monodisperse characteristic were obtained. The synthesis at molar ratio of 3:1 and reaction temperature of 140°C produced the uniform size and well-dispersed powders with the average size of 0.32 ± 0.06 micron. The bimetallic Ag-Cu powders were synthesized by introducing the prepared copper powders into the bath containing glycerol, EDTA, NH₄OH and AgNO₃. The effect of AgNO₃ concentration of 0.01 - 0.10 M and reaction time for 1 - 30 minutes on the silver layer thickness on the copper sheet were studied. It was found that at higher AgNO₃ concentration and longer reaction time resulted in thicker silver layer on the copper substrate. However, the reaction rate was decreased with the reaction time. The thickest silver layer of 0.242 micron was received in the condition of 0.10 M AgNO₃ and reacting for 30 minutes. The synthesis of bimetallic Ag-Cu powders by using 0.130-micron copper powders as starting material at the AgNO₃ concentration in the range of 0.01 - 0.10 M for 1 minute produced aggregated Ag-Cu powders with average size of 0.180 - 0.187 micron and silver content in the range of 62.80 wt% - 75.34wt%.