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金属粉末注射成形 (MIM)粘结剂中高分子物质的分解和排除是一个较缓慢的过程 ,对这一过程进行理论研究 ,有助于指导粘结剂的设计和脱脂过程优化 .为此 ,当Fe 2Ni粉末的注射成形坯经充分溶剂脱脂后 ,用热重法对坯块中的PMMA的热分解行为进行了理论研究和实验验证 .假设进行一级反应 ,根据各种升温速率的热重计算结果 ,得到了喂料中PMMA热分解反应速率的理论计算表达式 :ln(1-α) =1 33× 10 9t·exp(- 1479/T) ;对厚度为 6 .37mm的注射坯充分溶剂脱脂后 ,验证了坯块中PMMA分解速率 ,发现在 35 0℃和 40 0℃时等温脱脂的速率与理论值较接近 ,但低于理论值 ;经过优化 ,对 6 .37mm厚的注射坯 ,采取 5～ 10℃ /min的升温速度升温 ,可在 2h内完成热脱脂过程
Metal powder injection molding (MIM) binder polymer material decomposition and elimination is a relatively slow process, a theoretical study of this process will help guide the design of the binder and degreasing process optimization.To this end, when Fe 2Ni powder injection molded billets after solvent degreasing, thermal gravimetric analysis of the thermal decomposition behavior of PMMA in the billet theoretical research and experimental verification.If the first-order reaction, based on the thermal gravimetric calculation of various heating rates As a result, the theoretical calculation expression for the thermal decomposition reaction rate of PMMA in the feedstock was obtained: ln (1-α) = 1 33 × 10 9 t · exp (- 1479 / T) After degreasing, the decomposition rate of PMMA in the briquette was verified, and the rate of isothermal degreasing at 35 0 ℃ and 40 0 ℃ was close to the theoretical value but lower than the theoretical value. After optimization, Take 5 ~ 10 ℃ / min heating rate of heating, can be completed within 2h hot degreasing process