revised第五章 熱擴(kuò)滲

1、 滲硼層厚度、表面硬度與滲硼時(shí)間滲硼時(shí)間（小時(shí)）滲硼層厚度（mm）硬度（HV）30.045112040.052112050.0671160氫氧化鈉溶液 鹽酸 硫酸 腐蝕后試樣實(shí)物照片 滲硼與未滲硼試樣在H2SO4、HCL介質(zhì)中的腐蝕失重比較 試樣的磨損失重比較 Fig.1 XRD patterns of AISI 1045 steel treated with different boriding agents at 1213K：(a) without Nd2O3 addition，(b)with Nd2O3 addition.Fig.2 Optical micrographs of bori

2、ded AISI 1045 steel subjected to different process temperatures: (a) 1093K, (b) 1093K with Nd2O3 addition, (c) 1213K，(d) 1213K with Nd2O3 addition.Fig.3 Boride layer thickness vs. boriding time for various process temperatures.Ktd 2 )(0RTQeKK )(lnln0RTQKKFig.4 Growth rate constant vs. temperature of

3、 borided AISI 1045 steel.2BF3 + B4C = 3BF2+ 3B + C G5 (5)3KF + 3BF3 + 2Nd2O3 = 4NdF3 + 3KO2 + 3B G6 (6)2KO2 = K2O2 + O2 G7 (7)2BF3 + 3B4C + Nd2O3 + 6O2= 2NdF3 + 2B2O3 + B + 3CO G8 (8)2BF3 + B4C + 3Fe + 2O2 = 3FeF2 + B2O3 + 6B + CO G9 (9)B4C + 2KF + Fe + 3O2 = 2B + FeF2 + 2K2O + B2O3 + CO2 G10 (10)2B

4、F3 + SiC + 3Fe + 3O2 = 3FeF2 + SiO2 + B2O3 + CO G11 (11)B4C + 2KF + 3O2 = B +BF2 + B2O3 + K2O + CO G12 (12) Fig.6 Changes of Gibbs free energy as a temperature for different reactions. Fig.7 Element mapping on the surfaces of the AISI 1045 steel borided at 1053 K Fig.8 Element mapping on the surface

5、s of the AISI 1045 steel borided at 1133 K. Fig.9 EDS spectrum of tiny sphere on surface of RE-borided AISI 1045 steel at 1133 K.Fig.10 Element mapping on the surfaces of the AISI 1045 steel borided at 1213 K.離子氮化離子氮化早在1932年就由一個(gè)德國人發(fā)明了，上世紀(jì)上世紀(jì)60年年代在德國、瑞士等國開始應(yīng)用代在德國、瑞士等國開始應(yīng)用。我國是70年代開始研制和應(yīng)用的。原理原理： 就是把工件放入氮化爐中，抽真空至1.33Pa左右通入少量的氨氣氨氣，當(dāng)氣壓升到70Pa左右接通電源，工件是陰極，在陰極與陽極間加上直流高壓，就會(huì)產(chǎn)生輝光放電輝光放電。氣體電離了了，氮離子氮離子、氫離子氫離子就會(huì)在電場作用下沖向工件表面，產(chǎn)生大量的熱把工件加熱到熱把工件加熱到520-550，氮離子和氮原子就會(huì)氮離子和氮原子就會(huì)在工件表面吸附、擴(kuò)散，形成氮化層。保溫一段時(shí)間后，斷在工件表面吸附、擴(kuò)散，形成氮化層。保溫一段時(shí)間后，斷電、停氣、降溫