钴基合金-碳化钨复合涂层耐磨抗蚀性能研究

采用真空熔烧法制得钴基合金-碳化钨复合涂层.应用盘销式摩擦磨损试验机对不同碳化钨含量的复合涂层和淬火态45#钢进行了磨损试验.借助自设计振动装置,在10%HCl溶液及10%NaOH溶液中进行了室温全浸泡振动腐蚀试验.试验结果表明,复合涂层的耐磨性显著高于淬火钢,且其耐磨性随碳化钨含量的增加而提高,复合涂层在腐蚀液中耐蚀性也远高于45#钢.     

渗透钎焊法制备的WC复合涂层的磨损性能

WC复合涂层是一种有效减少工件磨损的保护涂层,目前国内外对渗透钎焊制备的WC复合涂层磨损机理的研究较少。利用渗透钎焊技术在Q235钢表面制备了镍铬合金-碳化钨复合涂层;观察了涂层经过砂轮摩擦后的磨损表面形貌,分析了WC含量对涂层耐磨性能的影响规律以及涂层磨损的微观机制。结果表明:影响涂层耐磨性的因素主要是涂层中的WC含量,涂层的耐磨性随着WC相含量的升高而提高;WC-Co用量为50%制得的涂层的磨损机理是砂轮硬质颗粒对涂层的磨粒磨损,而WC-Co用量10%制得的涂层,砂轮硬质颗粒对涂层的切割除造成少量的WC颗粒脱落外,主要是使大量粘结相镍铬合金韧性撕裂脱落,耐磨性很差,表面形貌为平面状撕裂断面,所以磨损断裂主要是以塑性变形为主。     

粉煤灰微珠填充环氧树脂复合涂层耐磨性能的研究

制备了粉煤灰微珠/环氧树脂复合材料涂层,并利用JM-V型磨耗仪对涂层材料进行了磨损试验,研究了粉煤灰微珠含量、微珠粒径以及试验负载和速度对复合涂层耐磨性能的影响。结果表明,随粉煤灰微珠含量的增加,涂层的耐磨性呈先增加后下降的趋势,当填充的微珠质量分数为15%时,复合材料涂层的耐磨性最佳。随微珠粒径的增大,微珠在磨损过程中更加容易破碎,导致复合材料涂层的耐磨性随之下降。对比不同载荷和速度下复合材料涂层的磨损试验结果发现,随负载的增加,复合材料涂层的耐磨性降低;加快试验速度,涂层材料的磨损量也随之变大。     

不同碳化钨含量对等离子弧熔覆镍基碳化钨涂层组织及性能的影响

采用等离子弧粉末熔覆技术在Q345钢表面熔覆镍基碳化钨涂层,研究了粉末中不同碳化钨含量对镍基碳化钨熔覆层组织及性能的影响.借助光学显微镜、扫描电镜及X射线衍射仪分析镍基碳化钨熔覆层的组织形貌,用显微硬度计和摩擦磨损实验机分别测量镍基碳化钨熔覆层的硬度和耐磨性.结果表明:镍基碳化钨熔覆层与基层之间呈冶金结合,涂层表面无气孔缺陷.镍基碳化钨涂层组织主要由碳化钨颗粒和镍基粘结相构成,碳化钨是WC和W2 C,镍基粘结相中包含SiC、Cr23 C6 、Ni3 Si、γ-Ni等物相.随着粉末中碳化钨含量从15% (质量分数,下同)增加至50% ,熔覆涂层组织中硬质相数量增多,其硬度和耐磨性显著提高.当碳化钨含量为50%时,熔覆涂层硬度高达1 024HV10且耐磨性最好.     

基于激光熔覆SiC/Ni复合涂层的耐磨性EI北大核心CSCD

采用预置粉末法,在Q235钢表面进行激光熔覆镍基SiC陶瓷涂层的实验研究。使用往复式磨损试验机对不同涂层材料的熔覆层进行干摩擦磨损实验,利用金相显微镜(OM),扫描电镜(SEM)观察和分析熔覆层的显微组织与磨损形貌。结果表明:在重载干滑动摩擦条件下,Ni基SiC复合涂层耐磨性得到显著提高;当复合粉末SiC含量为25%(质量分数)时,熔覆层耐磨性最佳;熔覆层的磨损机制以磨粒磨损为主,同时伴有黏着磨损特征,且随着SiC含量的增加,黏着磨损的特征愈加明显。     

