碳氮比对Ti(C,N)粉末抗氧化性的影响

The Effect of Carbon to Nitrogen Ratio on Oxidation Resistance of Ti(C,N) Powder

本文对不同碳氮比Ti(C,N)固溶体粉末分别进行了等温氧化和非等温氧化,通过TG-DSC热分析、氧化动力学分析和物相分析,研究了碳氮原子比对Ti(C,N)粉末氧化行为的影响。Ti(C,N)粉末在O2气流中从室温加热至1 000~1 200℃的非等温氧化,以及在650℃的静置空气中的等温氧化。结果表明,Ti(C,N)粉末在非等温氧化过程中,氧化过程可分为2个阶段或3个阶段,第1氧化阶段氧化脱氮占主导地位,第2氧化阶段氧化脱碳占主导地位,Ti(C0.5,N0.5)粉末表现出最优的抗氧化性能。在650℃的等温氧化中,Ti(C,N)粉末氧化遵循随机形核动力学模型,Ti(C0.7,N0.3)具有最小的一阶速率常数,表现出最优的抗氧化性能。初始氧化固体产物为锐钛矿结构TiO2,随氧化时间延长,逐渐向金红石结构TiO2转变。

In this paper,Ti(C,N) solid solution powders with different carbon to nitrogen ratios were subjected to isothermal oxidation and non-isothermal oxidation.Through TG-DSC thermal analysis,oxidation kinetic analysis and phase analysis,the effect of carbon to nitrogen ratio on the oxidation behavior of Ti(C,N) powder was studied.Ti(C,N) powders were heated from room temperature to non-isothermal oxidation of 1 000~1 200 ℃ in an O2 air flow and isothermal oxidation of Ti(C,N) powders at 650 ℃ in stationary air.The results show that in the non-isothermal oxidation process of Ti(C,N) powder,the oxidation process can be divided into two stages or three stages.In the first oxidation stage,denitrification is dominant,and in the second oxidation stage,decarburization is dominant,Ti(C0.5,N0.5) powder shows the best oxidation resistance.In the isothermal oxidation of 650 ℃,the oxidation of Ti(C,N) powder follows the random nucleation kinetic model.Ti(C0.7,N0.3) has the smallest first-order rate constant and shows the best oxidation resistance.The solid product of initial oxidation is anatase structure TiO2,and gradually transforms to rutile structure TiO2 as the oxidation time extends.