大气等离子喷涂TiB2-316L不锈钢基复合涂层及其耐磨性能

分别采用高能球磨制备了TiB2含量(质量分数)为10%的316L不锈钢基复合粉,高能球磨与喷雾干燥造粒工艺制备了TiB2含量(质量分数)为40%的316L不锈钢基复合粉,大气等离子喷涂制备相应的TiB2-316L不锈钢基金属陶瓷涂层与316L不锈钢涂层.室温下采用高速环块磨损试验研究TiB2-316L不锈钢基金属陶瓷涂层的磨损特性.采用X射线衍射分析涂层物相,扫描电镜分析喷涂粉末、涂层结构和摩擦副磨损表面形貌.结果表明,大气等离子喷涂两种制粉工艺获得的316L不锈钢基TiB2复合粉能获得较耐磨的316L不锈钢基TiB2复合涂层,耐磨性高于316L不锈钢涂层,且TiB2在复合涂层中增强涂层耐磨性的原因是TiB2颗粒在涂层316L韧性基体中充当强化相,且TiB2在摩擦接触处摩擦氧化形成的氧化产物具有自润滑特性,能减少涂层的磨损量.     

Development of cored wires for improving the abrasion wear resistance of austenitic stainless steel

Arc-sprayed coatings are an attractive means to protect components from abrasive wear provided they contain enough hard phases. Because of their hardness and toughness, 316L-TiB₂ cermets were selected as the basis for developing wear-resistant coatings. Cored wires composed of type 304 stainless steel sheaths filled with 10 to 65 wt% TiB₂,1 to 15 wt% additives, and the balance with 316L stainless steel were fabricated and arc-sprayed with air. The arc-sprayed stainless steel-TiB₂ coatings were abrasion tested and the volume loss measured with an optical profiloineter. The volume loss decreased as the proportion of TiB₂ increased. However, large differences in volume loss between coatings that contain about the same volumetric proportion of hard phases cannot be explained by a linear relationship. An inverse rule of mixing was proposed and found useful in determining the influence of different additives. Tin, added in the core as a fugitive liquid transfer agent, was the most powerful additive for improving the wear resistance of stainless steel-base coatings. These advanced arc-sprayed stainless steel-TiB2 coatings exhibit greater wear resistance than those obtained by arc spraying commercial solid and cored wires.     

V / Nb 对电弧喷涂马氏体不锈钢合金涂层组织和性能的影响

目的 研究添加 V 和 Nb 对电弧喷涂马氏体不锈钢合金层组织和性能的影响规律。 方法 研制不同 V 和 Nb 含量的新型马氏体不锈钢电弧喷涂药芯丝材,利用高速电弧喷涂设备在 Q235 低碳钢板表面制备耐磨合金涂层,并对合金涂层的组织结构和性能进行研究。 结果 所制备的合金涂层成形良好,孔隙率较低,结构致密;涂层显微硬度值达 523 HV0 . 1 ,与基材间的平均结合强度值达 35 . 48 MPa,V 和 Nb的添加提高了合金涂层的耐磨损性能。 结论 添加适量的 V 和 Nb 合金元素,可以促进碳化物硬质相颗粒的形成,提高马氏体不锈钢合金涂层的综合性能。     

Structure and sliding wear behavior of 321 stainless steel/Al composite coating deposited by high velocity arc spraying technique

A typical 321 stainless steel/aluminum composite coating （321/Al coating） was prepared by high velocity arc spraying technique （HVAS） with 321 stainless steel wire as the anode and aluminum wire as the cathode. The traditional 321 stainless steel coating was also prepared for comparison. Tribological properties of the coatings were evaluated with the ring-block wear tester under different conditions. The structure and worn surface of the coatings were analyzed by scanning electron microscopy（SEM）, X-ray diffractometry（XRD） and energy dispersion spectroscopy（EDS）. The results show that, except for aluminum phase addition in the 32 l/Al coating, no other phases are created compared with the 321 coating. However, due to the addition of aluminum, the 32 l/Al coating forms a type of ＂ductile/hard phases inter-deposited＂ structure and performs quite different tribological behavior. Under the dry sliding condition, the anti-wear property of 32 l/Al coating is about 42% lower than that of 321 coating. But under the oil lubricated conditions with or without 32 h oil-dipping pretreatment, the anti-wear property of 321/AI coating is about 9% and 5% higher than that of 321 coating, respectively. The anti-wear mechanism of the composite coating is mainly relevant to the decrease of oxide impurities and the strengthening action resulted from the ＂ductile/hard phases inter-deposited＂ coating structure.     