环模材料抗植物磨料磨损激光淬火工艺参数优化

为了探索提高环模材料抗植物磨料磨损的表面强化工艺,对环模常用材料45#钢进行激光淬火处理,通过磨料磨损试验,利用正交试验设计,探讨了不同激光淬火工艺参数对材料耐磨性的影响。试验数据分析显示:3个工艺参数对磨损量影响大小顺序为激光功率、扫描速度和光斑直径,耐磨性的最优参数组合为激光功率2050W、扫描速度20mm/s、光斑直径4mm。植物磨料对未经激光淬火的45#钢的磨损机制主要为显微切削+粘着磨损,激光淬火后的45#钢磨损机制主要为机械抛光+显微切削,且其表面犁削深度较之未经激光淬火处理的试件明显浅而窄。     

激光熔覆原位自生TiC颗粒增强镍基复合涂层的组织与耐磨性

采用预置粉末法在45钢表面进行激光熔覆镍基Ni60A+x%(SiC+Ti)(质量分数,下同)复合粉末涂层的实验研究。使用往复式磨损试验机对不同涂层材料的熔覆层进行干摩擦磨损实验,利用金相显微镜、扫描电镜(SEM)观察和分析熔覆层的显微组织与磨损形貌。结果表明:复合粉末通过原位反应生成弥散分布的TiC颗粒增强复合涂层,随着(SiC+Ti)含量的增加,颗粒状TiC的尺寸和数目逐渐增加;复合粉(SiC+Ti)含量达到60%时,微观组织有气孔和夹杂缺陷;复合粉(SiC+Ti)含量为48%时,熔覆层耐磨性最佳;复合涂层的磨损主要为磨粒磨损,机理为微观切削和挤压剥落。     

激光淬火功率对45~#钢抗植物磨料磨损性能的影响

本文以苜蓿草粉为典型植物磨料,系统研究了激光淬火功率对45~#钢抗植物磨料磨损性能的影响。试验结果表明:在实验条件下,材料表面硬度最大值可达679HV,材料硬度最大值在距表面0.2~0.4mm之间;激光淬火后的45~#钢抗植物磨料磨损性能远高于未经激光处理的试件。激光功率对材料硬度和耐磨性的影响趋势并不完全一致,耐磨性最好的试件硬度并非最高;植物磨料对激光淬火后的45~#钢的磨损机理主要为显微切削,与未经激光淬火的试件相比,激光淬火后的45~#钢表面犁削深度明显浅而窄,但当激光功率降至1750W时,塑变疲劳和碳化物剥落明显增加。研究结论可为农业机械金属材料的耐磨性设计提供依据。     

等离子表面Mo-Cr低合金高速钢的摩擦学特性

为了研究Q235钢表面冶金形成Mo-Cr低合金高速钢的摩擦学特性,利用双层辉光离子渗金属技术,在Q235钢表面进行Mo-Cr共渗,随后进行超饱和渗碳、淬火及回火复合处理.研究结果表明:Mo-Cr共渗层厚度在100 μm以上,表面Mo含量可达20%,Cr含量达到10%,超饱和渗碳表面含碳量超过2.0%,表面成分接近钼系高速钢.淬火及回火后表面硬度达到1300HV,超过一般冶金高速钢.磨损试验表明,摩擦系数随着接触应力的增加而增大,平均相对耐磨性是GCr15渗碳淬火钢的2.2倍.     

SiC和聚四氟乙烯填充聚酰胺酰亚胺复合涂层的制备及摩擦磨损行为

以Q235钢为基体材料,采用室温空压喷涂的方法制备了纯聚酰胺酰亚胺(PAI)涂层及SiC和聚四氟乙烯(PTFE)填充的PAI复合涂层。采用MMW-1型万能摩擦磨损试验机对涂层进行了摩擦磨损试验,当SiC和PTFE的填充量分别为10%和0.8%时,PAI复合涂层摩擦学性能达到最优。对于纯PAI和PAI+10%SiC复合涂层,在40 N的载荷下,滑动速率的增加会导致摩擦系数的降低,但会降低其耐磨性。然而,在120 N的高载荷下,其在低中滑动速率下表现出最高的摩擦系数和磨损率。对于SiC+10%SiC+0.8%PTFE复合涂层,由于PTFE的加入,随着载荷的增大,摩擦系数逐渐减小,而磨损率先增大后基本保持不变;滑动速率的提高只会减小摩擦系数和磨损率。热重曲线表明,复合涂层的起始分解温度为410℃,而纯PAI涂层起始分解温度为350℃。磨损涂层的扫描电镜图像揭示了涂层的磨损机理,纯PAI涂层为磨粒磨损,SiC/PAI复合涂层是犁耕磨损,而SiC/PTFE/PAI复合涂层摩擦后只有轻微的塑性形变。     

