等温退火对Ni-P、Ni-W-P镀层的晶粒尺寸和显微硬度的影响

研究了不同镀态结构的Ni-P、Ni-W-P镀层经等温退火后，其晶粒尺寸和硬度随退火时间的变化规律，镀层的热稳定性以及成分、结构和晶粒尺寸对镀层硬度的影响规律。结果表明，W元素可以促进Ni-P合金的非晶化，显著提高Ni-P镀层的硬度；Ni-（W）-P体系纳米晶镀层具有较好的热稳定性；等温退火获得的三元Ni-W-P单相纳米晶镀层在耐磨、耐蚀性能方面均优于同类非晶态镀层。     

表面活性剂和纳米PTFE对Ni-P-PTFE镀层力学和摩擦学性能的影响

在化学沉积Ni-P镀层的工艺基础上,通过改变镀液中添加的表面活性剂和纳米PTFE的含量,制备了Ni-P-PTFE复合镀层,并研究了镀液中表面活性剂和纳米PTFE的含量对复合镀层的力学和摩擦学性能的影响.研究结果表明:当镀液中的表面活性剂和纳米PTFE添加量均为6 g/L时,所得的Ni-P-PTFE复合镀层PTFE含量较高,具有优良的力学和摩擦学性能,其磨损机制主要为粘着磨损,并伴随轻微的磨粒磨损.     

Ni-P-金刚石化学复合镀层的组织结构及性能

研究了Ni-P-金刚石复合镀层的组织结构及性能特点，结果表明：复合镀层镀态时为非晶结构；镀层经300℃，1h的热处理后开始晶化，晶化后形成品相Ni和Ni3P；与Ni—P镀层相比，Ni-P-金刚石复合镀层具有更好的硬度和耐磨性，特别是在镀态时差别更明显；但复合镀层的耐蚀性和抗氧化能力低于普通Ni-P镀层。     

可溶性阳极电刷镀纳米晶Ni-Fe合金镀层的退火再强化

采用可溶性Ni阳极电刷镀方法制备纳米晶Ni-Fe合金镀层,利用XRD、SEM、TEM、显微硬度计等测试方法分析低温退火对镀层结构和性能的影响.结果表明:纳米晶Ni-Fe合金镀层的硬度随退火温度的升高而提高,在200 ℃时达到最大值,存在明显的退火再强化;继续提高退火温度导致镀层硬度降低;400 ℃退火后的镀层硬度与镀态的接近;纳米晶Ni-Fe合金镀层退火过程没有出现晶粒异常长大,表现出比纯Ni镀层更高的热稳定性.     

Ni-W-Cu-P沉积机制及在酸性溶液中的腐蚀行为

分别采用浸泡和电化学实验方法对Ni-W-Cu-P镀层在常温和高温20%H2SO4溶液中的耐蚀性进行了研究,用SEM,EDS及XRD对镀层的沉积机制、成分结构进行了分析.结果表明:球形Ni-W-Cu-P核心合并生长形成条状组织;共沉积W和Cu可显著提高Ni-W-Cu-P非晶的热稳定性;400℃热处理非晶的耐蚀性优于镀态非晶和500℃热处理纳米晶的;延长腐蚀时间,非晶和纳米晶镀层的腐蚀速率和腐蚀电流密度增大,阻抗则下降;Ni-W-Cu-P非晶和纳米晶镀层的腐蚀机制分别是选择性腐蚀和点腐蚀.     

人造海水温度对Ni-P和Ni-Cu-P合金镀层电化学行为的影响

采用化学镀技术在碳钢表面制备Ni-P和Ni-Cu-P镀层,通过电化学方法评定Ni-P和Ni-Cu-P镀层在人造海水中的耐蚀性。结果表明:非晶Ni-P和Ni-Cu-P、纳米晶Ni-Cu-P镀层的腐蚀电流密度均随着人造海水温度升高而增大,而阻抗值则减小;共沉积Cu有利于改善非晶Ni-P镀层的耐蚀性,但改善效果随着人造海水温度的升高而减小;400℃热处理可显著改善Ni-Cu-P镀层在人造海水中的耐蚀性,在80℃的人造海水中,热处理Ni-Cu-P镀层的腐蚀电流密度较镀态Ni-Cu-P镀层的低一个数量级。     

镍磷非晶纳米晶复合镀层的制备及其耐蚀性

对电沉积12．3％P（质量分数）镍磷合金进行热处理，部分晶化获得非晶纳米晶复合镀层。利用X射线衍射仪、透射电镜和高分辨透射电镜分析镀层的结构。结果表明，镀态时镀层呈典型的非晶态结构，控制热处理工艺可得到非晶纳米晶的复合镀层。通过动电位极化曲线（3．5％NaCI溶液）测定，得知部分晶化的镀层耐蚀性得到改善。由于具有少量纳米晶相镶嵌于连续非晶相上，非晶纳米晶复合结构的镍磷合金镀层耐蚀性优于非晶态镍磷合金镀层。     