Wear resistance and corrosion resistance of VCp particle reinforced stainless steel composites

1INTRODUCTIONRecently,the Fe-base composites prepared byin-situ reaction casting have attracted great inter-est[1,2].This technique is characterized to use thehigh temperature of the ferroalloy melt and pro-mote the chemical reaction between the carbon andalloying elements in the melt,then one or severalceramic particles with high strength and elasticmodulus will be generated[3,4].The amount anddistribution of the ceramic particles,such as TiC,WC,Cr7C3and VC,can be controlled by adjust…     

High Power Diode Laser-Treated HP-HVOF and Twin Wire Arc-Sprayed Coatings for Fossil Fuel Power Plants

This article deals with high power diode laser (HPDL) surface modification of twin wire arc-sprayed (TWAS) and high pressure high velocity oxy-fuel (HP-HVOF) coatings to combat solid particle erosion occurring in fossil fuel power plants. To overcome solid particle impact wear above 673 K, Cr₃C₂-NiCr-, Cr₃C₂-CoNiCrAlY-, and WC-CrC-Ni-based HVOF coatings are used. WC-CoCr-based HVOF coatings are generally used below 673 K. Twin wire arc (TWA) spraying of Tafa 140 MXC and SHS 7170 cored wires is used for a wide range of applications for a temperature up to 1073 K. Laser surface modification of high chromium stainless steels for steam valve components and LPST blades is carried out regularly. TWA spraying using SHS 7170 cored wire, HP-HVOF coating using WC-CoCr powder, Ti6Al4V alloy, and high chromium stainless steels (X20Cr13, AISI 410, X10CrNiMoV1222, 13Cr4Ni, 17Cr4Ni) were selected in the present study. Using robotically controlled parameters, HPDL surface treatments of TWAS-coated high strength X10CrNiMoV1222 stainless steel and HP-HVOF-coated AISI 410 stainless steel samples were carried out and these were compared with HPDL-treated high chromium stainless steels and titanium alloy for high energy particle impact wear (HEPIW) resistance. The HPDL surface treatment of the coatings has improved the HEPIW resistance manifold. The improvement in HPDL-treated stainless steels and titanium alloys is marginal and it is not comparable with that of HPDL-treated coatings. These coatings were also compared with “as-sprayed” coatings for fracture toughness, microhardness, microstructure, and phase analyses. The HEPIW resistance has a strong relationship with the product of fracture toughness and microhardness of the HPDL-treated HP-HVOF and TWAS SHS 7170 coatings. This development opens up a possibility of using HPDL surface treatments in specialized areas where the problem of HEPIW is very severe. The HEPIW resistance of HPDL-treated high chromium stainless steels and titanium alloys, HPDL-treated TWAS SHS 7170 and HP-HVOF coatings, and their micrographs and X-ray diffraction analysis is reported in this article.     

含碳化物陶瓷粉芯丝材电弧喷涂层的结构和性能

分别将WC、TiC、Cr3C2等碳化物陶瓷粉末与304不锈钢带轧制成3种粉芯丝材,采用电弧喷涂技术在Q235钢基体上制备铁基复合涂层.利用光学显微镜、SEM、XRD对3种涂层的形貌、相组成和磨损表面进行分析,并用湿砂橡胶轮磨损试验机(MLS-225)测试了涂层的抗磨粒磨损性能.结果表明,碳化物陶瓷粉末的加入使涂层的硬度和耐磨性显著提高,涂层的平均显微硬度值高达1100～1200 HV0.1.在本试验条件下,铁基复合涂层的耐磨性比Q235钢高6～18倍.塑性微切削和脆性剥落为涂层的主要磨粒磨损形式.     

