钢表面化学气相沉积碳化硅及其高温腐蚀行为

研究了耐热钢表面化学气相沉积碳化硅的工艺．比较了耐热钢、碳化钛膜和碳化钛／碳化硅双层膜在O2 Br2 Ar气氛中的高温腐蚀行为，通过热力学分析，解释了腐蚀动力学现象．证明了在耐热钢表面被覆碳化钛／碳化硅双层膜可以大幅度提高其抗高温腐蚀能力。     

熔盐被覆TiC初探

熔盐被覆TiC是目前国内外对硬质合金.模具钢等进行表面强化的一种最新方法;我们对W_6Mo_5Cr_4V_2、Cr_(12),WC_(50)CrMo及T12进行了试验,均得到一定的被覆层深及较高的硬度,对被覆工艺进行了一系列的探索,找到了较为理想的熔盐被覆TiC的工艺方法.     

自蔓延高温合成新型碳化钛磨料

采用自蔓延高温合成技术制备碳化钛磨料.考察了合成过程中钛粉粒度、C与Ti摩尔比率、稀释剂添加量、初始样品密度对燃烧温度、燃烧速率及产物化学组成的影响,测试和比较了碳化钛和其他磨料的研磨性能,并通过SEM分析了碳化钛、金刚石颗粒及相应被磨工件的表面形貌.结果表明:碳化钛的研磨能力可与人造金刚石相媲美,大大超过氧化铝、碳化硼和碳化硅.而碳化钛的高研磨能力是由颗粒的强切削力所致,人造金刚石则由颗粒的高硬度所致.     

2001年吉林工学院学报总目次

第一期ＰＢ ｇ ＳＡＮ弹性体对ＳＡＮ树脂的增韧张明耀 ,娄秀东 ,张会轩 ,程　卓 (1)………………………………………………对浸渍法制备Ｐｄ/Ｃ催化剂表面积影响因素的讨论丁春黎 ,朱永娟 ,顾　薇 (4 )…………………………………………填料层液体分布的理论及数学模型张秀莉 ,李　然 ,李锡源 ,麦本熙 (7)………………………………………………用球磨法制取ＷＣ Ｃｏ纳米粉陈亚军 ,金松哲 ,周振华 (11)…………………………………………………………………钢表面氯基熔盐被覆碳化钛工艺姜东梅 ,吴　化 ,王立新 (15 )………………………………     

在钢基体上进行碳化钛气相沉积

碳化钛复层具有高硬度,高耐磨性和低磨擦系数等特点,因此在制造超硬工具和在无法进行润滑的超高真空和高温下工作滚动轴承,以及要求具有高耐磨性的工件等方面有广泛作用。通过前一段工作,使在钢基体上进行碳化钛气相沉积的沉积温度降低至800—900℃。工艺特点是常压、低氢气流量并在炉中放入海绵钛,以强化工艺过程。同时,对基体进行予先化学热处理使碳化钛复层与基体间结合力提高30%,并可对已沉积后的工件进行淬火,回火以提高工件性能。现已将这一工艺成功地应用于制造瓷件修坯刀,加工铝合金和铜合金的机动丝锥,钻机的摩擦付等工件上,使这些工件的使用寿命大为提高。与此同时,本文拟应用化学热力学对化学气相沉积中某些反应进行讨论。     

高压下碳化钛热力学性质的第一性原理计算

碳化钛熔点高、硬度高、化学性能稳定性好,工业上主要用来制造金属陶瓷、耐热合金和硬质合金.采用平面波密度泛函理论广义梯度近似计算了碳化钛的弹性常数、晶格常数、体积模量,所得结果与实验和其它理论值相一致;通过准谐德拜模型预测了碳化钛的相对体积与压强,体积模量分别与压强和温度,热容与温度的变化关系,结果表明:温度对体积模量的影响远小于压强对体积模量的影响.该研究对碳化钛在高温高压下的应用具有指导意义.     