化学沉积 Ni-Mo-P 和 Ni-P 镀层退火晶化组织及耐蚀性

目的研究化学沉积Ni-4.11%Mo-6.50%P和Ni-9.19%P合金镀层退火晶化转变特征,通过定量表征镀层的晶化程度、晶粒尺寸及结晶相的质量分数,建立显微组织与耐蚀性的关联。方法采用XRD衍射技术和Jade软件分析,定量表征镀层的晶化组织特征,由SEM/EDS测试确定镀层的成分及表面形貌,通过浸泡腐蚀实验及金相显微观察,对比两种镀层的耐蚀性。结果 Ni-Mo-P镀层在低于400℃退火时,只有Ni相结晶;在≥400℃退火时,发生Ni3P晶化反应,同时伴有Ni-Mo固溶体的形成,600℃时的晶化程度为88.13%。相比之下,Ni-P镀层中Ni3P相开始析出的温度降至300℃,600℃时的晶化程度达到91%。在相同温度进行热处理时,Ni-Mo-P镀层晶粒尺寸小于Ni-P镀层。在发生Ni3P晶化反应的温度下,两种镀层中Ni3P的晶粒尺寸总是大于Ni相。在0.5 mol/L的H2SO4中,对于Ni-Mo-P镀层,除300℃外,其他温度下的热处理均能显著改善其耐蚀性;而对于Ni-P镀层,镀态下具有最好的耐蚀性能。在10%的HCl溶液中,退火温度为600℃时,Ni-Mo-P镀层的耐点蚀性能更好;而Ni-P合金则相反,镀态及低温200℃退火后的耐点蚀性能最好。结论 Mo的共沉积提高了Ni-Mo-P镀层Ni3P的析出温度,降低了镀层的晶化程度及晶粒尺寸;与Ni-P镀层相比,高温退火的Ni-Mo-P镀层表现出了优异的耐点蚀性能,但耐硫酸均匀腐蚀的性能较差。     

电沉积耐磨减摩纳米复合镀层的研究进展

纳米复合镀层比常规镀层具有更高的硬度和更加优良的摩擦学性能.评述了纳米复合镀层的电沉积工艺,包括纳米颗粒前处理、纳米颗粒添加量、电流、镀液pH值、镀液温度和搅拌方式等对镀层中纳米颗粒含量、镀层表面形貌及微观结构的影响,对纳米复合镀层摩擦学性能以及纳米颗粒耐磨减摩机理的研究进行了综述.     

热处理温度对Ni-Co-P合金镀层组织与性能的影响

研究了不同热处理温度对化学镀Ni-Co-P镀层组织和性能的影响.结果表明:在给定实验条件下,原始镀态Ni-Co-P镀层组织呈非晶结构胞状形态.随加热温度升高至400℃时,经XRD分析可知,镀态的非晶结构Ni-Co-P镀层发生部分晶化,析出亚稳相Ni12P5,500℃热处理后完全晶化,亚稳相转变为稳定的Ni,P相,镀层表面形貌变化不大,但当600℃热处理后镀层表面形貌由胞状变为蠕虫状.镀层硬度随热处理温度的升高先增后降,至400℃时硬度达到最高值,而后随温度的升高而下降,与组织结构的变化相吻合.研究还表明,Ni-Co-P镀层同Ni-P镀层相比,具有更优异的耐硫酸腐蚀性能.     

Improved microhardness and wear resistance of the as-deposited electroless Ni-P coating

The coatings with different phosphorus contents were obtained by varying the ratio of lactic acid to acetic acid in the electroless plating bath. With the increase of phosphorus content, the structure of the electroless Ni-P coating transformed from nanocrystalline to a mixture of nanocrystalline and amorphous phases, then to amorphous phase. A record high hardness value of 910 HV_0.1 of as-deposited Ni-P coating was obtained at 7.97 at.% phosphorus content, and high wear resistance was accordingly achieved. The refined nanocrystalline grains with an average size of ~ 4 nm were found to be responsible for the record high hardness and improved wear resistance of the as-deposited Ni-P coating.     