CrAlN coatings deposited by cathodic arc evaporation at different substrate bias

CrAlN is a good candidate as an alternative to conventional CrN coatings especially for high temperature oxidation-resistance applications. Different CrAlN coatings were deposited on hardened steel substrates by cathodic arc evaporation (CAE) from chromium-aluminum targets in a reactive nitrogen atmosphere at negative substrate bias between − 50 and − 400 V. The negative substrate bias has important effects on the deposition growth rate and crystalline structure. All our coatings presented hardness higher than conventional CrN coatings. The friction coefficient against alumina and tungsten carbide balls was around 0.6. The sliding wear coefficient of the CrAlN coatings was very low while an important wear was observed in the balls before a measurable wear were produced in the coatings. This effect was more pronounced as the negative substrate bias was increased.     

NAK80模具钢表面2种激光器熔覆Ni基碳化钨合金层组织结构及耐磨性比较

为了研究激光器对Ni基碳化钨合金熔覆层组织结构和性能的影响,分别采用Nd:YAG与CO2激光熔覆技术在NAK80模具钢表面制备了Ni基碳化钨合金层,利用X射线衍射仪(XRD)、扫描电镜(SEM)、能谱仪、显微硬度计以及摩擦磨损试验机测试分析了2种熔覆层的组织结构、显微硬度及耐磨性能。结果表明:2种熔覆层与基体之间均呈现良好的化学冶金结合;熔覆层组织主要为粗大的未熔碳化钨颗粒和均匀分布的树枝晶,Nd:YAG激光熔覆层的组织比CO2激光熔覆层的细小;2种熔覆层相结构主要包括WC,W2C,Cr23C6,NiCr,CrB2以及γ-Ni等;2种激光器熔覆处理后,NAK80模具钢表面硬度和耐磨性都得到显著改善,CO2激光熔覆层的硬度和耐磨性高于Nd:YAG激光熔覆层,2种激光熔覆试样的磨损机制均为磨粒磨损。     

Wear resistance of KhVG tool steel hardened with composite coatings based on titanium-chromium double carbide

Wear resistance of KhVG tool steel hardened with composite coatings based on titanium-chromium double carbide is studied by means of an automatic wear-measurement system. The influence of deposition methods—electrical discharge alloying and plasma spraying—as well as process variables on the wear resistance of coated steel is discussed. The composition and structure of specimen friction surfaces are examined. The authors of the paper have established the optimal operating conditions for the coatings as well as the most efficient deposition methods for the operation under experimental conditions studied.     

Tribological behaviour of mechanically synthesized titanium-boron carbide nanostructured coating

In this paper, titanium-boron carbide (Ti/B4C) nanocomposite coatings with different B4C nanoparticles contents were fabricated by surface mechanical attrition treatment (SMAT) method by using B4C nanoparticles with average nanoparticle size of 40 nm. The characteristics of the nanopowder and coatings were evaluated by microhardness test, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Friction and wear performances of nanocomposite coatings and pure titanium substrate were comparatively investigated, with the effect of the boron carbide content on the friction and wear behaviours to be emphasized. The results show the microhardness, friction and wear behaviours of nanocomposite coatings are closely related with boron carbide nanoparticle content. Nanocomposite coating with low B4C content shows somewhat (slight) increased microhardness and wear resistance than pure titanium substrate, while nanocomposite coating with high B4C content has much better (sharp increase) wear resistance than pure titanium substrate. The effect of B4C nanoparticles on microhardness and wear resistance was discussed.     