无氢化学气相沉积碳化钛

本文介绍了一种新的化学气相沉积碳化钛方法。用此法对几种常用的工具材料进行了沉积处理,并用金相观察、X射线结构分析、X射线光谱显微分析等手段测定了碳化钛沉积层的组织、结构和性能。应用此法于模具和某些易磨损机件上可较大地提高机件的使用寿命,且方法本身安全、经济,在一般的热处理设备条件下即能进行。     

Sucker浆纱机上浆机理浅析

将细号经纱在两种浆纱机上进行上浆工艺对比。通过上浆机理分析,阐述了Sucker浆纱机“四高”（即高压浆力、高温、高浓、高速）的上浆工艺特点。说明细号经纱在高压上浆条件下以“渗透为主,适量被覆”的上浆更利于提高织造效率。     

碳钢被覆金属碳化物过程中碳迁移扩散行为的探讨

本文对碳钢被覆金属碳化物过程中碳原子的迁移扩散行为进行了讨论。由于碳从基体向表面扩散形成碳化物,在基体与被覆层之间形成一假想的脱碳区△L,该区脱碳前的碳含量正好等于被覆层获得增量dl所需的碳原子总量。如果在被覆层获得增量dl的时间dt内,该区的碳能与远基体达到均匀化,则认为基体中的碳含量已足以维持被覆层的正常生长。本文对此进行了定量分析,导出了被覆金属碳化物钢中所需碳含量的数学表达式。     

钢中含碳量对其表面被覆TiC的影响

利用氯基熔盐在正常大气压下,对钢表面进行被覆TiC处理,可以得到高硬度、高耐磨性、高耐蚀性的TiC被覆层。研究表明,钢中含碳量及碳的存在形式对被覆层的形成过程有重要影响。通过对含碳量不同的钢种进行被覆处理,确定了在氯基熔盐被覆处理条件下,钢中所需的最低含碳量。     

TiC/Fe cermet coating by plasma cladding using asphalt as a carbonaceous precursor

A new Ti-Fe-C compound powder for plasma cladding was prepared by heating a mixture powder of ferrotitanium and asphalt pyro-lyzed as a carbonaceous precursor. The carbon by the pyrolysis of the asphalt acts as a reactive constituent as well as a binder in the compound powder. The TiC/Fe cermet coatings were prepared by plasma cladding with the compound powder. Results show that the Ti-Fe-C compound powder has a very tight structure, which can avoid the problem of the reactive constituent particles being separated during cladding. The TiC/Fe cermet coating presents a typical morphology of plasma cladding coatings with two different laminated layers: one is the composite layer in which the round fine TiC particles (<500 nm) are dispersed within a Fe matrix, the other is the paragentic layer of TiC and Ti2O3. The coating shows high hardness and excellent wear resistance. The surface hardness of the coating is 68 ± 5(HR30N). In the same fretting conditions, the wear area of Ni60 coating is about 11 times as much as the TiC/Fe cermet coating.     

TiC/Fe cermet coating by plasma cladding using asphalt as carbonaceous precursor

A new Ti-Fe-C compound powder for plasma cladding was prepared by heating a mixture powder of ferrotitanium and asphalt pyrolyzed as carbonaceous precursor. The carbon by the pyrolysis of the asphalt acts as a reactive constituent as well as a binder in the compound powder. TiC/Fe cermet coatings were prepared by plasma cladding with the compound powder. Results show that the Ti-Fe-C compound powder has a very tight structure, which can avoid the problem that reactive constituent particles are separated during cladding. The TiC/Fe cermet coating presents a typical morphology of plasma cladding coatings with two different laminated layers: one is the composite layers in which the round fine TiC particles (<500nm) are dispersed within a Fe matrix, the other is the paragentic layers of TiC and Ti₂O₃. The coating shows high hardness and excellent wear resistance. The surface hardness of the coating is 68±5(HR30N). In the same fretting conditions, the wear area of Ni60 coating is about 11 times as much as the TiC/Fe cermet coating.     

TiC/Fe cermet coating by plasma cladding using asphalt as carbonaceous precursor

A new Ti-Fe-C compound powder for plasma cladding was prepared by heating a mixture powder of ferrotitaniurn and asphalt pyro- lyzed as a carbonaceous precursor. The carbon by the pyrolysis of the asphalt acts as a reactive constituent as well as a binder in the compound powder. The TiC/Fe cermet coatings were prepared by plasma cladding with the compound powder. Results show that the Ti-Fe-C compound powder has a very tight structure, which can avoid the problem of the reactive constituent particles being separated during cladding. The TiC/Fe cermet coating presents a typical morphology of plasma cladding coatings with two different laminated layers： one is the composite layer in which the round fine TiC particles （〈500 nm） are dispersed within a Fe matrix, the other is the paragentic layer of TiC and Ti2O3. The coating shows high hardness and excellent wear resistance. The surface hardness of the coating is 68 ± 5（HR30N）. In the same fretting conditions, the wear area of Ni60 coating is about Ⅱ times as much as the TiC/Fe cermet coating.     

