【摘要】 本文根据离子扩渗技术特点,利用一种特殊的离子氮硼共渗方法,借助于离子探针、电子探针及扫描电子显微镜等手段着重研究了硼对钢离子氮化层的影响。更多还原

【Abstract】 lon-boriding was developed utilizing different mixed gases as carrier by some researchers, but processes they devetoped are frequently unapplicable to industrial practice for the risk of noxiousness, explosiveness or corrosiveness to container and pump. A new ionic process using NH3 + B for steels has therefore been specially designed to investigate experimentally the effect of boriding especially the effect of boron on NHs + B treated case of steel.Summary. Surfaces of three kinds of structural alloy steel as 35GrMo, 38CrMoAlA and 40Cr were examined after nitridings using NH3 and NH3 + B separately under conditions of 520℃, 8hr and 4×102 Pa, and comparisons are made in hardness, compactness and abrassive wear resistance. Measurement by means of IMS-300 inoic microprobe shows that boron content in-the case treated by NH3 + B is obviously higher than that by NH3 only. With the observation by a STM-1 type scanning electron microscope, the compactness of compound layer in NH3 + B treated specimens are higher than that in pure NH3 treated. In addition, the hardness of case of NH3 + B treated specimens is raised markedly by virtue of the penetration of boron and that it is evident that boron makes positive contribution to improving abrassive wear resistance of steel after NH3 + B treated. Fig.1 Schematic of abrassive wear testerFig.2 Boron distribution in 38CrMoAlA steel by ionic microprobe Real line. NH3 + B treated; Dotted line, pure NH3 treated. fig.3 Mass spectrum of 38CrMoAlA before ionic nitriding Fig.4 Mass spectrum of 38CrMoAlA NH3 + B treated Fig.5 Fe-B equilibrium diagram Fig.6 Hardness distribution of the three kinds of alloy steel concernedReal line:B adding; Dotted line:without B adding.38CrMoAlA; °35CrMo; ⊙40Cr. Fig.7 Test result of abrassive wear°B adding; without B adding.Tab.1 HT regime for steel specimens Tab.2 X-ray diffraction of specimens comparing NH3 + B treated withNH3 treated Photo 1 Distribution of N concentration (a) and secondary EMmicaropraph (b) of 38CrMoAlA NH3 treated Photo 2 Distribution of N concentration (a) and secondary EMmicrograph (b) of 38CrMoAlA NH3 + B treated Photo 3 Compound layer of 38CrMoAlA NH3 + B treated case Photo 4 Compound layer of 38CrMoAlA NH3 treated case更多还原