Ni-P-多壁碳纳米管复合镀层的制备及摩擦磨损性能(英文)

采用湿式球磨对多壁碳纳米管(MWNTs)预处理,通过化学镀制备Ni-P-MWNTs复合镀层;对45钢、传统Ni-P镀层和Ni-P-MWNTs复合镀层在干摩擦条件下的摩擦磨损性能进行考察和比较。结果表明,球磨后MWNTs长径比降低,长度均匀,且多数端部处于敞开状态。与45钢和Ni-P镀层相比,Ni-P-MWNTs复合镀层的减摩耐磨能力显著强化。当复合镀层中MWNTs的质量分数为0.74%~1.97%时,其摩擦因数和磨损率随MWNTs含量的增加而减少;对于MWNTs质量分数为1.97%的复合镀层,其摩擦因数和磨损率仅为0.08和6.22×10?15m3/(N·m)。复合镀层优良的摩擦磨损性能归因于MWNTs优异的力学性能和自润滑特性。     

High-temperature tribological properties of Ni-P alloy coatings deposited by electro-brush plating

High-temperature tribological properties of Ni-P alloy coatings processed by electro-brush plating on 20CrMo steel have been investigated. A ball-on-disc configuration was employed and 4 mm diameter Si3N4 balls were used as static counterpart. All the wear tests were carried out at 450°C for 180 min without lubricants. The electro-brush plating Ni-P coating is amorphous in as-deposited condition, and it becomes polycrystalline with the formation of Ni and Ni3P after heat treatment at 450°C for 1 h. The friction coefficient of the Ni-P coating is just 50% of that of the 20CrMo steel at the friction temperature of 450°C. A mild adhesive wear mechanism was found for the electro-brush plating Ni-P coating tested at 450°C, whereas for the 20CrMo steel at the same temperature a mixed adhesive and abrasive wear mechanism was observed.     

Nanoscratching deformation and fracture toughness of electroless Ni-P coatings

In the present investigation electroless Ni-P coatings were prepared. Structural characterizations indicated that the as-deposited coating had an amorphous structure with a P content of 23 at.%. The deformation behavior of an electrolessly amorphous Ni-P coating was investigated by using the Vickers indentation and the Tribo-indenter instrumented nano-indentation technique. The hardness of the Ni-P coating is remarkably improved after proper heat-treatment and the hardness is as high as 12.7 GPa for the coating annealed at 400 °C for 1 h. However, the cracks were observed during the indentation of the Ni-P coatings annealed at 400 °C and 500 °C for 1 h. The corresponding fracture toughness was evaluated as 2.58 MPa m^0.5 and 1.33 MPa m^0.5, respectively. Nanoscratching tests indicated that the wear resistance of the Ni-P coatings was improved significantly with an increasing ratio of hardness (H) to elastic modulus (E). It was observed that the friction coefficient increased from 0.083 ± 0.006 for the Ni-P coating annealed at 300 °C up to 1.337 ± 0.009 for the IF steel substrate, while the H/E simultaneously decreased from 0.084 (10.7/128) to 0.009 (1.85/200). The study revealed that the electrolessly amorphous Ni-P coating had offered better corrosion resistance than the Ni-P coatings after heat-treatment. An annealing temperature of 300 °C is preferentially suggested for the trade-off between the wear resistance property and anti-corrosion property of the Ni-P coating.     

AZ91D镁合金化学镀Ni-P及Ni-W-P镀层的结构与耐蚀性

在AZ91D镁合金上直接化学镀Ni-P和Ni-W-P镀层,并利用扫描电子显微镜、X射线衍射仪及电化学工作站研究后续热处理对化学镀层组织形貌、相组成及其耐蚀性的影响。结果表明,制备的Ni-P镀层为非晶态,而Ni-W-P镀层为纳米晶结构,两者在3.5%NaCl水溶液中的耐蚀性相当。热处理可以明显提高Ni-W-P镀层的耐蚀能力,但却稍微弱化Ni-P镀层的耐蚀能力,热处理后的Ni-W-P层自腐蚀电位相对于未处理的化学镀Ni-W-P或Ni-P层提高了约150 mV。     

Amorphization of Fe38Ni30Si16B14V2 surface layers by laser cladding

Fe38Ni30Si16B14V2 amorphous composite coatings were fabricated by laser cladding on AISI 1045 steel in order to increase the wear resistance. The phase and microstructure of the coatings were analyzed by X-ray diffractometry and transmission electron microscopy. The wear properties of the coatings were also investigated by means of sliding wear test. The results show that the coating consists of amorphous phase in majority and nanocrystalline phase in minority. The amorphous coatings can be obtained while the scanning speed is 3 500 mm/min and the laser power is 4.8 kW. With increase of the laser power, the amorphous phase in the coating increases when it is lower than 4.8 kW. A gradient distribution of the microhardness ranges from Hv0.2 1 208 to Hv0.2 891 in the coating from top surface of the coating to the substrate. The amorphous coating is found to possess better property of wear than AISI 1045 steel substrate.     