Wear behavior of high velocity arc sprayed 3Cr13 steel coating in oil containing sand

To improve the wear resistance of the machine components serving in desert areas, the 3Cr13 stainless steel coating was produced by the high velocity arc spraying technique. The microstructure and phase constitute of the coating were analyzed by SEM and XRD. The effects of sand content on the friction and wear behaviors of the coating under the lubrication of oil containing sand were investigated on a ball-on-disk tester. SEM was used to reveal the wear mechanisms of the coating. The results show that the wear volume increases with increasing the sand content in the oil, and the sprayed coating exhibits better triobological properties compared with the 1045 steel. The predominant wear mechanisms of the sprayed coating are micro-cutting, brittle fracture and delamination.     

铁基含TiC陶瓷粉电弧喷涂粉芯丝材的研究

采用电弧喷涂含TiC陶瓷粉末的粉芯丝材，在低碳钢基体上制备了铁基复合涂层。用MLS-225型湿砂橡胶轮磨损试验机测试了涂层的抗磨粒磨损性能。利用光学显微镜、SEM、XRD分析技术对涂层的显微组织结构、磨损表面和相组成进了研究。结果表明：采用电弧喷涂工艺可制备含TiC陶瓷硬质相的复合涂层，在铁基体上弥散分布着一定量的TiC硬质颗粒，使整个涂层得到强化，涂层显微硬度平均值约为1137HV0.1，涂层的抗磨粒磨损性能较好，相对Q235钢提高T6倍。涂层磨损机制主要为犁沟切削和脆性断裂。     

Tribological properties of TiC-Fe coatings obtained by plasma spraying reactive powders

Titanium carbide-based coatings have been considered for use in sliding wear resistance applications. Carbides embedded in a metal matrix would improve wear properties, providing a noncontinuous ceramic surface. TiC-Fe coatings obtained by plasma spraying of spray-dried TiC-Fe composite powders containing large and angular TiC particles are not expected to be as resistant as those containing TiC particles formed upon spraying. Coatings containing 60 vol% TiC dispersed in a steel matrix deposited by plasma spraying reactive micropellets, sintered reactive micropellets, and spray-dried TiC-Fe composite powders are compared. The sliding wear resistance of these coatings against steel was measured following the test procedure recommended by the Versailles Advanced Materials and Standards (VAMAS) program, and the inherent surface porosity was evaluated by image analysis. Results show that, after a 1-km sliding distance, TiC-Fe coatings obtained after spraying sintered reactive powders exhibit scar ring three times less deep than sprayed coatings using spray-dried TiC-Fe composite powders. For all coatings considered, porosity is detrimental to wear performance, because it generally lowers the coating strength and provides cavities that favor the adhesion of metal. However, porosity can have a beneficial effect by entrapping debris, thus reducing friction. The good wear behavior of TiC-Fe coatings manufactured by plasma spraying of sintered reactive powders is related to their low coefficient of friction against steel. This is due to the microstructure of these coatings, which consists of 0.3 to 1 μm TiC rounded particles embedded in a steel matrix. Presented at the International Conference on Metallurgical Coatings and Thin Films, ICMCTF-92, Apr 6–10, 1992, San Diego.     

Characteristics and corrosion performance of 80Ni-20Cr coating deposited by on-site thermal spraying

New controlled atmosphere on-site spraying systems were developed to deposit a high-quality coating with superior resistance to wet corrosion. Characteristics and corrosion resistance of coatings deposited by arc and flame spraying of wire in argon gas were compared with those of coatings deposited by conventional and low-pressure plasma techniques. It was found that the coating deposited by the arc spraying of wire in argon gas is free of oxides and possesses excellent corrosion resistance in chloride and acid solutions. The coating suffers slight pitting and crevice corrosion associated with the isolated pores and electric potential paths. Corrosion resistance was improved by using a modified spraying system.     

Microstructure and Wear Performance of Arc Sprayed Fe-FeB-WC Coatings

Two Fe-FeB-WC coatings were deposited on the Q235 steel substrate by arc spraying. The microstructure and the abrasive wear performance of the coatings were characterized by x-ray diffraction (XRD) and scanning electron microscope (SEM). The wear mechanisms of the coatings were examined. It was found that Fe-Cr alloy and Fe₂B are present in the coating as the main phases. The results showed that adding hard particle powders could obviously increase the hardness and wear resistance of the coatings. The average microhardness of the coatings was about 870 to 920 HV_0.1. The coatings exhibited excellent abrasive wear resistance, being 3.3 to 4.8 times higher than that of arc sprayed 3Cr13 coating.     

