气体氮碳共渗的动力学（二）

“化合物层”是指渗氮或氮碳共渗工件完全转变的外表层。这并不意味化合物层是均匀的、与工艺条件无关的．化合物层主要含有r相、e相、渗碳体．各种合金碳化物和氮化物等．因此．化合物层中也常常出现扩展的疏松层．     

9Cr2Mo钢冷轧辊断裂分析

本文所介绍的9Cr2Mo钢冷轧辊断裂事故,起因于中心孔部位的分层断口缺陷和针孔。而分层断口的形成,则与钢中碳化物沿奥氏体晶界大量析出有关。     

过渡金属碳化物的研究与应用进展

综述了过渡金属碳化物的结构与性质以及在各类反应中的应用研究进展,总结了碳化钨及碳化铝的催化性能,并预测了今后的发展方向和应用前景。     

碳化物陶瓷的研究现状及发展趋势

本文综述了现阶段碳化物陶瓷超细粉末的主要制备工艺以及烧结方法,同时指出了碳化物陶瓷今后的发展趋势。     

Evolution of carbides and carbon content in matrix of an ultra-high carbon sintered steel during heat treatment process

DTA, thermal expansion, XRD, and SEM were used to evaluate the effect of quenching temperature on the mechanical properties and microstructure of a novel sintered steel Fe-6Co-1Ni-5Cr-5Mo-1C. Lattice parameters and the mass fraction of carbon dissolved in the matrix of the steel quenched were investigated. It is discovered that the hardness of the steel increases with quench-ing temperature in the range of 840-900℃ and remains constant in the range of 900 to 1100℃. It decreases rapidly when the tem-perature is higher than 1100℃. The mass fraction of carbon dissolved in the matrix of the steel quenched at 840℃ is 0.38, but when the quenching temperature is increased to 1150℃, it increases to 0.98. The carbides formed during sintering are still present at grain boundaries and in the matrix of the steel quenched at low quenching temperatures, such as 840℃. When the quenching temperature is increased to 1150℃, most of the carbides at grain boundaries are dissolved with just a small amount of spherical M23C6 existing in the matrix of the quenched steel.     

用有机酸清洗碳化物垢层

本文叙述碳化物垢层对设备装置的危害以及给生产长周期运转带来的不良后果及我厂采用有机酸清洗除尿素循环加热器上碳化物垢层获得的效果。     

Effect of vanadium and chromium on the microstructural features of V–Cr–Mn–Ni spheroidal carbide cast irons

The objective of this investigation is to study the influence of vanadium（5.0wt%–10.0wt%） and chromium（0–9.0wt%） on the microstructure and hardness of Cr-V-Mn-Ni white cast irons with spheroidal vanadium carbides. The alloys＇ microstructural features are presented and discussed with regard to the distribution of phase elements. The structural constituents of the alloys are spheroidal VC, proeutectoid cementite, ledeburite eutectic, rosette-shaped carbide eutectic（based on M7C3）, pearlite, martensite, and austenite. Their combinations and area fraction（AF） ratios are reported to be influenced by the alloys＇ chemical composition. Spheroidized VC particles are found to be sites for the nucleation of carbide eutectics. Cr and V are shown to substitute each other in the VC and M7C3 carbides, respectively. Chromium alloying leads to the formation of a eutectic（γ-Fe ＋ М7С3）, preventing the appearance of proeutectoid cementite in the structure. Vanadium and chromium are revealed to increase the total carbide fraction and the amount of austenite in the matrix. Cr is observed to play a key role in controlling the metallic matrix microstructure.     

含共晶碳化物Fe—Cr—Mn合金在高温含硫气氛中的腐蚀研究

对含碳量为０．５０－２．６３％的Ｆｅ－Ｃｒ－Ｍ合金在８００℃下含硫混合气氛中进行腐蚀试验。用Ｘ射线物相分析法分析了腐蚀产物种类及其相对含量，观察测定了元素在腐蚀产物中的分布及试样亚表层共晶碳化物的腐蚀行为。     

金刚石沉积过程中硬质合金基体的相互作用

金刚石涂层在硬质合金基体上的沉积及其粘结强度明显取决于基体的成分。尤其在低碳硬质合金基体上沉积的过程中，基体从含碳介质中吸收碳，从而阻碍了硬质合金上金刚石涂层的形成。此过程占用了沉积过程的很长时间，并能使金刚石一硬质合金界面的一部分金刚石涂层分解，从而降低界面的粘结强度。为了研究沉积过程中这种作用，实验是在缺碳、含有少量1碳化物(Co3W3C)的基体上完成的，通过使用这种合金样品发现Co3W3C C转化成Co(C，W) WC的反应前沿从表面迁移到了整个材料中，这也证实碳已扩散到了基体中。本文表明，温度在900℃时C和W的扩散速率以及反应速率都很高足以使所有η碳化物转化成Co(C，W) WC：经20小时的沉积后反应前沿已进入基体中约0．9mm深。沉积过程中钴粘结剂中的碳饱和以及部分金刚石涂层的分解可通过对基体不同深度部分进行晶格常数测定和通过界面的SIMS测定进一步加以证实。