激光表面合金化制备TiC/Ti复合涂层的组织与性能

利用激光表面合金化技术在工业纯钛表面制备TiC/Ti复合涂层,并对复合涂层的组织与性能进行了分析和测试,对TiC的合成机理进行了探讨.研究结果表明,复合涂层由合金化层和热影响区组成.合金化层由TiC和α′-Ti构成,TiC的生长形貌包括树枝状、十字花瓣状、胞枝状以及针状,热影响区主要由α-′Ti构成.合金化层的平均显微硬度为HV 420.TiC的合成过程分为三个阶段:激光辐照时,固态C颗粒迅速扩散至激光熔池并被液态Ti包围;首先固-液结合界面处的Ti和C直接反应形成TiCx,随后液Ti扩散并穿过TiCx层与剩余的C进行反应,直至TiCx中C的浓度达到TiC中C的浓度,生成的TiC溶于液相中;快速凝固过程中,TiC从溶液中析出并长大.     

气相沉积TiC/TiN涂层的组织和性能的研究

本文对气相沉积法(CVD和PVD)获得的TiC/TiN涂层,通过金相显微镜和扫描电镜的观察,x射线相结构分析,以及硬度、结合力、开裂情况的测定与分析,弄清了涂层的显微组织和相结构,提出了涂层的形成机制。测定结果表明,涂层与基体间的结合力,在高速钢基体上由PVD法沉积的TiN涂层约为7.09kgf/mm~2,在T10钢基体上由CVD法沉积的TiC涂层约为93.82kgf/mm~2。还探讨了涂层的断裂机制,讨论了涂层组织与性能之间的关系。本文的上述研究,为稳定、高效制备优质TiC/TiN涂层提供了依据。     

Microstructure and mechanical properties of Ni-based composite coatings reinforced by in situ synthesized TiB2 + TiC by laser cladding

A Ni-based composite coating reinforced by in situ synthesized TiB₂ and TiC particles was fabricated on Ti6Al4V by laser cladding. An attempt was made to correlate the thermodynamic predictions and experimental observation. The microstructure and the microhardness profile across the coating were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and a hardness tester. It is found that the coating mainly consists of a large number of reinforcements (black blocky TiB₂, flower-like or equiaxial TiC, and fine acicular CrB) and the γ matrix. The hardness of TiB₂, TiC, and CrB reinforcements is much higher than that of the γ matrix. The dispersive distribution of such high hardness reinforcements causes the increase in hardness of the whole coating. The average value of the hardness is approximately Hv_0.2 700 in the coating. The hardness of the coating is obviously higher than that of the substrate due to the dispersion strengthening of reinforcements.     

原位自生TiC/Ni复合材料涂层滑动磨损行为

为了提高16Mn钢的干滑动磨损耐磨性能，以Ni60、钛粉和石墨粉为原料对16Mn钢表面进行感应熔敷处理，制备出以TiC颗粒为增强相的原位自生复合涂层，利用金相、SEM、XRD等技术分析了涂层的显微组织，在室温干滑动磨损试验条件下测试了涂层的耐磨性。结果表明：涂层中TiC颗粒均匀分布于共晶基体上，整个涂层组织均匀、无气孔、无裂纹：涂层与基材形成了良好的冶金结合，涂层具有很高的硬度，在室温干滑动磨损试验条件下具有优异的耐磨性能。     

激光熔覆原位合成TiC的Ni／TiC复合层显微组织与性能研究

利用5kW CO2激光器和同轴送粉的方法,在Q235钢基材表面原位合成强化相为TiC的Ni／TiC复合材料层。研究了不同Ni相对含量对熔覆层的显微组织形貌和相组成的影响,并进行了耐磨性试验。结果表明,熔覆层的物相构成为Ni和TiC,熔覆层耐磨性随Ni相对含量的减少而增大。