Electric arc deposition of carbon steel coatings with improved mechanical properties

To achieve high deposition rate and efficiency, electric arc spraying has been routinely used to deposit carbon steel coatings. Although retention of carbon in these coatings is poor due to the use of compressed air during spraying, the coatings are sufficiently hardened by brittle iron oxide inclusions to be suitable for hardfacing mechanical components used in mild adhesive and abrasive wear environments. However, carbon steel coatings can be employed for hardfacing mechanical components used in more aggressive wear environments, provided they are hardened by the carbon retention rather than by iron oxide inclu-sions. Therefore, to increase retention of carbon, reduce inclusion of iron oxides, and improve hardness and wear properties of carbon steel coatings, deposition experiments were carried out using an inexpen-sive nitrogen, which is produced on-site by a pressure swing adsorption or a membrane separation sys-tem, instead of compressed air during spraying.     

Mechanical and tribological properties of rhombohedral diamond-rich coatings grown on stainless steel by hot filament CVD

In this study, rhombohedral diamond-rich coatings were grown directly on stainless steel (SS) substrate and also on sputter deposited titanium nitride interlayer, by hot filament chemical vapour deposition technique. Grazing incidence X-ray diffraction measurement of the coatings confirmed the formation of polycrystalline rhombohedral phases of diamond. Field emission scanning electron microscopy revealed a jelly type morphology of the coatings. The coating deposited with titanium nitride interlayer showed improved resistance against scratch indentation, lower wear rate and had lower value of coefficient of friction in comparison to the coating deposited directly on SS.     

超高分子量聚乙烯/石墨烯复合涂层制备及其在海洋装备防护中的应用

目的采用热喷涂技术制备涂层,通过材料选择和结构设计,有效延缓海水对金属基底的腐蚀和冲蚀,并抑制海洋材料表面生物污损等对海洋材料的严重破坏。方法采用高能球磨法制备了聚乙烯-石墨烯(UHMWPE-graphene)复合粉末,用火焰喷涂技术在E235B碳钢基底表面制备UHMWPE和UHMWPE-graphene复合涂层。通过扫描电子显微镜和透射电子显微镜对原始粉末和涂层微观组织进行表征,并通过摩擦磨损实验、电化学测试、生物污损检测,分别评价涂层耐海水冲刷性能、耐腐蚀性能以及抗生物污损特性。结果相对于碳钢和UHMWPE涂层,UHMWPE-graphene复合涂层的腐蚀电位提高和腐蚀电流减小,预示着样品的耐腐蚀特性增强。由于UHMWPE-graphene复合涂层呈现疏水性以及更低的表面能,使其表现出优异的抵抗海藻贴附的能力。添加石墨烯的复合涂层的摩擦系数和磨损率比纯UHMWPE涂层均有一定程度的降低。添加石墨烯质量分数为0.5%时,涂层的摩擦系数由0.236降低到0.195,且磨损率下降了约26%。结论利用火焰热喷涂技术在碳钢表面成功制备了组织致密的UHMWPE涂层、UHMWPE-0.2%graphene和UHMWPE-0.5%graphene复合涂层。石墨烯的添加,能够有效提高涂层在模拟海洋环境中的耐蚀性、抗生物污损性及耐磨性。     

The effect of Mo content in plasma-sprayed Mo-NiCrBSi coating on the tribological behavior

NiCrBSi is a material popularly used as a hard thermal sprayed coating. The coating performs well as a wear resistant coating under low stress. At higher stress in metal-to-metal sliding wear condition, however, the NiCrBSi starts to experience surface deformation, which will inevitably lead to seizure as the stress increases. In order to improve the tribological properties of the NiCrBSi plasma-sprayed coating, Mo is added to the coating to reduce the friction between the coating and other metal contacting surface, thus, improving its dry sliding wear resistance. In this study, various amounts of Mo were mixed with NiCrBSi at 0, 25, 50, 75 and 100 wt.%. The powders were sprayed using an air plasma spraying technique onto stainless steel samples to form coatings, which were ground to achieve flat surfaces and a thickness of 350-400 μm. The mechanical properties of the coatings were determined. The coating samples were then tested using a reciprocation ball-on-flat tribometer. It was found that as the Mo/NiCrBSi ratio increases, the wear mechanism changes. Coatings containing 75%Mo and 25%NiCrBSi exhibit the highest wear depths corresponding to the cracking of the thin NiCrBSi splats. On the other hand, coatings containing 25%Mo and 75%NiCrBSi possess the lowest wear depths with no surface cracks. The presence of Mo covering the coating surface hinders the metal seizure between NiCrBSi and steel counter surface.     