超音速火焰喷涂Fe基非晶合金涂层材料的摩擦磨损性能研究

目的通过优化涂层制备工艺,制备致密的Fe基非晶合金涂层,以提高非晶合金涂层的耐磨性。方法采用活性燃烧高速燃气超音速火焰喷涂(AC-HVAF)技术,通过工艺优化,制备了组织致密的Fe基非晶合金涂层。利用场发射扫描电子显微镜、X射线衍射仪、维氏显微硬度计、摩擦磨损试验机、三维光学轮廓仪等设备,对非晶合金涂层的组织结构、摩擦性能和磨损机制进行了深入分析。结果 Fe基非晶合金涂层呈现典型的非晶结构,涂层厚度在300μm左右,涂层的平均显微硬度值高达1000HV0.1。在干摩擦试验条件下,Fe基非晶合金涂层的磨损量远低于304不锈钢材料,磨损率是304不锈钢基体的1/3~1/2。Fe基非晶合金涂层的磨损机制以疲劳磨损为主,伴随着氧化磨损。氧化磨损主要是由干摩擦过程中产生的摩擦热导致,氧化磨损加速了片层剥落。结论 Fe基非晶合金涂层孔隙率的降低和非晶相含量的提高,有利于稳定摩擦系数和改善涂层的耐磨损性能。     

低温热循环处理Fe基非晶粉末对爆炸喷涂涂层摩擦学性能的影响

目的提高爆炸喷涂Fe基非晶涂层的摩擦学性能。方法采用液氮-室温循环处理喷涂粉末,通过爆炸喷涂制备原始粉末和处理粉末对应涂层。利用X射线衍射仪(XRD)检测涂层非晶相,用维氏显微硬度计和球-盘式摩擦试验机分别测试涂层的显微硬度和摩擦学性能,用附带能谱仪的扫描电子显微镜(SEM)表征样品的组织形貌及特征区域的元素含量。结果粉末经低温热循环处理后,仍为非晶态组织,且未发生开裂和破碎现象。与原始粉末制备的涂层相比,低温热循环处理粉末制备的涂层孔隙率由1.0%降低至0.4%;未熔颗粒明显减少,粉末铺展更加充分;显微硬度略有降低(由845.4HV降至813.5HV),但测试误差明显减小,威布尔分布拟合直线斜率由7.1196升高至9.6414;摩擦系数由0.76降低至0.73,磨损更加稳定;磨损率相近,均在10−6次方数量级。结论Fe基非晶粉末经低温热循环处理后,其对应涂层的组织更为均匀致密,显微硬度分布更为均匀,摩擦磨损性能更为稳定,磨损机制由原始粉末制备涂层的疲劳剥层磨损,转变为以氧化磨损和塑性变形主导。     

Yb添加量对非晶态化学镀Ni-Yb-P镀层耐磨性能的影响

采用化学镀方法制备了非晶态Ni-P和Ni-Yb-P镀层,研究了稀土元素Yb添加量对镀层硬度和耐磨性能的影响。结果表明,Ni-Yb-P镀层的硬度随着Yb添加量的增加而提高,当镀液中YbN3O9.5H2O的添加量为200mg/L时,镀态下镀层的耐磨性能最佳。磨损试验发现,镀态下非晶态Ni-P镀层的磨损机制为粘着磨损和犁削磨损,其耐磨性能较差;随着稀土添加量的增加,镀层耐磨性能提高,但稀土添加量过高时,镀层耐磨性能又会下降。     

Identification of the wear mechanism on WC/C nanostructured coatings

A series of WC/C nanostructured films with carbon contents ranging from 30 to 70 at.% was deposited on M2 steel substrates by magnetron sputtering of WC and graphite targets in argon. Depending on the amorphous carbon (a-C) incorporated in the coatings, nanocrystalline coating (formed mainly by WC_{1 − x} and W₂C phases) or nanocomposite (WC_{1 − x}/a-C) were obtained with tunable mechanical and tribological properties. Ultrahardness values of 36–40 GPa were measured for the nanocrystalline samples whilst values between 16 and 23 GPa were obtained in the nanocomposite ones depending on the a-C content. The tribological properties were studied using a pin-on-disk tester versus steel (100Cr6) balls and 5 N of applied load in dry sliding conditions and the failure modes by scratch adhesion tests. Three different zones were identified according to the observed tribological behavior: I (μ > 0.8; adhesive wear), II (μ: 0.3–0.6; abrasive wear) and III (μ ~ 0.2; self-lubricated). The wear tracks and the ball scars were observed by scanning electron microscopy (SEM) and Raman spectroscopy in order to elucidate the tribochemical reactions appearing at the contact and to determine the wear mechanism present in each type. A correlation among structure, crystalline phases, a-C content and tribomechanical properties could be established for the series of WC/C coatings and extended to understand the trends observed in the literature for similar coatings.