(1. 北京工業(yè)大學 材料科學與工程學院，北京100124；
2. 北京工業(yè)大學 教育部新型功能材料重點實驗室，北京100124)
摘 要: 利用短流程原位反應合成技術制備超細WC-Co復合粉，其平均粒徑為300 nm，對此復合粉進行噴霧造粒以制備具有超細結構的熱噴涂粉末。采用標準漏斗法測量造粒粉末的松裝密度，并利用SEM觀察其形貌與結構，結合實驗測定結果與理論計算結果研究料漿成分、噴霧干燥溫度及初始粉末粒徑對造粒粉末松裝密度的影響規(guī)律。結果表明：料漿固含量最高可達70%(質量分數(shù))，此時造粒粉末松裝密度達到2.31 g/cm3；隨粘結劑含量的增高，造粒粉末松裝密度先增高后降低，最佳含量為2.5%(質量分數(shù))；分散劑最佳含量為1%~2%(質量分數(shù))；干燥溫度顯著影響造粒粉末形貌結構及松裝密度，最佳溫度為150 ℃；噴霧造粒粉末的最高密度實質上取決于初始粉末粒徑。
關鍵字: 超細WC-Co復合粉；原位合成；噴霧造粒；松裝密度
（1. College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China;
2. Key Laboratory of Advanced Functional Materials, Ministry of Education,
Beijing University of Technology, Beijing 100124, China）
Abstract:Spray granulation was carried out using the ultrafine WC-Co composite powders with an average particle size of 300 nm as the raw material which was rapidly synthesized by the technique of in situ reactions. The standard funnel method and scanning electron microscope (SEM) were employed to measure the apparent density and characterize the morphologies and structures of the granulated powders, respectively. Moreover, the influences of the slurry composition, the drying temperature and the particle size of raw powders on the apparent density of the granulated powders were studied by combining the experimental and theoretical calculation results. The results indicate that the apparent density of the granulated powders reaches 2.31 g/cm3 as the solid content of the slurry increases up to 70% (mass fraction). But with the increase of the organic binder content, the apparent density of the granulated powders firstly increases, and then drops down. The optimum binder content and dispersant content is 2.5% (mass fraction) and 1%−2% (mass fraction), respectively. The spray drying temperature greatly influences the morphology and the apparent density of the granulated powders and the optimum value is 150 ℃. The highest density of granulated powders essentially depends on the particle size of the raw powders.
Key words: ultrafine WC-Co composite powders; in-situ synthesis; spray granulation; apparent density