不同喷涂方法制备马氏体不锈钢涂层组织性能对比

采用电热爆炸定向喷涂和高速电弧喷涂技术,分别制备了3Cr13不锈钢涂层.使用扫描电子显微镜(SEM)、X射线能谱仪(EDAX)、X射线衍射仪(XRD)和纳米压痕仪等分析了两种涂层的组织形貌、元素分布、相结构、纳米硬度和弹性模量等.结果表明,电热爆炸定向喷涂层比高速电弧喷涂层更致密;前者氧化现象不明显,而后者较明显;前者与基体主要是冶金结合,而后者主要为机械结合;前者的纳米硬度和弹性模量分别达到了10.3 GPa和237.8 GPa,高于后者的7.6 GPa和183.3 GPa.     

Recycled hard metal-base wear-resistant composite coatings

The abrasion-erosion wear resistance of composite coatings from self-fluxing Ni-base alloy and WC-Co hard metal powders is evaluated. The resistance of thermal sprayed and melted NiCrSiB-(WC-Co) coatings was found to be markedly higher than that of NiCrSiB and slightly higher than that of comparative welded coatings. Microstructural and surface analyses were used to describe the coatings and the wear damage. Based on the principles of creating wear-resistant coatings and on experimental studies of wear resistance, high wear-resistant, composite NiCrSiB-(WC-Co) coatings were fabricated. These coatings exhibited 300% higher wear resistance than 0.45% C steel.     

Influence of the metallic matrix ratio on the wear resistance (dry and slurry abrasion) of plasma sprayed cermet (chromia/stainless steel) coatings

This work is related to the manufacturing and tribological testing of plasma sprayed cermet coatings of chromium oxide and stainless steel in order to obtain wear resistant coatings to dry and slurry abrasion. Raw materials were fused and crushed powders of chromium oxide (Cr₂O₃) with a particle size ranging from 20 to 45 μm and gas atomized stainless steel (iron base with 17 wt.% of Cr and 12 wt.% of Ni) with a particle size distribution between 20 and 53 μm. Both powders were simultaneously injected with two separated injectors in a direct current (DC) plasma jet (Ar-H₂ (25 vol.%) at atmospheric pressure (APS).The influence, on the coating micro-structural and tribological properties, of various stainless steel weight percentages in chromium oxide has been studied. All coatings exhibited a lamellar structure with a random distribution of the two materials. The effect of the percentage of stainless steel on the microstructure of the coating, studied by scanning electron microscopy (SEM), has shown that increasing the stainless steel percentage increased the coating cohesion. The increase of Cr₂O₃ in the coatings resulted in higher hardness and in lower weight losses during wear tests in dry abrasion. The study has also shown that the optimum stainless steel percentages in coatings were not identical to reach their maximum resistance to slurry or dry abrasion.     

碳化硼对电弧喷涂涂层性能的影响

将碳化硼(B4C)陶瓷粉末和其它合金元素与304L不锈钢带轧制成粉芯丝材,采用电弧喷涂技术制备金属陶瓷复合涂层.研究了B4C在电弧喷涂中的应用.利用XRD,SEM对涂层的形貌、相组成和磨损表面进行了分析.利用自行设计的高温磨粒磨损装置和高温冲蚀设备分别评价了B4C对涂层耐高温磨粒磨损性能和耐高温冲蚀性能的影响.结果表明,粉芯丝材喷涂工艺良好,B4C陶瓷与粉芯中其它组分反应,可以形成含Fe3B,CrB,FexN i23-xB6,Fe23(C,B)6,(Cr,Fe)7C3和Fe3C等硬质相的复合涂层,大幅度提高了涂层的硬度和耐磨耐冲蚀性能.