(1. 湖南工业大学 无机非金属材料工程技术湖南省重点实验室,
株洲 412007;
2. 中南大学 粉末冶金国家重点实验室, 长沙 410083)
摘 要: 采用分段真空烧结和化学分析等研究了纳米Ti(CN)基金属陶瓷压坯在烧结过程中的收缩行为、化学成分和性能的演变。 实验表明: 纳米混合料的压坯在低温下由于压制应力释放和剧烈的还原脱气(氧)反应造成压坯膨胀; 压坯中出现液相的温度比微米Ti(CN)粉末压坯的要低50 ℃。 由于高温氮的分解, 造成合金在温度达到1 400 ℃以后不但不收缩, 反而膨胀; 纳米Ti(CN)混合料压坯中的总碳含量和氧含量在600 ℃后逐步下降; 压坯中的氧含量在1 100~1 300 ℃时迅速下降, 压坯中的氮含量在1 100 ℃以后才开始下降, 在液相出现前形成高峰, 氮含量越高, 氮的损失越大。 纳米混合料的压坯必须经过压力烧结后才能获得高致密的合金,其断裂韧性要比微米金属陶瓷提高50%。
关键字: 纳米Ti(CN);金属陶瓷; 烧结收缩; 化学成分; 力学性能
chemical composition of millicron-Ti(CN)
base cermets during sintering
(1. Engineering Technology Province Key Laboratory of Inorganic and
Nonmetal Materials, Hunan Industry University, Zhuzhou 412007, China;
2. State Key Laboratory of Powder Metallurgy,
Central South University, Changsha 410083, China)
Abstract: Using chemical analysis and vacuum sintering in different temperatures, the evolvement of the shrinkage, chemical composition and properties of the nano-Ti(CN) base cermets during sintering process were studied. Because of pressing stress was released and the deoxidizing and outgassing(oxygen) were happened tempestuously, the nano-cermets green compact was expanded at about 600 ℃. The temperature of liquid phase appear is lower about 50 ℃ than that of micro Ti(CN) powders. Because of the decomposition of nitrogen, the nano-Ti(CN) base cermets began to expand after 1 400 ℃. The total carbon and oxygen content in nano-cermets green compact decline gradually with the increase of sintering temperature, the oxygen content decline rapidly between 1 100-1 300 ℃. The nitrogen content in nano-cermets begins to decline, the decline reach floodtide before the liquid phase appear, the higher of nitrogen content in nano-cermets is, the higher the declining amount is. Only by pressure sintering could the dense alloy be gained, the fracture toughness of nano-Ti(CN) base cermets increase by 50% compared with the micron one.
Key words: nano-Ti(CN); cermets; sintering shrinkage; chemical composition; mechanical properties