硬质合金深冷处理研究及其应用

硬质合金是目前使用较为广泛的工程材料,其具有硬度高、耐磨、耐热、耐腐蚀等一系列优良特性,尤其是它的高硬度和耐磨性。而到目前为止,深冷处理的详细研究主要集中在工具钢、高速钢等黑色金属上。本文根据硬质合金的一些力学特性,综述了深冷处理的发展历史、作用机理、处理工艺过程以及生产实际的应用。探究总结了深冷处理过后,硬质舍金性能及合金组织的变化,深冷处理后硬质合金中1）相含量增多且尺寸减小,Co对WC的粘结更紧密,但也有认为微观组织形貌变化不大的观点;Co相由面心立方向密排六方转变,而WC相变化不大。最后根据目前研究状况提出继续进行深冷处理技术研究的一些看法。     

Entwicklung hochverschleißbeständiger wolframschmelzkarbidbasierter Schichten auf Aluminiumbauteilen durch Plasma‐Pulver‐Auftragschweißen

Development of high wear‐resistant FTC‐based coatings on aluminium components using plasma transferred arc welding Nowadays, functional surfaces of components can be effectively protected from extreme wear with the help of fused tungsten carbide (FTC) coatings. The wear protection of steel components using FTC has been well known for many years. This paper presents the feasible study of improving the wear resistance of aluminium components with FTC particles using plasma powder arc welding. The FTC coatings are developed with two methods: one is the dispersion of carbide particles in aluminium and the other one is the combination of dispersing and alloying of FTC‐based composite powders. In this research, coatings within a thickness range of a few millimeters are developed with varying process parameters and compositions of the filler materials. The developed coating systems are tested with regard to their specific properties and their wear resistance. Finally, their application potential is presented.     

Influence of ion implantation and overlay coatings on various physico-mechanical and wear properties of stainless steel,titanium and aluminium

This work represents the data on the wear behaviour of 304 stainless steel, commercial grade titanium and commercial grade aluminium without and with different surface treatments, namely ion implantation of boron and nitrogen and overlay coatings of titanium carbide and nitride.The surface treatments were characterized by phase identification, hardness, bend strength, as well as adhesion of overlay coatings. Wear properties were evaluated in adhesive, erosive and abrasive modes of wear.The experimental results showed that surface treatments produced measurable changes in hardness and strength. The results of adhesive wear tests indicated that the wear resistance of all the substrate materials can be considerably improved by overlay coating with superhard materials in dry as well as lubricated test conditions. Ion implantation resulted in improvement of wear properties for only a limited regime of adhesive wear under lubricated conditions and for the abrasive mode of wear. Overlay coatings produced a marked improvement in abrasive wear tests under lubricated conditions on all substrate materials.     

Tribological behavior and wear mechanisms of Ti-C : H/TiC/TiCN/TiN/Ti coatings when sliding against steel, bronze and aluminum alloy rods

Ti _x%-C : H coatings of differing thicknesses and with various titanium concentrations were deposited on tungsten carbide disks by unbalanced magnetron sputtering. The mechanical properties, microstructure, and adhesion strength of these coating were measured. The tribology properties of the coatings against AISI 1045 steel, AA7075, AA6061 aluminum alloy, and bronze rods were tested by an oscillation sliding test machine with a line-contact wear mode under dry conditions. The microhardness of Ti _x%-C : H coatings increased with an increasing Ti concentration. The optimum coatings are composed of an intermediate layer of TiC/TiCN/TiN/Ti and a top layer of Ti _x%-C : H with x 20%. These coatings have an excellent wear resistance and a low friction coefficient when paired with a carbon steel or copper alloy. These pairs are marked by the mildly wear of the counterbodies of AISI 1045 steel and bronze. The coatings are less suitable for oscillation with the aluminum alloy under dry conditions due to severe adhesion damage.     

Understanding the dry sliding wear behaviour of atmospheric plasma-sprayed rare earth oxide coatings

In this paper, the friction and wear behaviours of Yttria Stabilized Zirconia (YSZ) coatings; Lanthanum Zirconate (LZ) coatings and Inconel 738 base material (BM) sliding against a sintered tungsten carbide surface were studied and compared under unlubricated conditions. Sliding experiments were performed in a pin-on-disc configuration. Further, relationships among porosity, normal load and disc speeds with respect to wear loss were derived by using the response surface methodology, and the wear mechanisms were discussed adequately. It was found that the wear resistance of the ceramic coatings gets deteriorated with the increase in the percentage volume of porosity.